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Main
Date: 03 Sep 2007 06:42:27
From: jim beam
Subject: "brittle" vs. non-ductile
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following peter cole's confusion on this subject, it seems we need a
little clarification of what constitutes "brittle" fracture.
"brittle" is where there is very little energy absorbed as the fracture
interface propagates through a material. glass is the classic example
of this - once a crack is present, it takes almost nothing to continue
the crack's progress to complete failure.
"ductile" however is a totally different animal. significant energy is
absorbed during ductile deformation. but ductile deformation is not
fracture, it's another process entirely! once ductile deformation has
occurred, fracture requires /further/ propagation energy.
fracture energy absorption is what determines whether a material is
"brittle" or not. cfrp is not brittle like glass. it is not ductile,
[the apparent, er, "confusion"] but it is typically not brittle -
significant energy is absorbed as the fracture interface progresses
[depending on fabrication and constituent materials of course].
indeed, fracture energy absorption in non-ductile composites can be so
high, they're actually used in applications /specifically/ for this
reason. anyone familiar with motorcycle helmet testing will be aware of
this. same for bullet-protective military helmets. both are
non-ductile composites with very high fracture energy absorption.
energy absorbed depends on constitution, but the principle applies, and
is worth repeating - it's energy absorbed on fracture interface
progression that determines toughness, not whether the material is ductile.
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Date: 12 Sep 2007 02:29:08
From: Chalo
Subject: Re: "brittle" vs. non-ductile
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Ryan Cousineau wrote:
>
> Chalo wrote:
> >
> > I have spent most of my adult life using my bike as regular
> > transportation. I see vanishingly few CFRP bikes in the course of my
> > riding around town, though I see lots and lots of other bikes.
>
> A decade ago, you could have said all of this about aluminum*. The
> rarity of CFRP bikes is at least as much a function of their cost as it
> is their suitability for utilitarian use (about which I make no
> submission), and since their benefits are primarily in the realm of
> weight and the creation of complex (for aerodynamics) shapes, of course
> the performance market was the early adopter.
I bought my first Aluminum bike, a Cannondale MTB, in 1988. It was my
main transportation for as long as I had it, and I began to see other
aluminum bikes parked in racks around town very shortly after I bought
mine. Around the same time, I noticed (only in shops, mind you) some
CFRP bikes like the Vitus and Specialized Allez Epic, followed closely
by Trek and Kestrel and many more behind them. Aluminum bike frames
may have beaten CFRP bike frames to the mainstream market, but not by
much. And aluminum bikes beat CFRP bikes to the grocery store bike
rack by 18 years and counting.
> Wait a decade, and some rather cheap bikes will have CFRP frames.
If anybody can figure out how to injection-mold a frame that contains
sufficiently long fibers, you will most definitely be correct in
this. I rather doubt that hand-laid fabric-based CFRP bikes will ever
be cost-effective, though.
> *A crueler man than I might point out that most bicycles on this
> continent are owned by people of average weight, with more money than
> time to ride, who don't lock their bikes up in public racks, and who
> ride on Sunday to no utilitarian purpose. I'm also sure you actually
> meant "do store their bikes inside,"
Right; I meant to say who don't store their bikes _outside_, but the
accumulated brain damage got ahead of me.
> but the image of an early 5200 OCLV
> left out in the rain, unloved, possibly with a wicker basket on the
> front, is too charming to let go of.
I reckon a chunky CFRP frame with a durable resilient coating (like
boat deck paint or spray bedliner for pickup trucks) could be an
excellent base for a bike that must sit out in the weather. Maybe it
could feature a full CFRP chaincase.
Chalo
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Date: 13 Sep 2007 03:05:36
From: Ryan Cousineau
Subject: Re: "brittle" vs. non-ductile
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In article <1189564148.708679.168590@k79g2000hse.googlegroups.com >,
Chalo <chalo.colina@gmail.com > wrote:
> Ryan Cousineau wrote:
> >
> > Chalo wrote:
> > >
> > > I have spent most of my adult life using my bike as regular
> > > transportation. I see vanishingly few CFRP bikes in the course of my
> > > riding around town, though I see lots and lots of other bikes.
> >
> > A decade ago, you could have said all of this about aluminum*. The
> > rarity of CFRP bikes is at least as much a function of their cost as it
> > is their suitability for utilitarian use (about which I make no
> > submission), and since their benefits are primarily in the realm of
> > weight and the creation of complex (for aerodynamics) shapes, of course
> > the performance market was the early adopter.
>
> I bought my first Aluminum bike, a Cannondale MTB, in 1988. It was my
> main transportation for as long as I had it, and I began to see other
> aluminum bikes parked in racks around town very shortly after I bought
> mine. Around the same time, I noticed (only in shops, mind you) some
> CFRP bikes like the Vitus and Specialized Allez Epic, followed closely
> by Trek and Kestrel and many more behind them. Aluminum bike frames
> may have beaten CFRP bike frames to the mainstream market, but not by
> much. And aluminum bikes beat CFRP bikes to the grocery store bike
> rack by 18 years and counting.
The Vitus 979 was introduced in 1979. And it was by no means the first
aluminum frame.
> > Wait a decade, and some rather cheap bikes will have CFRP frames.
>
> If anybody can figure out how to injection-mold a frame that contains
> sufficiently long fibers, you will most definitely be correct in
> this. I rather doubt that hand-laid fabric-based CFRP bikes will ever
> be cost-effective, though.
The number of processes that have proven amenable to automation is
staggering. I would have never thought that you could automate
wheel-building in a cost-effective fashion, e pur si muove.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
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Date: 13 Sep 2007 16:37:24
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <rcousine-3DC05E.20053612092007@news.telus.net >,
Ryan Cousineau <rcousine@sfu.ca > wrote:
> In article <1189564148.708679.168590@k79g2000hse.googlegroups.com>,
> Chalo <chalo.colina@gmail.com> wrote:
>
> > Ryan Cousineau wrote:
> > >
> > > Chalo wrote:
> > > >
> > > > I have spent most of my adult life using my bike as regular
> > > > transportation. I see vanishingly few CFRP bikes in the course
> > > > of my riding around town, though I see lots and lots of other
> > > > bikes.
> > >
> > > A decade ago, you could have said all of this about aluminum*.
> > > The rarity of CFRP bikes is at least as much a function of their
> > > cost as it is their suitability for utilitarian use (about which
> > > I make no submission), and since their benefits are primarily in
> > > the realm of weight and the creation of complex (for
> > > aerodynamics) shapes, of course the performance market was the
> > > early adopter.
> >
> > I bought my first Aluminum bike, a Cannondale MTB, in 1988. It was
> > my main transportation for as long as I had it, and I began to see
> > other aluminum bikes parked in racks around town very shortly after
> > I bought mine. Around the same time, I noticed (only in shops,
> > mind you) some CFRP bikes like the Vitus and Specialized Allez
> > Epic, followed closely by Trek and Kestrel and many more behind
> > them. Aluminum bike frames may have beaten CFRP bike frames to the
> > mainstream market, but not by much. And aluminum bikes beat CFRP
> > bikes to the grocery store bike rack by 18 years and counting.
>
> The Vitus 979 was introduced in 1979. And it was by no means the
> first aluminum frame.
Indeed, there were successful aluminum bikes made in the 1930s in France
by Barra and others.
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Date: 10 Sep 2007 17:50:06
From: Jay Beattie
Subject: Re: "brittle" vs. non-ductile
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On Sep 9, 8:11 pm, A Muzi <a...@yellowjersey.org > wrote:
> >> Let's defined catastrophic failure: the component breaks into two or
> >> more discrete pieces nearly instantaneously. This is typical of brittle
> >> materials (glass, for example) and not typical of metallic materials
> >> commonly used in bicycles
> Mike Jacoubowsky wrote:
> > That would have been my Mavic stem (looked to have been made by 3TTT).
> > Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> > I was sprinting when it happened. A aluminum, forged quill stem, single
> > bolt, not hinged. The section of stem that the handlebar-claming bolt
> > threaded into gave way. No, the threads didn't strip, the entire section
> > pulled away from the rest of the stem. Quite the rude thing to happen.
> > Points to consider- Aluminum. No prior warning. Catastrophic failure.
>
> I haven't been much involved in this thread for many reasons but if you
> think French stems are scary, what about all the aluminum Pivo bars
> which snapped right next to the stem? After observing many iterations
> of frame and equipment failures, I can match examples - and
> counterexamples- with anyone.
>
> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.
Frankly, I'm totally confused about this. Most of my serious riding is
done with an engineer friend who works in the industry (but not with
CF -- except that he gets pro-deals on everything and can afford a
mega-$ CF frame). I bring him up to speed on the latest RBT
CFcontroversy, and his comment is "do you see this stuff breaking all
over the place?" He backs off and echos the concern about using CF
where it can get mechanically damaged, but otherwise he thinks it is
proven in well made bike frames.
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Date: 10 Sep 2007 22:44:33
From: Jambo
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
"Jay Beattie" <jbeattie@lindsayhart.com > wrote in message
news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
> Frankly, I'm totally confused about this. Most of my serious riding is
> done with an engineer friend who works in the industry (but not with
> CF -- except that he gets pro-deals on everything and can afford a
> mega-$ CF frame). I bring him up to speed on the latest RBT
> CFcontroversy, and his comment is "do you see this stuff breaking all
> over the place?" He backs off and echos the concern about using CF
> where it can get mechanically damaged, but otherwise he thinks it is
> proven in well made bike frames.
The confusion is due to pinheads deliberately confusing direction of loads -
duty loads versus non-duty loads.
Put it this way - imagine one carbon fiber as a pencil. It's very strong in
compression and tension, as long as the load is parallel to its length (or
axis). However, put a load perpendicular to its axis, and you can easily
break the pencil. CF composites are made up of layers of carbon fiber, each
layer having carbon fibers all oriented in the same direction and held
together by (usually) an epoxy resin (the matrix). If you have
mutli-directional loads, you can make a component with layers of CF
laminate, with the layers having fibers oriented in various directions.
So, say you're designing a CF tube, intended to take up axial loads only (or
loads parallel to its length). You will naturally layer the CF laminates so
that the CF are oriented along the axial direction. If this is all you do,
and you now apply a load perpendicular to the tube, you will load the CF
perpendicularly, with only the matrix resisting most of the load (since
carbon fibers are quite weak with non-axial loads and will break much more
easily than if you load them axially (pencil analogy)).
Well then, layer the tube with laminates that have fibers oriented in
different directions, you say. Fine. So how do you align carbon fiber
laminates on a tube to counter a perpendicular load? Do CF frame
manufacturers do this? If not, how do they address this issue?
Compare that with a metal, which has the same property in all directions
(unless you talk about directional crystals and so forth, which is a
different topic altogether). All you need to do to increase a metal tube's
load capacity in the perpendicular direction is make it thicker.
The other issue that arises as a consequence is damage indication. You can
load a CF component in a direction perpendicular to its fibers, only
elastically deform the resin, but manage to break the fibers (or delaminate
the layers). This means that the laminate visually looks okay, but
underneath the fibers are broken (or the layers are delaminated).
Structural integrity is compromised, and although it may not fail straight
away, useful life is shortened.
If you also do this to an Al alloy, since Al alloys typically have a
magnitude greater elongation to failure than CF, you will need to apply a
higher load to break the metal structure. You can also tell if an Al tube
is dented.
Now beamboy tries to obfuscate and hide his poor understanding of these by
mixing it with fatigue characteristics, but it has nothing to do with
fatigue, everything to do with structural integrity. And it seems that this
is such an emotional issue, that people either think "CF components will
break like thin glass", or "CF is unbreakable and will last forever",
depending on how much they've invested in CF equipment. It's neither, but
it is only wise to use the caution that the aerospace industry employs in
how they use and maintain CF structures.
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Date: 11 Sep 2007 04:55:26
From: Ben C
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On 2007-09-11, Jambo <-@-.- > wrote:
>
> "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
> news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
>> Frankly, I'm totally confused about this. Most of my serious riding is
>> done with an engineer friend who works in the industry (but not with
>> CF -- except that he gets pro-deals on everything and can afford a
>> mega-$ CF frame). I bring him up to speed on the latest RBT
>> CFcontroversy, and his comment is "do you see this stuff breaking all
>> over the place?" He backs off and echos the concern about using CF
>> where it can get mechanically damaged, but otherwise he thinks it is
>> proven in well made bike frames.
>
> The confusion is due to pinheads deliberately confusing direction of loads -
> duty loads versus non-duty loads.
>
> Put it this way - imagine one carbon fiber as a pencil. It's very strong in
> compression and tension, as long as the load is parallel to its length (or
> axis). However, put a load perpendicular to its axis, and you can easily
> break the pencil.
I think that's a herring. The pencil breaks that way because its length
provides leverage making it easier to bring part of it to a high enough
stress for it to break. Pencils are slightly anisotropic but the grain
tends to run down the pencil and so they're actually stronger
transversely.
> CF composites are made up of layers of carbon fiber, each
> layer having carbon fibers all oriented in the same direction and held
> together by (usually) an epoxy resin (the matrix).
I thought that was one of the big benefits of CF construction-- you can
deliberately make it stronger in the directions it needs to be strong
in.
> If you have mutli-directional loads, you can make a component with
> layers of CF laminate, with the layers having fibers oriented in
> various directions.
> So, say you're designing a CF tube, intended to take up axial loads
> only (or loads parallel to its length). You will naturally layer the
> CF laminates so that the CF are oriented along the axial direction.
> If this is all you do,
Then it follows only that you are a stupid designer.
> and you now apply a load perpendicular to the tube, you will load the CF
> perpendicularly, with only the matrix resisting most of the load (since
> carbon fibers are quite weak with non-axial loads and will break much more
> easily than if you load them axially (pencil analogy)).
>
> Well then, layer the tube with laminates that have fibers oriented in
> different directions, you say. Fine. So how do you align carbon fiber
> laminates on a tube to counter a perpendicular load? Do CF frame
> manufacturers do this? If not, how do they address this issue?
Don't know. Colnago actually make carbon fibre tubes, presumably with
the fibres wrapping around the tube. So quite a good mix of directions.
[...]
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Date: 11 Sep 2007 11:25:28
From: Michael Press
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
In article
<slrnfecpg1.5i1.spamspam@bowser.marioworld >,
Ben C <spamspam@spam.eggs > wrote:
> On 2007-09-11, Jambo <-@-.-> wrote:
> >
> > "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
> > news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
> >> Frankly, I'm totally confused about this. Most of my serious riding is
> >> done with an engineer friend who works in the industry (but not with
> >> CF -- except that he gets pro-deals on everything and can afford a
> >> mega-$ CF frame). I bring him up to speed on the latest RBT
> >> CFcontroversy, and his comment is "do you see this stuff breaking all
> >> over the place?" He backs off and echos the concern about using CF
> >> where it can get mechanically damaged, but otherwise he thinks it is
> >> proven in well made bike frames.
> >
> > The confusion is due to pinheads deliberately confusing direction of loads -
> > duty loads versus non-duty loads.
> >
> > Put it this way - imagine one carbon fiber as a pencil. It's very strong in
> > compression and tension, as long as the load is parallel to its length (or
> > axis). However, put a load perpendicular to its axis, and you can easily
> > break the pencil.
>
> I think that's a herring.
Wood is a composite material, so the analogy is
excellent. No fishy smell. Wood easier to crush
transversely than longitudinally. That is why good
cutting blocks are made with the end grain on the
surface of the block. Wood is optimized to carry an
axial load. Tall timber. When wood is called upon act
as a beam as in a limb, it puts more material on the
side of the neutral axis that is in compression, the
underside.
Try breaking a small branch off a tree. First pull down
on it. You're breaking a sweat, not the branch. Now
push up. Crack! Off breaks the branch. Trees optimize
their lay up schedule for expected loads.
--
Michael Press
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Date: 11 Sep 2007 15:06:03
From: Ben C
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On 2007-09-11, Michael Press <rubrum@pacbell.net > wrote:
> In article
><slrnfecpg1.5i1.spamspam@bowser.marioworld>,
> Ben C <spamspam@spam.eggs> wrote:
>
>> On 2007-09-11, Jambo <-@-.-> wrote:
>> >
>> > "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
>> > news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
>> >> Frankly, I'm totally confused about this. Most of my serious riding is
>> >> done with an engineer friend who works in the industry (but not with
>> >> CF -- except that he gets pro-deals on everything and can afford a
>> >> mega-$ CF frame). I bring him up to speed on the latest RBT
>> >> CFcontroversy, and his comment is "do you see this stuff breaking all
>> >> over the place?" He backs off and echos the concern about using CF
>> >> where it can get mechanically damaged, but otherwise he thinks it is
>> >> proven in well made bike frames.
>> >
>> > The confusion is due to pinheads deliberately confusing direction of loads -
>> > duty loads versus non-duty loads.
>> >
>> > Put it this way - imagine one carbon fiber as a pencil. It's very strong in
>> > compression and tension, as long as the load is parallel to its length (or
>> > axis). However, put a load perpendicular to its axis, and you can easily
>> > break the pencil.
>>
>> I think that's a herring.
>
> Wood is a composite material, so the analogy is
> excellent. No fishy smell. Wood easier to crush
> transversely than longitudinally.
To crush, yes, but I still think a pencil would be easier to break if
the grain didn't run along its length but perpendicular to it.
The reason a pencil is easier to break by snapping it than by using it
like a pillar is leverage.
> That is why good
> cutting blocks are made with the end grain on the
> surface of the block.
And why pencils are optimized for chewing and sharpening.
> Wood is optimized to carry an
> axial load. Tall timber. When wood is called upon act
> as a beam as in a limb, it puts more material on the
> side of the neutral axis that is in compression, the
> underside.
>
> Try breaking a small branch off a tree. First pull down
> on it. You're breaking a sweat, not the branch. Now
> push up. Crack! Off breaks the branch. Trees optimize
> their lay up schedule for expected loads.
I didn't know there was a difference between pulling down and pushing up
on a branch.
The lay up schedule must depend on which evolves faster, elephants or
trees.
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Date: 12 Sep 2007 00:16:22
From: Michael Press
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
In article
<slrnfedt8u.5i1.spamspam@bowser.marioworld >,
Ben C <spamspam@spam.eggs > wrote:
> On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
[...]
> > Try breaking a small branch off a tree. First pull down
> > on it. You're breaking a sweat, not the branch. Now
> > push up. Crack! Off breaks the branch. Trees optimize
> > their lay up schedule for expected loads.
>
> I didn't know there was a difference between pulling down and pushing up
> on a branch.
I outlined an experiment. Go out and do it. Then you will know more.
Saw a tree limb transversely. Observe the growth pattern and
relate it to the direction of gravity.
Are there more fibers on the underside of the rings?
> The lay up schedule must depend on which evolves faster, elephants or
> trees.
Ah, humor.
--
Michael Press
|
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Date: 12 Sep 2007 08:38:20
From: Larry Dickman
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
In article <rubrum-293389.17162211092007@newsclstr02.news.prodigy.com >,
Michael Press <rubrum@pacbell.net > wrote:
> In article
> <slrnfedt8u.5i1.spamspam@bowser.marioworld>,
> Ben C <spamspam@spam.eggs> wrote:
>
> > On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
>
> [...]
>
> > > Try breaking a small branch off a tree. First pull down
> > > on it. You're breaking a sweat, not the branch. Now
> > > push up. Crack! Off breaks the branch. Trees optimize
> > > their lay up schedule for expected loads.
> >
> > I didn't know there was a difference between pulling down and pushing up
> > on a branch.
>
> I outlined an experiment. Go out and do it. Then you will know more.
> Saw a tree limb transversely. Observe the growth pattern and
> relate it to the direction of gravity.
> Are there more fibers on the underside of the rings?
>
> > The lay up schedule must depend on which evolves faster, elephants or
> > trees.
>
> Ah, humor.
I'm not sure what the point is here. Isn't lumber cut from the trunk and
not the branch?
|
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Date: 12 Sep 2007 16:29:19
From: Michael Press
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
In article
<LDickman-3C02F9.08381912092007@individual.net >,
Larry Dickman <LDickman@comcast.net > wrote:
> In article <rubrum-293389.17162211092007@newsclstr02.news.prodigy.com>,
> Michael Press <rubrum@pacbell.net> wrote:
>
> > In article
> > <slrnfedt8u.5i1.spamspam@bowser.marioworld>,
> > Ben C <spamspam@spam.eggs> wrote:
> >
> > > On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
> >
> > [...]
> >
> > > > Try breaking a small branch off a tree. First pull down
> > > > on it. You're breaking a sweat, not the branch. Now
> > > > push up. Crack! Off breaks the branch. Trees optimize
> > > > their lay up schedule for expected loads.
> > >
> > > I didn't know there was a difference between pulling down and pushing up
> > > on a branch.
> >
> > I outlined an experiment. Go out and do it. Then you will know more.
> > Saw a tree limb transversely. Observe the growth pattern and
> > relate it to the direction of gravity.
> > Are there more fibers on the underside of the rings?
> >
> > > The lay up schedule must depend on which evolves faster, elephants or
> > > trees.
> >
> > Ah, humor.
>
> I'm not sure what the point is here. Isn't lumber cut from the trunk and
> not the branch?
The point is not lumber, it is growth pattern of trees,
the orientation and distribution of fibers.
--
Michael Press
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Date: 12 Sep 2007 11:11:21
From: Ben C
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On 2007-09-12, Larry Dickman <LDickman@comcast.net > wrote:
> In article <rubrum-293389.17162211092007@newsclstr02.news.prodigy.com>,
> Michael Press <rubrum@pacbell.net> wrote:
>
>> In article
>> <slrnfedt8u.5i1.spamspam@bowser.marioworld>,
>> Ben C <spamspam@spam.eggs> wrote:
>>
>> > On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
>>
>> [...]
>>
>> > > Try breaking a small branch off a tree. First pull down
>> > > on it. You're breaking a sweat, not the branch. Now
>> > > push up. Crack! Off breaks the branch. Trees optimize
>> > > their lay up schedule for expected loads.
>> >
>> > I didn't know there was a difference between pulling down and pushing up
>> > on a branch.
>>
>> I outlined an experiment. Go out and do it. Then you will know more.
>> Saw a tree limb transversely. Observe the growth pattern and
>> relate it to the direction of gravity.
>> Are there more fibers on the underside of the rings?
>>
>> > The lay up schedule must depend on which evolves faster, elephants or
>> > trees.
>>
>> Ah, humor.
>
> I'm not sure what the point is here. Isn't lumber cut from the trunk and
> not the branch?
Normally the load on a branch is its weight, and that of all the leaves,
fruits, and anything hanging from it or sitting on it. So trees may have
evolved branches that are stronger downwards than upwards.
I would be interested to try Michael Press's experiment but trees are
sacred around here and pulling a branch off one is not an option.
The point about elephants is that they rip branches off trees and may
well have worked out that it's easier to get them off by pushing
upwards, if that is indeed the case.
The trees in areas populated by elephants therefore may have responded
by evolving branches that are equally strong upwards. This would be
interesting to investigate.
So that was the point about branches. As for where they get lumber from,
the trunk certainly, but perhaps the branches as well, I don't know.
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Date: 11 Sep 2007 15:40:26
From:
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On Tue, 11 Sep 2007 15:06:03 -0500, Ben C <spamspam@spam.eggs > wrote:
>On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
>> In article
>><slrnfecpg1.5i1.spamspam@bowser.marioworld>,
>> Ben C <spamspam@spam.eggs> wrote:
>>
>>> On 2007-09-11, Jambo <-@-.-> wrote:
>>> >
>>> > "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
>>> > news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
>>> >> Frankly, I'm totally confused about this. Most of my serious riding is
>>> >> done with an engineer friend who works in the industry (but not with
>>> >> CF -- except that he gets pro-deals on everything and can afford a
>>> >> mega-$ CF frame). I bring him up to speed on the latest RBT
>>> >> CFcontroversy, and his comment is "do you see this stuff breaking all
>>> >> over the place?" He backs off and echos the concern about using CF
>>> >> where it can get mechanically damaged, but otherwise he thinks it is
>>> >> proven in well made bike frames.
>>> >
>>> > The confusion is due to pinheads deliberately confusing direction of loads -
>>> > duty loads versus non-duty loads.
>>> >
>>> > Put it this way - imagine one carbon fiber as a pencil. It's very strong in
>>> > compression and tension, as long as the load is parallel to its length (or
>>> > axis). However, put a load perpendicular to its axis, and you can easily
>>> > break the pencil.
>>>
>>> I think that's a herring.
>>
>> Wood is a composite material, so the analogy is
>> excellent. No fishy smell. Wood easier to crush
>> transversely than longitudinally.
>
>To crush, yes, but I still think a pencil would be easier to break if
>the grain didn't run along its length but perpendicular to it.
>
>The reason a pencil is easier to break by snapping it than by using it
>like a pillar is leverage.
>
>> That is why good
>> cutting blocks are made with the end grain on the
>> surface of the block.
>
>And why pencils are optimized for chewing and sharpening.
>
>> Wood is optimized to carry an
>> axial load. Tall timber. When wood is called upon act
>> as a beam as in a limb, it puts more material on the
>> side of the neutral axis that is in compression, the
>> underside.
>>
>> Try breaking a small branch off a tree. First pull down
>> on it. You're breaking a sweat, not the branch. Now
>> push up. Crack! Off breaks the branch. Trees optimize
>> their lay up schedule for expected loads.
>
>I didn't know there was a difference between pulling down and pushing up
>on a branch.
>
>The lay up schedule must depend on which evolves faster, elephants or
>trees.
Dear Ben,
For what it's worth, J.E. Gordon's second table in "Structures" lists
approximate tensile strengths of various solids and mentions spruce,
favored for its strength:
Wood (air dry) :
along grain 15,000 psi
across grain 500 psi
That is, wood fibers pull apart (tensile strength) comparatively
easily when the fibers are pulled apart across the grain like this:
|
| | | | | | | |
Date: 11 Sep 2007 20:58:12
From: jim beam
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
carlfogel@comcast.net wrote:
> On Tue, 11 Sep 2007 15:06:03 -0500, Ben C <spamspam@spam.eggs> wrote:
>
>> On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
>>> In article
>>> <slrnfecpg1.5i1.spamspam@bowser.marioworld>,
>>> Ben C <spamspam@spam.eggs> wrote:
>>>
>>>> On 2007-09-11, Jambo <-@-.-> wrote:
>>>>> "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
>>>>> news:1189471806.190853.275260@50g2000hsm.googlegroups.com...
>>>>>> Frankly, I'm totally confused about this. Most of my serious riding is
>>>>>> done with an engineer friend who works in the industry (but not with
>>>>>> CF -- except that he gets pro-deals on everything and can afford a
>>>>>> mega-$ CF frame). I bring him up to speed on the latest RBT
>>>>>> CFcontroversy, and his comment is "do you see this stuff breaking all
>>>>>> over the place?" He backs off and echos the concern about using CF
>>>>>> where it can get mechanically damaged, but otherwise he thinks it is
>>>>>> proven in well made bike frames.
>>>>> The confusion is due to pinheads deliberately confusing direction of loads -
>>>>> duty loads versus non-duty loads.
>>>>>
>>>>> Put it this way - imagine one carbon fiber as a pencil. It's very strong in
>>>>> compression and tension, as long as the load is parallel to its length (or
>>>>> axis). However, put a load perpendicular to its axis, and you can easily
>>>>> break the pencil.
>>>> I think that's a herring.
>>> Wood is a composite material, so the analogy is
>>> excellent. No fishy smell. Wood easier to crush
>>> transversely than longitudinally.
>> To crush, yes, but I still think a pencil would be easier to break if
>> the grain didn't run along its length but perpendicular to it.
>>
>> The reason a pencil is easier to break by snapping it than by using it
>> like a pillar is leverage.
>>
>>> That is why good
>>> cutting blocks are made with the end grain on the
>>> surface of the block.
>> And why pencils are optimized for chewing and sharpening.
>>
>>> Wood is optimized to carry an
>>> axial load. Tall timber. When wood is called upon act
>>> as a beam as in a limb, it puts more material on the
>>> side of the neutral axis that is in compression, the
>>> underside.
>>>
>>> Try breaking a small branch off a tree. First pull down
>>> on it. You're breaking a sweat, not the branch. Now
>>> push up. Crack! Off breaks the branch. Trees optimize
>>> their lay up schedule for expected loads.
>> I didn't know there was a difference between pulling down and pushing up
>> on a branch.
>>
>> The lay up schedule must depend on which evolves faster, elephants or
>> trees.
>
> Dear Ben,
>
> For what it's worth, J.E. Gordon's second table in "Structures" lists
> approximate tensile strengths of various solids and mentions spruce,
> favored for its strength:
>
> Wood (air dry) :
> along grain 15,000 psi
> across grain 500 psi
>
> That is, wood fibers pull apart (tensile strength) comparatively
> easily when the fibers are pulled apart across the grain like this:
>
>
|
| | | | | | |
Date: 11 Sep 2007 17:33:21
From: Jambo
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
"Ben C" <spamspam@spam.eggs > wrote in message
news:slrnfedt8u.5i1.spamspam@bowser.marioworld...
> On 2007-09-11, Michael Press <rubrum@pacbell.net> wrote:
>> Wood is a composite material, so the analogy is
>> excellent. No fishy smell. Wood easier to crush
>> transversely than longitudinally.
>
> To crush, yes, but I still think a pencil would be easier to break if
> the grain didn't run along its length but perpendicular to it.
The analogy is the pencil as one carbon fiber, NOT a carbon fiber composite
made up of many fibers.
Regardless of how you picture it, breaking the pencil by loading it
perpendicularly WILL ALWAYS be easier than breaking it by axial loads, no
matter the length.
> The reason a pencil is easier to break by snapping it than by using it
> like a pillar is leverage.
No.
|
| | | | | | | |
Date: 11 Sep 2007 23:25:41
From:
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
Ben C? writes:
>>> Wood is a composite material, so the analogy is excellent. No
>>> fishy smell. Wood easier to crush transversely than
>>> longitudinally.
>> To crush, yes, but I still think a pencil would be easier to break
>> if the grain didn't run along its length but perpendicular to it.
> The analogy is the pencil as one carbon fiber, NOT a carbon fiber
> composite made up of many fibers.
> Regardless of how you picture it, breaking the pencil by loading it
> perpendicularly WILL ALWAYS be easier than breaking it by axial
> loads, no matter the length.
>> The reason a pencil is easier to break by snapping it than by using
>> it like a pillar is leverage.
I don't believe the model is a good analogy, although loading fibers
in tension rather than shear is what lies at the bottom of this. For
an example, saw a 1/4" slice off the end of a 2x4 and compare its
bending stiffness to a 2 x 1/4" lath (with longitudinal grain).
Bending a pencil, if you must, is putting the inside and outside of
its wood into tension and compression. Because it is so slim, it
cannot be readily bent in the other direction so the test isn't fair.
Jobst Brandt
|
| | | | | | | | |
Date: 12 Sep 2007 01:54:51
From: Ben C
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On 2007-09-11, jobst.brandt@stanfordalumni.org <jobst.brandt@stanfordalumni.org > wrote:
> Ben C? writes:
>
>>>> Wood is a composite material, so the analogy is excellent. No
>>>> fishy smell. Wood easier to crush transversely than
>>>> longitudinally.
>
>>> To crush, yes, but I still think a pencil would be easier to break
>>> if the grain didn't run along its length but perpendicular to it.
>
>> The analogy is the pencil as one carbon fiber, NOT a carbon fiber
>> composite made up of many fibers.
>
>> Regardless of how you picture it, breaking the pencil by loading it
>> perpendicularly WILL ALWAYS be easier than breaking it by axial
>> loads, no matter the length.
>
>>> The reason a pencil is easier to break by snapping it than by using
>>> it like a pillar is leverage.
>
> I don't believe the model is a good analogy, although loading fibers
> in tension rather than shear is what lies at the bottom of this. For
> an example, saw a 1/4" slice off the end of a 2x4 and compare its
> bending stiffness to a 2 x 1/4" lath (with longitudinal grain).
> Bending a pencil, if you must, is putting the inside and outside of
> its wood into tension and compression. Because it is so slim, it
> cannot be readily bent in the other direction so the test isn't fair.
Exactly, that's what I was trying to say. I still don't really know what
Jambo was talking about, but never mind.
|
| | | | |
Date: 11 Sep 2007 12:59:14
From: Jambo
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
"Ben C" <spamspam@spam.eggs > wrote in message
news:slrnfecpg1.5i1.spamspam@bowser.marioworld...
> On 2007-09-11, Jambo <-@-.-> wrote:
>> Put it this way - imagine one carbon fiber as a pencil. It's very strong
>> in
>> compression and tension, as long as the load is parallel to its length
>> (or
>> axis). However, put a load perpendicular to its axis, and you can easily
>> break the pencil.
>
> I think that's a herring.
It's called an analogy. A "red herring" is a misleading clue.
> The pencil breaks that way because its length
> provides leverage making it easier to bring part of it to a high enough
> stress for it to break.
Length is irrelevant in this case. Whatever the length of the pencil, it
will be stronger in the axial direction than otherwise.
> Pencils are slightly anisotropic but the grain
> tends to run down the pencil and so they're actually stronger
> transversely.
This doesn't make sense.
>
>> CF composites are made up of layers of carbon fiber, each
>> layer having carbon fibers all oriented in the same direction and held
>> together by (usually) an epoxy resin (the matrix).
>
> I thought that was one of the big benefits of CF construction-- you can
> deliberately make it stronger in the directions it needs to be strong
> in.
That's correct. My statement doesn't say anything contrary to that.
>> If you have mutli-directional loads, you can make a component with
>> layers of CF laminate, with the layers having fibers oriented in
>> various directions.
>
>> So, say you're designing a CF tube, intended to take up axial loads
>> only (or loads parallel to its length). You will naturally layer the
>> CF laminates so that the CF are oriented along the axial direction.
>> If this is all you do,
>
> Then it follows only that you are a stupid designer.
Just follow the post further before you jump in.
>> and you now apply a load perpendicular to the tube, you will load the CF
>> perpendicularly, with only the matrix resisting most of the load (since
>> carbon fibers are quite weak with non-axial loads and will break much
>> more
>> easily than if you load them axially (pencil analogy)).
>>
>> Well then, layer the tube with laminates that have fibers oriented in
>> different directions, you say. Fine. So how do you align carbon fiber
>> laminates on a tube to counter a perpendicular load? Do CF frame
>> manufacturers do this? If not, how do they address this issue?
>
> Don't know. Colnago actually make carbon fibre tubes, presumably with
> the fibres wrapping around the tube. So quite a good mix of directions.
You state "don't know", "presumably", then you conclude "quite a good mix of
directions". Not very logical, is it?
On the other hand, manufacturers like Titus blurt this:
"Exogrid - The most technically advanced tubing ever produced. Riders look
at our Exogrid bikes and think it is the coolest thing they've ever seen.
That it certainly is, but it is also so much more. Exogrid is like a match
made in heaven between titanium and carbon fiber - The ultimate fusion of
technologies. We take the incredible strength and feel of titanium, and add
the weight savings and stiffness of high modulus composites in order to
lighten, strengthen and tune the ride of each tube on your new frame. Here's
how it works: We start with an aerospace-grade titanium tube and "laser" cut
the center away until just a titanium skeleton remains. (In some cases we
remove up to ½ pound of titanium.) We then create a reinforcement of carbon
fiber that is both lighter and stiffer in certain directions than the
titanium material it replaces. You won't believe the ride! It's technology
that really makes a difference in the ride of your new bike."
Now why do you think Titus really found it beneficial to use Ti to reinforce
their CF tubes? Could it be that they found it beneficial in protecting the
CF parts? After all, CF alone should be able to do the job, right? Or
maybe it really is just because "Riders look at our Exogrid bikes and think
it is the coolest thing they've ever seen."
|
| |
Date: 10 Sep 2007 08:53:58
From: andresmuro@aol.com
Subject: Re: "brittle" vs. non-ductile
|
On Sep 9, 9:37 pm, "Mike Jacoubowsky" <mik...@ix.netcom.com > wrote:
> Chalo: I'm not going to go into everything in your reply point-by-point,
> because, for the most part, I agree!!!
>
> Carbon fiber isn't the ideal material for all kinds of bikes. I never
> suggested it was. Why spend a fortune for a bike that's going to get
> seriously dinged up in normal use? You wouldn't subject a super-light bike
> of *any* material to that kind of use. That's not what they're made for, at
> least not yet. The market for carbon fiber bikes is very specifically at the
> high-performance end of the market, and has yet to invade the utility bike
> market. For it to do so, they would, indeed, have to be made quite
> differently than they are now. Just as utility bikes of any other material
> are made differently from super-light performance-oriented models of the
> same material.
>
> HOWEVER---
>
> > The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> Characterizations of recreational riders, whether they be racers training,
> wannabes or weekend warriors, as "people in stretchy clown suits riding on
> plastic bikes" has nothing to do with the discussion at hand, and comes
> across as belittling, at best. We see a fair amount of that type of abuse
> here, and fine, I can take it. But what would happen if people were to make
> characterizations of the type of person who buys a cheapie *Mart bike
> (always, it seems ridden with flat tires) to get to their job, because they
> can't afford a car nor a decent bike... that somehow that group is less
> worthy than some category of "real" cyclist (according to whomever's
> definition)?
>
> You shouldn't see that here, nor would you. And if someone did, I should
> hope that a great many would come to the defense of those who are in such a
> position that their only use for a bike is basic transportation, and they
> could really care less about the bike's nobility, they'd rather be driving a
> car.
>
> The cycling world should be all-encompassing, not exclusionary. In my humble
> opinion. And you shouldn't seek to gain favor for an argument by making fun
> of any particular user group. Again, in my humble opinion.
>
> --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com
>
> "Chalo" <chalo.col...@gmail.com> wrote in message
>
> news:1189393836.784431.304160@r34g2000hsd.googlegroups.com...
>
> > Mike Jacoubowsky wrote:
>
> >> Tim McNamara wrote:
>
> >> > Unfortunately your carbon frame is not readily inspectable for damage.
> >> > I hope that is in in fact undamaged.
>
> >> The impact was in 2000; the frame remains in continuous use since then.
> >> The
> >> fork was replaced, due to a damaged steer column. It would have been
> >> replace
> >> anyway, since it would have failed the "common sense" test (being that
> >> nothing could have been designed to withstand that sort of impact, and
> >> thus
> >> it cannot be trusted). The frame might have failed the "common sense"
> >> test
> >> as well, except that I have yet to see, among the many (and I do mean
> >> many)
> >> thousands of carbon fiber frames that I have sold, a catastrophic failure
> >> that happened after an initial incident, and without warning. Please do
> >> not
> >> take this to mean a frame is safe after a crash. Rather, for my sample
> >> size,
> >> I see issues with forks, but not frames (dealing strictly with those that
> >> I
> >> have sold, which is admittedly a base of only one manufacturer).
>
> > In my observation, the group of people who ride CFRP bikes is very
> > self-selecting. They are, by and large, folks who:
>
> > - weigh close to the population median, or less
>
> > - have more money to spend than time to ride
>
> > - don't lock their bikes up in public racks
>
> > - don't store their bikes inside
>
> > - are conscious of their appearance and go to lengths to keep their
> > bikes clean and unscratched
>
> > - ride on Sunday on roads that don't go anywhere
>
> > - etc.
>
> > I have spent most of my adult life using my bike as regular
> > transportation. I see vanishingly few CFRP bikes in the course of my
> > riding around town, though I see lots and lots of other bikes. The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> > At those times, I have never noticed them doing any of the sort of
> > things that cause veteran commuter bikes to become dinged up and
> > stripped of sections of their decals and paint. I have never seem
> > them doing the sorts of things that made my Seattle bike messenger
> > friends wrap their bikes' frame tubes with tape and fit them with top
> > tube pads. I don't even see them doing the transportational sorts of
> > things that they might do in their cars.
>
> > I only see these folks doing what I've seen from groups of guys
> > driving Morgans or riding Panhead Harleys together-- wandering around
> > for the sake of wandering around, and for the purpose of showing off
> > their pampered shiny machines to each other and a bunch of other folks
> > who don't care. And I can't help but suspect that just like Morgans
> > and Panhead Harleys, CFRP bikes would be unreliable at best if used
> > regularly for most practical vehicular purposes. I could be wrong,
> > but the almost complete absence of CFRP bikes on the mean streets has
> > got to demonstrate _something_. I think that part of what it
> > demonstrates is a short half-life in the real world.
>
> > Chalo
Chalo is not off in his characterization. We look like a bunch of
clowns. I wear the clown outfit because it happens to be beneficial
for riding, but come-on we look like nerds, period. There are athletes
from two sports that need to stay out of coffee shops: cyclists and
baseball players.
Just like in Chalo's description, I ride my bike on weekends with
groups going nowhere for quite a while looking like a nerd. a lot of
my riding partners have carbon fiber bikes. These are the wealthiest
ones of the bunch. We all carry cells, so if something goes wrong, we
call someone to pick us up. We are middle aged nerds piling miles as a
way to face the insecurity that we are potbellied, grayhaired and
getting older by the second. I'd still rather do this than play golf.
I must say that I don't have a carbon fiber bike and I don't have
boutique wheels. In fact, my front wheel is a 36 spoke mavic ma 40.
someone noticed my wheel and asked me if that was from a cart. They
couldn't believe that it had so many spokes and that the rims where so
low profiled.
Andres
|
| |
Date: 10 Sep 2007 09:59:36
From: Chalo
Subject: Play cyclists, was Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>
> Chalo wrote:
> >
> > The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> Characterizations of recreational riders, whether they be racers training,
> wannabes or weekend warriors, as "people in stretchy clown suits riding on
> plastic bikes" has nothing to do with the discussion at hand, and comes
> across as belittling, at best.
Well, at least I didn't disparage their enthusiasm-- or their speed,
which is usually very respectable. But I have a distaste for that
approach to cycling. There's an analogous kind of motorcycle rider
that irritates me. During the many years I spent as a year-round, all-
weather motorcyclist, on any given sunny 80-degree day there would
appear quantities of young guys on new $10,000 sportbikes who wore
helmets matching their bikes' paint, along with t-shirts, shorts and
sneakers (or flip-flops). Sometimes they would bring their
underdressed girlfriends along for the ride. I'm sure these dudes are
great for the motorcycle retail business, but they are definitely not
so great for motorcycling as a movement. I sorta wish they'd take up
jetskiing or bungee-jumping instead, and leave real motorcyclists to
build their own reputation with the public.
It's a serious problem for cyclists that such a wide segment of the
non-cycling public regards bikes as toys. That perception costs some
cyclists' lives, and robs many others of the pleasure of sharing the
road in peace. Folks who take up cycling the way one might take up
paintball are a major impediment to growing the credibility of cycling
as a mode of transportation. (You might as well sell them on
paintball. I understand the inventory is easier to manage and the
margins are phenomenal.)
Chalo
|
| | |
Date: 10 Sep 2007 15:37:17
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Mon, 10 Sep 2007 09:59:36 -0000, Chalo <chalo.colina@gmail.com >
wrote:
>Mike Jacoubowsky wrote:
>>
>> Chalo wrote:
>> >
>> > The
>> > times I see lots of carbon bikes are when I get out relatively early
>> > on weekend mornings and happen to ride on relatively untrafficked
>> > roads on the perimeter of the city. At those times I see clumps of
>> > people in stretchy clown suits riding on plastic bikes.
>>
>> Characterizations of recreational riders, whether they be racers training,
>> wannabes or weekend warriors, as "people in stretchy clown suits riding on
>> plastic bikes" has nothing to do with the discussion at hand, and comes
>> across as belittling, at best.
>
>Well, at least I didn't disparage their enthusiasm-- or their speed,
>which is usually very respectable. But I have a distaste for that
>approach to cycling. There's an analogous kind of motorcycle rider
>that irritates me. During the many years I spent as a year-round, all-
>weather motorcyclist, on any given sunny 80-degree day there would
>appear quantities of young guys on new $10,000 sportbikes who wore
>helmets matching their bikes' paint, along with t-shirts, shorts and
>sneakers (or flip-flops). Sometimes they would bring their
>underdressed girlfriends along for the ride. I'm sure these dudes are
>great for the motorcycle retail business, but they are definitely not
>so great for motorcycling as a movement. I sorta wish they'd take up
>jetskiing or bungee-jumping instead, and leave real motorcyclists to
>build their own reputation with the public.
>
>It's a serious problem for cyclists that such a wide segment of the
>non-cycling public regards bikes as toys. That perception costs some
>cyclists' lives, and robs many others of the pleasure of sharing the
>road in peace. Folks who take up cycling the way one might take up
>paintball are a major impediment to growing the credibility of cycling
>as a mode of transportation. (You might as well sell them on
>paintball. I understand the inventory is easier to manage and the
>margins are phenomenal.)
>
>Chalo
Dear Chalo,
Personally, I'm not sure that you guys without skidplates are really
motorcyclists, but I can't say that you irritate me with your road
toys.
Cheers,
Carl Fogel
|
| | | |
Date: 10 Sep 2007 23:55:48
From: John Dacey
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Mon, 10 Sep 2007 15:37:17 -0600, carlfogel@comcast.net wrote:
>Personally, I'm not sure that you guys without skidplates are really
>motorcyclists, but I can't say that you irritate me with your road
>toys.
Of course, it's also a mystery to many folks why trials riders choose
to clambor across rocks on a motorcycle that wouldn't outpace a
glacier with the same agenda.
*********************************************
The Style Police: Men of Steel
Were I a lesser man, you might think me sanctimonious.
My modesty’s so false, it’s practic’ly felonious.
Others, you’ll discover, are a trifle acrimonious
When I dispense advice (I’m a cycling Polonius).
You’re bike’s completely wrong for you -- it’s really quite pathetic;
Offensive in each ev’ry way: material, cosmetic.
To fix the failures I’ve foretold (I’m also quite prophetic),
I’ll be your guide along the righteous path of the Ascetic.
Your frameset should be made of steel and fully lugged is the ideal.
Paint it in a boring color, something quite funereal.
The gravitas imbued in me from only using iron
Makes it the stuff of bicycles for which always I yearn.
I’ve castigated schoolgirls here with nary an apology
For questioning my treatises on wheel-spoke thanatology.
I’ll do the same for you, should you show the temerity
To challenge my encyclicals on bearing-ball asperity.
Avoid new-fangled fabrics with an effort most concerted.
Lycra, Cool-Max, Spandex are the cloths of the perverted --
About your every secret, your friends will be alerted.
So neophobes like me are most at home when we’re hairshirted.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
Phone: 305-273-4440
http://www.businesscycles.com
-------------------------------
|
| | | | |
Date: 11 Sep 2007 23:21:46
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Mon, 10 Sep 2007 23:55:48 -0400, John Dacey wrote:
> The Style Police: Men of Steel
>
> Were I a lesser man, you might think me sanctimonious.
> My modesty’s so false, it’s practic’ly felonious.
> Others, you’ll discover, are a trifle acrimonious
> When I dispense advice (I’m a cycling Polonius).
LOL. Saved :-)
|
| | |
Date: 10 Sep 2007 08:49:15
From: Tim McNamara
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
In article <1189418376.574775.209250@y42g2000hsy.googlegroups.com >,
Chalo <chalo.colina@gmail.com > wrote:
> Sometimes they would bring their underdressed girlfriends along for
> the ride.
You say this like it's a bad thing...
|
| |
Date: 10 Sep 2007 04:31:44
From:
Subject: What's a "cyclist"? [was Re: "brittle" vs. non-ductile]
|
On Sep 9, 11:37 pm, "Mike Jacoubowsky" <mik...@ix.netcom.com > wrote:
> Chalo wrote:
>
> > The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> Characterizations of recreational riders, whether they be racers training,
> wannabes or weekend warriors, as "people in stretchy clown suits riding on
> plastic bikes" has nothing to do with the discussion at hand, and comes
> across as belittling, at best. We see a fair amount of that type of abuse
> here, and fine, I can take it. But what would happen if people were to make
> characterizations of the type of person who buys a cheapie *Mart bike
> (always, it seems ridden with flat tires) to get to their job, because they
> can't afford a car nor a decent bike... that somehow that group is less
> worthy than some category of "real" cyclist (according to whomever's
> definition)?
>
> You shouldn't see that here, nor would you. And if someone did, I should
> hope that a great many would come to the defense of those who are in such a
> position that their only use for a bike is basic transportation, and they
> could really care less about the bike's nobility, they'd rather be driving a
> car.
>
> The cycling world should be all-encompassing, not exclusionary. In my humble
> opinion. And you shouldn't seek to gain favor for an argument by making fun
> of any particular user group. Again, in my humble opinion.
I agree with Mike's humble opinion.
And I agree, we shouldn't see that sort of snobbery here - the
belittling of utility riders. But let me quote from Buycycling
magazine, October 2007, regarding non-racy bikes and those who use
them for practical purposes: "After they have a few miles under their
wheels some of these utilitarian riders will be hooked and become
cyclists."
Oh? And what are they when they're actually using a bike for
practical transportation? Are they the underclass? Disadvantaged?
Freds? POBs? No, they're cyclists, dammit!
I suppose disparaging either style of cyclist is not a good thing.
But I certainly see a lot less to admire in a person for whom
"cycling" is just spending big bucks on a fragile toy they haul around
on their Escalade's roof rack so they can play racer.
When Buycycling magazine becomes all-encompassing and not
exclusionary, we'll have achieved something. But the magazine, and
it's fans, seem to have a long way to go. In view of that, Chalo's
mild remark seems pretty tame.
But that's just me and my personal taste, I suppose.
- Frank Krygowski
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| | |
Date: 10 Sep 2007 16:15:12
From: Luke
Subject: Re: What's a "cyclist"? [was Re: "brittle" vs. non-ductile]
|
In article <1189398704.863563.25200@r29g2000hsg.googlegroups.com >,
<frkrygow@gmail.com > wrote:
> > The cycling world should be all-encompassing, not exclusionary. In my humble
> > opinion. And you shouldn't seek to gain favor for an argument by making fun
> > of any particular user group. Again, in my humble opinion.
Noble sentiment that. Let's not restrict it to the velo-world!
|
| | |
Date: 10 Sep 2007 08:57:21
From: Doug Taylor
Subject: Re: What's a "cyclist"? [was Re: "brittle" vs. non-ductile]
|
On Mon, 10 Sep 2007 04:31:44 -0000, frkrygow@gmail.com wrote:
>I agree with Mike's humble opinion.
>
>And I agree, we shouldn't see that sort of snobbery here - the
>belittling of utility riders. But let me quote from Buycycling
>magazine, October 2007, regarding non-racy bikes and those who use
>them for practical purposes: "After they have a few miles under their
>wheels some of these utilitarian riders will be hooked and become
>cyclists."
>
>Oh? And what are they when they're actually using a bike for
>practical transportation? Are they the underclass? Disadvantaged?
>Freds? POBs? No, they're cyclists, dammit!
>
>I suppose disparaging either style of cyclist is not a good thing.
>But I certainly see a lot less to admire in a person for whom
>"cycling" is just spending big bucks on a fragile toy they haul around
>on their Escalade's roof rack so they can play racer.
>
>When Buycycling magazine becomes all-encompassing and not
>exclusionary, we'll have achieved something. But the magazine, and
>it's fans, seem to have a long way to go. In view of that, Chalo's
>mild remark seems pretty tame.
>
>But that's just me and my personal taste, I suppose.
This headline showed in our local paper last Friday:
"Bicyclist dies in collision with car."
Witnesses reported a man riding a bicycle down a hill, wearing a
baseball cap (NOT a helmet, note). The cap flew off his head; he
turned around and tried to catch it; he then ran a stop sign and
broadsided the car. Turns out he was - you guessed it - drunk as a
skunk.
Your call: "Bicyclist"? "Cyclist"? Drunk on a bike?
|
| | |
Date: 09 Sep 2007 22:48:21
From: Mike Jacoubowsky
Subject: Re: What's a "cyclist"? [was Re: "brittle" vs. non-ductile]
|
>> The cycling world should be all-encompassing, not exclusionary. In my
>> humble
>> opinion. And you shouldn't seek to gain favor for an argument by making
>> fun
>> of any particular user group. Again, in my humble opinion.
>
> I agree with Mike's humble opinion.
>
> And I agree, we shouldn't see that sort of snobbery here - the
> belittling of utility riders. But let me quote from Buycycling
> magazine, October 2007, regarding non-racy bikes and those who use
> them for practical purposes: "After they have a few miles under their
> wheels some of these utilitarian riders will be hooked and become
> cyclists."
>
> Oh? And what are they when they're actually using a bike for
> practical transportation? Are they the underclass? Disadvantaged?
> Freds? POBs? No, they're cyclists, dammit!
>
> I suppose disparaging either style of cyclist is not a good thing.
> But I certainly see a lot less to admire in a person for whom
> "cycling" is just spending big bucks on a fragile toy they haul around
> on their Escalade's roof rack so they can play racer.
>
> When Buycycling magazine becomes all-encompassing and not
> exclusionary, we'll have achieved something. But the magazine, and
> it's fans, seem to have a long way to go. In view of that, Chalo's
> mild remark seems pretty tame.
>
> But that's just me and my personal taste, I suppose.
>
> - Frank Krygowski
I doubt we'll see Bicycling Magazine become that sort of all-encompassing
product, because it wouldn't serve their financial model. They've chosen to
go after a certain type of advertiser, and built a format around that.
Regardless, I sincerely hope that people write letters and send emails to
them because of that remark. It's quite insulting.
Keep in mind that, just a few years ago, I wouldn't have seen it as that big
a thing myself. In my pre-DC Bike Summit days. Plain & simple truth is that
the economic model of my shop depends upon selling bikes that average over
$600. We build all bikes the same way, we service all customers the same
way, and our break-even point on a bike is somewhere around $500. Bikes we
sell for below that we lose money on, when we figure in all the costs
involved (time to build it, 30 day check, time to sell it, cost to floor it,
rent, advertising, all the stuff it costs to run a business). We sold
less-expensive bikes because we didn't want a family to buy their fancier
bikes from us, for example, and have to go someplace else for their kids
bikes. And there was always a sense that it all evened out in the end.
But now I see more to it than that. I have a role to play that goes beyond
just selling & servicing them. I also have an obligation to make sure people
have places to ride them, that they feel safe having their kids ride to
school, that the city doesn't do something stupid that causes grief for
cyclists. I might not be the person selling those bikes, but I benefit down
the road as more people ride, because it increases the overall appeal of
cycling, which means I'll sell more of the product that pays our bills. So
it's not as if it's a selfless desire on my part to make the world a better
place, although I would like to believe I can do something positive,
involving cycling, that can help to achieve that.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
<frkrygow@gmail.com > wrote in message
news:1189398704.863563.25200@r29g2000hsg.googlegroups.com...
> On Sep 9, 11:37 pm, "Mike Jacoubowsky" <mik...@ix.netcom.com> wrote:
>> Chalo wrote:
>>
>> > The
>> > times I see lots of carbon bikes are when I get out relatively early
>> > on weekend mornings and happen to ride on relatively untrafficked
>> > roads on the perimeter of the city. At those times I see clumps of
>> > people in stretchy clown suits riding on plastic bikes.
>>
>> Characterizations of recreational riders, whether they be racers
>> training,
>> wannabes or weekend warriors, as "people in stretchy clown suits riding
>> on
>> plastic bikes" has nothing to do with the discussion at hand, and comes
>> across as belittling, at best. We see a fair amount of that type of abuse
>> here, and fine, I can take it. But what would happen if people were to
>> make
>> characterizations of the type of person who buys a cheapie *Mart bike
>> (always, it seems ridden with flat tires) to get to their job, because
>> they
>> can't afford a car nor a decent bike... that somehow that group is less
>> worthy than some category of "real" cyclist (according to whomever's
>> definition)?
>>
>> You shouldn't see that here, nor would you. And if someone did, I should
>> hope that a great many would come to the defense of those who are in such
>> a
>> position that their only use for a bike is basic transportation, and they
>> could really care less about the bike's nobility, they'd rather be
>> driving a
>> car.
>>
>> The cycling world should be all-encompassing, not exclusionary. In my
>> humble
>> opinion. And you shouldn't seek to gain favor for an argument by making
>> fun
>> of any particular user group. Again, in my humble opinion.
>
> I agree with Mike's humble opinion.
>
> And I agree, we shouldn't see that sort of snobbery here - the
> belittling of utility riders. But let me quote from Buycycling
> magazine, October 2007, regarding non-racy bikes and those who use
> them for practical purposes: "After they have a few miles under their
> wheels some of these utilitarian riders will be hooked and become
> cyclists."
>
> Oh? And what are they when they're actually using a bike for
> practical transportation? Are they the underclass? Disadvantaged?
> Freds? POBs? No, they're cyclists, dammit!
>
> I suppose disparaging either style of cyclist is not a good thing.
> But I certainly see a lot less to admire in a person for whom
> "cycling" is just spending big bucks on a fragile toy they haul around
> on their Escalade's roof rack so they can play racer.
>
> When Buycycling magazine becomes all-encompassing and not
> exclusionary, we'll have achieved something. But the magazine, and
> it's fans, seem to have a long way to go. In view of that, Chalo's
> mild remark seems pretty tame.
>
> But that's just me and my personal taste, I suppose.
>
> - Frank Krygowski
>
>
|
| |
Date: 10 Sep 2007 03:10:36
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>
> Tim McNamara wrote:
> >
> > Unfortunately your carbon frame is not readily inspectable for damage.
> > I hope that is in in fact undamaged.
>
> The impact was in 2000; the frame remains in continuous use since then. The
> fork was replaced, due to a damaged steer column. It would have been replace
> anyway, since it would have failed the "common sense" test (being that
> nothing could have been designed to withstand that sort of impact, and thus
> it cannot be trusted). The frame might have failed the "common sense" test
> as well, except that I have yet to see, among the many (and I do mean many)
> thousands of carbon fiber frames that I have sold, a catastrophic failure
> that happened after an initial incident, and without warning. Please do not
> take this to mean a frame is safe after a crash. Rather, for my sample size,
> I see issues with forks, but not frames (dealing strictly with those that I
> have sold, which is admittedly a base of only one manufacturer).
In my observation, the group of people who ride CFRP bikes is very
self-selecting. They are, by and large, folks who:
- weigh close to the population median, or less
- have more money to spend than time to ride
- don't lock their bikes up in public racks
- don't store their bikes inside
- are conscious of their appearance and go to lengths to keep their
bikes clean and unscratched
- ride on Sunday on roads that don't go anywhere
- etc.
I have spent most of my adult life using my bike as regular
transportation. I see vanishingly few CFRP bikes in the course of my
riding around town, though I see lots and lots of other bikes. The
times I see lots of carbon bikes are when I get out relatively early
on weekend mornings and happen to ride on relatively untrafficked
roads on the perimeter of the city. At those times I see clumps of
people in stretchy clown suits riding on plastic bikes.
At those times, I have never noticed them doing any of the sort of
things that cause veteran commuter bikes to become dinged up and
stripped of sections of their decals and paint. I have never seem
them doing the sorts of things that made my Seattle bike messenger
friends wrap their bikes' frame tubes with tape and fit them with top
tube pads. I don't even see them doing the transportational sorts of
things that they might do in their cars.
I only see these folks doing what I've seen from groups of guys
driving Morgans or riding Panhead Harleys together-- wandering around
for the sake of wandering around, and for the purpose of showing off
their pampered shiny machines to each other and a bunch of other folks
who don't care. And I can't help but suspect that just like Morgans
and Panhead Harleys, CFRP bikes would be unreliable at best if used
regularly for most practical vehicular purposes. I could be wrong,
but the almost complete absence of CFRP bikes on the mean streets has
got to demonstrate _something_. I think that part of what it
demonstrates is a short half-life in the real world.
Chalo
|
| | |
Date: 12 Sep 2007 01:32:41
From: Ryan Cousineau
Subject: Re: "brittle" vs. non-ductile
|
In article <1189393836.784431.304160@r34g2000hsd.googlegroups.com >,
Chalo <chalo.colina@gmail.com > wrote:
> Mike Jacoubowsky wrote:
> >
> > Tim McNamara wrote:
> > >
> > > Unfortunately your carbon frame is not readily inspectable for damage.
> > > I hope that is in in fact undamaged.
> >
> > The impact was in 2000; the frame remains in continuous use since then. The
> > fork was replaced, due to a damaged steer column.
> In my observation, the group of people who ride CFRP bikes is very
> self-selecting. They are, by and large, folks who:
>
> - weigh close to the population median, or less
>
> - have more money to spend than time to ride
>
> - don't lock their bikes up in public racks
>
> - don't store their bikes inside
>
> - are conscious of their appearance and go to lengths to keep their
> bikes clean and unscratched
>
> - ride on Sunday on roads that don't go anywhere
>
> - etc.
>
> I have spent most of my adult life using my bike as regular
> transportation. I see vanishingly few CFRP bikes in the course of my
> riding around town, though I see lots and lots of other bikes.
A decade ago, you could have said all of this about aluminum*. The
rarity of CFRP bikes is at least as much a function of their cost as it
is their suitability for utilitarian use (about which I make no
submission), and since their benefits are primarily in the realm of
weight and the creation of complex (for aerodynamics) shapes, of course
the performance market was the early adopter.
Nowadays, a lot of bikes around town, even some very utilitarian daily
rides, are made of aluminum. You can buy aluminum bikes at department
stores for not much money, and even as urban-utility-oriented an outfit
as NYCBikes sells aluminum as a default frame material.
Wait a decade, and some rather cheap bikes will have CFRP frames.
*A crueler man than I might point out that most bicycles on this
continent are owned by people of average weight, with more money than
time to ride, who don't lock their bikes up in public racks, and who
ride on Sunday to no utilitarian purpose. I'm also sure you actually
meant "do store their bikes inside," but the image of an early 5200 OCLV
left out in the rain, unloved, possibly with a wicker basket on the
front, is too charming to let go of.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
|
| | |
Date: 10 Sep 2007 03:37:30
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
Chalo: I'm not going to go into everything in your reply point-by-point,
because, for the most part, I agree!!!
Carbon fiber isn't the ideal material for all kinds of bikes. I never
suggested it was. Why spend a fortune for a bike that's going to get
seriously dinged up in normal use? You wouldn't subject a super-light bike
of *any* material to that kind of use. That's not what they're made for, at
least not yet. The market for carbon fiber bikes is very specifically at the
high-performance end of the market, and has yet to invade the utility bike
market. For it to do so, they would, indeed, have to be made quite
differently than they are now. Just as utility bikes of any other material
are made differently from super-light performance-oriented models of the
same material.
HOWEVER---
> The
> times I see lots of carbon bikes are when I get out relatively early
> on weekend mornings and happen to ride on relatively untrafficked
> roads on the perimeter of the city. At those times I see clumps of
> people in stretchy clown suits riding on plastic bikes.
Characterizations of recreational riders, whether they be racers training,
wannabes or weekend warriors, as "people in stretchy clown suits riding on
plastic bikes" has nothing to do with the discussion at hand, and comes
across as belittling, at best. We see a fair amount of that type of abuse
here, and fine, I can take it. But what would happen if people were to make
characterizations of the type of person who buys a cheapie *Mart bike
(always, it seems ridden with flat tires) to get to their job, because they
can't afford a car nor a decent bike... that somehow that group is less
worthy than some category of "real" cyclist (according to whomever's
definition)?
You shouldn't see that here, nor would you. And if someone did, I should
hope that a great many would come to the defense of those who are in such a
position that their only use for a bike is basic transportation, and they
could really care less about the bike's nobility, they'd rather be driving a
car.
The cycling world should be all-encompassing, not exclusionary. In my humble
opinion. And you shouldn't seek to gain favor for an argument by making fun
of any particular user group. Again, in my humble opinion.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Chalo" <chalo.colina@gmail.com > wrote in message
news:1189393836.784431.304160@r34g2000hsd.googlegroups.com...
> Mike Jacoubowsky wrote:
>>
>> Tim McNamara wrote:
>> >
>> > Unfortunately your carbon frame is not readily inspectable for damage.
>> > I hope that is in in fact undamaged.
>>
>> The impact was in 2000; the frame remains in continuous use since then.
>> The
>> fork was replaced, due to a damaged steer column. It would have been
>> replace
>> anyway, since it would have failed the "common sense" test (being that
>> nothing could have been designed to withstand that sort of impact, and
>> thus
>> it cannot be trusted). The frame might have failed the "common sense"
>> test
>> as well, except that I have yet to see, among the many (and I do mean
>> many)
>> thousands of carbon fiber frames that I have sold, a catastrophic failure
>> that happened after an initial incident, and without warning. Please do
>> not
>> take this to mean a frame is safe after a crash. Rather, for my sample
>> size,
>> I see issues with forks, but not frames (dealing strictly with those that
>> I
>> have sold, which is admittedly a base of only one manufacturer).
>
> In my observation, the group of people who ride CFRP bikes is very
> self-selecting. They are, by and large, folks who:
>
> - weigh close to the population median, or less
>
> - have more money to spend than time to ride
>
> - don't lock their bikes up in public racks
>
> - don't store their bikes inside
>
> - are conscious of their appearance and go to lengths to keep their
> bikes clean and unscratched
>
> - ride on Sunday on roads that don't go anywhere
>
> - etc.
>
> I have spent most of my adult life using my bike as regular
> transportation. I see vanishingly few CFRP bikes in the course of my
> riding around town, though I see lots and lots of other bikes. The
> times I see lots of carbon bikes are when I get out relatively early
> on weekend mornings and happen to ride on relatively untrafficked
> roads on the perimeter of the city. At those times I see clumps of
> people in stretchy clown suits riding on plastic bikes.
>
> At those times, I have never noticed them doing any of the sort of
> things that cause veteran commuter bikes to become dinged up and
> stripped of sections of their decals and paint. I have never seem
> them doing the sorts of things that made my Seattle bike messenger
> friends wrap their bikes' frame tubes with tape and fit them with top
> tube pads. I don't even see them doing the transportational sorts of
> things that they might do in their cars.
>
> I only see these folks doing what I've seen from groups of guys
> driving Morgans or riding Panhead Harleys together-- wandering around
> for the sake of wandering around, and for the purpose of showing off
> their pampered shiny machines to each other and a bunch of other folks
> who don't care. And I can't help but suspect that just like Morgans
> and Panhead Harleys, CFRP bikes would be unreliable at best if used
> regularly for most practical vehicular purposes. I could be wrong,
> but the almost complete absence of CFRP bikes on the mean streets has
> got to demonstrate _something_. I think that part of what it
> demonstrates is a short half-life in the real world.
>
> Chalo
>
|
| | | |
Date: 15 Sep 2007 16:03:52
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me > wrote:
> ALARMISTS
Like the folks who insist we're in the fight of our lives against a
bunch of retarded jihadis?
|
| | | | |
Date: 15 Sep 2007 12:15:36
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
r15757@aol.com wrote:
> On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>
>> ALARMISTS
>
> Like the folks who insist we're in the fight of our lives against a
> bunch of retarded jihadis?
Yeah, you're right. Let's just relax.
|
| | | |
Date: 11 Sep 2007 23:20:40
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Mon, 10 Sep 2007 09:59:36 -0000, Chalo wrote:
> It's a serious problem for cyclists that such a wide segment of the
> non-cycling public regards bikes as toys. That perception costs some
> cyclists' lives, and robs many others of the pleasure of sharing the
> road in peace. Folks who take up cycling the way one might take up
> paintball are a major impediment to growing the credibility of cycling
> as a mode of transportation.
People who resent other people getting out and having fun riding
unless they pay their dues (presumably by plodding along on some
fat-tyred boat anchor to work or the shops at least 90% of the time)
are a major impediment to the credibility of the human race.
Most of the people I ride with also commute or shop by bike, at
least some of the time.
|
| | | | |
Date: 15 Sep 2007 16:17:11
From: andresmuro@aol.com
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 15, 4:39 pm, r15...@aol.com wrote:
> On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> > r15...@aol.com wrote:
> > > On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> > >> ALARMISTS
>
> > > Like the folks who insist we're in the fight of our lives against a
> > > bunch of retarded jihadis?
>
> > Yeah, you're right. Let's just relax.
>
> So those are our two choices? 'Just relax' or endless war for our very
> survival. Check.
>
> Seriously, the current path is creating more retarded jihadis than it
> does kill or capture them. You can't kill your way out of this mess.
Actually most Americans are pretty relaxed about the whole thing. They
drink beer, go riding, get the latest on Paris Hilton or Britney
Spears, etc. When I go to work, go riding or walk down the streets, I
don't see many people walking tense or worried about whatever the hell
is happening in Iraq, or wherever the hell young soldier kids and
tons of civilians are getting killed. The only ones that are not
relaxed are the poor kids that are getting killed and seriously
injured over there,their families and the civilian population over
there.
Andres
|
| | | | | |
Date: 15 Sep 2007 18:33:56
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
andresmuro@aol.com wrote:
> On Sep 15, 4:39 pm, r15...@aol.com wrote:
>> On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me> wrote:
>>
>>> r15...@aol.com wrote:
>>>> On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>>
>>>>> ALARMISTS
>>
>>>> Like the folks who insist we're in the fight of our lives against a
>>>> bunch of retarded jihadis?
>>
>>> Yeah, you're right. Let's just relax.
>>
>> So those are our two choices? 'Just relax' or endless war for our
>> very survival. Check.
>>
>> Seriously, the current path is creating more retarded jihadis than it
>> does kill or capture them. You can't kill your way out of this mess.
>
> Actually most Americans are pretty relaxed about the whole thing. They
> drink beer, go riding, get the latest on Paris Hilton or Britney
> Spears, etc. When I go to work, go riding or walk down the streets, I
> don't see many people walking tense or worried about whatever the hell
> is happening in Iraq, or wherever the hell young soldier kids and
> tons of civilians are getting killed. The only ones that are not
> relaxed are the poor kids that are getting killed and seriously
> injured over there,their families and the civilian population over
> there.
And yet military families remain supportive of the war effort and the
administration. Go figger.
|
| | | | |
Date: 15 Sep 2007 22:39:54
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me > wrote:
> r15...@aol.com wrote:
> > On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> >> ALARMISTS
>
> > Like the folks who insist we're in the fight of our lives against a
> > bunch of retarded jihadis?
>
> Yeah, you're right. Let's just relax.
So those are our two choices? 'Just relax' or endless war for our very
survival. Check.
Seriously, the current path is creating more retarded jihadis than it
does kill or capture them. You can't kill your way out of this mess.
|
| | | | | |
Date: 15 Sep 2007 15:55:04
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
r15757@aol.com wrote:
> On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me> wrote:
>> r15...@aol.com wrote:
>>> On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>>
>>>> ALARMISTS
>>
>>> Like the folks who insist we're in the fight of our lives against a
>>> bunch of retarded jihadis?
>>
>> Yeah, you're right. Let's just relax.
>
> So those are our two choices? 'Just relax' or endless war for our very
> survival. Check.
>
> Seriously, the current path is creating more retarded jihadis than it
> does kill or capture them. You can't kill your way out of this mess.
You're the one who changed the subject (conveniently snipping it, too) from
the FOOD POLICE to terrorism.
DO-GOODERS, ALARMISTS AND CONTROL FREAKS -- Aaaaaaaaaccccccckkkkkkkkk!
Bill "like, whatever, anonymous dude" S.
|
| | | | |
Date: 12 Sep 2007 20:18:45
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Tue, 11 Sep 2007 21:04:59 -0700, Mike Jacoubowsky wrote:
> It's not a guess.. A huge percentage of those lycra-clad racer types ride
> their bikes to the start of their group ride, and then ride back home
> afterward (I'm talking about regularly-scheduled rides, not centuries). In
> other words, for their chosen form of recreation, they're not using their
> cars to get there.
One of the reasons I don't race is that I'd have to drive about 70km (round
trip) to do it with the guys who keep pestering me to come along. If I have
to drive just to get to a ride, I rarely bother.
How do those downhill MTBers get to their rides, and back up those hills?
|
| | | | | |
Date: 13 Sep 2007 08:44:07
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 11:25:56 -0700, Jay Beattie wrote:
> In Oregon and Washington you get a lot of races out of the
> metropolitan areas and can drive a long way to ride a short race. My
> brother is an avid masters MTB racer and state champ who lives in
> Washington. He may drive hours to do a five minute down-hill race.
> Usually there is a cross-country race, too, but he has driven a long
> way to do only a brief down-hill event -- usually as a required event
> in some points series.
That's ridiculous. When your recreation turns into that sort of expensive
grind, it's time to take a good look at yourself IMHO.
|
| | | | | | |
Date: 13 Sep 2007 21:02:19
From: Mike Jacoubowsky
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
>> In Oregon and Washington you get a lot of races out of the
>> metropolitan areas and can drive a long way to ride a short race. My
>> brother is an avid masters MTB racer and state champ who lives in
>> Washington. He may drive hours to do a five minute down-hill race.
>> Usually there is a cross-country race, too, but he has driven a long
>> way to do only a brief down-hill event -- usually as a required event
>> in some points series.
>
> That's ridiculous. When your recreation turns into that sort of expensive
> grind, it's time to take a good look at yourself IMHO.
In my prior life, about 5.5 years of being an extremely competitive jr and
decent cat-2 (which meant riding cat-1/pro races), I often wondered who
those other 80 guys were. There were maybe 20 of us who consistently figured
in the finish; the rest of the guys were some sort of filler (pack fodder).
You saw them at the start, but rarely did any beyond the 20 or so "regulars"
figure in the finish stats.
Obviously, there's some motivation for those guys to be there. It's not
something I could relate to, and possibly not you either. I never could
quite figure out why they were there back in the day, but I feel a bit
differently about it now. I can see the point to being in a race that you
have no chance of finishing in the top-10, because maybe it's a way of
testing yourself to see where you are. Maybe you came in 10 minutes behind
the winners this race, but you were 15 last time. That's progress, and
progress can keep a dream fueled.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | | | | |
Date: 14 Sep 2007 13:45:38
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 15:11:29 -0700, Jay Beattie wrote:
> win a water bottle or crate of potato chips. Really, I once won a
> dozen bags of Kettle Chips (or however many come in a shipping box).
> That was the only time cycling put food on the table.-- Jay Beattie.
LOL. That reminds me of the strange fact that school sports fundraising
is usually accomplished by trying to sell cheap edible garbage, such as
chips and chocolate. Even food mfrs get in on the act, offering to give
schools money if their children collect the labels from enough bottles or
tins of their fattening junk.
|
| | | | | | |
Date: 12 Sep 2007 18:31:32
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Michael Warner wrote:
> On Wed, 12 Sep 2007 11:25:56 -0700, Jay Beattie wrote:
>
>> In Oregon and Washington you get a lot of races out of the
>> metropolitan areas and can drive a long way to ride a short race. My
>> brother is an avid masters MTB racer and state champ who lives in
>> Washington. He may drive hours to do a five minute down-hill race.
>> Usually there is a cross-country race, too, but he has driven a long
>> way to do only a brief down-hill event -- usually as a required event
>> in some points series.
>
> That's ridiculous. When your recreation turns into that sort of
> expensive grind, it's time to take a good look at yourself IMHO.
None of your (not at all humble) business. HTH
|
| | | | | | | |
Date: 16 Sep 2007 23:03:18
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 16, 11:30 pm, Chalo <chalo.col...@gmail.com > wrote:
> Jay Hill wrote:
>
> > Elite ruling members of
> > societies sending the middle and poor classes off to be cannon fodder
> > while they, the elites, avoid danger, then strut and wrap themselves in
> > their flags, has been going on for thousands of years.
>
> Nobody is poor enough to excuse being murderously stupid. The
> ingrained cultural habit of supporting the soldier but not the war is
> the equivalent of supporting the rapist but not a particular rape.
> We'll not be free of corrupt wars until we lose that habit.
>
> Chalo
These are still kids, for the most part. You can't blame kids for
doing what they are ordered to do. I can't, anyway.
Robert
|
| | | | | | | |
Date: 16 Sep 2007 22:24:50
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me > wrote:
> Bill "Hillary Lied; People Died" S.
True ... she was complicit along with so many others.
R.
|
| | | | | | | | |
Date: 16 Sep 2007 23:58:18
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
r15757@aol.com wrote:
> On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>
>> Bill "Hillary Lied; People Died" S.
>
> True ... she was complicit along with so many others.
Hillary didn't merely vote for the war; she went /beyond/ administration
claims in making the CASE for war. (For instance, she claimed a direct
connection between Saddam Hussein and A.Q.: " He has also given aid,
comfort, and sanctuary to terrorists, including Al Qaida members.")
Of course, she was probably right, but...
BS
|
| | | | | | | |
Date: 13 Sep 2007 15:25:18
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 22:31:38 -0700, Bill Sornson wrote:
> That why you deleted your comment (and its context) that prompted mine?
I quote the minimum that seems necessary. There's no conspiracy at work.
> I repeat: IT'S NONE OF YOUR BUSINESS.
I heard you the first time. Shouting doesn't make any difference (except to
make you sound like a bit of a moron).
> Bill "stop do-gooder control, dammit" S.
It seems as though it's undesirable /opinions/ you want to stop, not
control. Otherwise you'd wait until someone proposed that no-one outside
easy riding distance of the start of an amateur race be allowed to compete
in it.
|
| | | | | | | | |
Date: 13 Sep 2007 08:29:57
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Michael Warner wrote:
> On Wed, 12 Sep 2007 22:31:38 -0700, Bill Sornson wrote:
>> Bill "stop do-gooder control, dammit" S.
> It seems as though it's undesirable /opinions/ you want to stop, not
> control.
Bull. Do-gooders with /opinions/ are proposing /legislation/ left
and...well, more left every day.
> Otherwise you'd wait until someone proposed that no-one
> outside easy riding distance of the start of an amateur race be
> allowed to compete in it.
Well, when Jay merely said this: "My brother is an avid masters MTB racer
and state champ who lives in
Washington. He may drive hours to do a five minute down-hill race.", you
replied with this:
"That's ridiculous. When your recreation turns into that sort of expensive
grind, it's time to take a good look at yourself IMHO."
Sure /sounds/ like you think something should be done about it. Why don't
you make a RULE?
"Who the hell are you?"
-- Bart Simpson
|
| | | | | | | | | |
Date: 13 Sep 2007 15:33:00
From: Jay Hill
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
> Well, when Jay merely said this: "My brother is an avid masters MTB racer
> and state champ who lives in
Uh, to quote John Fogerty, "it ain't me" that you're quoting there.
Here's the rest of the song. It's about chicken hawk draft dodgers that
use their powerful parents' connections to dodge drafts, then send off
poor and middle class soldiers to get blown up or be killed, meanwhile
strutting and calling people who disagree with their policies cowards
and unpatriotic:
Some folks are born
made to wave the flag,
Ooh, they're red, white and blue.
And when the band plays "Hail to the chief,"
they point the cannon right at you.
It ain't me,
it ain't me.
I ain't no senator's son.
It ain't me,
it ain't me.
I ain't no fortunate one.
Some folks are born
silver spoon in hand,
Lord don't they help themselves.
But when the tax man comes to the door,
Lord, the house looks like a rummage sale.
It ain't me,
it ain't me.
I ain't no millionaire's son.
It ain't me,
it ain't me.
I ain't no fortunate one.
Some folks inherit
star spangled eyes,
Ooh, they send you down to war.
And when you ask them,
"How much should we give?"
They only answer "More! More! More!"
It ain't me,
it ain't me.
I ain't no military son.
It ain't me,
it ain't me.
I ain't no fortunate one.
It ain't me,
it ain't me.
I ain't no Fortunate Son.
|
| | | | | | | | | | |
Date: 13 Sep 2007 15:08:49
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Hill wrote:
> Bill Sornson wrote:
>
>> Well, when Jay merely said this: "My brother is an avid masters MTB
>> racer and state champ who lives in
>
> Uh, to quote John Fogerty, "it ain't me" that you're quoting there.
Jay Beattie. HTH
(Judging from what followed, I can see that you think everything's about
YOU. LOL )
|
| | | | | |
Date: 12 Sep 2007 15:56:14
From: Mike Jacoubowsky
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
>> It's not a guess.. A huge percentage of those lycra-clad racer types ride
>> their bikes to the start of their group ride, and then ride back home
>> afterward (I'm talking about regularly-scheduled rides, not centuries).
>> In
>> other words, for their chosen form of recreation, they're not using their
>> cars to get there.
>
> One of the reasons I don't race is that I'd have to drive about 70km
> (round
> trip) to do it with the guys who keep pestering me to come along. If I
> have
> to drive just to get to a ride, I rarely bother.
The biggest reason I rarely mountain bike is that I have very little spare
time to ride, and I'd have to waste half an hour each way getting to the
places to ride. That's time I could be out on my bike, and time I don't have
to be in my car spewing out whatever it spews.
> How do those downhill MTBers get to their rides, and back up those hills?
There's a reason they like ski runs that operate their lifts in the summer
for mountain bikes... personally, I like climbing as much as descending,
probably more so. Definitely more so, now that I think about it. Sometimes I
have to convince myself of that when I'm riding though!
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Michael Warner" <mvw@westnet.com.au > wrote in message
news:1ocvho0kogxsg.j9pnii3o2dgp$.dlg@40tude.net...
> On Tue, 11 Sep 2007 21:04:59 -0700, Mike Jacoubowsky wrote:
>
>> It's not a guess.. A huge percentage of those lycra-clad racer types ride
>> their bikes to the start of their group ride, and then ride back home
>> afterward (I'm talking about regularly-scheduled rides, not centuries).
>> In
>> other words, for their chosen form of recreation, they're not using their
>> cars to get there.
>
> One of the reasons I don't race is that I'd have to drive about 70km
> (round
> trip) to do it with the guys who keep pestering me to come along. If I
> have
> to drive just to get to a ride, I rarely bother.
>
> How do those downhill MTBers get to their rides, and back up those hills?
|
| | | | | | |
Date: 12 Sep 2007 18:46:50
From: Steve Gravrock
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On 2007-09-12, Mike Jacoubowsky <mikej1@ix.netcom.com > wrote:
>> How do those downhill MTBers get to their rides, and back up those hills?
>
> There's a reason they like ski runs that operate their lifts in the summer
> for mountain bikes... personally, I like climbing as much as descending,
> probably more so. Definitely more so, now that I think about it. Sometimes I
> have to convince myself of that when I'm riding though!
I'm not normally a downhiller but I did do a little bit of ski lift
biking a couple of weeks back. The trail I rode dropped something like
3300 feet in 8 or 9 miles. This was what I'd describe as a
hardtail-friendly donwhill trail. It didn't require rear suspension or a
long-travel fork but it was still challenging enough that I took nearly
an hour to descend it and had sore arms and legs even before I crashed
near the bottom. I don't think it would have been much fun at all if I'd
started out tired from the climb up.
The more serious downhill stuff can be just about unclimbable. The bikes
that are designed for it aren't exactly climbers either, although I did
once see a guy get up Ape Canyon on a DH bike. He actually outpaced me.
He also said that he threw up a number of times.
I know what you mean about having to convince yourself that you like
climbing. My favorite local off-road loop is a bit of a lung-buster
(for me anyway). I positively hate the climb while I'm doing it, but I
love it the minute I get to the top.
|
| | | | |
Date: 12 Sep 2007 20:12:29
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 01:02:35 -0000, Chalo wrote:
> How do you feel about people who drive "recreationally" in sports cars
> on public streets, rather than keeping their sport on the track and
> closed courses?
By "recreationally" do you mean "dangerously" or "without
the necessity of getting from A to B"? If the latter, then it's fine
with me. Of course some roadies ride dangerously, particular in groups,
but then so do many people travelling to B. I'd bet that at least half
of the non-roadies I see at night have no lights, for example.
> I don't dispute the right of lycras to use the streets as their gym
> and playground, I just find it bothersome that most of them will do
> that without returning the favor to their communities by using their
> bikes as transportation on those same streets.
I don't see how commuting or shopping by bike does anyone except
myself a favour, sorry, except in the most nebulous sense. It certainly
isn't a connection which is strong enough to justify criticizing people
for not being the kind of cyclist you prefer. If someone starts riding in
their spare time but still commutes by car, IMHO that's still a very
worthwhile improvement in their lifestyle.
|
| | | |
Date: 10 Sep 2007 20:02:55
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message
news:_Z2Fi.33239$RX.13365@newssvr11.news.prodigy.net...
> Chalo: I'm not going to go into everything in your reply point-by-point,
> because, for the most part, I agree!!!
>
> Carbon fiber isn't the ideal material for all kinds of bikes. I never
> suggested it was. Why spend a fortune for a bike that's going to get
> seriously dinged up in normal use? You wouldn't subject a super-light bike
> of *any* material to that kind of use. That's not what they're made for,
> at least not yet. The market for carbon fiber bikes is very specifically
> at the high-performance end of the market, and has yet to invade the
> utility bike market. For it to do so, they would, indeed, have to be made
> quite differently than they are now. Just as utility bikes of any other
> material are made differently from super-light performance-oriented models
> of the same material.
This is in fact the whole issue that's been raised in bike CF components.
If I can succinctly encapsulate, it is the higher risk of non-visible damage
with CF components compared to metal components, the types of damage caused
by handling, and wear and tear.
There is a lot of data supporting this fact in the aircraft industry, why
are you looking at the bike industry differently?
No one's arguing that CF cannot take higher duty loads than metals.
|
| |
Date: 08 Sep 2007 06:06:55
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>
> That someone you know has a bike that's 50 years old in daily service is
> likely a testament more to an extraordinarily overbuilt design, rather than
> the material used. If one were to build a fork of the same weight out of
> carbon fiber, it may very well achieve commendable life on the roads
> surrounding Baghdad! But why? Does it make sense to build something that
> will last from one generation to the next, or does it make more sense to
> optimize for the current user, and his/her typical lifespan of use
> (determined not by failure but more often by a desire to upgrade)?
As a dealer of new bikes, you might not fully appreciate the rich life
that good bikes tend to have after they pass from their original
owners to others. Stupid-light and stupid-cheap stuff tends to
migrate quickly to the trash, but one measure of the merit of a good
bike is how many hands it can pass through, how many folks it can
serve and entertain, on its journey between showroom and recycler.
Bikes need not be heavy to have several successive careers. But they
need to be durable, rebuildable, and lovable. Major manufacturers'
sporting bikes these days are increasingly unlikely to have any of
these virtues. How many of today's racy bikes will retain the lasting
charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
or a Paramount? Are the plastic wonderbikes of today going to outlast
their paint jobs? Will they be safe to ride if they do?
Chalo
|
| | |
Date: 08 Sep 2007 16:35:10
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> That someone you know has a bike that's 50 years old in daily service is
>> likely a testament more to an extraordinarily overbuilt design, rather
>> than
>> the material used. If one were to build a fork of the same weight out of
>> carbon fiber, it may very well achieve commendable life on the roads
>> surrounding Baghdad! But why? Does it make sense to build something that
>> will last from one generation to the next, or does it make more sense to
>> optimize for the current user, and his/her typical lifespan of use
>> (determined not by failure but more often by a desire to upgrade)?
>
> As a dealer of new bikes, you might not fully appreciate the rich life
> that good bikes tend to have after they pass from their original
> owners to others.
> Stupid-light and stupid-cheap stuff tends to
> migrate quickly to the trash, but one measure of the merit of a good
> bike is how many hands it can pass through, how many folks it can
> serve and entertain, on its journey between showroom and recycler.
"Heirloom-quality bikes" we call them.
That's one measurement of a *type* of bike, not necessarily a good bike (or
a bad bike, for that matter). There are still plenty of utility-style bikes
one can own, that will be as durable as what you long for, and even lighter.
But they are no longer state-of-the-art. Is that the issue here? That
state-of-the-art represents something far different now from back in the
day?
> Bikes need not be heavy to have several successive careers. But they
> need to be durable, rebuildable, and lovable. Major manufacturers'
> sporting bikes these days are increasingly unlikely to have any of
> these virtues. How many of today's racy bikes will retain the lasting
> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
> or a Paramount? Are the plastic wonderbikes of today going to outlast
> their paint jobs? Will they be safe to ride if they do?
You're building up those old bikes into something they never were. It may be
hard to believe, but I've seen more than one Hetchins fail. I've seen a
large number of PX-10s fail. And yes, even Paramounts fail at times (I sold
them back in the day). The reason you still see PX-10x out there is because,
dare I say it, most of them never got the sort of miles that bikes commonly
get today. This is especially obvious when you see one with the stock Pivo
stem. Those are mileage indicators; if you rode much, they would fail.
There are probably three main types of customer today. First is the guy or
girl (mostly guys) who just want to look the part. Buy all the fancy,
superlight stuff and have an expensive bike that they feel really good
about, but don't ride much. Then you've got the folk in the middle who
actually do enjoy riding, get out on weekends when they can, but it's not
something that defines who they are. These folk probably put in 1000-3000
miles/year. And finally you have those for whom cycling is their life, and
ride 6-15,000 miles/year. That last category is much bigger today than it
was in the era of the Hetchins and PX-10. Miles are getting put onto bikes &
equipment that only a very tiny number of people did back in the day.
But you suspect there's more to it than that, and there is. People don't buy
much of anything expecting it to last forever, and it's normal for people to
expect that many expensive items (TVs, for example) aren't to be repaired
but simply tossed out and replaced if something goes wrong. That sort of
thinking determines what's made available to people. And as long as people
are willing to accept it, the product engineers are going to work within
those parameters when they design something. If they have the choice of
designing something that will weigh 1/2 pound more but be repairable, vs
lighter and disposable if it breaks, they're going to go for lighter.
> Chalo
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | |
Date: 08 Sep 2007 23:53:43
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article
<2bAEi.25978$eY.14517@newssvr13.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> But you suspect there's more to it than that, and there is. People don't buy
> much of anything expecting it to last forever, and it's normal for people to
> expect that many expensive items (TVs, for example) aren't to be repaired
> but simply tossed out and replaced if something goes wrong. That sort of
> thinking determines what's made available to people. And as long as people
> are willing to accept it, the product engineers are going to work within
> those parameters when they design something. If they have the choice of
> designing something that will weigh 1/2 pound more but be repairable, vs
> lighter and disposable if it breaks, they're going to go for lighter.
I works both ways. It is easier and cheaper to built a
monolithic unrepairable TV with a built in failure rate
than to build a TV that is good, and good twenty years
later. I have one of the last good Sony televisions.
Had a problem and found a guy to repair it. Two
components on a solder board. He said Sony televisions
today have bad color, bad picture, and will not stay in
adjustment. My tv has a magnificent picture that has
not drifted in over a decade.
If the manufacturers only build monolithic TV's people
will only buy monolithic TV's.
--
Michael Press
|
| | |
Date: 08 Sep 2007 07:26:58
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Chalo wrote:
> Mike Jacoubowsky wrote:
>> That someone you know has a bike that's 50 years old in daily service is
>> likely a testament more to an extraordinarily overbuilt design, rather than
>> the material used. If one were to build a fork of the same weight out of
>> carbon fiber, it may very well achieve commendable life on the roads
>> surrounding Baghdad! But why? Does it make sense to build something that
>> will last from one generation to the next, or does it make more sense to
>> optimize for the current user, and his/her typical lifespan of use
>> (determined not by failure but more often by a desire to upgrade)?
>
> As a dealer of new bikes, you might not fully appreciate the rich life
> that good bikes tend to have after they pass from their original
> owners to others. Stupid-light and stupid-cheap stuff tends to
> migrate quickly to the trash, but one measure of the merit of a good
> bike is how many hands it can pass through, how many folks it can
> serve and entertain, on its journey between showroom and recycler.
>
> Bikes need not be heavy to have several successive careers. But they
> need to be durable, rebuildable, and lovable. Major manufacturers'
> sporting bikes these days are increasingly unlikely to have any of
> these virtues. How many of today's racy bikes will retain the lasting
> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
> or a Paramount? Are the plastic wonderbikes of today going to outlast
> their paint jobs? Will they be safe to ride if they do?
>
> Chalo
>
more than 30 years ago, i went to a materials lecture held by a supplier
to sikorski. part of the presentation was on rotor blades. according
to our guy, they were "quite happy" with composites in that application.
it seems the benefit was not only much extended service life, but also
something unanticipated - that of being more likely to survive bullet
strike in combat. that's not to say every blade was surviving every
strike, but apparently, older style aluminum blades had a dismal
survival rate. composite blades otoh, if they didn't fail immediately,
were much more likely to get you out of the hot zone, or better yet, get
you home.
now, bikes are not chopper rotors, and composites are not the answer to
everything, but well made, with quality constituents and due care,
composites can offer great solutions. and if 30 years of use is not a
period of time over which we can assess reliability, we may as well just
quit this whole aerospace business - man was never meant to fly - or cycle.
|
| | | |
Date: 08 Sep 2007 21:45:17
From: Jambo
Subject: Re: "brittle" vs. non-ductile - most stupid comments yet by jb
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:J5ydnY_RCbSuLH_bnZ2dnUVZ_hCdnZ2d@speakeasy.net...
>
> more than 30 years ago, i went to a materials lecture held by a supplier
> to sikorski. part of the presentation was on rotor blades. according to
> our guy, they were "quite happy" with composites in that application. it
> seems the benefit was not only much extended service life, but also
> something unanticipated - that of being more likely to survive bullet
> strike in combat. that's not to say every blade was surviving every
> strike, but apparently, older style aluminum blades had a dismal survival
> rate. composite blades otoh, if they didn't fail immediately, were much
> more likely to get you out of the hot zone, or better yet, get you home.
It's SikorskY, dumbass. Doubtful you were even there - did you read that
off Popular Science?
> now, bikes are not chopper rotors,
So why the fuck do you bring this up? Trying to beef up your resume by
dropping names like "Sikorski" (which is really Sikorsky, dumbass!).
> and composites are not the answer to everything,
So why the fuck do you bring this up?
> but well made, with quality constituents and due care, composites can
> offer great solutions.
Duh, thanks professor.
> and if 30 years of use is not a period of time over which we can assess
> reliability, we may as well just quit this whole aerospace business - man
> was never meant to fly - or cycle.
What a load of turd! Didn't you just say
1. "now, bikes are not chopper rotors"
2. "and composites are not the answer to everything"
So now you turn around and equate helo rotors to CF forks. After saying
they're not the same. And the issue isn't the aerospace application, it's
the BICYCLE application of CF.
Dumbass!
|
| | | | |
Date: 08 Sep 2007 22:31:37
From: Jambo
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:J5ydnY_RCbSuLH_bnZ2dnUVZ_hCdnZ2d@speakeasy.net...
>
>>
>> more than 30 years ago, i went to a materials lecture held by a supplier
>> to sikorski. part of the presentation was on rotor blades. according to
>> our guy, they were "quite happy" with composites in that application. it
>> seems the benefit was not only much extended service life, but also
>> something unanticipated - that of being more likely to survive bullet
>> strike in combat. that's not to say every blade was surviving every
>> strike, but apparently, older style aluminum blades had a dismal survival
>> rate. composite blades otoh, if they didn't fail immediately, were much
>> more likely to get you out of the hot zone, or better yet, get you home.
By the way, this story is total rubbish.
"More than 30 years ago" means 1977 and earlier. The Vietnam War has just
ended then.
There were no Sikorsky composite helicopter rotors in military applications
before and during the Vietnam War.
Composite helicopter rotors did not come into military use until the 1980s.
SO, where did your "bullet strike in combat" happen, dumbass? You need to
stop making up shit, no one's believing it. Maybe it's time to let go of
your nom de plume, even though you've invested years in bulshitting your way
through this ng.
|
| | | | | |
Date: 09 Sep 2007 07:50:33
From: jim beam
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
Jambo wrote:
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news:J5ydnY_RCbSuLH_bnZ2dnUVZ_hCdnZ2d@speakeasy.net...
>>
>>> more than 30 years ago, i went to a materials lecture held by a supplier
>>> to sikorski. part of the presentation was on rotor blades. according to
>>> our guy, they were "quite happy" with composites in that application. it
>>> seems the benefit was not only much extended service life, but also
>>> something unanticipated - that of being more likely to survive bullet
>>> strike in combat. that's not to say every blade was surviving every
>>> strike, but apparently, older style aluminum blades had a dismal survival
>>> rate. composite blades otoh, if they didn't fail immediately, were much
>>> more likely to get you out of the hot zone, or better yet, get you home.
>
> By the way, this story is total rubbish.
>
> "More than 30 years ago" means 1977 and earlier. The Vietnam War has just
> ended then.
>
> There were no Sikorsky composite helicopter rotors in military applications
> before and during the Vietnam War.
>
> Composite helicopter rotors did not come into military use until the 1980s.
bullshit!!! here's the very first chopper i look for, and guess what -
glass fiber blades, 1962.
http://www.chinook-helicopter.com/standards/areas/blade.html
chinook was a vietnam workhorse.
huey's also had composite blades. and sikorski sea kings.
>
> SO, where did your "bullet strike in combat" happen, dumbass? You need to
> stop making up shit, no one's believing it. Maybe it's time to let go of
> your nom de plume, even though you've invested years in bulshitting your way
> through this ng.
have you figured out what modulus is yet?
|
| | | | | | |
Date: 09 Sep 2007 11:52:40
From: Jambo
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:Y_6dnZelwuShlXnbnZ2dnUVZ_ternZ2d@speakeasy.net...
> Jambo wrote:
>> "More than 30 years ago" means 1977 and earlier. The Vietnam War has
>> just ended then.
>>
>> There were no Sikorsky composite helicopter rotors in military
>> applications before and during the Vietnam War.
>>
>> Composite helicopter rotors did not come into military use until the
>> 1980s.
>
> bullshit!!! here's the very first chopper i look for, and guess what -
> glass fiber blades, 1962.
>
> http://www.chinook-helicopter.com/standards/areas/blade.html
>
> chinook was a vietnam workhorse.
HAHAHAHA. CH-47D was introduced in 1982, DUMBASS! the A, B, and C models
had METAL ROTORS in VIETNAM!
You're a fucking liar!
> huey's also had composite blades.
HUEYS are BELL HELICOPTERS, not Sikorsky! They had metal rotors in Vietnam!
> and sikorski sea kings.
There is NO SUCH thing. There are SIKORSKY Sea Kings, which had METAL
rotors in the 1960s and 70s, composite rotors in the 80s!
Fucking liar!
>> SO, where did your "bullet strike in combat" happen, dumbass? You need
>> to stop making up shit, no one's believing it. Maybe it's time to let go
>> of your nom de plume, even though you've invested years in bulshitting
>> your way through this ng.
>
> have you figured out what modulus is yet?
HAHAHAHA! I know SPECIFIC MODULUS IS NOT THE SAME AS YOUNG'S MODULUS,
dumbass!
You're a liar AND a MORON, a classic combination!
|
| | | | | | | |
Date: 09 Sep 2007 12:27:40
From: Ben C
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
On 2007-09-09, Jambo <-@-.- > wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:Y_6dnZelwuShlXnbnZ2dnUVZ_ternZ2d@speakeasy.net...
>> Jambo wrote:
[...]
>> and sikorski sea kings.
>
> There is NO SUCH thing. There are SIKORSKY Sea Kings, which had METAL
> rotors in the 1960s and 70s, composite rotors in the 80s!
It's actually spelt СикорÑкий.
Thank you for giving me the opportunity to see if posting in UTF-8
works or if I still have it set up wrong.
In case I have, you can read about Igor Sikorskij and see how his name
is spelt in Cyrillic here:
http://www.hrono.ru/biograf/sikorski.html
or here:
http://ru.wikipedia.org/wiki/%D0%A1%D0%B8%D0%BA%D0%BE%D1%80%D1%81%D0%BA%D0%B8%D0%B9,_%D0%98%D0%B3%D0%BE%D1%80%D1%8C_%D0%98%D0%B2%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87
Sikorski and Sikorsky are both perfectly good transliterations.
|
| | | | | | | | |
Date: 09 Sep 2007 21:19:11
From: A Muzi
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
>> "jim beam" <spamvortex@bad.example.net> wrote:
> [...]
>>> and sikorski sea kings.
> Jambo <-@-.-> wrote:
>> There is NO SUCH thing. There are SIKORSKY Sea Kings, which had METAL
>> rotors in the 1960s and 70s, composite rotors in the 80s!
>
Ben C wrote:
> It's actually spelt СикорÑкий.
> Thank you for giving me the opportunity to see if posting in UTF-8
> works or if I still have it set up wrong.
> In case I have, you can read about Igor Sikorskij and see how his name
> is spelt in Cyrillic here:
> http://www.hrono.ru/biograf/sikorski.html
> or here:
> http://ru.wikipedia.org/wiki/%D0%A1%D0%B8%D0%BA%D0%BE%D1%80%D1%81%D0%BA%D0%B8%D0%B9,_%D0%98%D0%B3%D0%BE%D1%80%D1%8C_%D0%98%D0%B2%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87
> Sikorski and Sikorsky are both perfectly good transliterations.
For a Cyrillic based proper name, sure.
Not for the registered corporation.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | |
Date: 09 Sep 2007 16:45:17
From: Michael Press
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
In article
<slrnfe8b7u.cem.spamspam@bowser.marioworld >,
Ben C <spamspam@spam.eggs > wrote:
> On 2007-09-09, Jambo <-@-.-> wrote:
> > "jim beam" <spamvortex@bad.example.net> wrote in message
> > news:Y_6dnZelwuShlXnbnZ2dnUVZ_ternZ2d@speakeasy.net...
> >> Jambo wrote:
> [...]
> >> and sikorski sea kings.
> >
> > There is NO SUCH thing. There are SIKORSKY Sea Kings, which had METAL
> > rotors in the 1960s and 70s, composite rotors in the 80s!
>
> It's actually spelt СикорÑкий.
>
> Thank you for giving me the opportunity to see if posting in UTF-8
> works or if I still have it set up wrong.
>
> In case I have, you can read about Igor Sikorskij and see how his name
> is spelt in Cyrillic here:
>
> http://www.hrono.ru/biograf/sikorski.html
>
> or here:
>
> http://ru.wikipedia.org/wiki/%D0%A1%D0%B8%D0%BA%D0%BE%D1%80%D1%81%D0%BA%D0%B8%D0%B9,_%D0%98%D0%B3%D0%BE%D1%80%D1%8C_%D0%98%D0%B2%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87
>
> Sikorski and Sikorsky are both perfectly good transliterations.
The corporation does business under the name Sikorsky.
"Sikorsky" is spelled ess eye kay oh are ess kay why.
That is the spelling. Other spellings are incorrect.
--
Michael Press
|
| | | | | | | | |
Date: 09 Sep 2007 16:16:07
From: Jambo
Subject: Re: "brittle" vs. non-ductile - jb caught telling tall stories
|
"Ben C" <spamspam@spam.eggs > wrote in message
news:slrnfe8b7u.cem.spamspam@bowser.marioworld...
> In case I have, you can read about Igor Sikorskij and see how his name
> is spelt in Cyrillic here:
>
> http://www.hrono.ru/biograf/sikorski.html
>
> or here:
>
> http://ru.wikipedia.org/wiki/%D0%A1%D0%B8%D0%BA%D0%BE%D1%80%D1%81%D0%BA%D0%B8%D0%B9,_%D0%98%D0%B3%D0%BE%D1%80%D1%8C_%D0%98%D0%B2%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87
>
> Sikorski and Sikorsky are both perfectly good transliterations.
Good history lesson, but the company name is spelt Sikorsky. Even when they
were bought by UTC, the company kept its name, Sikorsky with a Y at the end.
Someone with minimal knowledge of the industry will know this.
And to set things straight, proving jb's manufactured resume and lying about
his background:
1973 is when Sikorsky S-70's first successful test flight using an all
composite, bearingless tail rotor. The S-70 became the UH-60 Black Hawk,
which entered service with the US Army in 1978
(http://www.airforce-technology.com/projects/black_hawk/).
In July 1976, Kaman (NOT Sikorsky) designs and begins manufacturing the
K-747 blade, the world's first production all-composite rotor blade for the
Bell AH-1 Cobra helicopter. Although the Cobra served in Vietnam, the
composite rotor did not see any service until after the Vietnam War.
So what was the mythical combat service helicopter with the composite rotors
in jb's tall story of his "materials lecture more than 30 years ago", i.e.
1977 and earlier? Let's even say he was off by a few years in his "story" -
what conflict did US Sikorsky helos with composite rotors see between 1976
and 1978?
The story's been made up, as most of his so-called "experiences", to try to
bolster his credentials as a "former metallurgist".
|
| | | |
Date: 08 Sep 2007 11:35:12
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Chalo wrote:
>> Mike Jacoubowsky wrote:
>>> That someone you know has a bike that's 50 years old in daily service is
>>> likely a testament more to an extraordinarily overbuilt design,
>>> rather than
>>> the material used. If one were to build a fork of the same weight out of
>>> carbon fiber, it may very well achieve commendable life on the roads
>>> surrounding Baghdad! But why? Does it make sense to build something that
>>> will last from one generation to the next, or does it make more sense to
>>> optimize for the current user, and his/her typical lifespan of use
>>> (determined not by failure but more often by a desire to upgrade)?
>>
>> As a dealer of new bikes, you might not fully appreciate the rich life
>> that good bikes tend to have after they pass from their original
>> owners to others. Stupid-light and stupid-cheap stuff tends to
>> migrate quickly to the trash, but one measure of the merit of a good
>> bike is how many hands it can pass through, how many folks it can
>> serve and entertain, on its journey between showroom and recycler.
>>
>> Bikes need not be heavy to have several successive careers. But they
>> need to be durable, rebuildable, and lovable. Major manufacturers'
>> sporting bikes these days are increasingly unlikely to have any of
>> these virtues. How many of today's racy bikes will retain the lasting
>> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
>> or a Paramount? Are the plastic wonderbikes of today going to outlast
>> their paint jobs? Will they be safe to ride if they do?
>>
>> Chalo
>>
>
> more than 30 years ago, i went to a materials lecture held by a supplier
> to sikorski. part of the presentation was on rotor blades. according
> to our guy, they were "quite happy" with composites in that application.
> it seems the benefit was not only much extended service life, but also
> something unanticipated - that of being more likely to survive bullet
> strike in combat. that's not to say every blade was surviving every
> strike, but apparently, older style aluminum blades had a dismal
> survival rate. composite blades otoh, if they didn't fail immediately,
> were much more likely to get you out of the hot zone, or better yet, get
> you home.
http://science.howstuffworks.com/black-hawk1.htm
Each blade consists of a titanium spar, which is a metal strip that runs
from the base of the blade to its tip, and a Nomex honeycomb material.
The blade skin and trailing edge are made of composite materials. The
stronger, leading edge of the blade is made of titanium and nickel and
is trimmed with an anti-erosion strip, which protects the blade from
wear as it skims across the tree tops or flies in abrasive desert air.
Mud and straw is a "composite", too. Nomex is not CF.
|
| | | | |
Date: 08 Sep 2007 08:58:45
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Chalo wrote:
>>> Mike Jacoubowsky wrote:
>>>> That someone you know has a bike that's 50 years old in daily
>>>> service is
>>>> likely a testament more to an extraordinarily overbuilt design,
>>>> rather than
>>>> the material used. If one were to build a fork of the same weight
>>>> out of
>>>> carbon fiber, it may very well achieve commendable life on the roads
>>>> surrounding Baghdad! But why? Does it make sense to build something
>>>> that
>>>> will last from one generation to the next, or does it make more
>>>> sense to
>>>> optimize for the current user, and his/her typical lifespan of use
>>>> (determined not by failure but more often by a desire to upgrade)?
>>>
>>> As a dealer of new bikes, you might not fully appreciate the rich life
>>> that good bikes tend to have after they pass from their original
>>> owners to others. Stupid-light and stupid-cheap stuff tends to
>>> migrate quickly to the trash, but one measure of the merit of a good
>>> bike is how many hands it can pass through, how many folks it can
>>> serve and entertain, on its journey between showroom and recycler.
>>>
>>> Bikes need not be heavy to have several successive careers. But they
>>> need to be durable, rebuildable, and lovable. Major manufacturers'
>>> sporting bikes these days are increasingly unlikely to have any of
>>> these virtues. How many of today's racy bikes will retain the lasting
>>> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
>>> or a Paramount? Are the plastic wonderbikes of today going to outlast
>>> their paint jobs? Will they be safe to ride if they do?
>>>
>>> Chalo
>>>
>>
>> more than 30 years ago, i went to a materials lecture held by a
>> supplier to sikorski. part of the presentation was on rotor blades.
>> according to our guy, they were "quite happy" with composites in that
>> application. it seems the benefit was not only much extended service
>> life, but also something unanticipated - that of being more likely to
>> survive bullet strike in combat. that's not to say every blade was
>> surviving every strike, but apparently, older style aluminum blades
>> had a dismal survival rate. composite blades otoh, if they didn't
>> fail immediately, were much more likely to get you out of the hot
>> zone, or better yet, get you home.
>
> http://science.howstuffworks.com/black-hawk1.htm
>
> Each blade consists of a titanium spar, which is a metal strip that runs
> from the base of the blade to its tip, and a Nomex honeycomb material.
> The blade skin and trailing edge are made of composite materials. The
> stronger, leading edge of the blade is made of titanium and nickel and
> is trimmed with an anti-erosion strip, which protects the blade from
> wear as it skims across the tree tops or flies in abrasive desert air.
>
> Mud and straw is a "composite", too. Nomex is not CF.
fuck: the honeycomb is nomex. that's the "filler" in the middle. the
titanium/nickel alloy /is/ the erosion strip. the load bearers, the
lower and upper surfaces, are composites.
they used to use glass, now they use carbon. i've seen these things
sectioned. what have you seen, other than a trivialized kiddies web page?
|
| | | | | |
Date: 08 Sep 2007 13:02:59
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Chalo wrote:
>>>> Mike Jacoubowsky wrote:
>>>>> That someone you know has a bike that's 50 years old in daily
>>>>> service is
>>>>> likely a testament more to an extraordinarily overbuilt design,
>>>>> rather than
>>>>> the material used. If one were to build a fork of the same weight
>>>>> out of
>>>>> carbon fiber, it may very well achieve commendable life on the roads
>>>>> surrounding Baghdad! But why? Does it make sense to build something
>>>>> that
>>>>> will last from one generation to the next, or does it make more
>>>>> sense to
>>>>> optimize for the current user, and his/her typical lifespan of use
>>>>> (determined not by failure but more often by a desire to upgrade)?
>>>>
>>>> As a dealer of new bikes, you might not fully appreciate the rich life
>>>> that good bikes tend to have after they pass from their original
>>>> owners to others. Stupid-light and stupid-cheap stuff tends to
>>>> migrate quickly to the trash, but one measure of the merit of a good
>>>> bike is how many hands it can pass through, how many folks it can
>>>> serve and entertain, on its journey between showroom and recycler.
>>>>
>>>> Bikes need not be heavy to have several successive careers. But they
>>>> need to be durable, rebuildable, and lovable. Major manufacturers'
>>>> sporting bikes these days are increasingly unlikely to have any of
>>>> these virtues. How many of today's racy bikes will retain the lasting
>>>> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
>>>> or a Paramount? Are the plastic wonderbikes of today going to outlast
>>>> their paint jobs? Will they be safe to ride if they do?
>>>>
>>>> Chalo
>>>>
>>>
>>> more than 30 years ago, i went to a materials lecture held by a
>>> supplier to sikorski. part of the presentation was on rotor blades.
>>> according to our guy, they were "quite happy" with composites in that
>>> application. it seems the benefit was not only much extended service
>>> life, but also something unanticipated - that of being more likely to
>>> survive bullet strike in combat. that's not to say every blade was
>>> surviving every strike, but apparently, older style aluminum blades
>>> had a dismal survival rate. composite blades otoh, if they didn't
>>> fail immediately, were much more likely to get you out of the hot
>>> zone, or better yet, get you home.
>>
>> http://science.howstuffworks.com/black-hawk1.htm
>>
>> Each blade consists of a titanium spar, which is a metal strip that
>> runs from the base of the blade to its tip, and a Nomex honeycomb
>> material. The blade skin and trailing edge are made of composite
>> materials. The stronger, leading edge of the blade is made of titanium
>> and nickel and is trimmed with an anti-erosion strip, which protects
>> the blade from wear as it skims across the tree tops or flies in
>> abrasive desert air.
>>
>> Mud and straw is a "composite", too. Nomex is not CF.
>
> fuck: the honeycomb is nomex. that's the "filler" in the middle. the
> titanium/nickel alloy /is/ the erosion strip. the load bearers, the
> lower and upper surfaces, are composites.
Yes, that's what they said (above).
>
> they used to use glass, now they use carbon.
So what?
> i've seen these things
> sectioned. what have you seen, other than a trivialized kiddies web page?
Big deal. See the section here:
<http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf >
fig. 9
If CF is carrying the load, why a Ti spar? What does "load bearing" have
to do with impact resistance? The reason composites have been used in
rotor blades is to get better fatigue life. The CF is protected with
metal because it's brittle.
This applies to bicycle frames how? You got one with Nomex honeycomb and
Ti impact protection? Caught with your pants down again.
|
| | | | | | |
Date: 08 Sep 2007 10:48:18
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Chalo wrote:
>>>>> Mike Jacoubowsky wrote:
>>>>>> That someone you know has a bike that's 50 years old in daily
>>>>>> service is
>>>>>> likely a testament more to an extraordinarily overbuilt design,
>>>>>> rather than
>>>>>> the material used. If one were to build a fork of the same weight
>>>>>> out of
>>>>>> carbon fiber, it may very well achieve commendable life on the roads
>>>>>> surrounding Baghdad! But why? Does it make sense to build
>>>>>> something that
>>>>>> will last from one generation to the next, or does it make more
>>>>>> sense to
>>>>>> optimize for the current user, and his/her typical lifespan of use
>>>>>> (determined not by failure but more often by a desire to upgrade)?
>>>>>
>>>>> As a dealer of new bikes, you might not fully appreciate the rich life
>>>>> that good bikes tend to have after they pass from their original
>>>>> owners to others. Stupid-light and stupid-cheap stuff tends to
>>>>> migrate quickly to the trash, but one measure of the merit of a good
>>>>> bike is how many hands it can pass through, how many folks it can
>>>>> serve and entertain, on its journey between showroom and recycler.
>>>>>
>>>>> Bikes need not be heavy to have several successive careers. But they
>>>>> need to be durable, rebuildable, and lovable. Major manufacturers'
>>>>> sporting bikes these days are increasingly unlikely to have any of
>>>>> these virtues. How many of today's racy bikes will retain the lasting
>>>>> charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
>>>>> or a Paramount? Are the plastic wonderbikes of today going to outlast
>>>>> their paint jobs? Will they be safe to ride if they do?
>>>>>
>>>>> Chalo
>>>>>
>>>>
>>>> more than 30 years ago, i went to a materials lecture held by a
>>>> supplier to sikorski. part of the presentation was on rotor
>>>> blades. according to our guy, they were "quite happy" with
>>>> composites in that application. it seems the benefit was not only
>>>> much extended service life, but also something unanticipated - that
>>>> of being more likely to survive bullet strike in combat. that's not
>>>> to say every blade was surviving every strike, but apparently, older
>>>> style aluminum blades had a dismal survival rate. composite blades
>>>> otoh, if they didn't fail immediately, were much more likely to get
>>>> you out of the hot zone, or better yet, get you home.
>>>
>>> http://science.howstuffworks.com/black-hawk1.htm
>>>
>>> Each blade consists of a titanium spar, which is a metal strip that
>>> runs from the base of the blade to its tip, and a Nomex honeycomb
>>> material. The blade skin and trailing edge are made of composite
>>> materials. The stronger, leading edge of the blade is made of
>>> titanium and nickel and is trimmed with an anti-erosion strip, which
>>> protects the blade from wear as it skims across the tree tops or
>>> flies in abrasive desert air.
>>>
>>> Mud and straw is a "composite", too. Nomex is not CF.
>>
>> fuck: the honeycomb is nomex. that's the "filler" in the middle.
>> the titanium/nickel alloy /is/ the erosion strip. the load bearers,
>> the lower and upper surfaces, are composites.
>
> Yes, that's what they said (above).
so why did you try using it as a contradiction? attempted deceit?
>
>>
>> they used to use glass, now they use carbon.
>
> So what?
because if you had been paying attention, that would be the next
question to ask.
>
>> i've seen these things sectioned. what have you seen, other than a
>> trivialized kiddies web page?
>
> Big deal. See the section here:
> <http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf>
> fig. 9
eh? is that supposed to contradict what i said?
>
> If CF is carrying the load, why a Ti spar? What does "load bearing" have
> to do with impact resistance?
ah, the great ethereal "impact". what does that mean exactly? define
it. and if bullet penetration survival is not sufficient for your
"impact" survival, perhaps you need to find some other movable yardstick
to try redefining.
> The reason composites have been used in
> rotor blades is to get better fatigue life. The CF is protected with
> metal because it's brittle.
no, it's because it doesn't like erosion.
>
> This applies to bicycle frames how? You got one with Nomex honeycomb and
> Ti impact protection? Caught with your pants down again.
eh? you bleat and moan about this so-called inferior material in bike
applications, yet in much more demanding aerospace applications, it's
ok? sorry, that deceit doesn't work.
|
| | | | | | | |
Date: 08 Sep 2007 14:47:29
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>>>> more than 30 years ago, i went to a materials lecture held by a
>>>>> supplier to sikorski. part of the presentation was on rotor
>>>>> blades. according to our guy, they were "quite happy" with
>>>>> composites in that application. it seems the benefit was not only
>>>>> much extended service life, but also something unanticipated - that
>>>>> of being more likely to survive bullet strike in combat. that's
>>>>> not to say every blade was surviving every strike, but apparently,
>>>>> older style aluminum blades had a dismal survival rate. composite
>>>>> blades otoh, if they didn't fail immediately, were much more likely
>>>>> to get you out of the hot zone, or better yet, get you home.
>>>>
>>>> http://science.howstuffworks.com/black-hawk1.htm
>>>>
>>>> Each blade consists of a titanium spar, which is a metal strip that
>>>> runs from the base of the blade to its tip, and a Nomex honeycomb
>>>> material. The blade skin and trailing edge are made of composite
>>>> materials. The stronger, leading edge of the blade is made of
>>>> titanium and nickel and is trimmed with an anti-erosion strip, which
>>>> protects the blade from wear as it skims across the tree tops or
>>>> flies in abrasive desert air.
>>>>
>>>> Mud and straw is a "composite", too. Nomex is not CF.
>>>
>>> fuck: the honeycomb is nomex. that's the "filler" in the middle.
>>> the titanium/nickel alloy /is/ the erosion strip. the load bearers,
>>> the lower and upper surfaces, are composites.
>>
>> Yes, that's what they said (above).
>
> so why did you try using it as a contradiction? attempted deceit?
I just pointed out that it is mostly not CF.
>>> they used to use glass, now they use carbon.
>>
>> So what?
>
> because if you had been paying attention, that would be the next
> question to ask.
OK. When "more than 30 years ago" you heard about the happy bullet
survival of the rotors, what were they using?
>>> i've seen these things sectioned. what have you seen, other than a
>>> trivialized kiddies web page?
>>
>> Big deal. See the section here:
>> <http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf>
>> fig. 9
>
> eh? is that supposed to contradict what i said?
Guess the CF content.
>> If CF is carrying the load, why a Ti spar? What does "load bearing"
>> have to do with impact resistance?
>
> ah, the great ethereal "impact". what does that mean exactly? define
> it. and if bullet penetration survival is not sufficient for your
> "impact" survival, perhaps you need to find some other movable yardstick
> to try redefining.
The meaning is well known. There are standard tests.
>> The reason composites have been used in rotor blades is to get better
>> fatigue life. The CF is protected with metal because it's brittle.
>
> no, it's because it doesn't like erosion.
Erosion from water? No, I think not.
>> This applies to bicycle frames how? You got one with Nomex honeycomb
>> and Ti impact protection? Caught with your pants down again.
>
> eh? you bleat and moan about this so-called inferior material in bike
> applications, yet in much more demanding aerospace applications, it's
> ok? sorry, that deceit doesn't work.
Yeah, that thing is built just like a Trek. Nice try.
|
| | | | | | | | |
Date: 09 Sep 2007 07:33:03
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>
>>>>>> more than 30 years ago, i went to a materials lecture held by a
>>>>>> supplier to sikorski. part of the presentation was on rotor
>>>>>> blades. according to our guy, they were "quite happy" with
>>>>>> composites in that application. it seems the benefit was not only
>>>>>> much extended service life, but also something unanticipated -
>>>>>> that of being more likely to survive bullet strike in combat.
>>>>>> that's not to say every blade was surviving every strike, but
>>>>>> apparently, older style aluminum blades had a dismal survival
>>>>>> rate. composite blades otoh, if they didn't fail immediately,
>>>>>> were much more likely to get you out of the hot zone, or better
>>>>>> yet, get you home.
>>>>>
>>>>> http://science.howstuffworks.com/black-hawk1.htm
>>>>>
>>>>> Each blade consists of a titanium spar, which is a metal strip that
>>>>> runs from the base of the blade to its tip, and a Nomex honeycomb
>>>>> material. The blade skin and trailing edge are made of composite
>>>>> materials. The stronger, leading edge of the blade is made of
>>>>> titanium and nickel and is trimmed with an anti-erosion strip,
>>>>> which protects the blade from wear as it skims across the tree tops
>>>>> or flies in abrasive desert air.
>>>>>
>>>>> Mud and straw is a "composite", too. Nomex is not CF.
>>>>
>>>> fuck: the honeycomb is nomex. that's the "filler" in the middle.
>>>> the titanium/nickel alloy /is/ the erosion strip. the load bearers,
>>>> the lower and upper surfaces, are composites.
>>>
>>> Yes, that's what they said (above).
>>
>> so why did you try using it as a contradiction? attempted deceit?
>
> I just pointed out that it is mostly not CF.
nor are cfrp frames, stems, seat posts, handlebars, etc - they're mostly
air.
>
>
>
>>>> they used to use glass, now they use carbon.
>>>
>>> So what?
>>
>> because if you had been paying attention, that would be the next
>> question to ask.
>
> OK. When "more than 30 years ago" you heard about the happy bullet
> survival of the rotors, what were they using?
glass. which is a composite fiber. glass fibers are brittle in case
you didn't know. and it was the only reliable fiber available in
quantity then. today, reliable carbon is available in quantity. and
it's stronger and lighter. the ability to hold a matrix together is no
different.
>
>>>> i've seen these things sectioned. what have you seen, other than a
>>>> trivialized kiddies web page?
>>>
>>> Big deal. See the section here:
>>> <http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf>
>>> fig. 9
>>
>> eh? is that supposed to contradict what i said?
>
> Guess the CF content.
guess the /load bearing/ content big guy.
>
>
>>> If CF is carrying the load, why a Ti spar? What does "load bearing"
>>> have to do with impact resistance?
>>
>> ah, the great ethereal "impact". what does that mean exactly? define
>> it. and if bullet penetration survival is not sufficient for your
>> "impact" survival, perhaps you need to find some other movable
>> yardstick to try redefining.
>
> The meaning is well known. There are standard tests.
so what qualifies as "impact" when you're trying to bleat about cfrp
frames? only something which achieves failure?
>
>>> The reason composites have been used in rotor blades is to get better
>>> fatigue life. The CF is protected with metal because it's brittle.
>>
>> no, it's because it doesn't like erosion.
>
> Erosion from water? No, I think not.
dude!!!! ice, the subject of that paper, is /highly/ erosive!!!
>
>
>>> This applies to bicycle frames how? You got one with Nomex honeycomb
>>> and Ti impact protection? Caught with your pants down again.
>>
>> eh? you bleat and moan about this so-called inferior material in bike
>> applications, yet in much more demanding aerospace applications, it's
>> ok? sorry, that deceit doesn't work.
>
> Yeah, that thing is built just like a Trek. Nice try.
no, trek don't bother to weight up their cores with honeycomb because
their cores don't need it! ridiculous statement.
|
| | | | | | | | | |
Date: 09 Sep 2007 13:31:30
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>
>>>>>>> more than 30 years ago, i went to a materials lecture held by a
>>>>>>> supplier to sikorski. part of the presentation was on rotor
>>>>>>> blades. according to our guy, they were "quite happy" with
>>>>>>> composites in that application. it seems the benefit was not
>>>>>>> only much extended service life, but also something unanticipated
>>>>>>> - that of being more likely to survive bullet strike in combat.
>>>>>>> that's not to say every blade was surviving every strike, but
>>>>>>> apparently, older style aluminum blades had a dismal survival
>>>>>>> rate. composite blades otoh, if they didn't fail immediately,
>>>>>>> were much more likely to get you out of the hot zone, or better
>>>>>>> yet, get you home.
>>>>>>
>>>>>> http://science.howstuffworks.com/black-hawk1.htm
>>>>>>
>>>>>> Each blade consists of a titanium spar, which is a metal strip
>>>>>> that runs from the base of the blade to its tip, and a Nomex
>>>>>> honeycomb material. The blade skin and trailing edge are made of
>>>>>> composite materials. The stronger, leading edge of the blade is
>>>>>> made of titanium and nickel and is trimmed with an anti-erosion
>>>>>> strip, which protects the blade from wear as it skims across the
>>>>>> tree tops or flies in abrasive desert air.
>>>>>>
>>>>>> Mud and straw is a "composite", too. Nomex is not CF.
>>>>>
>>>>> fuck: the honeycomb is nomex. that's the "filler" in the middle.
>>>>> the titanium/nickel alloy /is/ the erosion strip. the load
>>>>> bearers, the lower and upper surfaces, are composites.
>>>>
>>>> Yes, that's what they said (above).
>>>
>>> so why did you try using it as a contradiction? attempted deceit?
>>
>> I just pointed out that it is mostly not CF.
>
> nor are cfrp frames, stems, seat posts, handlebars, etc - they're mostly
> air.
Clever response! The epitome of "jim beam" "logic".
>
>>
>>
>>
>>>>> they used to use glass, now they use carbon.
>>>>
>>>> So what?
>>>
>>> because if you had been paying attention, that would be the next
>>> question to ask.
>>
>> OK. When "more than 30 years ago" you heard about the happy bullet
>> survival of the rotors, what were they using?
>
> glass. which is a composite fiber. glass fibers are brittle in case
> you didn't know.
Not nearly as brittle as CF, more brittle than Kevlar. If you're going
to talk composites, you'll have to qualify (unless you're just trying to
evade).
> and it was the only reliable fiber available in
> quantity then. today, reliable carbon is available in quantity. and
> it's stronger and lighter. the ability to hold a matrix together is no
> different.
You've got it backwards. The strength comes from the fiber, the matrix
holds the fiber together.
>>>>> i've seen these things sectioned. what have you seen, other than a
>>>>> trivialized kiddies web page?
>>>>
>>>> Big deal. See the section here:
>>>> <http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf>
>>>> fig. 9
>>>
>>> eh? is that supposed to contradict what i said?
>>
>> Guess the CF content.
>
> guess the /load bearing/ content big guy.
I'd say it's all bearing load, little man.
>
>>
>>
>>>> If CF is carrying the load, why a Ti spar? What does "load bearing"
>>>> have to do with impact resistance?
>>>
>>> ah, the great ethereal "impact". what does that mean exactly?
>>> define it. and if bullet penetration survival is not sufficient for
>>> your "impact" survival, perhaps you need to find some other movable
>>> yardstick to try redefining.
>>
>> The meaning is well known. There are standard tests.
>
> so what qualifies as "impact" when you're trying to bleat about cfrp
> frames? only something which achieves failure?
No, damage. Have you been following any of this?
>>>> The reason composites have been used in rotor blades is to get
>>>> better fatigue life. The CF is protected with metal because it's
>>>> brittle.
>>>
>>> no, it's because it doesn't like erosion.
>>
>> Erosion from water? No, I think not.
>
> dude!!!! ice, the subject of that paper, is /highly/ erosive!!!
Funny, they didn't mention that, they must have overlooked it.
"Erosion" in this context comes from hitting things with a rapidly
moving part. Brittle materials don't like that.
As I've said before, I'm not your dude. You're mistaken about that, too.
>>>> This applies to bicycle frames how? You got one with Nomex honeycomb
>>>> and Ti impact protection? Caught with your pants down again.
>>>
>>> eh? you bleat and moan about this so-called inferior material in
>>> bike applications, yet in much more demanding aerospace applications,
>>> it's ok? sorry, that deceit doesn't work.
>>
>> Yeah, that thing is built just like a Trek. Nice try.
>
> no, trek don't bother to weight up their cores with honeycomb because
> their cores don't need it! ridiculous statement.
Sure, one that I didn't make, you did.
You were trying to back up your contention of CF toughness by citing a
30 year old anecdote (of dubious veracity) about a fiberglass, Nomex
honeycomb and titanium structure's resistance to bullets. Then you get
caught. Then you try to weasel out of it. Then you cop an attitude as
you spew more crap. The "jim beam" tri-fecta.
|
| | | | | | | | | | |
Date: 10 Sep 2007 19:56:13
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Peter Cole" <peter_cole@comcast.net > wrote in message
news:T5WdncV_XOZusHnbnZ2dnUVZ_t6onZ2d@comcast.com...
>
> You were trying to back up your contention of CF toughness by citing a 30
> year old anecdote (of dubious veracity) about a fiberglass, Nomex
> honeycomb and titanium structure's resistance to bullets. Then you get
> caught. Then you try to weasel out of it. Then you cop an attitude as you
> spew more crap. The "jim beam" tri-fecta.
The anecote's just a made-up story, as proven in my other post.
|
| | | | | | | | | | |
Date: 09 Sep 2007 21:33:53
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>
>>>>>>>> more than 30 years ago, i went to a materials lecture held by a
>>>>>>>> supplier to sikorski. part of the presentation was on rotor
>>>>>>>> blades. according to our guy, they were "quite happy" with
>>>>>>>> composites in that application. it seems the benefit was not
>>>>>>>> only much extended service life, but also something
>>>>>>>> unanticipated - that of being more likely to survive bullet
>>>>>>>> strike in combat. that's not to say every blade was surviving
>>>>>>>> every strike, but apparently, older style aluminum blades had a
>>>>>>>> dismal survival rate. composite blades otoh, if they didn't
>>>>>>>> fail immediately, were much more likely to get you out of the
>>>>>>>> hot zone, or better yet, get you home.
>>>>>>>
>>>>>>> http://science.howstuffworks.com/black-hawk1.htm
>>>>>>>
>>>>>>> Each blade consists of a titanium spar, which is a metal strip
>>>>>>> that runs from the base of the blade to its tip, and a Nomex
>>>>>>> honeycomb material. The blade skin and trailing edge are made of
>>>>>>> composite materials. The stronger, leading edge of the blade is
>>>>>>> made of titanium and nickel and is trimmed with an anti-erosion
>>>>>>> strip, which protects the blade from wear as it skims across the
>>>>>>> tree tops or flies in abrasive desert air.
>>>>>>>
>>>>>>> Mud and straw is a "composite", too. Nomex is not CF.
>>>>>>
>>>>>> fuck: the honeycomb is nomex. that's the "filler" in the
>>>>>> middle. the titanium/nickel alloy /is/ the erosion strip. the
>>>>>> load bearers, the lower and upper surfaces, are composites.
>>>>>
>>>>> Yes, that's what they said (above).
>>>>
>>>> so why did you try using it as a contradiction? attempted deceit?
>>>
>>> I just pointed out that it is mostly not CF.
>>
>> nor are cfrp frames, stems, seat posts, handlebars, etc - they're
>> mostly air.
>
> Clever response! The epitome of "jim beam" "logic".
so you deny that? or is reality inconvenient to the tangled web you're
trying to weave.
>
>>
>>>
>>>
>>>
>>>>>> they used to use glass, now they use carbon.
>>>>>
>>>>> So what?
>>>>
>>>> because if you had been paying attention, that would be the next
>>>> question to ask.
>>>
>>> OK. When "more than 30 years ago" you heard about the happy bullet
>>> survival of the rotors, what were they using?
>>
>> glass. which is a composite fiber. glass fibers are brittle in case
>> you didn't know.
>
> Not nearly as brittle as CF, more brittle than Kevlar. If you're going
> to talk composites, you'll have to qualify (unless you're just trying to
> evade).
some carbon fibers are more brittle than others, but you can't just pick
one and use it to represent them all. well you can, but that would be
deceit. oh, wait....
>
>> and it was the only reliable fiber available in quantity then. today,
>> reliable carbon is available in quantity. and it's stronger and
>> lighter. the ability to hold a matrix together is no different.
>
> You've got it backwards. The strength comes from the fiber, the matrix
> holds the fiber together.
eh? no i haven't. do you bother to read this stuff? and don't put
false words in my mouth.
>
>
>>>>>> i've seen these things sectioned. what have you seen, other than
>>>>>> a trivialized kiddies web page?
>>>>>
>>>>> Big deal. See the section here:
>>>>> <http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR02-15.pdf>
>>>>> fig. 9
>>>>
>>>> eh? is that supposed to contradict what i said?
>>>
>>> Guess the CF content.
>>
>> guess the /load bearing/ content big guy.
>
> I'd say it's all bearing load, little man.
er, i took the trouble to point out which loads were being borne by
which component. but clearly that was inconvenient...
>
>>
>>>
>>>
>>>>> If CF is carrying the load, why a Ti spar? What does "load bearing"
>>>>> have to do with impact resistance?
>>>>
>>>> ah, the great ethereal "impact". what does that mean exactly?
>>>> define it. and if bullet penetration survival is not sufficient for
>>>> your "impact" survival, perhaps you need to find some other movable
>>>> yardstick to try redefining.
>>>
>>> The meaning is well known. There are standard tests.
>>
>> so what qualifies as "impact" when you're trying to bleat about cfrp
>> frames? only something which achieves failure?
>
> No, damage. Have you been following any of this?
define "impact"!!! static load can cause damage.
>
>>>>> The reason composites have been used in rotor blades is to get
>>>>> better fatigue life. The CF is protected with metal because it's
>>>>> brittle.
>>>>
>>>> no, it's because it doesn't like erosion.
>>>
>>> Erosion from water? No, I think not.
>>
>> dude!!!! ice, the subject of that paper, is /highly/ erosive!!!
>
> Funny, they didn't mention that, they must have overlooked it.
that's because they're worried about de-icing, not abrasion! oh,
whoops, was i not supposed to read that bit?
>
> "Erosion" in this context comes from hitting things with a rapidly
> moving part. Brittle materials don't like that.
is that meant to imply that ice is not erosive???
>
> As I've said before, I'm not your dude. You're mistaken about that, too.
ok then, i'll just point out that you're a prick. satisfied now?
>
>>>>> This applies to bicycle frames how? You got one with Nomex
>>>>> honeycomb and Ti impact protection? Caught with your pants down again.
>>>>
>>>> eh? you bleat and moan about this so-called inferior material in
>>>> bike applications, yet in much more demanding aerospace
>>>> applications, it's ok? sorry, that deceit doesn't work.
>>>
>>> Yeah, that thing is built just like a Trek. Nice try.
>>
>> no, trek don't bother to weight up their cores with honeycomb because
>> their cores don't need it! ridiculous statement.
>
> Sure, one that I didn't make, you did.
eh?
>
> You were trying to back up your contention of CF toughness by citing a
> 30 year old anecdote (of dubious veracity) about a fiberglass, Nomex
> honeycomb and titanium structure's resistance to bullets. Then you get
> caught. Then you try to weasel out of it. Then you cop an attitude as
> you spew more crap. The "jim beam" tri-fecta.
so just call me a liar! prick. because if you take the word of some
moron that doesn't know what modulus is, or even specific modulus after
two days of research, you truly are one.
|
| | | | | | | | | | |
Date: 09 Sep 2007 18:35:31
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <T5WdncV_XOZusHnbnZ2dnUVZ_t6onZ2d@comcast.com >,
Peter Cole <peter_cole@comcast.net > wrote:
> jim beam wrote:
> > Peter Cole wrote:
> >> jim beam wrote:
> >>> Peter Cole wrote:
> >>>> jim beam wrote:
> >>
> >>>>>>> more than 30 years ago, i went to a materials lecture held by
> >>>>>>> a supplier to sikorski. part of the presentation was on
> >>>>>>> rotor blades. according to our guy, they were "quite happy"
> >>>>>>> with composites in that application. it seems the benefit
> >>>>>>> was not only much extended service life, but also something
> >>>>>>> unanticipated - that of being more likely to survive bullet
> >>>>>>> strike in combat. that's not to say every blade was
> >>>>>>> surviving every strike, but apparently, older style aluminum
> >>>>>>> blades had a dismal survival rate. composite blades otoh, if
> >>>>>>> they didn't fail immediately, were much more likely to get
> >>>>>>> you out of the hot zone, or better yet, get you home.
> >>>>>>
> >>>>>> http://science.howstuffworks.com/black-hawk1.htm
> >>>>>>
> >>>>>> Each blade consists of a titanium spar, which is a metal strip
> >>>>>> that runs from the base of the blade to its tip, and a Nomex
> >>>>>> honeycomb material. The blade skin and trailing edge are made
> >>>>>> of composite materials. The stronger, leading edge of the
> >>>>>> blade is made of titanium and nickel and is trimmed with an
> >>>>>> anti-erosion strip, which protects the blade from wear as it
> >>>>>> skims across the tree tops or flies in abrasive desert air.
> >>>>>>
> >>>>>> Mud and straw is a "composite", too. Nomex is not CF.
> >>>>>
> >>>>> fuck: the honeycomb is nomex. that's the "filler" in the
> >>>>> middle. the titanium/nickel alloy /is/ the erosion strip. the
> >>>>> load bearers, the lower and upper surfaces, are composites.
> >>>>
> >>>> Yes, that's what they said (above).
> >>>
> >>> so why did you try using it as a contradiction? attempted
> >>> deceit?
> >>
> >> I just pointed out that it is mostly not CF.
> >
> > nor are cfrp frames, stems, seat posts, handlebars, etc - they're
> > mostly air.
>
> Clever response! The epitome of "jim beam" "logic".
No. you are seeing the result of religious epiphany. jim beam has
become a Taoist:
11. Thirty spokes are joined together in a wheel,
but it is the center hole
that allows the wheel to function.
We mold clay into a pot,
but it is the emptiness inside
that makes the vessel useful.
We fashion wood for a house,
but it is the emptiness inside
that makes it livable.
We work with the substantial,
but the emptiness is what we use.
|
| | |
Date: 08 Sep 2007 00:46:53
From:
Subject: Re: "brittle" vs. non-ductile
|
On Sat, 08 Sep 2007 06:06:55 -0000, Chalo <chalo.colina@gmail.com >
wrote:
>Mike Jacoubowsky wrote:
>>
>> That someone you know has a bike that's 50 years old in daily service is
>> likely a testament more to an extraordinarily overbuilt design, rather than
>> the material used. If one were to build a fork of the same weight out of
>> carbon fiber, it may very well achieve commendable life on the roads
>> surrounding Baghdad! But why? Does it make sense to build something that
>> will last from one generation to the next, or does it make more sense to
>> optimize for the current user, and his/her typical lifespan of use
>> (determined not by failure but more often by a desire to upgrade)?
>
>As a dealer of new bikes, you might not fully appreciate the rich life
>that good bikes tend to have after they pass from their original
>owners to others. Stupid-light and stupid-cheap stuff tends to
>migrate quickly to the trash, but one measure of the merit of a good
>bike is how many hands it can pass through, how many folks it can
>serve and entertain, on its journey between showroom and recycler.
>
>Bikes need not be heavy to have several successive careers. But they
>need to be durable, rebuildable, and lovable. Major manufacturers'
>sporting bikes these days are increasingly unlikely to have any of
>these virtues. How many of today's racy bikes will retain the lasting
>charm (to say nothing of the sound backbone) of a PX-10, a Hetchins,
>or a Paramount? Are the plastic wonderbikes of today going to outlast
>their paint jobs? Will they be safe to ride if they do?
>
>Chalo
Dear Mike & Chalo,
As a curious sidelight, high-wheeler penny-farthings are so scarce
nowadays because they became obsolete a few years after the
introduction of the safety bicycle and most of the the hundreds of
thousands of idle survivors were then gathered up and turned into
something more useful in metal drives during the wars.
Cheers,
Carl Fogel
|
| |
Date: 07 Sep 2007 22:33:22
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
Jay Beattie wrote:
>
> A Muzi wrote:
> >
> > Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
> > have, test equipment to nondestructively spot anomalies and/or damage in
> > composite materials for the Dreamliner. Boeing spokesman pointedly noted
> > that rapping a structural member with a quarter, the previous standard
> > test, is no longer considered sufficient to establish airworthiness.
>
> What if they used a fifty-cent piece. That would be twice as
> accurate.
Krugerrands are hundreds of times more refined, and getting more
accurate almost every day.
|
| |
Date: 07 Sep 2007 11:44:54
From: Jay Beattie
Subject: Re: "brittle" vs. non-ductile
|
On Sep 7, 10:29 am, A Muzi <a...@yellowjersey.org > wrote:
> frkry...@gmail.com wrote:
> > On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Peter Cole wrote:
> >>> Then how (if there are "warning signs") could there be:
> >>> "a lot of people out there riding on damaged (broken) carbon frames &
> >>> forks that aren't aware of it." ?
> >> simply pay attention big guy.
>
> > We all know it's pointless to argue with "jim beam," but since others
> > are reading: I think the advice he gives below is practically useless
> > for most people.
>
> >> 1. the bike comes with an owners manual outlining inspection and
> >> warnings.
>
> > In America, warnings are attached to every consumer device. Our
> > society is perpetually crying "Wolf!" and most people are no longer
> > believing the warnings. I believe we've reached a point where the
> > warnings serve only as legal ammunition in a court action.
>
> > Any consumer actually reading his CF bike's manual would have to
> > distinguish whether the CF inspection warnings are any more serious
> > than statements like "Always check the tightness of every bolt before
> > any ride" and "Never ride any bicycle at night." Most will assume all
> > such warnings are legal smokescreens.
>
> >> 2. ask advice on this forum from people that are familiar with the
> >> material and its failures.
>
> > :-) Trouble is, some poor sucker might believe advice from "jim
> > beam"!
>
> >> 3. ask bike shop owners that are familiar with the material and its
> >> failures.
>
> > Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
> > all bike shop owners get extensive training in evaluating CF damage.
> > I've been in bike shops where the kid on duty couldn't operate a quick
> > release properly! No, he wasn't the owner, but how does the average
> > consumer tell the difference?
>
> > I don't think the typical American sport cyclist has any idea about
> > the true advantages and disadvantages of CF. IMO, he has no
> > understanding deeper than "Lance used this. It's 30 grams lighter and
> > it looks cool. Buycycling gave it 7 chainrings. It's going to
> > finally let me beat Fred up that hill."
>
> > And I think it's a bad idea to whittle the practical factor of safety
> > down to the point where the typical American sport cyclist has to
> > pretend to be a CF-certified airframe mechanic. It's like designing
> > the next Mazda Miata with an all-composite suspension system, and
> > hoping nobody ever hits a curb.
>
> Right.
>
> Yes, we can sometimes spot damage. But we are clear that our inability
> to see damage is not an imprimatur of soundness. When in doubt
> post-crash we suggest replacement. Some riders do, some do not.
>
> Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
> have, test equipment to nondestructively spot anomalies and/or damage in
> composite materials for the Dreamliner. Boeing spokesman pointedly noted
> that rapping a structural member with a quarter, the previous standard
> test, is no longer considered sufficient to establish airworthiness.
What if they used a fifty-cent piece. That would be twice as
accurate. -- Jay Beattie.
|
| |
Date: 07 Sep 2007 10:02:26
From: Jay Beattie
Subject: Re: "brittle" vs. non-ductile
|
On Sep 7, 8:24 am, "Jambo" <-...@-.- > wrote:
> "jim beam" <spamvor...@bad.example.net> wrote in message
>
> news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>
> > Peter Cole wrote:
> >> The aircraft industry works to higher standards than joe (jim) consumer.
> >> That's the point.
>
> > i /hate/ to point this out, but the people that /started/ using cfrp in
> > bikes used experience /from/ the aerospace industry. damn.
>
> This is your say so, not fact. Geez, you're incredibly gullible.
Another point of clarification: are CF bicycle frames over built,
vis., stronger than necessary to take in to consideration the
limitations of the material? I ask this because I have not see an
epidemic of broken CF frames or forks, and I have been riding CF forks
for over 15 years (different ones). I have seen broken CF forks, but
only at the crown glue joint or at the crown steerer (aluminum steerer
and crown). I remember the early problems with the BB insert in the
Trek CF frames, but that was a different type of bonding problem and
not delamination like we are discussing here. I don't seem to
remember any more broken CF frames than, let's say, Al (e.g.
Cannondale was having a hard time there for a few years with the 2.8
design). I ride a Cannondale, so I am not trying to justify a CF
purchase. I am just trying to get a handle on the real risk to the
average rider of a decent CF frame.-- Jay Beattie.
|
| | |
Date: 13 Sep 2007 15:11:29
From: Jay Beattie
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 13, 2:02 pm, "Mike Jacoubowsky" <Mi...@ChainReaction.com >
wrote:
> >> In Oregon and Washington you get a lot of races out of the
> >> metropolitan areas and can drive a long way to ride a short race. My
> >> brother is an avid masters MTB racer and state champ who lives in
> >> Washington. He may drive hours to do a five minute down-hill race.
> >> Usually there is a cross-country race, too, but he has driven a long
> >> way to do only a brief down-hill event -- usually as a required event
> >> in some points series.
>
> > That's ridiculous. When your recreation turns into that sort of expensive
> > grind, it's time to take a good look at yourself IMHO.
>
> In my prior life, about 5.5 years of being an extremely competitive jr and
> decent cat-2 (which meant riding cat-1/pro races), I often wondered who
> those other 80 guys were. There were maybe 20 of us who consistently figured
> in the finish; the rest of the guys were some sort of filler (pack fodder).
> You saw them at the start, but rarely did any beyond the 20 or so "regulars"
> figure in the finish stats.
>
> Obviously, there's some motivation for those guys to be there. It's not
> something I could relate to, and possibly not you either. I never could
> quite figure out why they were there back in the day, but I feel a bit
> differently about it now. I can see the point to being in a race that you
> have no chance of finishing in the top-10, because maybe it's a way of
> testing yourself to see where you are. Maybe you came in 10 minutes behind
> the winners this race, but you were 15 last time. That's progress, and
> progress can keep a dream fueled.
You do it because you like it! I raced on and off for almost 20 years
and never amounted to much, but I had a good time and got to ride with
friends and do the team thing. Gas was cheap; I could get a placing if
the stars aligned. But when the kid and house came along, I just did
not have the time to train -- and I did not have the natural talent to
race without lots of training. Races turned in to death marches, so I
called it quits. I had no physical gifts -- just tenacity and desire,
and when those things went way -- fuhgeta bout it. Even if I had
talent, why ignore my family for the weekend to drive some place to
win a water bottle or crate of potato chips. Really, I once won a
dozen bags of Kettle Chips (or however many come in a shipping box).
That was the only time cycling put food on the table.-- Jay Beattie.
|
| | |
Date: 12 Sep 2007 23:07:18
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 5:41 pm, Michael Warner <m...@westnet.com.au > wrote:
> On Wed, 12 Sep 2007 15:56:24 -0700, r15...@aol.com wrote:
> > Just a half hour? Consider yourself lucky. An hour of driving for a
> > several-hour long trail ride is well worth it.
>
> Worth it to you, maybe, but what does the planet think about it?
I imagine the planet would like us to hurry up and use up all the oil,
spew all the emissions that we're going to spew so it can get on with
the business of shucking us off. The earth will still be here spinning
like it does, working up a new ecosystem long after we've ruined our
own ability to exist on its surface. In short, I don't think the earth
gives a shit.
Also, after bike commuting nearly every workday for the past 20 years,
I may have accrued more 'carbon credits' than the average American,
eh?
Robert
|
| | |
Date: 08 Sep 2007 15:39:35
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Jay Beattie" <jbeattie@lindsayhart.com > wrote in message
news:1189184546.941992.244120@o80g2000hse.googlegroups.com...
> Another point of clarification: are CF bicycle frames over built,
> vis., stronger than necessary to take in to consideration the
> limitations of the material?
Who really knows, since manufacturers never publish the design loads of
their frames. If they did, we'd also be able to calculate fatigue lives of
Al alloy frames. With the standardization of particular tube sizes, maybe
sizing of frame tubes is merely historical. What should be reasonably done
by manufacturers is to compare the strength and loads that can be "safely"
withstood by metal frames, and design the CF frames accordingly. Do they do
this? Your guess is as good as mine. The point is that we should not
assume that "aerospace experience" has been transferred across to the bike
industry because if they have, then critical things such as design loads and
fatigue lives need to be analyzed for bike frames as well.
> I ask this because I have not see an
> epidemic of broken CF frames or forks, and I have been riding CF forks
> for over 15 years (different ones).
I haven't heard an epidemic of broken Al frames either. I have seen many
broken CF handlebars and seatposts. However, it doesn't deflect from the
fact that CF is easier to damage by low impact loads from directions
different to duty loads (e.g. a fork being hit on the legs). Now THAT's
aerospace experience.
> I have seen broken CF forks, but
> only at the crown glue joint or at the crown steerer (aluminum steerer
> and crown). I remember the early problems with the BB insert in the
> Trek CF frames, but that was a different type of bonding problem and
> not delamination like we are discussing here. I don't seem to
> remember any more broken CF frames than, let's say, Al (e.g.
> Cannondale was having a hard time there for a few years with the 2.8
> design). I ride a Cannondale, so I am not trying to justify a CF
> purchase. I am just trying to get a handle on the real risk to the
> average rider of a decent CF frame.-- Jay Beattie.
Breaking frames may not be as dramatic nor as likely to result in severe
injury (although I can be enlightened from that notion). But breaking
handlebars, stems and seatposts is definitely likely to be - and that goes
for Al alloys too, for sure. However, given CF's characteristic for lower
damage tolerance (than metals) in directions different to fiber orientation,
why increase the risk?
|
| | | |
Date: 12 Sep 2007 23:21:45
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 11:15 pm, Michael Warner <m...@westnet.com.au > wrote:
> On Wed, 12 Sep 2007 18:31:32 -0700, Bill Sornson wrote:
> > None of your (not at all humble) business.
>
> If you post something here, you're inviting opinions about it. And given
> what we're doing to the world's oil supply and atmosphere, spending
> hours driving somewhere just to roll down a hill and go home again is
> certainly something I have an opinion about.
That degree of raging self-righteousness is generally accompanied by
a heaping helping of hypocrisy. But not in 'Michael Warner.' He has
eliminated all frivolous energy consumption from his daily existence.
Robert
|
| | | | |
Date: 13 Sep 2007 08:32:28
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
r15757@aol.com wrote:
> On Sep 12, 11:15 pm, Michael Warner <m...@westnet.com.au> wrote:
>> On Wed, 12 Sep 2007 18:31:32 -0700, Bill Sornson wrote:
>>> None of your (not at all humble) business.
>>
>> If you post something here, you're inviting opinions about it. And
>> given what we're doing to the world's oil supply and atmosphere,
>> spending hours driving somewhere just to roll down a hill and go
>> home again is certainly something I have an opinion about.
>
> That degree of raging self-righteousness is generally accompanied by
> a heaping helping of hypocrisy. But not in 'Michael Warner.' He has
> eliminated all frivolous energy consumption from his daily existence.
Bingo.
|
| | | | |
Date: 13 Sep 2007 19:27:50
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 23:21:45 -0700, r15757@aol.com wrote:
> That degree of raging self-righteousness is generally accompanied by
> a heaping helping of hypocrisy. But not in 'Michael Warner.'
Oh, and I do apologize for cravenly hiding behind my real name,
'r15757'. LOL. What I've always heard about AOL users must be true.
|
| | | | |
Date: 13 Sep 2007 17:54:22
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 23:21:45 -0700, r15757@aol.com wrote:
> That degree of raging self-righteousness is generally accompanied by
> a heaping helping of hypocrisy. But not in 'Michael Warner.' He has
> eliminated all frivolous energy consumption from his daily existence.
You can tell that from there? Since you have telemetric access to my
power and gas meters, please send me daily updates :-)
|
| | | |
Date: 10 Sep 2007 14:33:43
From:
Subject: Re: What's a "cyclist"? [was Re: "brittle" vs. non-ductile]
|
On Sep 10, 8:57 am, Doug Taylor <dtay...@dreamscape.com > wrote:
>
>
> Witnesses reported a man riding a bicycle down a hill, wearing a
> baseball cap (NOT a helmet, note). The cap flew off his head; he
> turned around and tried to catch it; he then ran a stop sign and
> broadsided the car. Turns out he was - you guessed it - drunk as a
> skunk.
>
> Your call: "Bicyclist"? "Cyclist"? Drunk on a bike?
All three, I'd say.
And the last part should be discouraged, since there are indications
drunk cyclists are a very large percentage of the few cycling
fatalities in America. If we could stop those guys from getting
killed, cycling's data would look even better.
It would make a lot more difference than our current focus on hat
styles.
- Frank Krygowski
|
| | | |
Date: 08 Sep 2007 21:17:14
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> I have seen broken CF forks, but
>> only at the crown glue joint or at the crown steerer (aluminum steerer
>> and crown). I remember the early problems with the BB insert in the
>> Trek CF frames, but that was a different type of bonding problem and
>> not delamination like we are discussing here. I don't seem to
>> remember any more broken CF frames than, let's say, Al (e.g.
>> Cannondale was having a hard time there for a few years with the 2.8
>> design). I ride a Cannondale, so I am not trying to justify a CF
>> purchase. I am just trying to get a handle on the real risk to the
>> average rider of a decent CF frame.-- Jay Beattie.
>
> Breaking frames may not be as dramatic nor as likely to result in severe
> injury (although I can be enlightened from that notion). But breaking
> handlebars, stems and seatposts is definitely likely to be - and that goes
> for Al alloys too, for sure. However, given CF's characteristic for lower
> damage tolerance (than metals) in directions different to fiber
> orientation, why increase the risk?
I agree. Materials that fail in common use should be banned from bikes.
Oh, darn. All those failing aluminum stems... crap. That's quite a few
thousand dollars of inventory I'm going to have to dump. And the failed
Belleri handlebars. Crap. That's going to be many thousands of dollars more
of inventory I can't trust.
Oh, darn. All those steel frames that buckled under impact, causing the
front wheel to make contact with the downtube and throwing the rider
violently. Crap. We can't use steel for frames anymore.
Oh, darn. All those titanium frames that had sheared downtubes, due to
cracks beginning at the downtube cable guides. Crap.
Oh, wait, nevermind. It wasn't the material that was the issue, it was how
it was used. Incredibly dangerous failure modes, yet nobody was calling for
manufacturers to stop using aluminum, steel or titanium for bike parts.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Jambo" <-@-.- > wrote in message
news:46e2fa4a$0$32515$4c368faf@roadrunner.com...
>
> "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
> news:1189184546.941992.244120@o80g2000hse.googlegroups.com...
>> Another point of clarification: are CF bicycle frames over built,
>> vis., stronger than necessary to take in to consideration the
>> limitations of the material?
>
> Who really knows, since manufacturers never publish the design loads of
> their frames. If they did, we'd also be able to calculate fatigue lives
> of Al alloy frames. With the standardization of particular tube sizes,
> maybe sizing of frame tubes is merely historical. What should be
> reasonably done by manufacturers is to compare the strength and loads that
> can be "safely" withstood by metal frames, and design the CF frames
> accordingly. Do they do this? Your guess is as good as mine. The point
> is that we should not assume that "aerospace experience" has been
> transferred across to the bike industry because if they have, then
> critical things such as design loads and fatigue lives need to be analyzed
> for bike frames as well.
>
>> I ask this because I have not see an
>> epidemic of broken CF frames or forks, and I have been riding CF forks
>> for over 15 years (different ones).
>
> I haven't heard an epidemic of broken Al frames either. I have seen many
> broken CF handlebars and seatposts. However, it doesn't deflect from the
> fact that CF is easier to damage by low impact loads from directions
> different to duty loads (e.g. a fork being hit on the legs). Now THAT's
> aerospace experience.>> I have seen broken CF forks, but
>> only at the crown glue joint or at the crown steerer (aluminum steerer
>> and crown). I remember the early problems with the BB insert in the
>> Trek CF frames, but that was a different type of bonding problem and
>> not delamination like we are discussing here. I don't seem to
>> remember any more broken CF frames than, let's say, Al (e.g.
>> Cannondale was having a hard time there for a few years with the 2.8
>> design). I ride a Cannondale, so I am not trying to justify a CF
>> purchase. I am just trying to get a handle on the real risk to the
>> average rider of a decent CF frame.-- Jay Beattie.
>
> Breaking frames may not be as dramatic nor as likely to result in severe
> injury (although I can be enlightened from that notion). But breaking
> handlebars, stems and seatposts is definitely likely to be - and that goes
> for Al alloys too, for sure. However, given CF's characteristic for lower
> damage tolerance (than metals) in directions different to fiber
> orientation, why increase the risk?
>
>
|
| | | | |
Date: 13 Sep 2007 06:53:21
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 13, 1:31 am, "Bill Sornson" <as...@ask.me > wrote:
>
>
> That why you deleted your comment (and its context) that prompted mine?
:-) Bill Sornson has been hanging around Usenet for many years. Yet
he _still_ can't understand that it's normal to delete parts of
posts. He still can't understand that anyone _else_ can read the
entire previous post with a click of the mouse button - or less.
Can you imagine a live conversation with this guy? He'd force you to
always repeat everything he said before adding a comment of your
own!
- Frank Krygowski
|
| | | | |
Date: 09 Sep 2007 13:29:14
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article <ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> Oh, wait, nevermind. It wasn't the material that was the issue, it was how
> it was used. Incredibly dangerous failure modes, yet nobody was calling for
> manufacturers to stop using aluminum, steel or titanium for bike parts.
Nobody is calling for manufacturers to stop using anything.
--
Michael Press
|
| | | | | |
Date: 10 Sep 2007 01:18:28
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> Oh, wait, nevermind. It wasn't the material that was the issue, it was
>> how
>> it was used. Incredibly dangerous failure modes, yet nobody was calling
>> for
>> manufacturers to stop using aluminum, steel or titanium for bike parts.
>
> Nobody is calling for manufacturers to stop using anything.
>
> --
> Michael Press
Perhaps not. Could you sum up what is being suggested? It certainly appears
that there are several posters who are saying that carbon fiber is not
appropriate for critical (parts that, if they fail, could cause serious
injury or death) bicycle parts.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Michael Press" <rubrum@pacbell.net > wrote in message
news:rubrum-68E5D1.13291409092007@newsclstr03.news.prodigy.net...
> In article <ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> Oh, wait, nevermind. It wasn't the material that was the issue, it was
>> how
>> it was used. Incredibly dangerous failure modes, yet nobody was calling
>> for
>> manufacturers to stop using aluminum, steel or titanium for bike parts.
>
> Nobody is calling for manufacturers to stop using anything.
>
> --
> Michael Press
|
| | | | | | |
Date: 09 Sep 2007 19:47:13
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article
<EX0Fi.26112$eY.15959@newssvr13.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> Oh, wait, nevermind. It wasn't the material that was the issue, it was
> >> how
> >> it was used. Incredibly dangerous failure modes, yet nobody was calling
> >> for
> >> manufacturers to stop using aluminum, steel or titanium for bike parts.
> >
> > Nobody is calling for manufacturers to stop using anything.
>
> Perhaps not. Could you sum up what is being suggested? It certainly appears
> that there are several posters who are saying that carbon fiber is not
> appropriate for critical (parts that, if they fail, could cause serious
> injury or death) bicycle parts.
Carbon fiber composite structures are easily damaged
when struck on the surface. The strike can cause
delamination and broken fibers. The damage can be
invisible. The compromised structure will deteriorate
and fail without warning. Warning is when the structure
starts to behave differently such as wallowing while
steering can indicate a compromised head tube joint in
a metal frame.
Personally, I think manufacturers can eventually figure
out how to make frames from carbon fiber composite that
will resist direct strike damage. Or perhaps they could
put an indicater layer that would signal a no go
condition. I do not see how they can deal with the
brittle fracture dynamics of carbon fiber composites. I
think they may know more than they say, but essentially
cannot say it. I do not think the manufacturers are
evil.
--
Michael Press
|
| | | | | | | |
Date: 09 Sep 2007 21:56:41
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Michael Press wrote:
> In article
> <EX0Fi.26112$eY.15959@newssvr13.news.prodigy.net>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>>>> Oh, wait, nevermind. It wasn't the material that was the issue, it was
>>>> how
>>>> it was used. Incredibly dangerous failure modes, yet nobody was calling
>>>> for
>>>> manufacturers to stop using aluminum, steel or titanium for bike parts.
>>> Nobody is calling for manufacturers to stop using anything.
>> Perhaps not. Could you sum up what is being suggested? It certainly appears
>> that there are several posters who are saying that carbon fiber is not
>> appropriate for critical (parts that, if they fail, could cause serious
>> injury or death) bicycle parts.
>
> Carbon fiber composite structures are easily damaged
> when struck on the surface. The strike can cause
> delamination and broken fibers.
define "strike" and put numbers to it. without that, you're just
ignoring reality that cfrp bike components are used daily, globally, by
millions of people, and the incidence of failure is below the noise of
other bike system failures.
> The damage can be
> invisible.
just like metal fatigue. only carbon has better fatigue characteristics.
> The compromised structure will deteriorate
> and fail without warning.
now that's a massive exaggeration. the probability of carbon suddenly
shattering like glass, no warning, is slim to zero. typical failure is
that of tearing and progressive fracture, over time, accompanied by much
audible warning.
> Warning is when the structure
> starts to behave differently such as wallowing while
> steering can indicate a compromised head tube joint in
> a metal frame.
>
> Personally, I think manufacturers can eventually figure
> out how to make frames from carbon fiber composite that
> will resist direct strike damage.
really? what numbers should they design to? oh, wait, we haven't
defined "impact" yet.
> Or perhaps they could
> put an indicater layer that would signal a no go
> condition.
they could embed microphones too and they can be monitored by the flight
controller...
> I do not see how they can deal with the
> brittle fracture dynamics of carbon fiber composites.
if you haven't studied the subject, why are you expressing underinformed
worries as fact? metal fatigue is a highly complex subject and full of
anomalies - why are you not even-handedly expressing similar concerns in
that department also?
> I
> think they may know more than they say, but essentially
> cannot say it. I do not think the manufacturers are
> evil.
sure they know more - they know they need to embed microphones for
monitoring by the flight controller!
|
| | | | | | | | |
Date: 10 Sep 2007 20:30:41
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:-vKdnbLEC8oXU3nbnZ2dnUVZ_ryqnZ2d@speakeasy.net...
> Michael Press wrote:
>> Carbon fiber composite structures are easily damaged
>> when struck on the surface. The strike can cause
>> delamination and broken fibers.
>
> define "strike" and put numbers to it. without that, you're just ignoring
> reality that cfrp bike components are used daily, globally, by millions of
> people, and the incidence of failure is below the noise of other bike
> system failures.
Strike is easily understood by everyone except beamboy. It's pretty
obvious, but here: www.dictionary.com
>> The damage can be
>> invisible.
>
> just like metal fatigue. only carbon has better fatigue characteristics.
But we're not talking about fatigue, we're talking about low impact damage,
moron.
>> The compromised structure will deteriorate
>> and fail without warning.
>
> now that's a massive exaggeration. the probability of carbon suddenly
> shattering like glass, no warning, is slim to zero. typical failure is
> that of tearing and progressive fracture, over time, accompanied by much
> audible warning.
That's right, CF talks to you when they're failing, don't they?
Tell that to the good folks at Boeing, Lockeed-Martin, Bell, SIKORSKY...
you've hit upon a new principle of physics!
>> Personally, I think manufacturers can eventually figure
>> out how to make frames from carbon fiber composite that
>> will resist direct strike damage.
>
> really? what numbers should they design to? oh, wait, we haven't defined
> "impact" yet.
A cursory glance at aerospace literature will give you the numbers, beamboy.
Google is your friend, but you're too fucktardy.
>> Or perhaps they could
>> put an indicater layer that would signal a no go
>> condition.
>
> they could embed microphones too and they can be monitored by the flight
> controller...
Which would be you, beamboy? After all, you're th CF whisperer...
>> I do not see how they can deal with the
>> brittle fracture dynamics of carbon fiber composites.
>
> if you haven't studied the subject, why are you expressing underinformed
> worries as fact? metal fatigue is a highly complex subject and full of
> anomalies - why are you not even-handedly expressing similar concerns in
> that department also?
Because metal fatigue and low damage tolerance of CF composites ARE TWO
DIFFERENT TOPICS, MORON!
You get to be too much sometimes.
>
>> I
>> think they may know more than they say, but essentially
>> cannot say it. I do not think the manufacturers are
>> evil.
>
> sure they know more - they know they need to embed microphones for
> monitoring by the flight controller!
And get beamboy to be the CF Whisperer!
|
| | | | | | |
Date: 09 Sep 2007 20:58:13
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <EX0Fi.26112$eY.15959@newssvr13.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> Oh, wait, nevermind. It wasn't the material that was the issue, it
> >> was how it was used. Incredibly dangerous failure modes, yet
> >> nobody was calling for manufacturers to stop using aluminum, steel
> >> or titanium for bike parts.
> >
> > Nobody is calling for manufacturers to stop using anything.
>
> Perhaps not. Could you sum up what is being suggested? It certainly
> appears that there are several posters who are saying that carbon
> fiber is not appropriate for critical (parts that, if they fail,
> could cause serious injury or death) bicycle parts.
That is exactly what I am saying. I won't presume to speak for anyone
else. Could CF be made suitable through the use of different resins?
Different layup schedules? More layers? I don't know and will leave
that to people who do.
As for whether manufacturers should stop using it, that of course is up
to them. I will not buy a CF frame, fork, seatpost, stem or handlebar
for the reasons I have previously cited which are supported by
literature previously referenced. I don't make that decision for anyone
else. They may want to buy the things, and given the number of CF bikes
I see around here the market seems to be ample. For my uses, CF offers
no significant benefits over other materials and poses significant
drawbacks.
|
| | | | | | | |
Date: 10 Sep 2007 02:31:40
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> > Nobody is calling for manufacturers to stop using anything.
>>
>> Perhaps not. Could you sum up what is being suggested? It certainly
>> appears that there are several posters who are saying that carbon
>> fiber is not appropriate for critical (parts that, if they fail,
>> could cause serious injury or death) bicycle parts.
>
> That is exactly what I am saying. I won't presume to speak for anyone
> else. Could CF be made suitable through the use of different resins?
> Different layup schedules? More layers? I don't know and will leave
> that to people who do.
>
> As for whether manufacturers should stop using it, that of course is up
> to them. I will not buy a CF frame, fork, seatpost, stem or handlebar
> for the reasons I have previously cited which are supported by
> literature previously referenced. I don't make that decision for anyone
> else. They may want to buy the things, and given the number of CF bikes
> I see around here the market seems to be ample. For my uses, CF offers
> no significant benefits over other materials and poses significant
> drawbacks.
Tim: Thanks. I thought I was missing the point, going nuts, or a combination
of the two! Symptoms for which the obvious cure could only be removal of
carbon fiber from my diet. : >)
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-505934.20580809092007@news.iphouse.com...
> In article <EX0Fi.26112$eY.15959@newssvr13.news.prodigy.net>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> >> Oh, wait, nevermind. It wasn't the material that was the issue, it
>> >> was how it was used. Incredibly dangerous failure modes, yet
>> >> nobody was calling for manufacturers to stop using aluminum, steel
>> >> or titanium for bike parts.
>> >
>> > Nobody is calling for manufacturers to stop using anything.
>>
>> Perhaps not. Could you sum up what is being suggested? It certainly
>> appears that there are several posters who are saying that carbon
>> fiber is not appropriate for critical (parts that, if they fail,
>> could cause serious injury or death) bicycle parts.
>
> That is exactly what I am saying. I won't presume to speak for anyone
> else. Could CF be made suitable through the use of different resins?
> Different layup schedules? More layers? I don't know and will leave
> that to people who do.
>
> As for whether manufacturers should stop using it, that of course is up
> to them. I will not buy a CF frame, fork, seatpost, stem or handlebar
> for the reasons I have previously cited which are supported by
> literature previously referenced. I don't make that decision for anyone
> else. They may want to buy the things, and given the number of CF bikes
> I see around here the market seems to be ample. For my uses, CF offers
> no significant benefits over other materials and poses significant
> drawbacks.
|
| | | | | | | | |
Date: 10 Sep 2007 08:43:38
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <g02Fi.4189$FO2.312@newssvr14.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> > Nobody is calling for manufacturers to stop using anything.
> >>
> >> Perhaps not. Could you sum up what is being suggested? It
> >> certainly appears that there are several posters who are saying
> >> that carbon fiber is not appropriate for critical (parts that, if
> >> they fail, could cause serious injury or death) bicycle parts.
> >
> > That is exactly what I am saying. I won't presume to speak for
> > anyone else. Could CF be made suitable through the use of
> > different resins? Different layup schedules? More layers? I don't
> > know and will leave that to people who do.
> >
> > As for whether manufacturers should stop using it, that of course
> > is up to them. I will not buy a CF frame, fork, seatpost, stem or
> > handlebar for the reasons I have previously cited which are
> > supported by literature previously referenced. I don't make that
> > decision for anyone else. They may want to buy the things, and
> > given the number of CF bikes I see around here the market seems to
> > be ample. For my uses, CF offers no significant benefits over
> > other materials and poses significant drawbacks.
>
> Tim: Thanks. I thought I was missing the point, going nuts, or a
> combination of the two!
Nope, that's just the usual consequence of long Usenet threads. Things
get blurry after a couple hundred posts and the thread finally dies
because no one is sure what the topic is any more.
> Symptoms for which the obvious cure could only be removal of carbon
> fiber from my diet. :>)
:-)
|
| | | | |
Date: 09 Sep 2007 12:23:04
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message
news:ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com...
>> Breaking frames may not be as dramatic nor as likely to result in severe
>> injury (although I can be enlightened from that notion). But breaking
>> handlebars, stems and seatposts is definitely likely to be - and that
>> goes for Al alloys too, for sure. However, given CF's characteristic for
>> lower damage tolerance (than metals) in directions different to fiber
>> orientation, why increase the risk?
>
> I agree. Materials that fail in common use should be banned from bikes.
>
> Oh, darn. All those failing aluminum stems... crap. That's quite a few
> thousand dollars of inventory I'm going to have to dump. And the failed
> Belleri handlebars. Crap. That's going to be many thousands of dollars
> more of inventory I can't trust.
You fail to see the point. CF has lower damage tolerance than Al.
> Oh, darn. All those steel frames that buckled under impact, causing the
> front wheel to make contact with the downtube and throwing the rider
> violently. Crap. We can't use steel for frames anymore.
You fail to see the point. CF has lower damage tolerance than steel.
> Oh, darn. All those titanium frames that had sheared downtubes, due to
> cracks beginning at the downtube cable guides. Crap.
You fail to see the point. CF has lower damage tolerance than Ti.
> Oh, wait, nevermind. It wasn't the material that was the issue, it was how
> it was used. Incredibly dangerous failure modes, yet nobody was calling
> for manufacturers to stop using aluminum, steel or titanium for bike
> parts.
You fail to see the point. CF has lower damage tolerance than Al, steel,
and Ti.
Mike, ad absurdum arguments rarely, if ever, advances knowledge. Take a
deep breath and re-read what you've been posted. Since you've already
admitted that inspection techniques for bike CF frames are inadequate, the
question you can answer is, tell us what the difference is between
manufacturers recommendations on how to inspect/deal with damage to CF and
Al, Ti, and steel.
|
| | | | | |
Date: 09 Sep 2007 09:53:53
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
> You fail to see the point. CF has lower damage tolerance than Al, steel,
> and Ti.
>
> Mike, ad absurdum arguments rarely, if ever, advances knowledge. Take a
> deep breath and re-read what you've been posted. Since you've already
> admitted that inspection techniques for bike CF frames are inadequate, the
> question you can answer is, tell us what the difference is between
> manufacturers recommendations on how to inspect/deal with damage to CF and
> Al, Ti, and steel.
Are you saying that the only property that matters is not how resistant to
"damage" something is, but how it reacts once damaged?
As there's no universal meaning to "damage tolerance" perhaps you could give
us your definition? That might clear up a few things here.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Jambo" <-@-.- > wrote in message
news:46e41dbc$0$28798$4c368faf@roadrunner.com...
>
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote in message
> news:ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com...
>
>>> Breaking frames may not be as dramatic nor as likely to result in severe
>>> injury (although I can be enlightened from that notion). But breaking
>>> handlebars, stems and seatposts is definitely likely to be - and that
>>> goes for Al alloys too, for sure. However, given CF's characteristic
>>> for lower damage tolerance (than metals) in directions different to
>>> fiber orientation, why increase the risk?
>>
>> I agree. Materials that fail in common use should be banned from bikes.
>>
>> Oh, darn. All those failing aluminum stems... crap. That's quite a few
>> thousand dollars of inventory I'm going to have to dump. And the failed
>> Belleri handlebars. Crap. That's going to be many thousands of dollars
>> more of inventory I can't trust.
>
> You fail to see the point. CF has lower damage tolerance than Al.
>
>> Oh, darn. All those steel frames that buckled under impact, causing the
>> front wheel to make contact with the downtube and throwing the rider
>> violently. Crap. We can't use steel for frames anymore.
>
> You fail to see the point. CF has lower damage tolerance than steel.
>
>> Oh, darn. All those titanium frames that had sheared downtubes, due to
>> cracks beginning at the downtube cable guides. Crap.
>
> You fail to see the point. CF has lower damage tolerance than Ti.
>
>> Oh, wait, nevermind. It wasn't the material that was the issue, it was
>> how it was used. Incredibly dangerous failure modes, yet nobody was
>> calling for manufacturers to stop using aluminum, steel or titanium for
>> bike parts.
>
> You fail to see the point. CF has lower damage tolerance than Al, steel,
> and Ti.
>
> Mike, ad absurdum arguments rarely, if ever, advances knowledge. Take a
> deep breath and re-read what you've been posted. Since you've already
> admitted that inspection techniques for bike CF frames are inadequate, the
> question you can answer is, tell us what the difference is between
> manufacturers recommendations on how to inspect/deal with damage to CF and
> Al, Ti, and steel.
>
>
|
| | | | | | |
Date: 10 Sep 2007 20:20:28
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message
news:CyVEi.2079$Sd4.139@nlpi061.nbdc.sbc.com...
>> You fail to see the point. CF has lower damage tolerance than Al, steel,
>> and Ti.
>>
>> Mike, ad absurdum arguments rarely, if ever, advances knowledge. Take a
>> deep breath and re-read what you've been posted. Since you've already
>> admitted that inspection techniques for bike CF frames are inadequate,
>> the question you can answer is, tell us what the difference is between
>> manufacturers recommendations on how to inspect/deal with damage to CF
>> and Al, Ti, and steel.
>
> Are you saying that the only property that matters is not how resistant to
> "damage" something is, but how it reacts once damaged?
No, quite the opposite. The two properties that matter to any material used
in bikes are how damage resistant it is, and how it reacts once damaged.
> As there's no universal meaning to "damage tolerance" perhaps you could
> give us your definition? That might clear up a few things here.
I've been outlining that all throughout my other posts. Damage tolerance is
the ability of a component made up of a particular material, to resist
impacts that compromise its structural integrity. CF composites can be very
strong, durable, and damage resistant when loaded along the direction of the
carbon fibers. However, in directions off the length of the carbon fibers,
carbon fiber acts in a BRITTLE manner, i.e you can easily sever the fibers.
In this case the plastic matrix is the only thing that will resist the
perpendicular load to the carbon fiber. (analogy: take a pencil - try to
break it by loading it axially, along its length. Now try to break it by
loading it perpendicular to its length).
So composites manufacturers get around this by determining all the loads
that the component will undergo, and the directions of these loads.
Different carbon fiber layers are then oriented to align with the direction
of all these loads.
The question you need to ask is: have the CF bike frame/handlebar/seatpost
manufacturers considered all the loads that their components are going to
undergo, including those that are "off-design" such as the dings and other
low-velocity impacts that well used bikes suffer (tree branch hits on the
fork legs, bike lock strikes on frame tubes, loads on top tubes by bike
racks)? Are there carbon fibers aligned to deal with these impacts?
So what is the difference between manufacturers' recommendations on
inspecting CF frames, vs inspecting metal frames?
|
| | | | |
Date: 09 Sep 2007 06:55:24
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>>> I have seen broken CF forks, but
>>> only at the crown glue joint or at the crown steerer (aluminum steerer
>>> and crown). I remember the early problems with the BB insert in the
>>> Trek CF frames, but that was a different type of bonding problem and
>>> not delamination like we are discussing here. I don't seem to
>>> remember any more broken CF frames than, let's say, Al (e.g.
>>> Cannondale was having a hard time there for a few years with the 2.8
>>> design). I ride a Cannondale, so I am not trying to justify a CF
>>> purchase. I am just trying to get a handle on the real risk to the
>>> average rider of a decent CF frame.-- Jay Beattie.
>> Breaking frames may not be as dramatic nor as likely to result in severe
>> injury (although I can be enlightened from that notion). But breaking
>> handlebars, stems and seatposts is definitely likely to be - and that goes
>> for Al alloys too, for sure. However, given CF's characteristic for lower
>> damage tolerance (than metals) in directions different to fiber
>> orientation, why increase the risk?
>
> I agree. Materials that fail in common use should be banned from bikes.
>
> Oh, darn. All those failing aluminum stems... crap. That's quite a few
> thousand dollars of inventory I'm going to have to dump. And the failed
> Belleri handlebars. Crap. That's going to be many thousands of dollars more
> of inventory I can't trust.
>
> Oh, darn. All those steel frames that buckled under impact, causing the
> front wheel to make contact with the downtube and throwing the rider
> violently. Crap. We can't use steel for frames anymore.
>
> Oh, darn. All those titanium frames that had sheared downtubes, due to
> cracks beginning at the downtube cable guides. Crap.
>
> Oh, wait, nevermind. It wasn't the material that was the issue, it was how
> it was used. Incredibly dangerous failure modes, yet nobody was calling for
> manufacturers to stop using aluminum, steel or titanium for bike parts.
>
10 points.
> --Mike-- Chain Reaction Bicycles
> www.ChainReactionBicycles.com
>
>
> "Jambo" <-@-.-> wrote in message
> news:46e2fa4a$0$32515$4c368faf@roadrunner.com...
>> "Jay Beattie" <jbeattie@lindsayhart.com> wrote in message
>> news:1189184546.941992.244120@o80g2000hse.googlegroups.com...
>>> Another point of clarification: are CF bicycle frames over built,
>>> vis., stronger than necessary to take in to consideration the
>>> limitations of the material?
>> Who really knows, since manufacturers never publish the design loads of
>> their frames. If they did, we'd also be able to calculate fatigue lives
>> of Al alloy frames. With the standardization of particular tube sizes,
>> maybe sizing of frame tubes is merely historical. What should be
>> reasonably done by manufacturers is to compare the strength and loads that
>> can be "safely" withstood by metal frames, and design the CF frames
>> accordingly. Do they do this? Your guess is as good as mine. The point
>> is that we should not assume that "aerospace experience" has been
>> transferred across to the bike industry because if they have, then
>> critical things such as design loads and fatigue lives need to be analyzed
>> for bike frames as well.
>>
>>> I ask this because I have not see an
>>> epidemic of broken CF frames or forks, and I have been riding CF forks
>>> for over 15 years (different ones).
>> I haven't heard an epidemic of broken Al frames either. I have seen many
>> broken CF handlebars and seatposts. However, it doesn't deflect from the
>> fact that CF is easier to damage by low impact loads from directions
>> different to duty loads (e.g. a fork being hit on the legs). Now THAT's
>> aerospace experience.>> I have seen broken CF forks, but
>>> only at the crown glue joint or at the crown steerer (aluminum steerer
>>> and crown). I remember the early problems with the BB insert in the
>>> Trek CF frames, but that was a different type of bonding problem and
>>> not delamination like we are discussing here. I don't seem to
>>> remember any more broken CF frames than, let's say, Al (e.g.
>>> Cannondale was having a hard time there for a few years with the 2.8
>>> design). I ride a Cannondale, so I am not trying to justify a CF
>>> purchase. I am just trying to get a handle on the real risk to the
>>> average rider of a decent CF frame.-- Jay Beattie.
>> Breaking frames may not be as dramatic nor as likely to result in severe
>> injury (although I can be enlightened from that notion). But breaking
>> handlebars, stems and seatposts is definitely likely to be - and that goes
>> for Al alloys too, for sure. However, given CF's characteristic for lower
>> damage tolerance (than metals) in directions different to fiber
>> orientation, why increase the risk?
>
>>
>
>
|
| | | | |
Date: 09 Sep 2007 06:31:27
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> I agree. Materials that fail in common use should be banned from
> bikes.
>
> Oh, darn. All those failing aluminum stems... crap. That's quite a
> few thousand dollars of inventory I'm going to have to dump. And the
> failed Belleri handlebars. Crap. That's going to be many thousands of
> dollars more of inventory I can't trust.
Like this tem owned by a friend, who discovered this condition the day
after a 104 mile ride we undertook on hilly road including gravel and
rough pavement?
http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
How would a CF stem have fared with cracking like this?
> Oh, darn. All those steel frames that buckled under impact, causing
> the front wheel to make contact with the downtube and throwing the
> rider violently. Crap. We can't use steel for frames anymore.
>
> Oh, darn. All those titanium frames that had sheared downtubes, due
> to cracks beginning at the downtube cable guides. Crap.
>
> Oh, wait, nevermind. It wasn't the material that was the issue, it
> was how it was used. Incredibly dangerous failure modes, yet nobody
> was calling for manufacturers to stop using aluminum, steel or
> titanium for bike parts.
As hyperbole goes, this doesn't work very well. The failure mode for
these materials is rarely catastrophic unlike CF and is thus not
"incredibly" dangerous. The problem with steel frame in your example
was the impact- a CF frame would have shattered rather than bending.
The problem with the titanium frames didn't result in the downtube just
snapping.
|
| | | | | |
Date: 09 Sep 2007 09:04:39
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> bikes.
>>
>> Oh, darn. All those failing aluminum stems... crap. That's quite a
>> few thousand dollars of inventory I'm going to have to dump. And the
>> failed Belleri handlebars. Crap. That's going to be many thousands of
>> dollars more of inventory I can't trust.
>
> Like this tem owned by a friend, who discovered this condition the day
> after a 104 mile ride we undertook on hilly road including gravel and
> rough pavement?
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
>
> How would a CF stem have fared with cracking like this?
It doesn't matter whether a carbon fiber stem would have survived with a
crack like that; the relevant question is whether it would have developed
that crack.
>> Oh, darn. All those steel frames that buckled under impact, causing
>> the front wheel to make contact with the downtube and throwing the
>> rider violently. Crap. We can't use steel for frames anymore.
>>
>> Oh, darn. All those titanium frames that had sheared downtubes, due
>> to cracks beginning at the downtube cable guides. Crap.
>>
>> Oh, wait, nevermind. It wasn't the material that was the issue, it
>> was how it was used. Incredibly dangerous failure modes, yet nobody
>> was calling for manufacturers to stop using aluminum, steel or
>> titanium for bike parts.
>
> As hyperbole goes, this doesn't work very well. The failure mode for
> these materials is rarely catastrophic unlike CF and is thus not
> "incredibly" dangerous.
That's the part of this discussion I find so incredible. Catastrophic
failure modes have been around for as long as manufacturing. Carbon fiber
didn't invent them. Carbon fiber didn't cause them. Flawed designs &
manufacturing did. Back in the day, we saw a lot of "catastrophic" failures.
People have either forgotten about that, or else, because those failures
were on "tried & true" technology, materials that had been around for some
time, they were, for some reason, tolerated. Why?
There is obviously something appealing about taking on the latest technology
and putting it down. It becomes a fun game, apparently, to see someone post
a picture of a failed frame on the Internet and, without ANY corroboration
of the JRA (Just Riding Along) story, extrapolate wildly from it.
The smartest person I know in the "warranty" department (which I put in
quotes because most of what he deals with isn't actually a "warranty"), when
presented a failure that might be questionable, always ask one simple
question. "What do you think *really* happened?" It gets you to thinking a
bit outside the oral or written history actually presented. And sometimes
you get a customer with a "JRA" and you ask him (almost always a "him" by
the way) "What do you think really happened" and, hold down the fort, they
will actually tell you. Bizarre yet true. They come in claiming it's a JRA,
but you ask for details and yikes, it's something entirely different.
> The problem with steel frame in your example
> was the impact- a CF frame would have shattered rather than bending.
> The problem with the titanium frames didn't result in the downtube just
> snapping.
You're making an assumption that is rarely correct. Modern carbon frames &
forks will, I will claim, generally "survive" a head-on impact more readily
than the steel frames of yesteryear. They will not survive as readily an
impact from the side. These claims come from observations over many years,
many product lines, many customers, many impacts.
And the titanium frame that you didn't think resulted in a downtube
snapping? Think again. I was there. Time between first hearing something and
failure was about 3 miles. We obviously aborted the ride after hearing a
strange noise and running it down (a very small tear on the downtube), and
decided to ride back to where he'd parked his car, 6 relatively-flat miles
away. After three miles the tube had torn through and I had to go get my
car. The failure was definitely catastrophic, although since we were keeping
an eye on it there was no injury, no crash. If we hadn't figured out what
the noise was coming from, it could have been otherwise.
If we want to get personal, I did the carbon bike into car gig myself. 16mph
into the side of a Mustang some kid backed out of his driveway onto the
road. My teeth fared much worse than my bike.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | | | | |
Date: 13 Sep 2007 21:08:33
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
>
> Jay Hill wrote:
> >
> > PS. You should learn-up about trans fats, there, Homer.
>
> Lard Police. What's next?!?
There are no trans fats of any kind in lard. Almost all trans fat is
artificial and harmful, and the coverup for it by the American food
oil industry is why wholesome fats like coconut oil and palm oil have
been unfairly maligned as unhealthy. The move to ban trans fats here
and there isn't about forcing people to adopt a healthy diet (which
would be impossible to do); it's about stopping businesses from
feeding people things that injure them.
Like Jay says, you should read up on it.
http://en.wikipedia.org/wiki/Trans_fat
http://www.unu.edu/Unupress/food/8F142e/8F142E0d.htm
Chalo
|
| | | | | | | |
Date: 13 Sep 2007 20:48:59
From: Michael Press
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
n article
<1189717713.770344.228000@k79g2000hse.googlegroups.com > ,
Chalo <chalo.colina@gmail.com > wrote:
> Bill Sornson wrote:
>> Jay Hill wrote:
>>>
>>> PS. You should learn-up about trans fats, there, Homer.
>>
>> Lard Police. What's next?!?
>
> There are no trans fats of any kind in lard. Almost all trans fat is
> artificial and harmful, and the coverup for it by the American food
> oil industry is why wholesome fats like coconut oil and palm oil have
> been unfairly maligned as unhealthy. The move to ban trans fats here
> and there isn't about forcing people to adopt a healthy diet (which
> would be impossible to do); it's about stopping businesses from
> feeding people things that injure them.
>
> Like Jay says, you should read up on it.
>
> http://en.wikipedia.org/wiki/Trans_fat
> http://www.unu.edu/Unupress/food/8F142e/8F142E0d.htm
My approach is that I am the best analytic laboratory.
If it tastes good it is good for me. I will eat food
that tastes good; but too much stops tasting good and
then I stop eating. The great thing here in the USA is
that food labels must list ingredients, and I have read
them from the time I could read at all. I stopped
eating hydrogenated fats decades ago; they do not taste
good. I stay with butter, eggs, olive oil, nuts, and
red meat for my fat. Imagine my gratification when a
twenty year study by some good folk in Massachusetts
determined that eating hydrogenated fats provided no
health benefit over butter.
--
Michael Press
|
| | | | | | | | |
Date: 14 Sep 2007 00:40:50
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Michael Press wrote:
> n article
> <1189717713.770344.228000@k79g2000hse.googlegroups.com> ,
> Chalo <chalo.colina@gmail.com> wrote:
>> Bill Sornson wrote:
>>> Jay Hill wrote:
>>>>
>>>> PS. You should learn-up about trans fats, there, Homer.
>>>
>>> Lard Police. What's next?!?
>>
>> There are no trans fats of any kind in lard. Almost all trans fat is
>> artificial and harmful, and the coverup for it by the American food
>> oil industry is why wholesome fats like coconut oil and palm oil have
>> been unfairly maligned as unhealthy. The move to ban trans fats here
>> and there isn't about forcing people to adopt a healthy diet (which
>> would be impossible to do); it's about stopping businesses from
>> feeding people things that injure them.
>>
>> Like Jay says, you should read up on it.
>>
>> http://en.wikipedia.org/wiki/Trans_fat
>> http://www.unu.edu/Unupress/food/8F142e/8F142E0d.htm
>
> My approach is that I am the best analytic laboratory.
> If it tastes good it is good for me. I will eat food
> that tastes good; but too much stops tasting good and
> then I stop eating. The great thing here in the USA is
> that food labels must list ingredients, and I have read
> them from the time I could read at all. I stopped
> eating hydrogenated fats decades ago; they do not taste
> good. I stay with butter, eggs, olive oil, nuts, and
> red meat for my fat. Imagine my gratification when a
> twenty year study by some good folk in Massachusetts
> determined that eating hydrogenated fats provided no
> health benefit over butter.
Exactly.
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Date: 14 Sep 2007 08:12:56
From: Peter Cole
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
> Michael Press wrote:
>> The great thing here in the USA is
>> that food labels must list ingredients, and I have read
>> them from the time I could read at all.
> Exactly.
Not exactly.
<http://en.wikipedia.org/wiki/Trans_fat >
"Before 2006, consumers in the United States could not directly
determine the presence (or quantity) of trans fats in food products.
This information could only be inferred from the ingredient list,
notably from the partially hydrogenated ingredients."
"Do-gooders" at work.
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Date: 14 Sep 2007 08:54:23
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> Bill Sornson wrote:
>> Michael Press wrote:
>>> The great thing here in the USA is
>>> that food labels must list ingredients, and I have read
>>> them from the time I could read at all.
>
>> Exactly.
>
> Not exactly.
Exactly NOT what I was replying to, but nicely misleading!
Bill "can see why poor ol' jim beam gets so exasperated" S.
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Date: 14 Sep 2007 14:39:14
From: Peter Cole
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
> Peter Cole wrote:
>> Bill Sornson wrote:
>>> Michael Press wrote:
>>>> The great thing here in the USA is
>>>> that food labels must list ingredients, and I have read
>>>> them from the time I could read at all.
>>> Exactly.
>> Not exactly.
>
> Exactly NOT what I was replying to, but nicely misleading!
>
> Bill "can see why poor ol' jim beam gets so exasperated" S.
>
>
Kind of hard to know what your "exactly" was referring to since you
tacked it to a long paragraph.
My context (which you snipped) was regarding the presence of information
at all.
I understand that you are in opposition to the "nanny state" (forgive me
if I abbreviate the complexity & depth). I was merely pointing out that
information should be neutral and available, but it has taken quite a
fight to get there.
To clarify, I don't take a stand (not one that I feel like defending
here anyway) on the whole government protecting people from themselves
thing, but I do think that at least the information should be available
(which it hasn't always been). Perhaps that's too nuanced, but I am a
liberal.
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Date: 14 Sep 2007 15:30:46
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> Bill Sornson wrote:
>> Peter Cole wrote:
>>> Bill Sornson wrote:
>>>> Michael Press wrote:
>>>>> The great thing here in the USA is
>>>>> that food labels must list ingredients, and I have read
>>>>> them from the time I could read at all.
>>>> Exactly.
>>> Not exactly.
>>
>> Exactly NOT what I was replying to, but nicely misleading!
>>
>> Bill "can see why poor ol' jim beam gets so exasperated" S.
>>
>>
>
> Kind of hard to know what your "exactly" was referring to since you
> tacked it to a long paragraph.
I see these endless back & forth arguments between you and beam, and neither
of you trim ANYTHING. (Makes them all but unreadable, BTW, but then no one
else is interested anyway.)
Yet here you decided to trim the "meat" (intended) of what Press wrote and
with which I agreed and left instead some off-hand remark about labels,
implying that that was what prompted my comment.
I repeat: nicely misleading.
Bill "almost Floggeresque" S.
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Date: 15 Sep 2007 08:47:21
From: Peter Cole
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
> Peter Cole wrote:
>> Bill Sornson wrote:
>>> Peter Cole wrote:
>>>> Bill Sornson wrote:
>>>>> Michael Press wrote:
>>>>>> The great thing here in the USA is
>>>>>> that food labels must list ingredients, and I have read
>>>>>> them from the time I could read at all.
>>>>> Exactly.
>>>> Not exactly.
>>> Exactly NOT what I was replying to, but nicely misleading!
>>>
>>> Bill "can see why poor ol' jim beam gets so exasperated" S.
>>>
>>>
>> Kind of hard to know what your "exactly" was referring to since you
>> tacked it to a long paragraph.
>
> I see these endless back & forth arguments between you and beam, and neither
> of you trim ANYTHING.
I frequently trim. Of course trimming exposes you to the criticism that
you're trimming context to mislead.
> (Makes them all but unreadable, BTW, but then no one
> else is interested anyway.)
If you say so.
> Yet here you decided to trim the "meat" (intended) of what Press wrote and
> with which I agreed and left instead some off-hand remark about labels,
> implying that that was what prompted my comment.
>
> I repeat: nicely misleading.
MP made several points in the paragraph you said "Exactly" to:
1) Bad food tastes bad (to him).
2) The USA is great because it labels food.
3) He doesn't eat hydrogenated fats.
3) He eats other fats.
4) He was gratified by a study that said margarine wasn't better than
butter.
The prior context was Chalo's remark that big business was/is covering
up the unhealthy effects of trans fats. Which was a response to your
"Lard Police" one-liner.
I apologize if your "Exactly" only applied to the last thing MP said
(the study), but, to me, the context indicated that you felt his remarks
were a rebuttal of the need for government regulation of food content.
My remark was in support of Chalo's previous argument that the industry
does indeed resist food labeling, which MP likes/needs to support his
strategy.
"Misleading"? I don't know. Not intentionally. Given the prior context,
singling out MP's #2 above doesn't seem so. You have to admit your
"Exactly" was a bit ambiguous.
Anyway, do you support government food labeling standards, or not? Is
labeling trans fat content part of the "Lard Police" charge?
>
> Bill "almost Floggeresque" S.
>
>
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Date: 14 Sep 2007 04:09:38
From: still me
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 20:48:59 -0700, Michael Press <rubrum@pacbell.net >
wrote:
>My approach is that I am the best analytic laboratory.
>If it tastes good it is good for me.
Sound scientific strategy (not!)
>I will eat food
>that tastes good; but too much stops tasting good and
>then I stop eating. The great thing here in the USA is
>that food labels must list ingredients, and I have read
>them from the time I could read at all.
And how do you know what the effects of certain substances are on your
body? By taste ?
>I stopped
>eating hydrogenated fats decades ago; they do not taste
>good. I stay with butter, eggs, olive oil, nuts, and
>red meat for my fat. Imagine my gratification when a
>twenty year study by some good folk in Massachusetts
>determined that eating hydrogenated fats provided no
>health benefit over butter.
Convenient coincidence for your diet strategy.
PS. - the red meat ain't real good for you.
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Date: 14 Sep 2007 18:26:44
From: Michael Press
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
In article
<s72ke3dmt54933fumbofolftgijivi2vj6@4ax.com >,
still me <wheeledBob@yahoo.com > wrote:
> On Thu, 13 Sep 2007 20:48:59 -0700, Michael Press <rubrum@pacbell.net>
> wrote:
>
> >My approach is that I am the best analytic laboratory.
> >If it tastes good it is good for me.
>
> Sound scientific strategy (not!)
The best scientists experiment on themselves.
I try to emulate them.
> >I will eat food
> >that tastes good; but too much stops tasting good and
> >then I stop eating. The great thing here in the USA is
> >that food labels must list ingredients, and I have read
> >them from the time I could read at all.
>
> And how do you know what the effects of certain substances are on your
> body? By taste ?
I said `taste' to include other sensations, such
as digestive activity, sense of health, and hangovers.
> >I stopped
> >eating hydrogenated fats decades ago; they do not taste
> >good. I stay with butter, eggs, olive oil, nuts, and
> >red meat for my fat. Imagine my gratification when a
> >twenty year study by some good folk in Massachusetts
> >determined that eating hydrogenated fats provided no
> >health benefit over butter.
>
> Convenient coincidence for your diet strategy.
I will match mine with anyone's.
For instance, I will never criticize
the diet of anyone else.
> PS. - the red meat ain't real good for you.
How good is it?
--
Michael Press
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Date: 13 Sep 2007 15:11:49
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo wrote:
> Bill Sornson wrote:
>>
>> Jay Hill wrote:
>>>
>>> PS. You should learn-up about trans fats, there, Homer.
>>
>> Lard Police. What's next?!?
>
> There are no trans fats of any kind in lard. Almost all trans fat is
> artificial and harmful, and the coverup for it by the American food
> oil industry is why wholesome fats like coconut oil and palm oil have
> been unfairly maligned as unhealthy. The move to ban trans fats here
> and there isn't about forcing people to adopt a healthy diet (which
> would be impossible to do); it's about stopping businesses from
> feeding people things that injure them.
Coming from a morbidly obese person, I find this...ironic.
> Like Jay says, you should read up on it.
>
> http://en.wikipedia.org/wiki/Trans_fat
> http://www.unu.edu/Unupress/food/8F142e/8F142E0d.htm
So after you ban/outlaw that, what's next?
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Date: 17 Sep 2007 10:25:35
From: andresmuro@aol.com
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 17, 10:27 am, "Bill Sornson" <as...@ask.me > wrote:
> andresm...@aol.com wrote:
> > On Sep 17, 9:38 am, "Bill Sornson" <as...@ask.me> wrote:
> >> r15...@aol.com wrote:
> >>> On Sep 17, 12:58 am, "Bill Sornson" <as...@ask.me> wrote:
> >>>> r15...@aol.com wrote:
> >>>>> On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>
> >>>>>> Bill "Hillary Lied; People Died" S.
>
> >>>>> True ... she was complicit along with so many others.
>
> >>>> Hillary didn't merely vote for the war; she went /beyond/
> >>>> administration claims in making the CASE for war. (For instance,
> >>>> she claimed a direct connection between Saddam Hussein and A.Q.: "
> >>>> He has also given aid, comfort, and sanctuary to terrorists,
> >>>> including Al Qaida members.")
>
> >>>> Of course, she was probably right, but...
>
> >>> Like many others, she clamored on board the troopship because she
> >>> thought invading Iraq would be an easy endeavor.
>
> >>> This for her was some seriously poor judgment.
>
> >> Today she says she was against it from the start. And none of her
> >> opponents (except a wife or two) OR the press will press her on it.
>
> >> Do they fear for their kneecaps or what? (Of course, that "Shoe
> >> Guy" -- Hsu? -- was /supposed/ to wind up dead. Even wrote a
> >> suicide note -- or someone did -- but he screwed 'em by not dying.
> >> Yet.)
>
> >> Bill "maybe Sandy Burglar will do the deed...he owes people, you
> >> know" S.
>
> > That's because the liberal media is owned by the liberal corporations,
> > namely aol time warner, viacom, fox/clear channel, disney, etc. They
> > area also funded through advertisement by ATT, Pfizer, Nabisco,
> > Sasetru, Magnolia, Chevron, Exxon, all state, etc.
>
> > All these liberal corporation have ordered their employees not to
> > question H Clinton. These liberal corporations feel that it is unfair
> > for the Republicans not to tax them, to give them subsidies and to
> > spend lots of money in the war. So, they want a morel liberal
> > government that will tax them more, end all corporate subsidies, offer
> > socialized medicine and spend more on education, less in the military
> > and less in huge corporate contracts. So, to that end, these
> > corporations are supporting a liberal.
>
> > Makes perfect sense to me.
>
> So why won't they ask her tough questions? (Like, other than the above, how
> she can claim to be pro-woman yet helped destroy the women who accused her
> hubby of abuse, lewd behavior and even rape? Were they ALL liars???)
>
> Kneecaps, I tells ya. Kneecaps.
I don't know what they ask since I don't watch news on TV and I don't
give a hoot about what politicians claim. H Clinton is the Senator
from NY so, she gets mucho support from IPAC. She is partly owned by
them and by the israeli vote. I hate all politicians. They are owned
by the lobbyists. the only one that I like so far is Obama, and that
is only because of the Obama Girl.
Regardless of what Hilary, Obama, or Cunt.. sorry, I meant pussy,
sorry, I meant Bush have to say. The war is fucked.
Andres
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Date: 09 Sep 2007 18:32:11
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <sQUEi.2074$Sd4.1410@nlpi061.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> bikes.
> >>
> >> Oh, darn. All those failing aluminum stems... crap. That's quite a
> >> few thousand dollars of inventory I'm going to have to dump. And
> >> the failed Belleri handlebars. Crap. That's going to be many
> >> thousands of dollars more of inventory I can't trust.
> >
> > Like this tem owned by a friend, who discovered this condition the
> > day after a 104 mile ride we undertook on hilly road including
> > gravel and rough pavement?
> >
> > http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
> >
> > How would a CF stem have fared with cracking like this?
>
> It doesn't matter whether a carbon fiber stem would have survived
> with a crack like that; the relevant question is whether it would
> have developed that crack.
Nope. Stuff breaks. The world is not optimal. How does a material
deal with those facts? Does it fail catastrophically or gradually? The
photographs show a gradual failure.
> >> Oh, darn. All those steel frames that buckled under impact,
> >> causing the front wheel to make contact with the downtube and
> >> throwing the rider violently. Crap. We can't use steel for frames
> >> anymore.
> >>
> >> Oh, darn. All those titanium frames that had sheared downtubes,
> >> due to cracks beginning at the downtube cable guides. Crap.
> >>
> >> Oh, wait, nevermind. It wasn't the material that was the issue, it
> >> was how it was used. Incredibly dangerous failure modes, yet
> >> nobody was calling for manufacturers to stop using aluminum, steel
> >> or titanium for bike parts.
> >
> > As hyperbole goes, this doesn't work very well. The failure mode
> > for these materials is rarely catastrophic unlike CF and is thus
> > not "incredibly" dangerous.
>
> That's the part of this discussion I find so incredible. Catastrophic
> failure modes have been around for as long as manufacturing. Carbon
> fiber didn't invent them. Carbon fiber didn't cause them. Flawed
> designs & manufacturing did. Back in the day, we saw a lot of
> "catastrophic" failures. People have either forgotten about that, or
> else, because those failures were on "tried & true" technology,
> materials that had been around for some time, they were, for some
> reason, tolerated. Why?
Previous materials with widespread use have not had the catastrophic
failure issues prevalent in CF composites. When CF fails, it tends to
fail right now, boom. Other materials have not shown that tendency.
The exception has been failed welds, particularly in titanium and
aluminum. That is less about materials properties than about faulty
manufacturing processes.
Let's defined catastrophic failure: the component breaks into two or
more discrete pieces nearly instantaneously. This is typical of brittle
materials (glass, for example) and not typical of metallic materials
commonly used in bicycles
> There is obviously something appealing about taking on the latest
> technology and putting it down.
New materials have different properties that might be beneficial and
different properties that might be detrimental. We have seen the
"latest technology" repeatedly prove to be unsuitable for the
applications for which it was marketed. There is legitimate question
about the suitability of CF composites for use in bicycles. The issues
raised here are those mirrored in the materials literature and mirrored
in the published statements of manufacturers that use this material-
including Trek and Calfee.
> It becomes a fun game, apparently, to see someone post a picture of a
> failed frame on the Internet and, without ANY corroboration of the
> JRA (Just Riding Along) story, extrapolate wildly from it.
I have, along with others, tried very hard to avoid extrapolating about
that specific frame because we don't have enough information about the
crash or the condition of the frame before the crash.
> The smartest person I know in the "warranty" department (which I put
> in quotes because most of what he deals with isn't actually a
> "warranty"), when presented a failure that might be questionable,
> always ask one simple question. "What do you think *really*
> happened?" It gets you to thinking a bit outside the oral or written
> history actually presented. And sometimes you get a customer with a
> "JRA" and you ask him (almost always a "him" by the way) "What do you
> think really happened" and, hold down the fort, they will actually
> tell you. Bizarre yet true. They come in claiming it's a JRA, but you
> ask for details and yikes, it's something entirely different.
Yup. And since not JRA is normal use of bicycles, that raises
significant concerns about the toughness and damage resistance of the
materials used in critical components of bicycles. There are some that
can easily get you severely injured, disabled or killed if they fail
catastrophically.
> > The problem with steel frame in your example was the impact- a CF
> > frame would have shattered rather than bending. The problem with
> > the titanium frames didn't result in the downtube just snapping.
>
> You're making an assumption that is rarely correct. Modern carbon
> frames & forks will, I will claim, generally "survive" a head-on
> impact more readily than the steel frames of yesteryear. They will
> not survive as readily an impact from the side. These claims come
> from observations over many years, many product lines, many
> customers, many impacts.
Please define "survive."
> And the titanium frame that you didn't think resulted in a downtube
> snapping? Think again. I was there. Time between first hearing
> something and failure was about 3 miles. We obviously aborted the
> ride after hearing a strange noise and running it down (a very small
> tear on the downtube), and decided to ride back to where he'd parked
> his car, 6 relatively-flat miles away. After three miles the tube had
> torn through and I had to go get my car. The failure was definitely
> catastrophic, although since we were keeping an eye on it there was
> no injury, no crash. If we hadn't figured out what the noise was
> coming from, it could have been otherwise.
The rider had advanced warning and had a non-catastrophic failure.
Catastrophic does not mean that the tube broke. Catastrophic failure is
nearly instantaneous.
> If we want to get personal, I did the carbon bike into car gig
> myself. 16mph into the side of a Mustang some kid backed out of his
> driveway onto the road. My teeth fared much worse than my bike.
Unfortunately your carbon frame is not readily inspectable for damage.
I hope that is in in fact undamaged.
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Date: 13 Sep 2007 21:20:57
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
A Muzi wrote:
>
> Michael Warner wrote:
> >
> > A Muzi wrote:
> >>
> >> All regulation shares that aspect. If not at the outset, regulated and
> >> regulators wise up later.
> >
> > The supposedly regulated usually end up the winners, because they're
> > able to buy off the regulator and/or hire better lawyers to find lucrative
> > loopholes in the regulations. Until there's a disaster on the order of what
> > Enron did to California's power supply, anyway.
>
> Taxi drivers, surgeons, land developers, endlessly by its nature.
What you're talking about is intrinsic to corruption, not regulation.
Traffic is regulated, and it generally works better that way.
Regulation often comes first, and then corruption slips in later, as
you suggest. The fact that they are independent of each other is
illustrated by the fact that corruption tends to be rampant even where
there is no regulation.
Note that our current executive administration is anti-regulation but
pro-corruption. That's pretty much what "no-bid contract" means--
let's cut out the middleman/regulator, corrupt or not.
Chalo
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Date: 10 Sep 2007 01:15:25
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
> Let's defined catastrophic failure: the component breaks into two or
> more discrete pieces nearly instantaneously. This is typical of brittle
> materials (glass, for example) and not typical of metallic materials
> commonly used in bicycles
That would have been my Mavic stem (looked to have been made by 3TTT).
Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
I was sprinting when it happened. A aluminum, forged quill stem, single
bolt, not hinged. The section of stem that the handlebar-claming bolt
threaded into gave way. No, the threads didn't strip, the entire section
pulled away from the rest of the stem. Quite the rude thing to happen.
Points to consider- Aluminum. No prior warning. Catastrophic failure.
>> And the titanium frame that you didn't think resulted in a downtube
>> snapping? Think again. I was there. Time between first hearing
>> something and failure was about 3 miles. We obviously aborted the
>> ride after hearing a strange noise and running it down (a very small
>> tear on the downtube), and decided to ride back to where he'd parked
>> his car, 6 relatively-flat miles away. After three miles the tube had
>> torn through and I had to go get my car. The failure was definitely
>> catastrophic, although since we were keeping an eye on it there was
>> no injury, no crash. If we hadn't figured out what the noise was
>> coming from, it could have been otherwise.
>
> The rider had advanced warning and had a non-catastrophic failure.
> Catastrophic does not mean that the tube broke. Catastrophic failure is
> nearly instantaneous.
Had he been descending instead of riding on a level, smooth road, there is
every likelihood the noise would not have been noticed above normal road &
wind noise levels, and the failure would have been quite catastrophic.
>> If we want to get personal, I did the carbon bike into car gig
>> myself. 16mph into the side of a Mustang some kid backed out of his
>> driveway onto the road. My teeth fared much worse than my bike.
>
> Unfortunately your carbon frame is not readily inspectable for damage.
> I hope that is in in fact undamaged.
The impact was in 2000; the frame remains in continuous use since then. The
fork was replaced, due to a damaged steer column. It would have been replace
anyway, since it would have failed the "common sense" test (being that
nothing could have been designed to withstand that sort of impact, and thus
it cannot be trusted). The frame might have failed the "common sense" test
as well, except that I have yet to see, among the many (and I do mean many)
thousands of carbon fiber frames that I have sold, a catastrophic failure
that happened after an initial incident, and without warning. Please do not
take this to mean a frame is safe after a crash. Rather, for my sample size,
I see issues with forks, but not frames (dealing strictly with those that I
have sold, which is admittedly a base of only one manufacturer).
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-944D14.18321109092007@news.iphouse.com...
> In article <sQUEi.2074$Sd4.1410@nlpi061.nbdc.sbc.com>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> >> bikes.
>> >>
>> >> Oh, darn. All those failing aluminum stems... crap. That's quite a
>> >> few thousand dollars of inventory I'm going to have to dump. And
>> >> the failed Belleri handlebars. Crap. That's going to be many
>> >> thousands of dollars more of inventory I can't trust.
>> >
>> > Like this tem owned by a friend, who discovered this condition the
>> > day after a 104 mile ride we undertook on hilly road including
>> > gravel and rough pavement?
>> >
>> > http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
>> >
>> > How would a CF stem have fared with cracking like this?
>>
>> It doesn't matter whether a carbon fiber stem would have survived
>> with a crack like that; the relevant question is whether it would
>> have developed that crack.
>
> Nope. Stuff breaks. The world is not optimal. How does a material
> deal with those facts? Does it fail catastrophically or gradually? The
> photographs show a gradual failure.
>
>> >> Oh, darn. All those steel frames that buckled under impact,
>> >> causing the front wheel to make contact with the downtube and
>> >> throwing the rider violently. Crap. We can't use steel for frames
>> >> anymore.
>> >>
>> >> Oh, darn. All those titanium frames that had sheared downtubes,
>> >> due to cracks beginning at the downtube cable guides. Crap.
>> >>
>> >> Oh, wait, nevermind. It wasn't the material that was the issue, it
>> >> was how it was used. Incredibly dangerous failure modes, yet
>> >> nobody was calling for manufacturers to stop using aluminum, steel
>> >> or titanium for bike parts.
>> >
>> > As hyperbole goes, this doesn't work very well. The failure mode
>> > for these materials is rarely catastrophic unlike CF and is thus
>> > not "incredibly" dangerous.
>>
>> That's the part of this discussion I find so incredible. Catastrophic
>> failure modes have been around for as long as manufacturing. Carbon
>> fiber didn't invent them. Carbon fiber didn't cause them. Flawed
>> designs & manufacturing did. Back in the day, we saw a lot of
>> "catastrophic" failures. People have either forgotten about that, or
>> else, because those failures were on "tried & true" technology,
>> materials that had been around for some time, they were, for some
>> reason, tolerated. Why?
>
> Previous materials with widespread use have not had the catastrophic
> failure issues prevalent in CF composites. When CF fails, it tends to
> fail right now, boom. Other materials have not shown that tendency.
> The exception has been failed welds, particularly in titanium and
> aluminum. That is less about materials properties than about faulty
> manufacturing processes.
>
> Let's defined catastrophic failure: the component breaks into two or
> more discrete pieces nearly instantaneously. This is typical of brittle
> materials (glass, for example) and not typical of metallic materials
> commonly used in bicycles
>
>> There is obviously something appealing about taking on the latest
>> technology and putting it down.
>
> New materials have different properties that might be beneficial and
> different properties that might be detrimental. We have seen the
> "latest technology" repeatedly prove to be unsuitable for the
> applications for which it was marketed. There is legitimate question
> about the suitability of CF composites for use in bicycles. The issues
> raised here are those mirrored in the materials literature and mirrored
> in the published statements of manufacturers that use this material-
> including Trek and Calfee.
>
>> It becomes a fun game, apparently, to see someone post a picture of a
>> failed frame on the Internet and, without ANY corroboration of the
>> JRA (Just Riding Along) story, extrapolate wildly from it.
>
> I have, along with others, tried very hard to avoid extrapolating about
> that specific frame because we don't have enough information about the
> crash or the condition of the frame before the crash.
>
>> The smartest person I know in the "warranty" department (which I put
>> in quotes because most of what he deals with isn't actually a
>> "warranty"), when presented a failure that might be questionable,
>> always ask one simple question. "What do you think *really*
>> happened?" It gets you to thinking a bit outside the oral or written
>> history actually presented. And sometimes you get a customer with a
>> "JRA" and you ask him (almost always a "him" by the way) "What do you
>> think really happened" and, hold down the fort, they will actually
>> tell you. Bizarre yet true. They come in claiming it's a JRA, but you
>> ask for details and yikes, it's something entirely different.
>
> Yup. And since not JRA is normal use of bicycles, that raises
> significant concerns about the toughness and damage resistance of the
> materials used in critical components of bicycles. There are some that
> can easily get you severely injured, disabled or killed if they fail
> catastrophically.
>
>> > The problem with steel frame in your example was the impact- a CF
>> > frame would have shattered rather than bending. The problem with
>> > the titanium frames didn't result in the downtube just snapping.
>>
>> You're making an assumption that is rarely correct. Modern carbon
>> frames & forks will, I will claim, generally "survive" a head-on
>> impact more readily than the steel frames of yesteryear. They will
>> not survive as readily an impact from the side. These claims come
>> from observations over many years, many product lines, many
>> customers, many impacts.
>
> Please define "survive."
>
>> And the titanium frame that you didn't think resulted in a downtube
>> snapping? Think again. I was there. Time between first hearing
>> something and failure was about 3 miles. We obviously aborted the
>> ride after hearing a strange noise and running it down (a very small
>> tear on the downtube), and decided to ride back to where he'd parked
>> his car, 6 relatively-flat miles away. After three miles the tube had
>> torn through and I had to go get my car. The failure was definitely
>> catastrophic, although since we were keeping an eye on it there was
>> no injury, no crash. If we hadn't figured out what the noise was
>> coming from, it could have been otherwise.
>
> The rider had advanced warning and had a non-catastrophic failure.
> Catastrophic does not mean that the tube broke. Catastrophic failure is
> nearly instantaneous.
>
>> If we want to get personal, I did the carbon bike into car gig
>> myself. 16mph into the side of a Mustang some kid backed out of his
>> driveway onto the road. My teeth fared much worse than my bike.
>
> Unfortunately your carbon frame is not readily inspectable for damage.
> I hope that is in in fact undamaged.
|
| | | | | | | | |
Date: 13 Sep 2007 23:08:12
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
>
> Chalo wrote:
> >
> > The move to ban trans fats here
> > and there isn't about forcing people to adopt a healthy diet (which
> > would be impossible to do); it's about stopping businesses from
> > feeding people things that injure them.
>
> Coming from a morbidly obese person, I find this...ironic.
I don't know what my body weight has to do with it. I don't eat trans
fats when I know they're there; I have good cardiovascular health and
good blood lipids, just like you'd expect from a vegetarian, skillful
cook, and regular cyclist.
The issue isn't good or bad dietary habits, it's harmful adulterants,
like the diacetyl in popcorn that recently came to light. Why would
you want to eat an ingredient that causes "popcorn worker's lung? And
why would you want to eat a dangerous hydrogenated fat when a
wholesome natural fat will do the job just as well if not better?
> So after you ban/outlaw that, what's next?
The next poisonous additive that corporate business is feeding us to
save a nickel, that's what. I wonder what sort of problem you could
possibly have with that? Before the Pure Food and Drug Act, people
got floor sweepings in their pepper, lead pigment in their cheese, and
iodine in their whiskey. We don't have to worry as much about such
stuff these days, but that's largely because of efforts like those now
being used against trans fats and diacetyl.
Chalo
|
| | | | | | | | | |
Date: 13 Sep 2007 17:49:52
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo wrote:
> Bill Sornson wrote:
>>
>> Chalo wrote:
>>>
>>> The move to ban trans fats here
>>> and there isn't about forcing people to adopt a healthy diet (which
>>> would be impossible to do); it's about stopping businesses from
>>> feeding people things that injure them.
>>
>> Coming from a morbidly obese person, I find this...ironic.
>
> I don't know what my body weight has to do with it. I don't eat trans
> fats when I know they're there; I have good cardiovascular health and
> good blood lipids, just like you'd expect from a vegetarian, skillful
> cook, and regular cyclist.
Not everyone /chooses/ to eat healthy foods. (Or what do-gooders pronounce
are healthy foods.)
> The issue isn't good or bad dietary habits, it's harmful adulterants,
> like the diacetyl in popcorn that recently came to light. Why would
> you want to eat an ingredient that causes "popcorn worker's lung? And
> why would you want to eat a dangerous hydrogenated fat when a
> wholesome natural fat will do the job just as well if not better?
>
>> So after you ban/outlaw that, what's next?
>
> The next poisonous additive that corporate business is feeding us to
> save a nickel, that's what. I wonder what sort of problem you could
> possibly have with that? Before the Pure Food and Drug Act, people
> got floor sweepings in their pepper, lead pigment in their cheese, and
> iodine in their whiskey. We don't have to worry as much about such
> stuff these days, but that's largely because of efforts like those now
> being used against trans fats and diacetyl.
Wait six months; some study will say they're /good for you/.
ALARMISTS AND DO-GOODERS! Aaaaccccckkkkkkk.
|
| | | | | | | | | | |
Date: 13 Sep 2007 21:36:44
From: Tim McNamara
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
In article <46e9daab$0$19571$4c368faf@roadrunner.com >,
"Bill Sornson" <askme@ask.me > wrote:
> Chalo wrote:
> > Bill Sornson wrote:
> >>
> >> Chalo wrote:
> >>>
> >>> The move to ban trans fats here and there isn't about forcing
> >>> people to adopt a healthy diet (which would be impossible to do);
> >>> it's about stopping businesses from feeding people things that
> >>> injure them.
> >>
> >> Coming from a morbidly obese person, I find this...ironic.
> >
> > I don't know what my body weight has to do with it. I don't eat
> > trans fats when I know they're there; I have good cardiovascular
> > health and good blood lipids, just like you'd expect from a
> > vegetarian, skillful cook, and regular cyclist.
>
> Not everyone /chooses/ to eat healthy foods. (Or what do-gooders
> pronounce are healthy foods.)
>
> > The issue isn't good or bad dietary habits, it's harmful
> > adulterants, like the diacetyl in popcorn that recently came to
> > light. Why would you want to eat an ingredient that causes
> > "popcorn worker's lung? And why would you want to eat a dangerous
> > hydrogenated fat when a wholesome natural fat will do the job just
> > as well if not better?
> >
> >> So after you ban/outlaw that, what's next?
> >
> > The next poisonous additive that corporate business is feeding us
> > to save a nickel, that's what. I wonder what sort of problem you
> > could possibly have with that? Before the Pure Food and Drug Act,
> > people got floor sweepings in their pepper, lead pigment in their
> > cheese, and iodine in their whiskey. We don't have to worry as
> > much about such stuff these days, but that's largely because of
> > efforts like those now being used against trans fats and diacetyl.
>
> Wait six months; some study will say they're /good for you/.
>
> ALARMISTS AND DO-GOODERS! Aaaaccccckkkkkkk.
Feel free to eat the Big Macs and the French fries and the cheese food.
Make your fried chicken and pie crusts with Crisco. Dig in. Don't let
those do-gooders get you down.
|
| | | | | | | | | | | |
Date: 14 Sep 2007 00:38:54
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Tim McNamara wrote:
> In article <46e9daab$0$19571$4c368faf@roadrunner.com>,
> "Bill Sornson" <askme@ask.me> wrote:
>> Wait six months; some study will say they're /good for you/.
>>
>> ALARMISTS AND DO-GOODERS! Aaaaccccckkkkkkk.
>
> Feel free to eat the Big Macs and the French fries and the cheese
> food. Make your fried chicken and pie crusts with Crisco. Dig in.
> Don't let those do-gooders get you down.
As usual, Timmy /completely/ misses the point. (Hint: just because I don't
own a gas-guzzling SUV doesn't mean I'm in favor of /banning/ them. HTH.)
|
| | | | | | | | | | | |
Date: 14 Sep 2007 04:14:08
From: still me
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 21:36:44 -0500, Tim McNamara
<timmcn@bitstream.net > wrote:
>Feel free to eat the Big Macs and the French fries and the cheese food.
>Make your fried chicken and pie crusts with Crisco. Dig in. Don't let
>those do-gooders get you down.
Yeah, go for it Sorni, and help your like-minded friends to do the
same! (I love it when belligerence and self-imposed ignorance is used
to counter science).
|
| | | | | | | | | | | | |
Date: 14 Sep 2007 00:39:54
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
still a clueless anonymous simpleton wrote:
> On Thu, 13 Sep 2007 21:36:44 -0500, Tim McNamara
> <timmcn@bitstream.net> wrote:
>
>> Feel free to eat the Big Macs and the French fries and the cheese
>> food. Make your fried chicken and pie crusts with Crisco. Dig in.
>> Don't let those do-gooders get you down.
>
> Yeah, go for it Sorni, and help your like-minded friends to do the
> same! (I love it when belligerence and self-imposed ignorance is used
> to counter science).
WHHHHHHHHOOOOOOOOOOOOOOOSSSSSSSSSSSSSSSHHHHHHHHHHHHH.
HTH
|
| | | | | | | | |
Date: 09 Sep 2007 22:11:31
From: A Muzi
Subject: Re: "brittle" vs. non-ductile
|
>> Let's defined catastrophic failure: the component breaks into two or
>> more discrete pieces nearly instantaneously. This is typical of brittle
>> materials (glass, for example) and not typical of metallic materials
>> commonly used in bicycles
Mike Jacoubowsky wrote:
> That would have been my Mavic stem (looked to have been made by 3TTT).
> Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> I was sprinting when it happened. A aluminum, forged quill stem, single
> bolt, not hinged. The section of stem that the handlebar-claming bolt
> threaded into gave way. No, the threads didn't strip, the entire section
> pulled away from the rest of the stem. Quite the rude thing to happen.
> Points to consider- Aluminum. No prior warning. Catastrophic failure.
I haven't been much involved in this thread for many reasons but if you
think French stems are scary, what about all the aluminum Pivo bars
which snapped right next to the stem? After observing many iterations
of frame and equipment failures, I can match examples - and
counterexamples- with anyone.
Mike has a good point - "sudden catastrophic failure" anecdotes abound
in all materials. Here on r.b.t., though, we haven't made the leap from
anecdote to data or a unified theory yet. Neither 'carbon good' nor
'carbon bad' have convinced me.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | | |
Date: 10 Sep 2007 22:17:40
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article <13e9ddqndl12m9e@corp.supernews.com >,
A Muzi <am@yellowjersey.org > wrote:
> >> Let's defined catastrophic failure: the component breaks into two or
> >> more discrete pieces nearly instantaneously. This is typical of brittle
> >> materials (glass, for example) and not typical of metallic materials
> >> commonly used in bicycles
>
> Mike Jacoubowsky wrote:
> > That would have been my Mavic stem (looked to have been made by 3TTT).
> > Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> > I was sprinting when it happened. A aluminum, forged quill stem, single
> > bolt, not hinged. The section of stem that the handlebar-claming bolt
> > threaded into gave way. No, the threads didn't strip, the entire section
> > pulled away from the rest of the stem. Quite the rude thing to happen.
> > Points to consider- Aluminum. No prior warning. Catastrophic failure.
>
> I haven't been much involved in this thread for many reasons but if you
> think French stems are scary, what about all the aluminum Pivo bars
> which snapped right next to the stem? After observing many iterations
> of frame and equipment failures, I can match examples - and
> counterexamples- with anyone.
>
> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.
The anecdotes abound; the painstaking forensic
examinations of the aftermath are scarce on the ground.
Show me the pictures of all the broken parts;
macrophotgraphs of the fractures in good light. Tell me
the complete story, the impact history, the
embarrassing details of the incident.
--
Michael Press
|
| | | | | | | | | |
Date: 10 Sep 2007 16:35:49
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
In article <13e9ddqndl12m9e@corp.supernews.com >, A Muzi
<am@yellowjersey.org > wrote:
> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.
Good point. Vis materials, if there's a r.b.t. consensus I've noticed
it's this: 'stoopid lite' for utility/casual purposes is a mistake, be
it steel, Al, low spoke counts, or CF. But where that threshold falls
is up for further debate!
|
| | | | | | | | |
Date: 09 Sep 2007 19:34:05
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article
<NU0Fi.26110$eY.16870@newssvr13.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> > Let's defined catastrophic failure: the component breaks into two or
> > more discrete pieces nearly instantaneously. This is typical of brittle
> > materials (glass, for example) and not typical of metallic materials
> > commonly used in bicycles
>
> That would have been my Mavic stem (looked to have been made by 3TTT).
> Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> I was sprinting when it happened. A aluminum, forged quill stem, single
> bolt, not hinged. The section of stem that the handlebar-claming bolt
> threaded into gave way. No, the threads didn't strip, the entire section
> pulled away from the rest of the stem. Quite the rude thing to happen.
>
> Points to consider- Aluminum. No prior warning. Catastrophic failure.
You did not say that you examined the fracture for corrosion,
corrosion that means it had been separating over time.
(Your replies are not prefaced with attribution information.
Would you look into that?)
--
Michael Press
|
| | | | | | | | | |
Date: 10 Sep 2007 03:22:27
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
> You did not say that you examined the fracture for corrosion,
> corrosion that means it had been separating over time.
Obviously, nothing was noticed, prior to the failure. Which, of course, is
the point. It was entirely unexpected. But to answer the question, no, no
corrosion, it was a poor forging.
> (Your replies are not prefaced with attribution information.
> Would you look into that?)
Didn't I include the entire prior post intact at the bottom of my reply? I'm
not sure what you're saying.
> --
> Michael Press
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Michael Press" <rubrum@pacbell.net > wrote in message
news:rubrum-959459.19340509092007@newsclstr03.news.prodigy.net...
> In article
> <NU0Fi.26110$eY.16870@newssvr13.news.prodigy.net>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> > Let's defined catastrophic failure: the component breaks into two or
>> > more discrete pieces nearly instantaneously. This is typical of
>> > brittle
>> > materials (glass, for example) and not typical of metallic materials
>> > commonly used in bicycles
>>
>> That would have been my Mavic stem (looked to have been made by 3TTT).
>> Absolutely zero warning. No noise, no looseness. A real-life JRA. Well,
>> OK,
>> I was sprinting when it happened. A aluminum, forged quill stem, single
>> bolt, not hinged. The section of stem that the handlebar-claming bolt
>> threaded into gave way. No, the threads didn't strip, the entire section
>> pulled away from the rest of the stem. Quite the rude thing to happen.
>>
>> Points to consider- Aluminum. No prior warning. Catastrophic failure.
>
> You did not say that you examined the fracture for corrosion,
> corrosion that means it had been separating over time.
>
> (Your replies are not prefaced with attribution information.
> Would you look into that?)
>
> --
> Michael Press
|
| | | | | | | | | | |
Date: 10 Sep 2007 01:15:20
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article
<TL2Fi.33237$RX.24468@newssvr11.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> > You did not say that you examined the fracture for corrosion,
> > corrosion that means it had been separating over time.
>
> Obviously, nothing was noticed, prior to the failure. Which, of course, is
> the point. It was entirely unexpected. But to answer the question, no, no
> corrosion, it was a poor forging.
>
> > (Your replies are not prefaced with attribution information.
> > Would you look into that?)
>
> Didn't I include the entire prior post intact at the bottom of my reply? I'm
> not sure what you're saying.
Oh. I see the attribution information in the middle of the
message body, and I expected to see it at the beginning of
the message body. Nevermind.
> "Michael Press" <rubrum@pacbell.net> wrote in message
> news:rubrum-959459.19340509092007@newsclstr03.news.prodigy.net...
> > In article
> > <NU0Fi.26110$eY.16870@newssvr13.news.prodigy.net>,
> > "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >
> >> > Let's defined catastrophic failure: the component breaks into two or
> >> > more discrete pieces nearly instantaneously. This is typical of
> >> > brittle
> >> > materials (glass, for example) and not typical of metallic materials
> >> > commonly used in bicycles
> >>
> >> That would have been my Mavic stem (looked to have been made by 3TTT).
> >> Absolutely zero warning. No noise, no looseness. A real-life JRA. Well,
> >> OK,
> >> I was sprinting when it happened. A aluminum, forged quill stem, single
> >> bolt, not hinged. The section of stem that the handlebar-claming bolt
> >> threaded into gave way. No, the threads didn't strip, the entire section
> >> pulled away from the rest of the stem. Quite the rude thing to happen.
> >>
> >> Points to consider- Aluminum. No prior warning. Catastrophic failure.
> >
> > You did not say that you examined the fracture for corrosion,
> > corrosion that means it had been separating over time.
> >
> > (Your replies are not prefaced with attribution information.
> > Would you look into that?)
> >
> > --
> > Michael Press
--
Michael Press
|
| | | | | | | | | | | |
Date: 10 Sep 2007 16:52:07
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> Didn't I include the entire prior post intact at the bottom of my reply?
>> I'm
>> not sure what you're saying.
>
> Oh. I see the attribution information in the middle of the
> message body, and I expected to see it at the beginning of
> the message body. Nevermind.
I realize my "style" is a bit different than most. I have trouble reading
through 200-line postings trying to find what's new & relevant, so when I'm
adding something to a long-ish thread, I'll put the part that's relevant to
what I'm adding at the top (along with my reply) and then include the whole
post below.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Michael Press" <rubrum@pacbell.net > wrote in message
news:rubrum-18F53B.01152010092007@newsclstr03.news.prodigy.net...
> In article
> <TL2Fi.33237$RX.24468@newssvr11.news.prodigy.net>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> > You did not say that you examined the fracture for corrosion,
>> > corrosion that means it had been separating over time.
>>
>> Obviously, nothing was noticed, prior to the failure. Which, of course,
>> is
>> the point. It was entirely unexpected. But to answer the question, no, no
>> corrosion, it was a poor forging.
>>
>> > (Your replies are not prefaced with attribution information.
>> > Would you look into that?)
>>
>> Didn't I include the entire prior post intact at the bottom of my reply?
>> I'm
>> not sure what you're saying.
>
> Oh. I see the attribution information in the middle of the
> message body, and I expected to see it at the beginning of
> the message body. Nevermind.
>
>> "Michael Press" <rubrum@pacbell.net> wrote in message
>> news:rubrum-959459.19340509092007@newsclstr03.news.prodigy.net...
>> > In article
>> > <NU0Fi.26110$eY.16870@newssvr13.news.prodigy.net>,
>> > "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>> >
>> >> > Let's defined catastrophic failure: the component breaks into two
>> >> > or
>> >> > more discrete pieces nearly instantaneously. This is typical of
>> >> > brittle
>> >> > materials (glass, for example) and not typical of metallic materials
>> >> > commonly used in bicycles
>> >>
>> >> That would have been my Mavic stem (looked to have been made by 3TTT).
>> >> Absolutely zero warning. No noise, no looseness. A real-life JRA.
>> >> Well,
>> >> OK,
>> >> I was sprinting when it happened. A aluminum, forged quill stem,
>> >> single
>> >> bolt, not hinged. The section of stem that the handlebar-claming bolt
>> >> threaded into gave way. No, the threads didn't strip, the entire
>> >> section
>> >> pulled away from the rest of the stem. Quite the rude thing to happen.
>> >>
>> >> Points to consider- Aluminum. No prior warning. Catastrophic failure.
>> >
>> > You did not say that you examined the fracture for corrosion,
>> > corrosion that means it had been separating over time.
>> >
>> > (Your replies are not prefaced with attribution information.
>> > Would you look into that?)
>> >
>> > --
>> > Michael Press
>
> --
> Michael Press
|
| | | | | | |
Date: 09 Sep 2007 13:38:29
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article <sQUEi.2074$Sd4.1410@nlpi061.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> That's the part of this discussion I find so incredible. Catastrophic
> failure modes have been around for as long as manufacturing. Carbon fiber
> didn't invent them. Carbon fiber didn't cause them. Flawed designs &
> manufacturing did. Back in the day, we saw a lot of "catastrophic" failures.
> People have either forgotten about that, or else, because those failures
> were on "tried & true" technology, materials that had been around for some
> time, they were, for some reason, tolerated. Why?
Metals give warning. We can look for and _see_ cracks
in metal frames. A compromised metal frame rides wonky.
I have experienced it myself. Looked, and behold! a
crack in the frame. Catastrophic failure is failure
that gives no warning. Catastrophic failure is _not_
failure that gives warning that is then ignored by the
rider.
--
Michael Press
|
| | | | | | | |
Date: 09 Sep 2007 21:09:17
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Michael Press wrote:
> In article <sQUEi.2074$Sd4.1410@nlpi061.nbdc.sbc.com>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> That's the part of this discussion I find so incredible. Catastrophic
>> failure modes have been around for as long as manufacturing. Carbon fiber
>> didn't invent them. Carbon fiber didn't cause them. Flawed designs &
>> manufacturing did. Back in the day, we saw a lot of "catastrophic" failures.
>> People have either forgotten about that, or else, because those failures
>> were on "tried & true" technology, materials that had been around for some
>> time, they were, for some reason, tolerated. Why?
>
> Metals give warning. We can look for and _see_ cracks
> in metal frames. A compromised metal frame rides wonky.
if you're lucky - there's no guarantee this will be the case.
> I have experienced it myself. Looked, and behold! a
> crack in the frame. Catastrophic failure is failure
> that gives no warning. Catastrophic failure is _not_
> failure that gives warning that is then ignored by the
> rider.
>
|
| | | | | |
Date: 09 Sep 2007 07:25:44
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Tim McNamara wrote:
> In article <ftKEi.2078$ZA5.1418@nlpi068.nbdc.sbc.com>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>> I agree. Materials that fail in common use should be banned from
>> bikes.
>>
>> Oh, darn. All those failing aluminum stems... crap. That's quite a
>> few thousand dollars of inventory I'm going to have to dump. And the
>> failed Belleri handlebars. Crap. That's going to be many thousands of
>> dollars more of inventory I can't trust.
>
> Like this tem owned by a friend, who discovered this condition the day
> after a 104 mile ride we undertook on hilly road including gravel and
> rough pavement?
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
>
> How would a CF stem have fared with cracking like this?
a quality carbon stem wouldn't have cracked! but nor would quality
aluminum within its service life.
>
>> Oh, darn. All those steel frames that buckled under impact, causing
>> the front wheel to make contact with the downtube and throwing the
>> rider violently. Crap. We can't use steel for frames anymore.
>>
>> Oh, darn. All those titanium frames that had sheared downtubes, due
>> to cracks beginning at the downtube cable guides. Crap.
>>
>> Oh, wait, nevermind. It wasn't the material that was the issue, it
>> was how it was used. Incredibly dangerous failure modes, yet nobody
>> was calling for manufacturers to stop using aluminum, steel or
>> titanium for bike parts.
>
> As hyperbole goes, this doesn't work very well. The failure mode for
> these materials is rarely catastrophic unlike CF
eh? that aluminum stem failure is catastrophic. and carbon rarely
fails without warning.
> and is thus not
> "incredibly" dangerous. The problem with steel frame in your example
> was the impact- a CF frame would have shattered rather than bending.
so you say, but at a stress level many times /after/ that at which the
steel would have crumpled.
> The problem with the titanium frames didn't result in the downtube just
> snapping.
no, it buckles. at stress levels well below that of carbon.
|
| | | | | | |
Date: 09 Sep 2007 12:30:35
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:-5adnduNwvH1n3nbnZ2dnUVZ_vHinZ2d@speakeasy.net...
> Tim McNamara wrote:
>>
>> Like this tem owned by a friend, who discovered this condition the day
>> after a 104 mile ride we undertook on hilly road including gravel and
>> rough pavement?
>>
>> http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
>>
>> How would a CF stem have fared with cracking like this?
>
> a quality carbon stem wouldn't have cracked!
HAHAHAHA! A CF stem would have sung its heart out for you, telling you it's
cracking, wouldn't it fucktard?
> but nor would quality aluminum within its service life.
You're also a master of the bleeding obvious, aintcha?
> eh? that aluminum stem failure is catastrophic. and carbon rarely fails
> without warning.
HAHAHAHAHA! That's right, CF talks to you, doesn't it fucktard? That is
the funniest delusion you have yet, moron.
> so you say, but at a stress level many times /after/ that at which the
> steel would have crumpled.
Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."
HAHAHAHAHA! Moron.
>> The problem with the titanium frames didn't result in the downtube just
>> snapping.
>
> no, it buckles. at stress levels well below that of carbon.
Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."
|
| | | | |
Date: 09 Sep 2007 14:54:53
From: Aeek
Subject: Re: "brittle" vs. non-ductile
|
On Sat, 8 Sep 2007 21:17:14 -0700, "Mike Jacoubowsky"
<mikej1@ix.netcom.com > wrote:
>I agree. Materials that fail in common use should be banned from bikes.
>
>Oh, darn. All those failing aluminum stems... crap. That's quite a few
>thousand dollars of inventory I'm going to have to dump. And the failed
>Belleri handlebars. Crap. That's going to be many thousands of dollars more
>of inventory I can't trust.
>
>Oh, darn. All those steel frames that buckled under impact, causing the
>front wheel to make contact with the downtube and throwing the rider
>violently. Crap. We can't use steel for frames anymore.
>
>Oh, darn. All those titanium frames that had sheared downtubes, due to
>cracks beginning at the downtube cable guides. Crap.
>
>Oh, wait, nevermind. It wasn't the material that was the issue, it was how
>it was used. Incredibly dangerous failure modes, yet nobody was calling for
>manufacturers to stop using aluminum, steel or titanium for bike parts.
The common factor isn't the materials, its the rider. Clearly we
shouldn't use anything where there is a human involved. Oh, hang on.
|
| | |
Date: 07 Sep 2007 18:23:20
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jay Beattie wrote:
> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
>> "jim beam" <spamvor...@bad.example.net> wrote in message
>>
>> news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>>
>>> Peter Cole wrote:
>>>> The aircraft industry works to higher standards than joe (jim) consumer.
>>>> That's the point.
>>> i /hate/ to point this out, but the people that /started/ using cfrp in
>>> bikes used experience /from/ the aerospace industry. damn.
>> This is your say so, not fact. Geez, you're incredibly gullible.
>
> Another point of clarification: are CF bicycle frames over built,
> vis., stronger than necessary to take in to consideration the
> limitations of the material?
absolutely. the reynolds forks testing showed their carbon fork failure
at _three times_ the stress level of steel.
> I ask this because I have not see an
> epidemic of broken CF frames or forks, and I have been riding CF forks
> for over 15 years (different ones). I have seen broken CF forks, but
> only at the crown glue joint or at the crown steerer (aluminum steerer
> and crown). I remember the early problems with the BB insert in the
> Trek CF frames, but that was a different type of bonding problem and
> not delamination like we are discussing here. I don't seem to
> remember any more broken CF frames than, let's say, Al (e.g.
> Cannondale was having a hard time there for a few years with the 2.8
> design). I ride a Cannondale, so I am not trying to justify a CF
> purchase. I am just trying to get a handle on the real risk to the
> average rider of a decent CF frame.-- Jay Beattie.
there is nothing intrinsically wrong with cfrp, [as your own experience
shows] and much that is intrinsically excellent. the only real concern
is q.c. by the manufacturer. on that basis, i'd only have something
made by a big volume, known name manufacturer that can afford to throw
away mistakes. and who takes quality seriously. made in usa, made in
europe, or made by giant in taiwan is your best choice.
|
| | | |
Date: 09 Sep 2007 12:16:23
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:QPednTJFMesVZHzbnZ2dnUVZ_s_inZ2d@speakeasy.net...
> Jay Beattie wrote:
>> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
>>> "jim beam" <spamvor...@bad.example.net> wrote in message
>>>
>>> news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>>>
>>>> Peter Cole wrote:
>>>>> The aircraft industry works to higher standards than joe (jim)
>>>>> consumer.
>>>>> That's the point.
>>>> i /hate/ to point this out, but the people that /started/ using cfrp in
>>>> bikes used experience /from/ the aerospace industry. damn.
>>> This is your say so, not fact. Geez, you're incredibly gullible.
>>
>> Another point of clarification: are CF bicycle frames over built,
>> vis., stronger than necessary to take in to consideration the
>> limitations of the material?
>
> absolutely. the reynolds forks testing showed their carbon fork failure
> at _three times_ the stress level of steel.
Yeah, that's right, you take marketing material and mistake it for technical
publication!
HAHAHAHA! Moron!
> there is nothing intrinsically wrong with cfrp, [as your own experience
> shows] and much that is intrinsically excellent.
Says a "former metallurgist" who doesn't know the difference between
specific modulus and young's modulus!
> the only real concern is q.c. by the manufacturer.
Yeah, them Chinese manufacturers are shifty bastards, aren't they?
> on that basis, i'd only have something made by a big volume, known name
> manufacturer that can afford to throw away mistakes. and who takes
> quality seriously. made in usa, made in europe, or made by giant in
> taiwan is your best choice.
Says a lying fucktard!
>
|
| | |
Date: 07 Sep 2007 20:06:23
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <1189184546.941992.244120@o80g2000hse.googlegroups.com >,
Jay Beattie <jbeattie@lindsayhart.com > wrote:
> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
> > "jim beam" <spamvor...@bad.example.net> wrote in message
> >
> > news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
> >
> > > Peter Cole wrote:
> > >> The aircraft industry works to higher standards than joe (jim)
> > >> consumer. That's the point.
> >
> > > i /hate/ to point this out, but the people that /started/ using
> > > cfrp in bikes used experience /from/ the aerospace industry.
> > > damn.
> >
> > This is your say so, not fact. Geez, you're incredibly gullible.
>
> Another point of clarification: are CF bicycle frames over built,
> vis., stronger than necessary to take in to consideration the
> limitations of the material? I ask this because I have not see an
> epidemic of broken CF frames or forks, and I have been riding CF
> forks for over 15 years (different ones).
Therein is one of the issues in judging the long term safety and
durability of CF frames and forks: they just have not been in service
very long. I know people with steel frames and forks that have been in
use 35+ years, and I know of people whose daily rider bikes are 50+
years old. These bikes are still safe and sound- will that be the same
for CF? We won't know for another 35 years or so. And we may not know
even then, as currently the folks who tend to buy CF bikes tend to
replace their equipment with newer, more up-to-date stuff every couple
of years anyway.
|
| | | |
Date: 07 Sep 2007 22:49:44
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> Another point of clarification: are CF bicycle frames over built,
>> vis., stronger than necessary to take in to consideration the
>> limitations of the material? I ask this because I have not see an
>> epidemic of broken CF frames or forks, and I have been riding CF
>> forks for over 15 years (different ones).
>
> Therein is one of the issues in judging the long term safety and
> durability of CF frames and forks: they just have not been in service
> very long. I know people with steel frames and forks that have been in
> use 35+ years, and I know of people whose daily rider bikes are 50+
> years old. These bikes are still safe and sound- will that be the same
> for CF? We won't know for another 35 years or so. And we may not know
> even then, as currently the folks who tend to buy CF bikes tend to
> replace their equipment with newer, more up-to-date stuff every couple
> of years anyway.
Unless you believe that something happens to the fork, either steel or
carbon, while it is just sitting there, un-used, a track record of 15+ years
is more than adequate to judge the service life & safety of a carbon fiber
fork. It's actual use (on the road) that matters, and as we have seen steel
forks fail in the past at anywhere from 30-80k miles (some fail sooner, some
last longer, but that's approximates the average service life we've seen
over time), the history of carbon forks, as an indicator of overall life &
safety, becomes clear after no more than 10 years, as that will see a fair
amount of product achieve that sort of mileage.
That someone you know has a bike that's 50 years old in daily service is
likely a testament more to an extraordinarily overbuilt design, rather than
the material used. If one were to build a fork of the same weight out of
carbon fiber, it may very well achieve commendable life on the roads
surrounding Baghdad! But why? Does it make sense to build something that
will last from one generation to the next, or does it make more sense to
optimize for the current user, and his/her typical lifespan of use
(determined not by failure but more often by a desire to upgrade)?
The worst thing about this thread is the inference that other materials
don't fail in normal use. They have in the past. They do today. And they
will continue to fail tomorrow. It's generally not the material that causes
a failure, it's how it's used. I would suggest that the rate of frame
failures in aluminum, steel & ti frames has probably increased since carbon
fiber came on the market. Why? Because manufacturers have tried to mimic the
weight of a carbon fiber frame using materials that really aren't suitable
for that purpose. Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
But if you created a well-build carbon fiber frame at any of those weights,
it could be impossible to kill. But that's not what people are looking for
with carbon fiber, so it shouldn't be a huge surprise that's not what they
get.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-6CF468.20062307092007@news.iphouse.com...
> In article <1189184546.941992.244120@o80g2000hse.googlegroups.com>,
> Jay Beattie <jbeattie@lindsayhart.com> wrote:
>
>> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
>> > "jim beam" <spamvor...@bad.example.net> wrote in message
>> >
>> > news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>> >
>> > > Peter Cole wrote:
>> > >> The aircraft industry works to higher standards than joe (jim)
>> > >> consumer. That's the point.
>> >
>> > > i /hate/ to point this out, but the people that /started/ using
>> > > cfrp in bikes used experience /from/ the aerospace industry.
>> > > damn.
>> >
>> > This is your say so, not fact. Geez, you're incredibly gullible.
>>
>> Another point of clarification: are CF bicycle frames over built,
>> vis., stronger than necessary to take in to consideration the
>> limitations of the material? I ask this because I have not see an
>> epidemic of broken CF frames or forks, and I have been riding CF
>> forks for over 15 years (different ones).
>
> Therein is one of the issues in judging the long term safety and
> durability of CF frames and forks: they just have not been in service
> very long. I know people with steel frames and forks that have been in
> use 35+ years, and I know of people whose daily rider bikes are 50+
> years old. These bikes are still safe and sound- will that be the same
> for CF? We won't know for another 35 years or so. And we may not know
> even then, as currently the folks who tend to buy CF bikes tend to
> replace their equipment with newer, more up-to-date stuff every couple
> of years anyway.
|
| | | | |
Date: 08 Sep 2007 23:37:43
From: Michael Press
Subject: Re: "brittle" vs. non-ductile
|
In article <ZJqEi.5926$z_5.862@nlpi069.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> Another point of clarification: are CF bicycle frames over built,
> >> vis., stronger than necessary to take in to consideration the
> >> limitations of the material? I ask this because I have not see an
> >> epidemic of broken CF frames or forks, and I have been riding CF
> >> forks for over 15 years (different ones).
> >
> > Therein is one of the issues in judging the long term safety and
> > durability of CF frames and forks: they just have not been in service
> > very long. I know people with steel frames and forks that have been in
> > use 35+ years, and I know of people whose daily rider bikes are 50+
> > years old. These bikes are still safe and sound- will that be the same
> > for CF? We won't know for another 35 years or so. And we may not know
> > even then, as currently the folks who tend to buy CF bikes tend to
> > replace their equipment with newer, more up-to-date stuff every couple
> > of years anyway.
>
> Unless you believe that something happens to the fork, either steel or
> carbon, while it is just sitting there, un-used, a track record of 15+ years
> is more than adequate to judge the service life & safety of a carbon fiber
> fork. It's actual use (on the road) that matters, and as we have seen steel
> forks fail in the past at anywhere from 30-80k miles (some fail sooner, some
> last longer, but that's approximates the average service life we've seen
> over time), the history of carbon forks, as an indicator of overall life &
> safety, becomes clear after no more than 10 years, as that will see a fair
> amount of product achieve that sort of mileage.
>
> That someone you know has a bike that's 50 years old in daily service is
> likely a testament more to an extraordinarily overbuilt design, rather than
> the material used. If one were to build a fork of the same weight out of
> carbon fiber, it may very well achieve commendable life on the roads
> surrounding Baghdad! But why? Does it make sense to build something that
> will last from one generation to the next, or does it make more sense to
> optimize for the current user, and his/her typical lifespan of use
> (determined not by failure but more often by a desire to upgrade)?
>
> The worst thing about this thread is the inference that other materials
> don't fail in normal use. They have in the past. They do today. And they
> will continue to fail tomorrow. It's generally not the material that causes
> a failure, it's how it's used. I would suggest that the rate of frame
> failures in aluminum, steel & ti frames has probably increased since carbon
> fiber came on the market. Why? Because manufacturers have tried to mimic the
> weight of a carbon fiber frame using materials that really aren't suitable
> for that purpose. Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
> But if you created a well-build carbon fiber frame at any of those weights,
> it could be impossible to kill. But that's not what people are looking for
> with carbon fiber, so it shouldn't be a huge surprise that's not what they
You are glossing over the reports here describing the
fragility of carbon fiber resin composites. There _is_
a material difference between carbon fiber resin and
other bicycle frame materials. Difference in impact
resistance, difference in failure mode, and difference
in ease of damage assessment.
As a retailer with a reputation to maintain you should
bring technological arguments to bear or gracefully
hold your peace. Saying that it makes no difference in
practice may not be the best course.
--
Michael Press
|
| | | | | |
Date: 09 Sep 2007 07:21:10
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Michael Press wrote:
> In article <ZJqEi.5926$z_5.862@nlpi069.nbdc.sbc.com>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>>>> Another point of clarification: are CF bicycle frames over built,
>>>> vis., stronger than necessary to take in to consideration the
>>>> limitations of the material? I ask this because I have not see an
>>>> epidemic of broken CF frames or forks, and I have been riding CF
>>>> forks for over 15 years (different ones).
>>> Therein is one of the issues in judging the long term safety and
>>> durability of CF frames and forks: they just have not been in service
>>> very long. I know people with steel frames and forks that have been in
>>> use 35+ years, and I know of people whose daily rider bikes are 50+
>>> years old. These bikes are still safe and sound- will that be the same
>>> for CF? We won't know for another 35 years or so. And we may not know
>>> even then, as currently the folks who tend to buy CF bikes tend to
>>> replace their equipment with newer, more up-to-date stuff every couple
>>> of years anyway.
>> Unless you believe that something happens to the fork, either steel or
>> carbon, while it is just sitting there, un-used, a track record of 15+ years
>> is more than adequate to judge the service life & safety of a carbon fiber
>> fork. It's actual use (on the road) that matters, and as we have seen steel
>> forks fail in the past at anywhere from 30-80k miles (some fail sooner, some
>> last longer, but that's approximates the average service life we've seen
>> over time), the history of carbon forks, as an indicator of overall life &
>> safety, becomes clear after no more than 10 years, as that will see a fair
>> amount of product achieve that sort of mileage.
>>
>> That someone you know has a bike that's 50 years old in daily service is
>> likely a testament more to an extraordinarily overbuilt design, rather than
>> the material used. If one were to build a fork of the same weight out of
>> carbon fiber, it may very well achieve commendable life on the roads
>> surrounding Baghdad! But why? Does it make sense to build something that
>> will last from one generation to the next, or does it make more sense to
>> optimize for the current user, and his/her typical lifespan of use
>> (determined not by failure but more often by a desire to upgrade)?
>>
>> The worst thing about this thread is the inference that other materials
>> don't fail in normal use. They have in the past. They do today. And they
>> will continue to fail tomorrow. It's generally not the material that causes
>> a failure, it's how it's used. I would suggest that the rate of frame
>> failures in aluminum, steel & ti frames has probably increased since carbon
>> fiber came on the market. Why? Because manufacturers have tried to mimic the
>> weight of a carbon fiber frame using materials that really aren't suitable
>> for that purpose. Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
>> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
>> But if you created a well-build carbon fiber frame at any of those weights,
>> it could be impossible to kill. But that's not what people are looking for
>> with carbon fiber, so it shouldn't be a huge surprise that's not what they
>
> You are glossing over the reports here describing the
> fragility of carbon fiber resin composites. There _is_
> a material difference between carbon fiber resin and
> other bicycle frame materials. Difference in impact
> resistance, difference in failure mode, and difference
> in ease of damage assessment.
but there are latent issues with metallic systems!!! example: aluminum
was the "fatigue prone" whipping boy until carbon somehow attracted the
attention of the professional bleaters instead.
>
> As a retailer with a reputation to maintain you should
> bring technological arguments to bear or gracefully
> hold your peace. Saying that it makes no difference in
> practice may not be the best course.
ridiculous - if anyone is qualified to relate their experience of how
this stuff holds up in real world usage, the guy that sells it and that
handles any failures or warranty claims is /just/ the guy to relate
their experience. professional bleaters with no personal experience are
precisely /not/ the people qualified to speak.
|
| | | | | | |
Date: 09 Sep 2007 12:26:48
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:-5adndiNwvHFnHnbnZ2dnUVZ_vGinZ2d@speakeasy.net...
> Michael Press wrote:
>> You are glossing over the reports here describing the fragility of carbon
>> fiber resin composites. There _is_ a material difference between carbon
>> fiber resin and other bicycle frame materials. Difference in impact
>> resistance, difference in failure mode, and difference in ease of damage
>> assessment.
>
> but there are latent issues with metallic systems!!! example: aluminum
> was the "fatigue prone" whipping boy until carbon somehow attracted the
> attention of the professional bleaters instead.
You're just swiping at invisible ghosts in your head, and using them as
arguments. Idiot.
>> As a retailer with a reputation to maintain you should bring
>> technological arguments to bear or gracefully hold your peace. Saying
>> that it makes no difference in practice may not be the best course.
>
> ridiculous - if anyone is qualified to relate their experience of how this
> stuff holds up in real world usage, the guy that sells it and that handles
> any failures or warranty claims is /just/ the guy to relate their
> experience.
Ah, I see. Don't worry about conflict of interest, where the guy might be
trying to sell you expensive CF frames and components. Ignore research
scientists, Universities, research programs that have been going on for
decades because they don't agree with your opinion. Yeah, that's a good
path to take. HAHAHAHA!
> professional bleaters with no personal experience are precisely /not/ the
> people qualified to speak.
So what the fuck are you doing bleating on about it?
|
| | | | |
Date: 08 Sep 2007 16:57:46
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <ZJqEi.5926$z_5.862@nlpi069.nbdc.sbc.com >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >> Another point of clarification: are CF bicycle frames over built,
> >> vis., stronger than necessary to take in to consideration the
> >> limitations of the material? I ask this because I have not see an
> >> epidemic of broken CF frames or forks, and I have been riding CF
> >> forks for over 15 years (different ones).
> >
> > Therein is one of the issues in judging the long term safety and
> > durability of CF frames and forks: they just have not been in
> > service very long. I know people with steel frames and forks that
> > have been in use 35+ years, and I know of people whose daily rider
> > bikes are 50+ years old. These bikes are still safe and sound-
> > will that be the same for CF? We won't know for another 35 years
> > or so. And we may not know even then, as currently the folks who
> > tend to buy CF bikes tend to replace their equipment with newer,
> > more up-to-date stuff every couple of years anyway.
>
> Unless you believe that something happens to the fork, either steel
> or carbon, while it is just sitting there, un-used, a track record of
> 15+ years is more than adequate to judge the service life & safety of
> a carbon fiber fork.
Do we know whether there are any aging-related changes in the composite
materials used in bicycles? Or perhaps more to the point, do we know
there are *no* aging-related changes? I don't know one way or another.
But I do know that bikes get damage even when sitting around- somebody
knocks the shovels and rakes over in the garage and they hit the bike,
someone misjudges parking the car and knocks the bike over, etc. Well,
not my bikes because they hang up in the basement out of harm's way, but
many people's bikes just live out in the garage. CF tends to tolerate
those outrageous slings and arrows less gracefully than metals. Around
here that includes freeze-thaw cycles anywhere from -40F to 110F. Does
ultraviolet light affect the CF or the epoxy material? Are there
chemical reactions with atmospheric gases or perhaps things like
gasoline vapors, paint thinner vapors etc?
> It's actual use (on the road) that matters, and as we have seen steel
> forks fail in the past at anywhere from 30-80k miles (some fail
> sooner, some last longer, but that's approximates the average service
> life we've seen over time), the history of carbon forks, as an
> indicator of overall life & safety, becomes clear after no more than
> 10 years, as that will see a fair amount of product achieve that sort
> of mileage.
I've never seen a steel fork failure in the 35 or so years that I have
been dealing with bikes as an enthusiast, but then I only have a few
years of bike shop experience and you have seen thousands more bikes
than I. The odds of you seeing those things is much greater than mine.
> That someone you know has a bike that's 50 years old in daily service
> is likely a testament more to an extraordinarily overbuilt design,
> rather than the material used. If one were to build a fork of the
> same weight out of carbon fiber, it may very well achieve commendable
> life on the roads surrounding Baghdad! But why? Does it make sense to
> build something that will last from one generation to the next, or
> does it make more sense to optimize for the current user, and his/her
> typical lifespan of use (determined not by failure but more often by
> a desire to upgrade)?
That's a defense for planned obsolescence and underbuilding by design to
gain dubious improvements in performance that sound good in marketing
and make no beneficial difference when the rubber meets the road.
Even Lance Armstrong's "optimized" Trek didn't survive the Bag Handle
Crash, suffering a broken chainstay in the process. He only had to ride
it 10 km further, but what if that fracture had been unnoticed and he
had had to rider that bike down a technical descent with the typical
steep cliffs at the side of the road? A material that can just break in
a crash like that is not a suitable material for a bicycle. IMHO, YMMV,
yadda yadda yaddda but I will never buy one.
> The worst thing about this thread is the inference that other
> materials don't fail in normal use. They have in the past. They do
> today. And they will continue to fail tomorrow.
But differences in the failure process are significant. The reports I
have read indicate that CF fails catastrophically and often without
significant warning. Fractures propagate through steel fairly slowly
giving the rider a chance to observe and prevent catastrophic failure.
The original post that started all this was a CF Scott frame that
essentially shattered in a crash.
> It's generally not the material that causes a failure, it's how it's
> used.
That's just a truism. You could build a bicycle from pasta and it
wouldn't fail so long as you didn't try to ride it.
> I would suggest that the rate of frame failures in aluminum, steel &
> ti frames has probably increased since carbon fiber came on the
> market. Why? Because manufacturers have tried to mimic the weight of
> a carbon fiber frame using materials that really aren't suitable for
> that purpose. Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge
> territory.
The failure modes are different for those materials than CF. They
aren't brittle, aren't damaged as easily and fractures don't propagate
as rapidly. We do agree that stoopid lite is stoopid lite no matter
what material is used.
> But if you created a well-build carbon fiber frame at any
> of those weights, it could be impossible to kill. But that's not what
> people are looking for with carbon fiber, so it shouldn't be a huge
> surprise that's not what they get.
Until we see it, we'll never know.
|
| | | | | |
Date: 09 Sep 2007 00:52:10
From:
Subject: Re: "brittle" vs. non-ductile
|
Tim McNamara writes:
>>>> Another point of clarification: are CF bicycle frames over built,
>>>> vis., stronger than necessary to take in to consideration the
>>>> limitations of the material? I ask this because I have not see an
>>>> epidemic of broken CF frames or forks, and I have been riding CF
>>>> forks for over 15 years (different ones).
>>> Therein is one of the issues in judging the long term safety and
>>> durability of CF frames and forks: they just have not been in
>>> service very long. I know people with steel frames and forks that
>>> have been in use 35+ years, and I know of people whose daily rider
>>> bikes are 50+ years old. These bikes are still safe and sound-
>>> will that be the same for CF? We won't know for another 35 years
>>> or so. And we may not know even then, as currently the folks who
>>> tend to buy CF bikes tend to replace their equipment with newer,
>>> more up-to-date stuff every couple of years anyway.
>> Unless you believe that something happens to the fork, either steel
>> or carbon, while it is just sitting there, un-used, a track record of
>> 15+ years is more than adequate to judge the service life & safety of
>> a carbon fiber fork.
> Do we know whether there are any aging-related changes in the
> composite materials used in bicycles? Or perhaps more to the point,
> do we know there are *no* aging-related changes? I don't know one
> way or another. But I do know that bikes get damage even when
> sitting around- somebody knocks the shovels and rakes over in the
> garage and they hit the bike, someone misjudges parking the car and
> knocks the bike over, etc. Well, not my bikes because they hang up
> in the basement out of harm's way, but many people's bikes just live
> out in the garage. CF tends to tolerate those outrageous slings and
> arrows less gracefully than metals. Around here that includes
> freeze-thaw cycles anywhere from -40F to 110F. Does ultraviolet
> light affect the CF or the epoxy material? Are there chemical
> reactions with atmospheric gases or perhaps things like gasoline
> vapors, paint thinner vapors etc?
Recall Spinergy four-blade wheels with carbon fiber "spokes". These
lost all their tension through thermal cycling in the back of the car
and probably age... and then they failed in rattling compression under
lateral collapse. I was always glad I wasn't present when failure
occurred as one of these rode by, the four spokes fluttering loosely.
It is tension that gives wheels lateral strength, especially ones with
narrow hub width.
>> It's actual use (on the road) that matters, and as we have seen steel
>> forks fail in the past at anywhere from 30-80k miles (some fail
>> sooner, some last longer, but that's approximates the average service
>> life we've seen over time), the history of carbon forks, as an
>> indicator of overall life & safety, becomes clear after no more than
>> 10 years, as that will see a fair amount of product achieve that sort
>> of mileage.
Jobst Brandt
|
| | | | | | |
Date: 09 Sep 2007 06:49:24
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
jobst.brandt@stanfordalumni.org wrote:
> Tim McNamara writes:
>
>>>>> Another point of clarification: are CF bicycle frames over built,
>>>>> vis., stronger than necessary to take in to consideration the
>>>>> limitations of the material? I ask this because I have not see an
>>>>> epidemic of broken CF frames or forks, and I have been riding CF
>>>>> forks for over 15 years (different ones).
>
>>>> Therein is one of the issues in judging the long term safety and
>>>> durability of CF frames and forks: they just have not been in
>>>> service very long. I know people with steel frames and forks that
>>>> have been in use 35+ years, and I know of people whose daily rider
>>>> bikes are 50+ years old. These bikes are still safe and sound-
>>>> will that be the same for CF? We won't know for another 35 years
>>>> or so. And we may not know even then, as currently the folks who
>>>> tend to buy CF bikes tend to replace their equipment with newer,
>>>> more up-to-date stuff every couple of years anyway.
>
>>> Unless you believe that something happens to the fork, either steel
>>> or carbon, while it is just sitting there, un-used, a track record of
>>> 15+ years is more than adequate to judge the service life & safety of
>>> a carbon fiber fork.
>
>> Do we know whether there are any aging-related changes in the
>> composite materials used in bicycles? Or perhaps more to the point,
>> do we know there are *no* aging-related changes? I don't know one
>> way or another. But I do know that bikes get damage even when
>> sitting around- somebody knocks the shovels and rakes over in the
>> garage and they hit the bike, someone misjudges parking the car and
>> knocks the bike over, etc. Well, not my bikes because they hang up
>> in the basement out of harm's way, but many people's bikes just live
>> out in the garage. CF tends to tolerate those outrageous slings and
>> arrows less gracefully than metals. Around here that includes
>> freeze-thaw cycles anywhere from -40F to 110F. Does ultraviolet
>> light affect the CF or the epoxy material? Are there chemical
>> reactions with atmospheric gases or perhaps things like gasoline
>> vapors, paint thinner vapors etc?
>
> Recall Spinergy four-blade wheels with carbon fiber "spokes". These
> lost all their tension through thermal cycling in the back of the car
> and probably age... and then they failed in rattling compression under
> lateral collapse. I was always glad I wasn't present when failure
> occurred as one of these rode by, the four spokes fluttering loosely.
> It is tension that gives wheels lateral strength,
no it's not - it's bracing angle that gives lateral strength! reduce
the angle to zero and see how much lateral strength you have!!!
superimposed tension is a zero-sum game. imparting "compressive
strength" on a skinny spoke wire comes at the expense of "borrowing"
compressive strength [and thus load capacity] from the rim.
> especially ones with
> narrow hub width.
yeah, bracing angle, not tension.
>
>>> It's actual use (on the road) that matters, and as we have seen steel
>>> forks fail in the past at anywhere from 30-80k miles (some fail
>>> sooner, some last longer, but that's approximates the average service
>>> life we've seen over time), the history of carbon forks, as an
>>> indicator of overall life & safety, becomes clear after no more than
>>> 10 years, as that will see a fair amount of product achieve that sort
>>> of mileage.
>
|
| | | | | | |
Date: 08 Sep 2007 18:39:27
From: bfd
Subject: Re: "brittle" vs. non-ductile
|
<jobst.brandt@stanfordalumni.org > wrote in message
news:46e343ba$0$14134$742ec2ed@news.sonic.net...
> Tim McNamara writes:
>
>>>>> Another point of clarification: are CF bicycle frames over built,
>>>>> vis., stronger than necessary to take in to consideration the
>>>>> limitations of the material? I ask this because I have not see an
>>>>> epidemic of broken CF frames or forks, and I have been riding CF
>>>>> forks for over 15 years (different ones).
>
>>>> Therein is one of the issues in judging the long term safety and
>>>> durability of CF frames and forks: they just have not been in
>>>> service very long. I know people with steel frames and forks that
>>>> have been in use 35+ years, and I know of people whose daily rider
>>>> bikes are 50+ years old. These bikes are still safe and sound-
>>>> will that be the same for CF? We won't know for another 35 years
>>>> or so. And we may not know even then, as currently the folks who
>>>> tend to buy CF bikes tend to replace their equipment with newer,
>>>> more up-to-date stuff every couple of years anyway.
>
>>> Unless you believe that something happens to the fork, either steel
>>> or carbon, while it is just sitting there, un-used, a track record of
>>> 15+ years is more than adequate to judge the service life & safety of
>>> a carbon fiber fork.
>
>> Do we know whether there are any aging-related changes in the
>> composite materials used in bicycles? Or perhaps more to the point,
>> do we know there are *no* aging-related changes? I don't know one
>> way or another. But I do know that bikes get damage even when
>> sitting around- somebody knocks the shovels and rakes over in the
>> garage and they hit the bike, someone misjudges parking the car and
>> knocks the bike over, etc. Well, not my bikes because they hang up
>> in the basement out of harm's way, but many people's bikes just live
>> out in the garage. CF tends to tolerate those outrageous slings and
>> arrows less gracefully than metals. Around here that includes
>> freeze-thaw cycles anywhere from -40F to 110F. Does ultraviolet
>> light affect the CF or the epoxy material? Are there chemical
>> reactions with atmospheric gases or perhaps things like gasoline
>> vapors, paint thinner vapors etc?
>
> Recall Spinergy four-blade wheels with carbon fiber "spokes". These
> lost all their tension through thermal cycling in the back of the car
> and probably age... and then they failed in rattling compression under
> lateral collapse. I was always glad I wasn't present when failure
> occurred as one of these rode by, the four spokes fluttering loosely.
> It is tension that gives wheels lateral strength, especially ones with
> narrow hub width.
>
I agree that Spinergy carbon "spokes" appear to be dangerous. However, a
carbon spoke is alot different than a carbon frame. For example, I bought a
USED Calfee carbon fiber frame with a Kestrel carbon fork in 1997 that was
made in 1994 and had approximately 2500 miles of use by the previous owner.
I have put over 25,000 miles since purchasing as I average about 2500 miles
or so per year (hard to get in more mileage with 2 small children). I have
crashed the bike several times, including personal injury to myself. So far,
I have not experience any problems with the carbon fiber frame or fork. I
do inspect both the frame and fork and have seen any sort of damage that
causes concern. There have been paint chips, but I them up with clear nail
polish.
Similarly, Craig Calfee says there are several high mileage riders riding
his frames since he started making carbon frames in 1987. I believe one has
over 200,000 miles on his frame and several others have over 100,000 miles.
You need to check with Craig to find out exactly how many and who these
individual riders are.
|
| | | | | | | |
Date: 08 Sep 2007 22:39:13
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"bfd" <bfd853@comcast.net > wrote in message
news:md-dnRqIu-Na037bnZ2dnUVZ_uOmnZ2d@comcast.com...
> For example, I bought a USED Calfee carbon fiber frame with a Kestrel
> carbon fork in 1997 that was made in 1994 and had approximately 2500 miles
> of use by the previous owner. I have put over 25,000 miles since
> purchasing as I average about 2500 miles or so per year (hard to get in
> more mileage with 2 small children).
Good for you. No one said CF frames fatigue faster than any other material
frames.
> I have crashed the bike several times, including personal injury to
> myself. So far, I have not experience any problems with the carbon fiber
> frame or fork. I do inspect both the frame and fork and have seen any
> sort of damage that causes concern. There have been paint chips, but I
> them up with clear nail polish.
Great. Again, no one said that every and any crash will result in CF frame
failure. Without knowing the forces involved in your crashes, it's only
deduction that you did not damage it.
> Similarly, Craig Calfee says there are several high mileage riders riding
> his frames since he started making carbon frames in 1987. I believe one
> has over 200,000 miles on his frame and several others have over 100,000
> miles. You need to check with Craig to find out exactly how many and who
> these individual riders are.
Durability of CF under duty load is not in question. Low tolerance for
damage for non-duty loads, in parts of the CF components not meant to take
loads, is the issue.
|
| | | | | | | | |
Date: 09 Sep 2007 07:02:00
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jambo wrote:
> "bfd" <bfd853@comcast.net> wrote in message
> news:md-dnRqIu-Na037bnZ2dnUVZ_uOmnZ2d@comcast.com...
>> For example, I bought a USED Calfee carbon fiber frame with a Kestrel
>> carbon fork in 1997 that was made in 1994 and had approximately 2500 miles
>> of use by the previous owner. I have put over 25,000 miles since
>> purchasing as I average about 2500 miles or so per year (hard to get in
>> more mileage with 2 small children).
>
> Good for you. No one said CF frames fatigue faster than any other material
> frames.
>
>> I have crashed the bike several times, including personal injury to
>> myself. So far, I have not experience any problems with the carbon fiber
>> frame or fork. I do inspect both the frame and fork and have seen any
>> sort of damage that causes concern. There have been paint chips, but I
>> them up with clear nail polish.
>
> Great. Again, no one said that every and any crash will result in CF frame
> failure. Without knowing the forces involved in your crashes, it's only
> deduction that you did not damage it.
and it's only presumption that you did!
>
>> Similarly, Craig Calfee says there are several high mileage riders riding
>> his frames since he started making carbon frames in 1987. I believe one
>> has over 200,000 miles on his frame and several others have over 100,000
>> miles. You need to check with Craig to find out exactly how many and who
>> these individual riders are.
>
> Durability of CF under duty load is not in question. Low tolerance for
> damage for non-duty loads, in parts of the CF components not meant to take
> loads, is the issue.
>
>
so, to recap, carbon is good, except for when it's not. brilliant.
|
| | | | | | | | | |
Date: 10 Sep 2007 20:50:05
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:L5SdnS-G2oJEYX7bnZ2dnUVZ_qqgnZ2d@speakeasy.net...
> Jambo wrote:
>>
>> Great. Again, no one said that every and any crash will result in CF
>> frame failure. Without knowing the forces involved in your crashes, it's
>> only deduction that you did not damage it.
>
> and it's only presumption that you did!
Eh? I deduced his crash cause? You been hitting the sauce again beamboy?
> so, to recap, carbon is good, except for when it's not. brilliant.
HAHAHAHAHA! Excellent example of beamboy's height of intellectual capacity
to understand!
Do you understand anisotropy? Look it up, then look up CFC anisotropy, then
look up surface damage, then... oh sheeit, just get a new brain, beamboy!
Thanks beamboy, you sure crack me up (like a CF handlebar!)
|
| | | | | |
Date: 09 Sep 2007 00:47:02
From:
Subject: Re: "brittle" vs. non-ductile
|
Tim McNamara writes:
>>>> Another point of clarification: are CF bicycle frames over built,
>>>> vis., stronger than necessary to take in to consideration the
>>>> limitations of the material? I ask this because I have not see an
>>>> epidemic of broken CF frames or forks, and I have been riding CF
>>>> forks for over 15 years (different ones).
>>> Therein is one of the issues in judging the long term safety and
>>> durability of CF frames and forks: they just have not been in
>>> service very long. I know people with steel frames and forks that
>>> have been in use 35+ years, and I know of people whose daily rider
>>> bikes are 50+ years old. These bikes are still safe and sound-
>>> will that be the same for CF? We won't know for another 35 years
>>> or so. And we may not know even then, as currently the folks who
>>> tend to buy CF bikes tend to replace their equipment with newer,
>>> more up-to-date stuff every couple of years anyway.
>> Unless you believe that something happens to the fork, either steel
>> or carbon, while it is just sitting there, un-used, a track record of
>> 15+ years is more than adequate to judge the service life & safety of
>> a carbon fiber fork.
> Do we know whether there are any aging-related changes in the
> composite materials used in bicycles? Or perhaps more to the point,
> do we know there are *no* aging-related changes? I don't know one
> way or another. But I do know that bikes get damage even when
> sitting around- somebody knocks the shovels and rakes over in the
> garage and they hit the bike, someone misjudges parking the car and
> knocks the bike over, etc. Well, not my bikes because they hang up
> in the basement out of harm's way, but many people's bikes just live
> out in the garage. CF tends to tolerate those outrageous slings and
> arrows less gracefully than metals. Around here that includes
> freeze-thaw cycles anywhere from -40F to 110F. Does ultraviolet
> light affect the CF or the epoxy material? Are there chemical
> reactions with atmospheric gases or perhaps things like gasoline
> vapors, paint thinner vapors etc?
Recall Spinergy four-blade wheels with carbon fiber "spokes". These
lost all their tension through thermal cycling in the back of the car
and probably age... and then they failed in rattling compression under
lateral collapse. I always glad I wasn't present when failure
occurred as one of these rode by, the four spokes fluttering loosely.
It is tension that gives wheels lateral strength, especially ones with
narrow hub width.
>> It's actual use (on the road) that matters, and as we have seen steel
>> forks fail in the past at anywhere from 30-80k miles (some fail
>> sooner, some last longer, but that's approximates the average service
>> life we've seen over time), the history of carbon forks, as an
>> indicator of overall life & safety, becomes clear after no more than
>> 10 years, as that will see a fair amount of product achieve that sort
>> of mileage.
Jobst Brandt
|
| | | | |
Date: 08 Sep 2007 13:07:20
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>
> The worst thing about this thread is the inference that other materials
> don't fail in normal use.
No, the worst thing is the *mode* of CF failure.
> Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
> But if you created a well-build carbon fiber frame at any of those weights,
> it could be impossible to kill. But that's not what people are looking for
> with carbon fiber, so it shouldn't be a huge surprise that's not what they
> get.
Sure, they get what, a 2.1lb frame? Why bring this up? Nobody is going
to make the "no kill" CF frame. Who would want it?
|
| | | | | |
Date: 08 Sep 2007 21:05:10
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> The worst thing about this thread is the inference that other materials
>> don't fail in normal use.
>
> No, the worst thing is the *mode* of CF failure.
>
> > Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
>> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
>> But if you created a well-build carbon fiber frame at any of those
>> weights, it could be impossible to kill. But that's not what people are
>> looking for with carbon fiber, so it shouldn't be a huge surprise that's
>> not what they get.
>
> Sure, they get what, a 2.1lb frame? Why bring this up? Nobody is going to
> make the "no kill" CF frame. Who would want it?
That's actually not true. We're beginning to see lesser-performance, heavier
carbon fiber frames used in less-expensive bikes. They don't ride as
smoothly, they're not as light, and generally just don't feel as lively as
the leading-edge products, but frankly, some of the stuff we're now seeing
is probably going to be one heck of a dent into a car before having a
problem itself. These frames will run close to 3 pounds, so on the one hand,
they lose the appeal of ultra-lightweight that people come to expect from
carbon fiber. But on the other hand, they're probably going to outlast many
cycling careers.
But the question is, will people buy a carbon frame that weighs more, and
costs more, than a similarly-equipped bike with an aluminum frame?
Unfortunately, nobody in the bike biz is going to promote such bikes as
being ultra-durable, because the inference will be that other bikes aren't
(and, obviously, not just inference but fact). More likely the only reason
such bikes will sell is because people will want to buy in on the coolness
of carbon fiber, and the added strength will be an incidental benefit that
they'll know nothing of.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | | | |
Date: 08 Sep 2007 10:50:33
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> Mike Jacoubowsky wrote:
>>
>> The worst thing about this thread is the inference that other
>> materials don't fail in normal use.
>
> No, the worst thing is the *mode* of CF failure.
yeah - it takes 3x the stress of steel, and resists fatigue much better
while being lighter - that's a /real/ "worst thing".
>
> > Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
>> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge
>> territory. But if you created a well-build carbon fiber frame at any
>> of those weights, it could be impossible to kill. But that's not what
>> people are looking for with carbon fiber, so it shouldn't be a huge
>> surprise that's not what they get.
>
> Sure, they get what, a 2.1lb frame? Why bring this up? Nobody is going
> to make the "no kill" CF frame. Who would want it?
that's just being a prick.
|
| | | | |
Date: 08 Sep 2007 07:27:44
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>>> Another point of clarification: are CF bicycle frames over built,
>>> vis., stronger than necessary to take in to consideration the
>>> limitations of the material? I ask this because I have not see an
>>> epidemic of broken CF frames or forks, and I have been riding CF
>>> forks for over 15 years (different ones).
>> Therein is one of the issues in judging the long term safety and
>> durability of CF frames and forks: they just have not been in service
>> very long. I know people with steel frames and forks that have been in
>> use 35+ years, and I know of people whose daily rider bikes are 50+
>> years old. These bikes are still safe and sound- will that be the same
>> for CF? We won't know for another 35 years or so. And we may not know
>> even then, as currently the folks who tend to buy CF bikes tend to
>> replace their equipment with newer, more up-to-date stuff every couple
>> of years anyway.
>
> Unless you believe that something happens to the fork, either steel or
> carbon, while it is just sitting there, un-used, a track record of 15+ years
> is more than adequate to judge the service life & safety of a carbon fiber
> fork. It's actual use (on the road) that matters, and as we have seen steel
> forks fail in the past at anywhere from 30-80k miles (some fail sooner, some
> last longer, but that's approximates the average service life we've seen
> over time), the history of carbon forks, as an indicator of overall life &
> safety, becomes clear after no more than 10 years, as that will see a fair
> amount of product achieve that sort of mileage.
>
> That someone you know has a bike that's 50 years old in daily service is
> likely a testament more to an extraordinarily overbuilt design, rather than
> the material used. If one were to build a fork of the same weight out of
> carbon fiber, it may very well achieve commendable life on the roads
> surrounding Baghdad! But why? Does it make sense to build something that
> will last from one generation to the next, or does it make more sense to
> optimize for the current user, and his/her typical lifespan of use
> (determined not by failure but more often by a desire to upgrade)?
>
> The worst thing about this thread is the inference that other materials
> don't fail in normal use. They have in the past. They do today. And they
> will continue to fail tomorrow. It's generally not the material that causes
> a failure, it's how it's used. I would suggest that the rate of frame
> failures in aluminum, steel & ti frames has probably increased since carbon
> fiber came on the market. Why? Because manufacturers have tried to mimic the
> weight of a carbon fiber frame using materials that really aren't suitable
> for that purpose. Sub 3.5lb steel frames, sub 2.8lb aluminum frames, sub
> 3.1-3.3lb ti frames... they're all in dangerous, bleeding-edge territory.
> But if you created a well-build carbon fiber frame at any of those weights,
> it could be impossible to kill. But that's not what people are looking for
> with carbon fiber, so it shouldn't be a huge surprise that's not what they
> get.
bravo! well said.
>
> --Mike-- Chain Reaction Bicycles
> www.ChainReactionBicycles.com
>
>
> "Tim McNamara" <timmcn@bitstream.net> wrote in message
> news:timmcn-6CF468.20062307092007@news.iphouse.com...
>> In article <1189184546.941992.244120@o80g2000hse.googlegroups.com>,
>> Jay Beattie <jbeattie@lindsayhart.com> wrote:
>>
>>> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
>>>> "jim beam" <spamvor...@bad.example.net> wrote in message
>>>>
>>>> news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>>>>
>>>>> Peter Cole wrote:
>>>>>> The aircraft industry works to higher standards than joe (jim)
>>>>>> consumer. That's the point.
>>>>> i /hate/ to point this out, but the people that /started/ using
>>>>> cfrp in bikes used experience /from/ the aerospace industry.
>>>>> damn.
>>>> This is your say so, not fact. Geez, you're incredibly gullible.
>>> Another point of clarification: are CF bicycle frames over built,
>>> vis., stronger than necessary to take in to consideration the
>>> limitations of the material? I ask this because I have not see an
>>> epidemic of broken CF frames or forks, and I have been riding CF
>>> forks for over 15 years (different ones).
>> Therein is one of the issues in judging the long term safety and
>> durability of CF frames and forks: they just have not been in service
>> very long. I know people with steel frames and forks that have been in
>> use 35+ years, and I know of people whose daily rider bikes are 50+
>> years old. These bikes are still safe and sound- will that be the same
>> for CF? We won't know for another 35 years or so. And we may not know
>> even then, as currently the folks who tend to buy CF bikes tend to
>> replace their equipment with newer, more up-to-date stuff every couple
>> of years anyway.
>
>
|
| | | | | |
Date: 09 Sep 2007 12:17:14
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:J5ydnY7RCbT9LH_bnZ2dnUVZ_hCdnZ2d@speakeasy.net...
>
> bravo! well said.
Eh, moron, he just confirmed that your bleatings are idiotic!
|
| | | |
Date: 07 Sep 2007 19:08:52
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Tim McNamara wrote:
> In article <1189184546.941992.244120@o80g2000hse.googlegroups.com>,
> Jay Beattie <jbeattie@lindsayhart.com> wrote:
>
>> On Sep 7, 8:24 am, "Jambo" <-...@-.-> wrote:
>>> "jim beam" <spamvor...@bad.example.net> wrote in message
>>>
>>> news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
>>>
>>>> Peter Cole wrote:
>>>>> The aircraft industry works to higher standards than joe (jim)
>>>>> consumer. That's the point.
>>>> i /hate/ to point this out, but the people that /started/ using
>>>> cfrp in bikes used experience /from/ the aerospace industry.
>>>> damn.
>>> This is your say so, not fact. Geez, you're incredibly gullible.
>> Another point of clarification: are CF bicycle frames over built,
>> vis., stronger than necessary to take in to consideration the
>> limitations of the material? I ask this because I have not see an
>> epidemic of broken CF frames or forks, and I have been riding CF
>> forks for over 15 years (different ones).
>
> Therein is one of the issues in judging the long term safety and
> durability of CF frames and forks: they just have not been in service
> very long.
10+ years is just not good enough! bring back bushing chains!
> I know people with steel frames and forks that have been in
> use 35+ years, and I know of people whose daily rider bikes are 50+
> years old. These bikes are still safe and sound-
how do you /know/ they are??? have you x-rayed? ultrasound?
magnaflux? [etc.]
> will that be the same
> for CF? We won't know for another 35 years or so. And we may not know
> even then, as currently the folks who tend to buy CF bikes tend to
> replace their equipment with newer, more up-to-date stuff every couple
> of years anyway.
typical timmy logic - metal that hasn't yet failed must be ok, but
carbon that hasn't yet failed isn't!!! what a retard.
|
| |
Date: 07 Sep 2007 14:57:33
From:
Subject: Re: "brittle" vs. non-ductile
|
On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net > wrote:
> Peter Cole wrote:
> >
>
> > Then how (if there are "warning signs") could there be:
> > "a lot of people out there riding on damaged (broken) carbon frames &
> > forks that aren't aware of it." ?
>
> simply pay attention big guy.
We all know it's pointless to argue with "jim beam," but since others
are reading: I think the advice he gives below is practically useless
for most people.
> 1. the bike comes with an owners manual outlining inspection and
> warnings.
In America, warnings are attached to every consumer device. Our
society is perpetually crying "Wolf!" and most people are no longer
believing the warnings. I believe we've reached a point where the
warnings serve only as legal ammunition in a court action.
Any consumer actually reading his CF bike's manual would have to
distinguish whether the CF inspection warnings are any more serious
than statements like "Always check the tightness of every bolt before
any ride" and "Never ride any bicycle at night." Most will assume all
such warnings are legal smokescreens.
> 2. ask advice on this forum from people that are familiar with the
> material and its failures.
:-) Trouble is, some poor sucker might believe advice from "jim
beam"!
> 3. ask bike shop owners that are familiar with the material and its
> failures.
Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
all bike shop owners get extensive training in evaluating CF damage.
I've been in bike shops where the kid on duty couldn't operate a quick
release properly! No, he wasn't the owner, but how does the average
consumer tell the difference?
I don't think the typical American sport cyclist has any idea about
the true advantages and disadvantages of CF. IMO, he has no
understanding deeper than "Lance used this. It's 30 grams lighter and
it looks cool. Buycycling gave it 7 chainrings. It's going to
finally let me beat Fred up that hill."
And I think it's a bad idea to whittle the practical factor of safety
down to the point where the typical American sport cyclist has to
pretend to be a CF-certified airframe mechanic. It's like designing
the next Mazda Miata with an all-composite suspension system, and
hoping nobody ever hits a curb.
- Frank Krygowski
|
| | |
Date: 07 Sep 2007 12:29:22
From: A Muzi
Subject: Re: "brittle" vs. non-ductile
|
frkrygow@gmail.com wrote:
> On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Peter Cole wrote:
>>> Then how (if there are "warning signs") could there be:
>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>> forks that aren't aware of it." ?
>> simply pay attention big guy.
>
> We all know it's pointless to argue with "jim beam," but since others
> are reading: I think the advice he gives below is practically useless
> for most people.
>
>> 1. the bike comes with an owners manual outlining inspection and
>> warnings.
>
> In America, warnings are attached to every consumer device. Our
> society is perpetually crying "Wolf!" and most people are no longer
> believing the warnings. I believe we've reached a point where the
> warnings serve only as legal ammunition in a court action.
>
> Any consumer actually reading his CF bike's manual would have to
> distinguish whether the CF inspection warnings are any more serious
> than statements like "Always check the tightness of every bolt before
> any ride" and "Never ride any bicycle at night." Most will assume all
> such warnings are legal smokescreens.
>
>> 2. ask advice on this forum from people that are familiar with the
>> material and its failures.
>
> :-) Trouble is, some poor sucker might believe advice from "jim
> beam"!
>
>> 3. ask bike shop owners that are familiar with the material and its
>> failures.
>
> Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
> all bike shop owners get extensive training in evaluating CF damage.
> I've been in bike shops where the kid on duty couldn't operate a quick
> release properly! No, he wasn't the owner, but how does the average
> consumer tell the difference?
>
> I don't think the typical American sport cyclist has any idea about
> the true advantages and disadvantages of CF. IMO, he has no
> understanding deeper than "Lance used this. It's 30 grams lighter and
> it looks cool. Buycycling gave it 7 chainrings. It's going to
> finally let me beat Fred up that hill."
>
> And I think it's a bad idea to whittle the practical factor of safety
> down to the point where the typical American sport cyclist has to
> pretend to be a CF-certified airframe mechanic. It's like designing
> the next Mazda Miata with an all-composite suspension system, and
> hoping nobody ever hits a curb.
Right.
Yes, we can sometimes spot damage. But we are clear that our inability
to see damage is not an imprimatur of soundness. When in doubt
post-crash we suggest replacement. Some riders do, some do not.
Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
have, test equipment to nondestructively spot anomalies and/or damage in
composite materials for the Dreamliner. Boeing spokesman pointedly noted
that rapping a structural member with a quarter, the previous standard
test, is no longer considered sufficient to establish airworthiness.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 07 Sep 2007 18:25:28
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
A Muzi wrote:
> frkrygow@gmail.com wrote:
>> On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net> wrote:
>>> Peter Cole wrote:
>>>> Then how (if there are "warning signs") could there be:
>>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>>> forks that aren't aware of it." ?
>>> simply pay attention big guy.
>>
>> We all know it's pointless to argue with "jim beam," but since others
>> are reading: I think the advice he gives below is practically useless
>> for most people.
>>
>>> 1. the bike comes with an owners manual outlining inspection and
>>> warnings.
>>
>> In America, warnings are attached to every consumer device. Our
>> society is perpetually crying "Wolf!" and most people are no longer
>> believing the warnings. I believe we've reached a point where the
>> warnings serve only as legal ammunition in a court action.
>>
>> Any consumer actually reading his CF bike's manual would have to
>> distinguish whether the CF inspection warnings are any more serious
>> than statements like "Always check the tightness of every bolt before
>> any ride" and "Never ride any bicycle at night." Most will assume all
>> such warnings are legal smokescreens.
>>
>>> 2. ask advice on this forum from people that are familiar with the
>>> material and its failures.
>>
>> :-) Trouble is, some poor sucker might believe advice from "jim
>> beam"!
>>
>>> 3. ask bike shop owners that are familiar with the material and its
>>> failures.
>>
>> Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
>> all bike shop owners get extensive training in evaluating CF damage.
>> I've been in bike shops where the kid on duty couldn't operate a quick
>> release properly! No, he wasn't the owner, but how does the average
>> consumer tell the difference?
>>
>> I don't think the typical American sport cyclist has any idea about
>> the true advantages and disadvantages of CF. IMO, he has no
>> understanding deeper than "Lance used this. It's 30 grams lighter and
>> it looks cool. Buycycling gave it 7 chainrings. It's going to
>> finally let me beat Fred up that hill."
>>
>> And I think it's a bad idea to whittle the practical factor of safety
>> down to the point where the typical American sport cyclist has to
>> pretend to be a CF-certified airframe mechanic. It's like designing
>> the next Mazda Miata with an all-composite suspension system, and
>> hoping nobody ever hits a curb.
>
> Right.
fud.
>
> Yes, we can sometimes spot damage. But we are clear that our inability
> to see damage
but you can hear it. just like you wouldn't stand on a plank that made
cracking noises under your weight, don't ride carbon that does the same.
> is not an imprimatur of soundness. When in doubt
> post-crash we suggest replacement. Some riders do, some do not.
if no damage was evident, and it was silent, i wouldn't replace.
indeed, i haven't replaced my carbon fork after the wheel-smashing
incident. works fine - still no evidence of problem.
>
> Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
> have, test equipment to nondestructively spot anomalies and/or damage in
> composite materials for the Dreamliner. Boeing spokesman pointedly noted
> that rapping a structural member with a quarter, the previous standard
> test, is no longer considered sufficient to establish airworthiness.
i think the f.a.a. is going to be the best judge of this, not fudsters
on r.b.t or the chic trib.
|
| | | | |
Date: 08 Sep 2007 15:47:28
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:QPednS1FMeuVZ3zbnZ2dnUVZ_s_inZ2d@speakeasy.net...
> fud.
Another devastating counter from fucktard.
>> Yes, we can sometimes spot damage. But we are clear that our inability to
>> see damage
>
> but you can hear it. just like you wouldn't stand on a plank that made
> cracking noises under your weight, don't ride carbon that does the same.
HAHAHAHA! Arr Captain Moron, cracking of CF is immediately followed by
failure! You should get a job with Boeing, inspecting CF by listening for
cracking noises! HAHAHAHAHA! You'd make their day!
>> is not an imprimatur of soundness. When in doubt post-crash we suggest
>> replacement. Some riders do, some do not.
>
> if no damage was evident, and it was silent, i wouldn't replace.
Morons like YOU wouldn't. We know that.
> indeed, i haven't replaced my carbon fork after the wheel-smashing
> incident. works fine - still no evidence of problem.
Not that you know there isn't a problem, but you've just guessed it.
Hopefully your luck will run out soon!
>>
>> Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
>> have, test equipment to nondestructively spot anomalies and/or damage in
>> composite materials for the Dreamliner. Boeing spokesman pointedly noted
>> that rapping a structural member with a quarter, the previous standard
>> test, is no longer considered sufficient to establish airworthiness.
>
> i think the f.a.a. is going to be the best judge of this, not fudsters on
> r.b.t or the chic trib.
Nor one "jim beam", metallurgist wannabe, faker extraordinaire and all-round
loser! Go attend some arithmetic classes, moron!
|
| | | | | |
Date: 09 Sep 2007 07:58:00
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jambo wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:QPednS1FMeuVZ3zbnZ2dnUVZ_s_inZ2d@speakeasy.net...
>> fud.
>
> Another devastating counter from fucktard.
>
>>> Yes, we can sometimes spot damage. But we are clear that our inability to
>>> see damage
>> but you can hear it. just like you wouldn't stand on a plank that made
>> cracking noises under your weight, don't ride carbon that does the same.
>
> HAHAHAHA! Arr Captain Moron, cracking of CF is immediately followed by
> failure! You should get a job with Boeing, inspecting CF by listening for
> cracking noises! HAHAHAHAHA! You'd make their day!
er, since you work in aerospace and all, you'd /know/ that they embed
microphones into the fiber to listen for precisely that, wouldn't you?
oh, wait, perhaps not.
>
>>> is not an imprimatur of soundness. When in doubt post-crash we suggest
>>> replacement. Some riders do, some do not.
>> if no damage was evident, and it was silent, i wouldn't replace.
>
> Morons like YOU wouldn't. We know that.
>
>> indeed, i haven't replaced my carbon fork after the wheel-smashing
>> incident. works fine - still no evidence of problem.
>
> Not that you know there isn't a problem, but you've just guessed it.
> Hopefully your luck will run out soon!
>
>>> Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
>>> have, test equipment to nondestructively spot anomalies and/or damage in
>>> composite materials for the Dreamliner. Boeing spokesman pointedly noted
>>> that rapping a structural member with a quarter, the previous standard
>>> test, is no longer considered sufficient to establish airworthiness.
>> i think the f.a.a. is going to be the best judge of this, not fudsters on
>> r.b.t or the chic trib.
>
> Nor one "jim beam", metallurgist wannabe, faker extraordinaire and all-round
> loser! Go attend some arithmetic classes, moron!
funny. for a guy that tried to show up like mr. super-composites,
lecturing the proles and admonishing the peon aerospace techs that
didn't know their business, you've done a remarkably good job of
tripping over your cape. it's highly entertaining!
|
| | | | | | |
Date: 10 Sep 2007 20:54:35
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:Qa6dnTKAc5hklHnbnZ2dnUVZ_h2pnZ2d@speakeasy.net...
> Jambo wrote:
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news:QPednS1FMeuVZ3zbnZ2dnUVZ_s_inZ2d@speakeasy.net...
>>> fud.
>>
>> Another devastating counter from fucktard.
>>
>>>> Yes, we can sometimes spot damage. But we are clear that our inability
>>>> to see damage
>>> but you can hear it. just like you wouldn't stand on a plank that made
>>> cracking noises under your weight, don't ride carbon that does the same.
>>
>> HAHAHAHA! Arr Captain Moron, cracking of CF is immediately followed by
>> failure! You should get a job with Boeing, inspecting CF by listening
>> for cracking noises! HAHAHAHAHA! You'd make their day!
>
> er, since you work in aerospace and all, you'd /know/ that they embed
> microphones into the fiber to listen for precisely that, wouldn't you? oh,
> wait, perhaps not.
So tell me beamboy, what aircraft is flying out there that has microphones
in their CF components? Take your time, no need to dream up a "materials
lecture more than 30 years ago"....
>> Nor one "jim beam", metallurgist wannabe, faker extraordinaire and
>> all-round loser! Go attend some arithmetic classes, moron!
>
> funny. for a guy that tried to show up like mr. super-composites,
> lecturing the proles and admonishing the peon aerospace techs that didn't
> know their business, you've done a remarkably good job of tripping over
> your cape. it's highly entertaining!
HAHAHA! So tell me beamboy, what aircraft is flying out there that has
microphones in their CF components? Take your time, no need to dream up a
"materials lecture more than 30 years ago"....
|
| | | |
Date: 07 Sep 2007 12:30:54
From:
Subject: Re: "brittle" vs. non-ductile
|
On Fri, 07 Sep 2007 12:29:22 -0500, A Muzi <am@yellowjersey.org >
wrote:
>frkrygow@gmail.com wrote:
>> On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net> wrote:
>>> Peter Cole wrote:
>>>> Then how (if there are "warning signs") could there be:
>>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>>> forks that aren't aware of it." ?
>>> simply pay attention big guy.
>>
>> We all know it's pointless to argue with "jim beam," but since others
>> are reading: I think the advice he gives below is practically useless
>> for most people.
>>
>>> 1. the bike comes with an owners manual outlining inspection and
>>> warnings.
>>
>> In America, warnings are attached to every consumer device. Our
>> society is perpetually crying "Wolf!" and most people are no longer
>> believing the warnings. I believe we've reached a point where the
>> warnings serve only as legal ammunition in a court action.
>>
>> Any consumer actually reading his CF bike's manual would have to
>> distinguish whether the CF inspection warnings are any more serious
>> than statements like "Always check the tightness of every bolt before
>> any ride" and "Never ride any bicycle at night." Most will assume all
>> such warnings are legal smokescreens.
>>
>>> 2. ask advice on this forum from people that are familiar with the
>>> material and its failures.
>>
>> :-) Trouble is, some poor sucker might believe advice from "jim
>> beam"!
>>
>>> 3. ask bike shop owners that are familiar with the material and its
>>> failures.
>>
>> Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
>> all bike shop owners get extensive training in evaluating CF damage.
>> I've been in bike shops where the kid on duty couldn't operate a quick
>> release properly! No, he wasn't the owner, but how does the average
>> consumer tell the difference?
>>
>> I don't think the typical American sport cyclist has any idea about
>> the true advantages and disadvantages of CF. IMO, he has no
>> understanding deeper than "Lance used this. It's 30 grams lighter and
>> it looks cool. Buycycling gave it 7 chainrings. It's going to
>> finally let me beat Fred up that hill."
>>
>> And I think it's a bad idea to whittle the practical factor of safety
>> down to the point where the typical American sport cyclist has to
>> pretend to be a CF-certified airframe mechanic. It's like designing
>> the next Mazda Miata with an all-composite suspension system, and
>> hoping nobody ever hits a curb.
>
>Right.
>
>Yes, we can sometimes spot damage. But we are clear that our inability
>to see damage is not an imprimatur of soundness. When in doubt
>post-crash we suggest replacement. Some riders do, some do not.
>
>Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
>have, test equipment to nondestructively spot anomalies and/or damage in
>composite materials for the Dreamliner. Boeing spokesman pointedly noted
>that rapping a structural member with a quarter, the previous standard
>test, is no longer considered sufficient to establish airworthiness.
Dear Andrew,
In a bold new move, Nepalese pre-flight inspectors now slaughter goats
instead of using the venerable coin-tapping rendered useless by
inflation:
http://www.freerepublic.com/focus/f-news/1890995/posts
Cheers,
Carl Fogel
|
| | | | |
Date: 07 Sep 2007 15:42:16
From: A Muzi
Subject: Re: "brittle" vs. non-ductile
|
>>> jim beam <spamvor...@bad.example.net> wrote:
>>>> Peter Cole wrote:
>>>>> Then how (if there are "warning signs") could there be:
>>>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>>>> forks that aren't aware of it." ?
>>>> simply pay attention big guy.
>>> We all know it's pointless to argue with "jim beam," but since others
>>> are reading: I think the advice he gives below is practically useless
>>> for most people.
>>>> 1. the bike comes with an owners manual outlining inspection and
>>>> warnings.
>>> In America, warnings are attached to every consumer device. Our
>>> society is perpetually crying "Wolf!" and most people are no longer
>>> believing the warnings. I believe we've reached a point where the
>>> warnings serve only as legal ammunition in a court action.
>>>
>>> Any consumer actually reading his CF bike's manual would have to
>>> distinguish whether the CF inspection warnings are any more serious
>>> than statements like "Always check the tightness of every bolt before
>>> any ride" and "Never ride any bicycle at night." Most will assume all
>>> such warnings are legal smokescreens.
>>>
>>>> 2. ask advice on this forum from people that are familiar with the
>>>> material and its failures.
>>> :-) Trouble is, some poor sucker might believe advice from "jim
>>> beam"!
>>>
>>>> 3. ask bike shop owners that are familiar with the material and its
>>>> failures.
>> frkrygow@gmail.com wrote:
>>> Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
>>> all bike shop owners get extensive training in evaluating CF damage.
>>> I've been in bike shops where the kid on duty couldn't operate a quick
>>> release properly! No, he wasn't the owner, but how does the average
>>> consumer tell the difference?
>>>
>>> I don't think the typical American sport cyclist has any idea about
>>> the true advantages and disadvantages of CF. IMO, he has no
>>> understanding deeper than "Lance used this. It's 30 grams lighter and
>>> it looks cool. Buycycling gave it 7 chainrings. It's going to
>>> finally let me beat Fred up that hill."
>>>
>>> And I think it's a bad idea to whittle the practical factor of safety
>>> down to the point where the typical American sport cyclist has to
>>> pretend to be a CF-certified airframe mechanic. It's like designing
>>> the next Mazda Miata with an all-composite suspension system, and
>>> hoping nobody ever hits a curb.
> A Muzi <am@yellowjersey.org> wrote:
>> Right.
>> Yes, we can sometimes spot damage. But we are clear that our inability
>> to see damage is not an imprimatur of soundness. When in doubt
>> post-crash we suggest replacement. Some riders do, some do not.
>>
>> Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet
>> have, test equipment to nondestructively spot anomalies and/or damage in
>> composite materials for the Dreamliner. Boeing spokesman pointedly noted
>> that rapping a structural member with a quarter, the previous standard
>> test, is no longer considered sufficient to establish airworthiness.
carlfogel@comcast.net wrote:
> In a bold new move, Nepalese pre-flight inspectors now slaughter goats
> instead of using the venerable coin-tapping rendered useless by
> inflation:
>
> http://www.freerepublic.com/focus/f-news/1890995/posts
Does that work with Chinese carbon BSOs? Or only Nepali? (I once filed
an H-1B for a Tibetan, claiming I needed a Tibetan bike mechanic to work
on Tibetan bikes. INS signed off right away on that one!)
We have a copy of Gene Daniels' all-time-best wheelbuilding directions
on our truing stand [I paraphrase] "sprinkle some chicken blood, do a
little dance (counterclockwise) holding a bag of spokes..."
I suppose a sacrificed goat can add that little je ne sais quoi when the
manufacturer doesn't either.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 07 Sep 2007 10:42:09
From: Bill Sornson
Subject: Re: "brittle" vs. non-ductile
|
A Muzi wrote:
> rapping a structural member with a quarter
Family newsgoup, buddy.
Bill "note to self: go tap the Mad One" S.
|
| | |
Date: 07 Sep 2007 10:37:48
From: Ben C
Subject: Re: "brittle" vs. non-ductile
|
On 2007-09-07, frkrygow@gmail.com <frkrygow@gmail.com > wrote:
> On Sep 6, 11:57 pm, jim beam <spamvor...@bad.example.net> wrote:
[...]
>> 2. ask advice on this forum from people that are familiar with the
>> material and its failures.
>
>:-) Trouble is, some poor sucker might believe advice from "jim
> beam"!
When he has ever given bad advice?
[...]
> And I think it's a bad idea to whittle the practical factor of safety
> down to the point where the typical American sport cyclist has to
> pretend to be a CF-certified airframe mechanic. It's like designing
> the next Mazda Miata with an all-composite suspension system, and
> hoping nobody ever hits a curb.
Now I'm confused. I was pleased to learn a few days ago that cycling is
basically safer than sitting on a sofa watching TV. But not if I use a
CF frame?
|
| | | |
Date: 07 Sep 2007 16:24:49
From:
Subject: Re: "brittle" vs. non-ductile
|
Ben C? writes:
>>> 2. ask advice on this forum from people that are familiar with the
>>> material and its failures.
>> Trouble is, some poor sucker might believe advice from "jim beam"!
> When he has ever given bad advice?
>> And I think it's a bad idea to whittle the practical factor of
>> safety down to the point where the typical American sport cyclist
>> has to pretend to be a CF-certified airframe mechanic. It's like
>> designing the next Mazda Miata with an all-composite suspension
>> system, and hoping nobody ever hits a curb.
> Now I'm confused. I was pleased to learn a few days ago that cycling
> is basically safer than sitting on a sofa watching TV. But not if I
> use a CF frame?
I think he got it. I think he's got it! ('enry 'iggins).
Jobst Brandt
|
| |
Date: 07 Sep 2007 01:23:53
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
Jay Beattie wrote:
>
> Jambo wrote:
> >
> > If people want to use CFRP on bikes, fine and well, but it will do them good
> > to be aware of the pitfalls.
>
> Why is Boeing making planes out of this stuff? Are they using
> something different than we see in bikes?
Yes. They are using fanatical (and fantastically expensive) quality
control and ongoing scheduled inspection.
Chalo
|
| |
Date: 06 Sep 2007 18:08:09
From: Jay Beattie
Subject: Re: "brittle" vs. non-ductile
|
On Sep 6, 5:55 pm, "Jambo" <-...@-.- > wrote:
> "Mike Jacoubowsky" <Mi...@ChainReaction.com> wrote in message
>
> news:td0Ei.1471$4J3.776@newssvr22.news.prodigy.net...
>
> >> Then how (if there are "warning signs") could there be:
> >> "a lot of people out there riding on damaged (broken) carbon frames &
> >> forks that aren't aware of it." ?
>
> > Because, as pointed out previously, people either don't know what to look
> > for, or don't want to look for it (wishful thinking, wanting to believe
> > everything's OK since the bike can be ridden) or a combination of the two.
>
> > The statement is factual. That it's difficult for some to comprehend is
> > obvious, but that doesn't change that it's true.
>
> The point is that to rely only on visual inspection for CFRP damage is
> foolish, since
> 1. as you say, people don't know what to look for or
> 2. don't wanna look; but also
> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
> there.
>
> It's also quite stupid to rely on any noise that CFRP may make when it gets
> damaged. CFRP failure is catastrophic, and depending on the component, the
> loud crack is the last thing you hear before things go not so nice. If it's
> on a component like a handlebar, seatpost or fork, hope you have good health
> cover.
>
> If people want to use CFRP on bikes, fine and well, but it will do them good
> to be aware of the pitfalls.
Why is Boeing making planes out of this stuff? Are they using
something different than we see in bikes? -- Jay Beattie.
|
| | |
Date: 06 Sep 2007 21:35:37
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Jay Beattie" <jbeattie@lindsayhart.com > wrote in message
news:1189127289.034487.241030@d55g2000hsg.googlegroups.com...
> On Sep 6, 5:55 pm, "Jambo" <-...@-.-> wrote:
>> The point is that to rely only on visual inspection for CFRP damage is
>> foolish, since
>> 1. as you say, people don't know what to look for or
>> 2. don't wanna look; but also
>> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
>> there.
>>
>> It's also quite stupid to rely on any noise that CFRP may make when it
>> gets
>> damaged. CFRP failure is catastrophic, and depending on the component,
>> the
>> loud crack is the last thing you hear before things go not so nice. If
>> it's
>> on a component like a handlebar, seatpost or fork, hope you have good
>> health
>> cover.
>>
>> If people want to use CFRP on bikes, fine and well, but it will do them
>> good
>> to be aware of the pitfalls.
>
> Why is Boeing making planes out of this stuff? Are they using
> something different than we see in bikes? -- Jay Beattie.
CFRP is good for planes because its strength to weight ratio is better than
Al alloys, it has higher fatigue limits, and since its desirable properties
can be made directional (i.e. it's anisotropic), a component can be made
thinner with CFRP than if metal alloys are used. However, all aircraft
manufacturers using CFRP invest heavily in continual, regular
non-destructive inspection and damage assessment techniques. Why? It's
long been recognized that CFRPs can get significantly damaged without any
visible clues (i.e. sub-surface damage), due to low velocity impacts
perpendicular to the duty loads, e.g. a dropped hammer on a composite wing
skin, or a blow to a composite panel. Once significantly damaged, failure
is catastrophic.
In terms of numbers, as in my other posts:
1. in the elastic range, CFRPs have similar stress/strain characteristics as
Al alloys (ratio around 0.4 - 0.5). This means that what can dent an Al
alloy can also damage a CFRP, but the latter may not exhibit visible clues
2. in the plastic range, where deformations are permanent, CFRPs have
elongation to failure of about 1.4 %, whereas Al alloys typically have 25%.
This means that once the load has exceeded the elastic limit, CFRP will fail
catastrophically compared to Al.
So, Boeing makes plane components out of this stuff, but it also spends a
lot of money in making sure the stuff is always ok to fly, by more rigorous
non-eyeball inspections compared with Al alloys.
|
| |
Date: 06 Sep 2007 15:31:01
From: andresmuro@aol.com
Subject: Re: "brittle" vs. non-ductile
|
On Sep 6, 2:46 pm, Tim McNamara <tim...@bitstream.net > wrote:
> In article <Y7OdnauzzZigxn3bnZ2dnUVZ_qrin...@comcast.com>,
> Peter Cole <peter_c...@comcast.net> wrote:
>
> > Luke wrote:
> > > In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejn...@speakeasy.net>, jim
> > > beam
>
> > >> bottom line, i smell "agenda" in this question, and it has nothing
> > >> to do with curiosity about materials.
>
> > > Lotta aromas circulating...I detect overtones of bull feces in your
> > > evasiveness.
>
> > You're learning why arguing with this guy is pointless.
>
> Except for the rather sad entertainment factor of watching him flail
> about yet again, clueless as to why his arguments sink like stones and
> retreating into puerile name calling. He's probably entertained, too,
> since he can go on with it for weeks and weeks at a time.
He provides lots of entertainment for me. In fact I have made a
request that you guys keep these arguments up. Why would anyone want
to plonk anyone. If I don't wanna read a message, I simply skip it.
But I always look forward to the discussions between jb and everyone
else. I really like it when jb starts calling people names. Keep it
up.
Andres
|
| | |
Date: 06 Sep 2007 22:57:10
From: _
Subject: Re: "brittle" vs. non-ductile
|
On Thu, 06 Sep 2007 15:31:01 -0700, andresmuro@aol.com wrote:
> On Sep 6, 2:46 pm, Tim McNamara <tim...@bitstream.net> wrote:
>> In article <Y7OdnauzzZigxn3bnZ2dnUVZ_qrin...@comcast.com>,
>> Peter Cole <peter_c...@comcast.net> wrote:
>>
>>> Luke wrote:
>>> > In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejn...@speakeasy.net>, jim
>>> > beam
>>
>>> >> bottom line, i smell "agenda" in this question, and it has nothing
>>> >> to do with curiosity about materials.
>>
>>> > Lotta aromas circulating...I detect overtones of bull feces in your
>>> > evasiveness.
>>
>>> You're learning why arguing with this guy is pointless.
>>
>> Except for the rather sad entertainment factor of watching him flail
>> about yet again, clueless as to why his arguments sink like stones and
>> retreating into puerile name calling. He's probably entertained, too,
>> since he can go on with it for weeks and weeks at a time.
>
> He provides lots of entertainment for me. In fact I have made a
> request that you guys keep these arguments up. Why would anyone want
> to plonk anyone. If I don't wanna read a message, I simply skip it.
> But I always look forward to the discussions between jb and everyone
> else. I really like it when jb starts calling people names. Keep it
> up.
>
Insults are a sign that the person using them has no other way of support
their argument. "jim beam" is perhaps r.b.t.'s most prolifc example,
followed by Messers Ozark and Sornson (though these two latter have perhaps
a higher ratio of purility to just plain nonsense).
|
| |
Date: 04 Sep 2007 11:02:26
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> following peter cole's confusion on this subject, it seems we need a
> little clarification of what constitutes "brittle" fracture.
>
> "brittle" is where there is very little energy absorbed as the fracture
> interface propagates through a material. glass is the classic example
> of this - once a crack is present, it takes almost nothing to continue
> the crack's progress to complete failure.
>
> "ductile" however is a totally different animal. significant energy is
> absorbed during ductile deformation. but ductile deformation is not
> fracture, it's another process entirely! once ductile deformation has
> occurred, fracture requires /further/ propagation energy.
>
> fracture energy absorption is what determines whether a material is
> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
> [the apparent, er, "confusion"] but it is typically not brittle -
> significant energy is absorbed as the fracture interface progresses
> [depending on fabrication and constituent materials of course].
>
> indeed, fracture energy absorption in non-ductile composites can be so
> high, they're actually used in applications /specifically/ for this
> reason. anyone familiar with motorcycle helmet testing will be aware of
> this. same for bullet-protective military helmets. both are
> non-ductile composites with very high fracture energy absorption. energy
> absorbed depends on constitution, but the principle applies, and is
> worth repeating - it's energy absorbed on fracture interface progression
> that determines toughness, not whether the material is ductile.
>
What's this the 4th thread? You can keep going but it seems like you
haven't convinced anybody yet. It might help if you cited *any* source
supporting your unique view.
You're confusing fatigue with brittle failure and CF composites with
Kevlar composites/hybrids (among other things).
Yes, CF is sometimes mixed with other materials in applications like
body armor, but the purpose is not to absorb energy, but to stiffen the
assembly to avoid blunt force trauma. Again, you're confusing force with
energy, which you have done consistently through these threads.
CF composites can be used to design energy absorbing *structures* (F1
nose & tail boxes), but that involves crushable geometries that absorb
energy in a very specific manner. CF is not usually used in a direct
energy absorption role but as in a supporting strengthening/stiffening
role (as in hoop strength reinforcement in fiberglass vault poles)
That's not how bike parts are designed, so comparisons are misleading.
As everyone in the industry seems to know, low velocity impacts lead to
microcracks in the matrix, which eventually coalesce into macro cracks
and sudden failure. This is cumulative and not easily detected.
If a parts designer simply optimizes for CF specific strength and
modulus, they're stuck with low impact resistance and brittle failure.
That's how CF bike parts are generally designed.
|
| | |
Date: 04 Sep 2007 20:22:45
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> following peter cole's confusion on this subject, it seems we need a
>> little clarification of what constitutes "brittle" fracture.
>>
>> "brittle" is where there is very little energy absorbed as the
>> fracture interface propagates through a material. glass is the
>> classic example of this - once a crack is present, it takes almost
>> nothing to continue the crack's progress to complete failure.
>>
>> "ductile" however is a totally different animal. significant energy
>> is absorbed during ductile deformation. but ductile deformation is
>> not fracture, it's another process entirely! once ductile deformation
>> has occurred, fracture requires /further/ propagation energy.
>>
>> fracture energy absorption is what determines whether a material is
>> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
>> [the apparent, er, "confusion"] but it is typically not brittle -
>> significant energy is absorbed as the fracture interface progresses
>> [depending on fabrication and constituent materials of course].
>>
>> indeed, fracture energy absorption in non-ductile composites can be so
>> high, they're actually used in applications /specifically/ for this
>> reason. anyone familiar with motorcycle helmet testing will be aware
>> of this. same for bullet-protective military helmets. both are
>> non-ductile composites with very high fracture energy absorption.
>> energy absorbed depends on constitution, but the principle applies,
>> and is worth repeating - it's energy absorbed on fracture interface
>> progression that determines toughness, not whether the material is
>> ductile.
>>
>
> What's this the 4th thread? You can keep going but it seems like you
> haven't convinced anybody yet. It might help if you cited *any* source
> supporting your unique view.
eh? i'm starting a new thread because your [typical] obfuscation is so
convoluted, i really can't be bothered to untangle it. and you keep
getting away from the central point - you don't understand materials.
>
> You're confusing fatigue with brittle failure
no i'm not - you're [wrongly] asserting that low ductility means brittle.
> and CF composites with
> Kevlar composites/hybrids (among other things).
no, but you'd love to put those words of deliberate deceit into my mouth.
>
> Yes, CF is sometimes mixed with other materials in applications like
> body armor, but the purpose is not to absorb energy, but to stiffen the
> assembly to avoid blunt force trauma.
er, that is somewhat "confused".
> Again, you're confusing force with
> energy,
no - that's a statement of deliberate deceit.
> which you have done consistently through these threads.
see above.
>
> CF composites can be used to design energy absorbing *structures* (F1
> nose & tail boxes), but that involves crushable geometries that absorb
> energy in a very specific manner.
no amount of "crushable geometries" would matter if the material were in
fact "brittle". truth is, the /material/ absorbs energy on fracture,
hence their use. "crushable geometry" would mean nothing if the parts
were made of glass.
> CF is not usually used in a direct
> energy absorption role but as in a supporting strengthening/stiffening
> role (as in hoop strength reinforcement in fiberglass vault poles)
> That's not how bike parts are designed, so comparisons are misleading.
no, you're trying to deceive again.
>
> As everyone in the industry seems to know, low velocity impacts
without numbers, "impact" is an utterly meaningless word - it's the
ephemeral straw-clutch by one desperately seeking to stir fear,
uncertainty and doubt.
> lead to
> microcracks in the matrix,
again, without numbers, that is a meaningless statement. [handily
deceitful though.] with composites, the discontinuity between fiber and
matrix accounts for a good deal of short range "problem". there are
ways of addressing but not overcoming this. different matrix materials,
even carbon nanotube in the matrix resin, has significant benefits -
hence easton's use for instance.
> which eventually coalesce into macro cracks
> and sudden failure.
and not if they don't. just like metal fatigue and dislocation migration.
> This is cumulative and not easily detected.
just like metal fatigue and dislocation migration.
interestingly, i don't see you ringing the bells of armageddon about
metal fatigue and how everyone needs x-ray and ultrasound on their metal
frames. but you're trying to deceive, so that's to be expected.
>
> If a parts designer simply optimizes for CF specific strength and
> modulus, they're stuck with low impact resistance and brittle failure.
bullshit. you don't know what "brittle" means and you're trying to
deceive by misuse of that word.
> That's how CF bike parts are generally designed.
that's suppositional bullshit.
|
| | | |
Date: 05 Sep 2007 10:11:23
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> following peter cole's confusion on this subject, it seems we need a
>>> little clarification of what constitutes "brittle" fracture.
>>>
>>> "brittle" is where there is very little energy absorbed as the
>>> fracture interface propagates through a material. glass is the
>>> classic example of this - once a crack is present, it takes almost
>>> nothing to continue the crack's progress to complete failure.
>>>
>>> "ductile" however is a totally different animal. significant energy
>>> is absorbed during ductile deformation. but ductile deformation is
>>> not fracture, it's another process entirely! once ductile
>>> deformation has occurred, fracture requires /further/ propagation
>>> energy.
>>>
>>> fracture energy absorption is what determines whether a material is
>>> "brittle" or not. cfrp is not brittle like glass. it is not
>>> ductile, [the apparent, er, "confusion"] but it is typically not
>>> brittle - significant energy is absorbed as the fracture interface
>>> progresses [depending on fabrication and constituent materials of
>>> course].
>>>
>>> indeed, fracture energy absorption in non-ductile composites can be
>>> so high, they're actually used in applications /specifically/ for
>>> this reason. anyone familiar with motorcycle helmet testing will be
>>> aware of this. same for bullet-protective military helmets. both
>>> are non-ductile composites with very high fracture energy absorption.
>>> energy absorbed depends on constitution, but the principle applies,
>>> and is worth repeating - it's energy absorbed on fracture interface
>>> progression that determines toughness, not whether the material is
>>> ductile.
>>>
>>
>> What's this the 4th thread? You can keep going but it seems like you
>> haven't convinced anybody yet. It might help if you cited *any* source
>> supporting your unique view.
>
> eh? i'm starting a new thread because your [typical] obfuscation is so
> convoluted, i really can't be bothered to untangle it. and you keep
> getting away from the central point - you don't understand materials.
Really? Prove it by citing anything other than your own opinions.
>
>>
>> You're confusing fatigue with brittle failure
>
> no i'm not - you're [wrongly] asserting that low ductility means brittle.
No, I'm not. What's the ductility of Kevlar?
>
>> and CF composites with Kevlar composites/hybrids (among other things).
>
> no, but you'd love to put those words of deliberate deceit into my mouth.
OK, show me the "bullet-protective military helmet" made from CF composite.
>> Yes, CF is sometimes mixed with other materials in applications like
>> body armor, but the purpose is not to absorb energy, but to stiffen
>> the assembly to avoid blunt force trauma.
>
> er, that is somewhat "confused".
No, it's factual.
>
>
>> Again, you're confusing force with energy,
>
> no - that's a statement of deliberate deceit.
No, CF composites can withstand high forces but normally don't absorb
much energy. Otherwise, CF would be used instead of Kevlar for body
armor, since it's lighter.
>> which you have done consistently through these threads.
>
> see above.
See below above.
>
>>
>> CF composites can be used to design energy absorbing *structures* (F1
>> nose & tail boxes), but that involves crushable geometries that absorb
>> energy in a very specific manner.
>
> no amount of "crushable geometries" would matter if the material were in
> fact "brittle". truth is, the /material/ absorbs energy on fracture,
> hence their use. "crushable geometry" would mean nothing if the parts
> were made of glass.
Composite assemblies (like tubes) can absorb a lot of energy if the
failure mode is precisely controlled, like tube eversion, see
<http://www.touchbriefing.com/pdf/11/auto031_r_dyckhoff.pdf >
"The high amount of energy absorbed in
this comprises several components:
• the deformation energy of the aramid fibre
component;
• the rupture energy of the carbon fibre
component, including fractures in the matrix;
• the internal friction resulting from shear forces as
the angular structure of the fabric changes during
eversion and expansion of the tube; and
• a friction component caused as the partically
destroyed, everted laminate is forced over the
intact outer surface of the tube."
>> CF is not usually used in a direct energy absorption role but as in a
>> supporting strengthening/stiffening role (as in hoop strength
>> reinforcement in fiberglass vault poles) That's not how bike parts are
>> designed, so comparisons are misleading.
>
> no, you're trying to deceive again.
No, take a look at current state of the art vaulting pole designs. Why
aren't they all CF?
>> As everyone in the industry seems to know, low velocity impacts
>
> without numbers, "impact" is an utterly meaningless word - it's the
> ephemeral straw-clutch by one desperately seeking to stir fear,
> uncertainty and doubt.
The numbers are there, it's been intensively studied.
>
>> lead to microcracks in the matrix,
>
> again, without numbers, that is a meaningless statement. [handily
> deceitful though.] with composites, the discontinuity between fiber and
> matrix accounts for a good deal of short range "problem". there are
> ways of addressing but not overcoming this. different matrix materials,
> even carbon nanotube in the matrix resin, has significant benefits -
> hence easton's use for instance.
I guess that's an agreement?
>
>> which eventually coalesce into macro cracks and sudden failure.
>
> and not if they don't.
Why wouldn't they? It's a cumulative process.
just like metal fatigue and dislocation migration.
You say that like it's a good thing.
>> This is cumulative and not easily detected.
>
> just like metal fatigue and dislocation migration.
Similar, but worse in that it makes an already brittle material more
brittle.
> interestingly, i don't see you ringing the bells of armageddon about
> metal fatigue and how everyone needs x-ray and ultrasound on their metal
> frames. but you're trying to deceive, so that's to be expected.
I don't use aluminum forks, either.
>> If a parts designer simply optimizes for CF specific strength and
>> modulus, they're stuck with low impact resistance and brittle failure.
>
> bullshit. you don't know what "brittle" means and you're trying to
> deceive by misuse of that word.
>
>> That's how CF bike parts are generally designed.
>
> that's suppositional bullshit.
Two calls of "bullshit" with no backup. Typical.
|
| | | | |
Date: 05 Sep 2007 21:05:01
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
<snip crap >
translation of the peter cole position: "cfrp is brittle. except for
when it's not."
tremendous. you should be a lawyer.
|
| | | | | |
Date: 06 Sep 2007 15:52:37
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
> <snip crap>
>
> translation of the peter cole position: "cfrp is brittle. except for
> when it's not."
>
> tremendous. you should be a lawyer.
Saying that's a whole lot easier than actually finding a source to
support your claims, isn't it? Put up or shut up (for the nth time).
|
| |
Date: 03 Sep 2007 19:42:54
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
>
> Chalo wrote:
> >
> > Every time we've seen a CFRP bike part that has been hit or loaded
> > hard enough to break it, it has been broken completely through. That
> > seems to indicate the the energy to complete a fracture isn't much, at
> > least for carbon-epoxy such as we see in bikes.
>
> once metal starts to fracture, it usually breaks completely through as well.
But the first-- and often the only-- sign of overload failure in a
metal frame is plastic deformation. The paint cracks, but the metal
remains intact. Not so with a CFRP frame. One second it's okay, the
next second you're skidding on your face/butt/elbows/etc.
Chalo
|
| | |
Date: 03 Sep 2007 13:30:08
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Chalo wrote:
> jim beam wrote:
>> Chalo wrote:
>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>> hard enough to break it, it has been broken completely through. That
>>> seems to indicate the the energy to complete a fracture isn't much, at
>>> least for carbon-epoxy such as we see in bikes.
>> once metal starts to fracture, it usually breaks completely through as well.
>
> But the first-- and often the only-- sign of overload failure in a
> metal frame is plastic deformation. The paint cracks, but the metal
> remains intact. Not so with a CFRP frame.
but in my experience, you usually have lots of audible warning.
> One second it's okay, the
> next second you're skidding on your face/butt/elbows/etc.
if you ignore the audible, yes. you don't stand on timber planking
that's making cracking noises do you?
|
| | | |
Date: 03 Sep 2007 16:41:34
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
In article <_OSdnfFvXOdM80HbnZ2dnUVZ_o_inZ2d@speakeasy.net >, jim beam
<spamvortex@bad.example.net > wrote:
> Chalo wrote:
> > jim beam wrote:
> >> Chalo wrote:
> >>> Every time we've seen a CFRP bike part that has been hit or loaded
> >>> hard enough to break it, it has been broken completely through. That
> >>> seems to indicate the the energy to complete a fracture isn't much, at
> >>> least for carbon-epoxy such as we see in bikes.
> >> once metal starts to fracture, it usually breaks completely through as
> >> well.
> >
> > But the first-- and often the only-- sign of overload failure in a
> > metal frame is plastic deformation. The paint cracks, but the metal
> > remains intact. Not so with a CFRP frame.
>
> but in my experience, you usually have lots of audible warning.
Just what is your experience? Is it statistically relevant?
|
| | | | |
Date: 03 Sep 2007 14:32:04
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> In article <_OSdnfFvXOdM80HbnZ2dnUVZ_o_inZ2d@speakeasy.net>, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> Chalo wrote:
>>> jim beam wrote:
>>>> Chalo wrote:
>>>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>>>> hard enough to break it, it has been broken completely through. That
>>>>> seems to indicate the the energy to complete a fracture isn't much, at
>>>>> least for carbon-epoxy such as we see in bikes.
>>>> once metal starts to fracture, it usually breaks completely through as
>>>> well.
>>> But the first-- and often the only-- sign of overload failure in a
>>> metal frame is plastic deformation. The paint cracks, but the metal
>>> remains intact. Not so with a CFRP frame.
>> but in my experience, you usually have lots of audible warning.
>
> Just what is your experience? Is it statistically relevant?
eh? the privilege of arguing against me lies with /you/ big guy, not me
- so feel free to go ahead and present your own information. whenever
you're ready...
|
| | | | | |
Date: 05 Sep 2007 17:36:43
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
<spamvortex@bad.example.net > wrote:
>
>eh? the privilege of arguing against me lies with /you/ big guy, not me
>- so feel free to go ahead and present your own information. whenever
>you're ready...
"privilege of arguing against me"?! Consider me truly debased at
receiving such a distinction! LOL!
My intent was not to argue, it was to know more. Up thread you wrote
that in your experience CF failure is preceded by much 'audible
warning'. Will you be more specific?
|
| | | | | | |
Date: 05 Sep 2007 21:43:01
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> eh? the privilege of arguing against me lies with /you/ big guy, not me
>> - so feel free to go ahead and present your own information. whenever
>> you're ready...
>
> "privilege of arguing against me"?! Consider me truly debased at
> receiving such a distinction! LOL!
>
> My intent was not to argue, it was to know more. Up thread you wrote
> that in your experience CF failure is preceded by much 'audible
> warning'. Will you be more specific?
i think you should d.a.g.s. first.
|
| | | | | | | |
Date: 06 Sep 2007 01:28:51
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
In article <75GdnbmOm_zIGELbnZ2dnUVZ_sDinZ2d@speakeasy.net >, jim beam
<spamvortex@bad.example.net > wrote:
> Luke wrote:
> > On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
> > <spamvortex@bad.example.net> wrote:
> >
> >> eh? the privilege of arguing against me lies with /you/ big guy, not me
> >> - so feel free to go ahead and present your own information. whenever
> >> you're ready...
> >
> > "privilege of arguing against me"?! Consider me truly debased at
> > receiving such a distinction! LOL!
> >
> > My intent was not to argue, it was to know more. Up thread you wrote
> > that in your experience CF failure is preceded by much 'audible
> > warning'. Will you be more specific?
>
> i think you should d.a.g.s. first.
A quick search of rbt archives, key words "jim beam carbon failure"
yielded 397 results. A quick scan -- I don't have the time to wade
through the whole list -- reveals many rancorous threads; is there an
example among the results comprising a detailed description of a carbon
component failing you?
|
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Date: 06 Sep 2007 05:52:49
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> In article <75GdnbmOm_zIGELbnZ2dnUVZ_sDinZ2d@speakeasy.net>, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> Luke wrote:
>>> On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
>>> <spamvortex@bad.example.net> wrote:
>>>
>>>> eh? the privilege of arguing against me lies with /you/ big guy, not me
>>>> - so feel free to go ahead and present your own information. whenever
>>>> you're ready...
>>> "privilege of arguing against me"?! Consider me truly debased at
>>> receiving such a distinction! LOL!
>>>
>>> My intent was not to argue, it was to know more. Up thread you wrote
>>> that in your experience CF failure is preceded by much 'audible
>>> warning'. Will you be more specific?
>> i think you should d.a.g.s. first.
>
> A quick search of rbt archives, key words "jim beam carbon failure"
> yielded 397 results. A quick scan -- I don't have the time to wade
> through the whole list
and i do???
> -- reveals many rancorous threads;
that is not relevant to an innocent question.
> is there an
> example among the results comprising a detailed description of a carbon
> component failing you?
the answers are out there.
bottom line, i smell "agenda" in this question, and it has nothing to do
with curiosity about materials.
|
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Date: 06 Sep 2007 10:29:56
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net >, jim beam
<spamvortex@bad.example.net > wrote:
> Luke wrote:
> > In article <75GdnbmOm_zIGELbnZ2dnUVZ_sDinZ2d@speakeasy.net>, jim beam
> > <spamvortex@bad.example.net> wrote:
> >
> >> Luke wrote:
> >>> On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
> >>> <spamvortex@bad.example.net> wrote:
> >>>
> >>>> eh? the privilege of arguing against me lies with /you/ big guy, not me
> >>>> - so feel free to go ahead and present your own information. whenever
> >>>> you're ready...
> >>> "privilege of arguing against me"?! Consider me truly debased at
> >>> receiving such a distinction! LOL!
> >>>
> >>> My intent was not to argue, it was to know more. Up thread you wrote
> >>> that in your experience CF failure is preceded by much 'audible
> >>> warning'. Will you be more specific?
> >> i think you should d.a.g.s. first.
> >
> > A quick search of rbt archives, key words "jim beam carbon failure"
> > yielded 397 results. A quick scan -- I don't have the time to wade
> > through the whole list
>
> and i do???
Evidently not. So consult your memory, it's much quicker.
>
> > -- reveals many rancorous threads;
>
> that is not relevant to an innocent question.
>
True. No need to have inserted it.
>
> > is there an
> > example among the results comprising a detailed description of a carbon
> > component failing you?
>
> the answers are out there.
You have them, pass them along.
>
> bottom line, i smell "agenda" in this question, and it has nothing to do
> with curiosity about materials.
Lotta aromas circulating...I detect overtones of bull feces in your
evasiveness.
|
| | | | | | | | | | |
Date: 06 Sep 2007 20:25:04
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> Luke wrote:
>>> In article <75GdnbmOm_zIGELbnZ2dnUVZ_sDinZ2d@speakeasy.net>, jim beam
>>> <spamvortex@bad.example.net> wrote:
>>>
>>>> Luke wrote:
>>>>> On Mon, 03 Sep 2007 14:32:04 -0700, jim beam
>>>>> <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> eh? the privilege of arguing against me lies with /you/ big guy, not me
>>>>>> - so feel free to go ahead and present your own information. whenever
>>>>>> you're ready...
>>>>> "privilege of arguing against me"?! Consider me truly debased at
>>>>> receiving such a distinction! LOL!
>>>>>
>>>>> My intent was not to argue, it was to know more. Up thread you wrote
>>>>> that in your experience CF failure is preceded by much 'audible
>>>>> warning'. Will you be more specific?
>>>> i think you should d.a.g.s. first.
>>> A quick search of rbt archives, key words "jim beam carbon failure"
>>> yielded 397 results. A quick scan -- I don't have the time to wade
>>> through the whole list
>> and i do???
>
> Evidently not. So consult your memory, it's much quicker.
>
>>> -- reveals many rancorous threads;
>> that is not relevant to an innocent question.
>>
> True. No need to have inserted it.
>
>>> is there an
>>> example among the results comprising a detailed description of a carbon
>>> component failing you?
>> the answers are out there.
>
> You have them, pass them along.
>
>> bottom line, i smell "agenda" in this question, and it has nothing to do
>> with curiosity about materials.
>
> Lotta aromas circulating...I detect overtones of bull feces in your
> evasiveness.
which is exactly where you were intending to go from the start, hence my
original comment. present your own work - i'm not going to do your
arguing for you.
|
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Date: 07 Sep 2007 11:50:32
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:lvednY1OnJUNWX3bnZ2dnUVZ_uHinZ2d@speakeasy.net...
> which is exactly where you were intending to go from the start, hence my
> original comment. present your own work - i'm not going to do your
> arguing for you.
Translation - "I can't remember the bullshit I spewed before, and I've
spewed so much, why don't you remind me which one you're talking about, lest
I conradict myself yet again".
|
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Date: 07 Sep 2007 18:21:59
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jambo wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:lvednY1OnJUNWX3bnZ2dnUVZ_uHinZ2d@speakeasy.net...
>> which is exactly where you were intending to go from the start, hence my
>> original comment. present your own work - i'm not going to do your
>> arguing for you.
>
> Translation - "I can't remember the bullshit I spewed before, and I've
> spewed so much, why don't you remind me which one you're talking about, lest
> I conradict myself yet again".
ah, the guy that doesn't know what modulus is! don't worry, the meds
will kick in shortly.
|
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Date: 06 Sep 2007 15:55:42
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
>> bottom line, i smell "agenda" in this question, and it has nothing to do
>> with curiosity about materials.
>
> Lotta aromas circulating...I detect overtones of bull feces in your
> evasiveness.
You're learning why arguing with this guy is pointless.
|
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Date: 06 Sep 2007 20:35:21
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> Luke wrote:
>> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
>
>>> bottom line, i smell "agenda" in this question, and it has nothing to
>>> do with curiosity about materials.
>>
>> Lotta aromas circulating...I detect overtones of bull feces in your
>> evasiveness.
>
> You're learning why arguing with this guy is pointless.
but you don't argue. you merely make up some gainsay position, try to
justify it with bullshit, then continue to repeat yourself in the hope
that repetition will obliterate the real facts. "cfrp is brittle -
except for when it's not". what a crock.
|
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Date: 07 Sep 2007 08:53:19
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> Luke wrote:
>>> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
>>
>>>> bottom line, i smell "agenda" in this question, and it has nothing
>>>> to do with curiosity about materials.
>>>
>>> Lotta aromas circulating...I detect overtones of bull feces in your
>>> evasiveness.
>>
>> You're learning why arguing with this guy is pointless.
>
> but you don't argue. you merely make up some gainsay position, try to
> justify it with bullshit, then continue to repeat yourself in the hope
> that repetition will obliterate the real facts. "cfrp is brittle -
> except for when it's not". what a crock.
It's not "a crock". Easy example: uniaxial, brittle on axis, non-brittle
off. Too hard?
|
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Date: 07 Sep 2007 06:19:48
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> Luke wrote:
>>>> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
>>>
>>>>> bottom line, i smell "agenda" in this question, and it has nothing
>>>>> to do with curiosity about materials.
>>>>
>>>> Lotta aromas circulating...I detect overtones of bull feces in your
>>>> evasiveness.
>>>
>>> You're learning why arguing with this guy is pointless.
>>
>> but you don't argue. you merely make up some gainsay position, try to
>> justify it with bullshit, then continue to repeat yourself in the hope
>> that repetition will obliterate the real facts. "cfrp is brittle -
>> except for when it's not". what a crock.
>
> It's not "a crock". Easy example: uniaxial, brittle on axis, non-brittle
> off. Too hard?
a configuration not used in bike componentry - too obvious?
|
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Date: 06 Sep 2007 15:46:03
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
|
In article <Y7OdnauzzZigxn3bnZ2dnUVZ_qrinZ2d@comcast.com >,
Peter Cole <peter_cole@comcast.net > wrote:
> Luke wrote:
> > In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim
> > beam
>
> >> bottom line, i smell "agenda" in this question, and it has nothing
> >> to do with curiosity about materials.
> >
> > Lotta aromas circulating...I detect overtones of bull feces in your
> > evasiveness.
>
> You're learning why arguing with this guy is pointless.
Except for the rather sad entertainment factor of watching him flail
about yet again, clueless as to why his arguments sink like stones and
retreating into puerile name calling. He's probably entertained, too,
since he can go on with it for weeks and weeks at a time.
|
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Date: 06 Sep 2007 20:31:39
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Tim McNamara wrote:
> In article <Y7OdnauzzZigxn3bnZ2dnUVZ_qrinZ2d@comcast.com>,
> Peter Cole <peter_cole@comcast.net> wrote:
>
>> Luke wrote:
>>> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim
>>> beam
>>>> bottom line, i smell "agenda" in this question, and it has nothing
>>>> to do with curiosity about materials.
>>> Lotta aromas circulating...I detect overtones of bull feces in your
>>> evasiveness.
>> You're learning why arguing with this guy is pointless.
>
> Except for the rather sad entertainment factor of watching him flail
> about yet again, clueless as to why his arguments sink like stones and
> retreating into puerile name calling. He's probably entertained, too,
> since he can go on with it for weeks and weeks at a time.
timmy, you're a retard.
|
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Date: 06 Sep 2007 16:26:48
From: Paul Myron Hobson
Subject: Re: "brittle" vs. non-ductile
|
>> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
>>> bottom line, i smell "agenda" in this question, and it has nothing to
>>> do with curiosity about materials.
> Luke wrote:
>> Lotta aromas circulating...I detect overtones of bull feces in your
>> evasiveness.
Peter Cole wrote:
> You're learning why arguing with this guy is pointless.
Oh god. I gotta ask: why do you keep it up? I plonked him, but that
was kind of pointless since there are some many responses to him.
\\paul
|
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Date: 06 Sep 2007 18:32:52
From: Luke
Subject: Re: "brittle" vs. non-ductile
|
In article <fbpnq9$lnj$1@news-int2.gatech.edu >, Paul Myron Hobson
<phobson@gatech.edu > wrote:
> >> In article <0eadnV90W_i_ZULbnZ2dnUVZ_uejnZ2d@speakeasy.net>, jim beam
> >>> bottom line, i smell "agenda" in this question, and it has nothing to
> >>> do with curiosity about materials.
>
> > Luke wrote:
> >> Lotta aromas circulating...I detect overtones of bull feces in your
> >> evasiveness.
>
> Peter Cole wrote:
> > You're learning why arguing with this guy is pointless.
>
>
> Oh god. I gotta ask: why do you keep it up? I plonked him, but that
> was kind of pointless since there are some many responses to him.
>
> \\paul
I hope that Peter et al continue to keep it up. That is, that they
still engage and debate with the goal of determining fact -- in spite
of how unsavory and infantile the behavior of their antagonists. This
forum would suffer and we'd be the poorer otherwise.
Over the years I've greatly benefitted by jb's posts -- I suspect many
others have as well. jb's value, aside from comic relief of course, is
this: his characteristic ploys of obfuscation and disingenuousness
often require very precise and articulate technical responses from his
repudiators. These eloquent arguments are frequently among the most
educational r.b.t has to offer.
|
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Date: 06 Sep 2007 19:37:51
From: Paul Myron Hobson
Subject: Re: "brittle" vs. non-ductile
|
Luke wrote:
> Over the years I've greatly benefitted by jb's posts -- I suspect many
> others have as well. jb's value, aside from comic relief of course, is
> this: his characteristic ploys of obfuscation and disingenuousness
> often require very precise and articulate technical responses from his
> repudiators. These eloquent arguments are frequently among the most
> educational r.b.t has to offer.
I'll admit, this is a good point I had not considered. Though, lately,
it all seems to come down to:
XX: I don't think that's the case. Care to give a reference?
jb: dumbass
XX: Dude, just cite something explaining that I'm wrong.
jb: red herring. stop moving the goal post, fucktard.
...x100
That's what I find very little value in. Sifting through all that is
becoming less and worthwhile as well :/
\\paul
|
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Date: 06 Sep 2007 20:30:12
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Paul Myron Hobson wrote:
> Luke wrote:
>> Over the years I've greatly benefitted by jb's posts -- I suspect many
>> others have as well. jb's value, aside from comic relief of course, is
>> this: his characteristic ploys of obfuscation and disingenuousness
>> often require very precise and articulate technical responses from his
>> repudiators. These eloquent arguments are frequently among the most
>> educational r.b.t has to offer.
>
> I'll admit, this is a good point I had not considered. Though, lately,
> it all seems to come down to:
>
> XX: I don't think that's the case. Care to give a reference?
> jb: dumbass
> XX: Dude, just cite something explaining that I'm wrong.
> jb: red herring. stop moving the goal post, fucktard.
> ...x100
>
> That's what I find very little value in. Sifting through all that is
> becoming less and worthwhile as well :/
is this a stupidity contest or a circle jerk?
if you guys want to go ahead and believe someone blowing smoke up your
ass about materials properties that they they repeatedly prove they
don't understand, then god bless you and pray for some kind of divine
intervention when you come to make important decisions in life - because
you're going to need it if you're that gullible.
|
| |
Date: 03 Sep 2007 16:48:24
From: Chalo
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
>
> fracture energy absorption is what determines whether a material is
> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
> [the apparent, er, "confusion"] but it is typically not brittle -
> significant energy is absorbed as the fracture interface progresses
> [depending on fabrication and constituent materials of course].
Every time we've seen a CFRP bike part that has been hit or loaded
hard enough to break it, it has been broken completely through. That
seems to indicate the the energy to complete a fracture isn't much, at
least for carbon-epoxy such as we see in bikes.
Chalo
|
| | |
Date: 03 Sep 2007 20:50:23
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
>> fracture energy absorption is what determines whether a material is
>> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
>> [the apparent, er, "confusion"] but it is typically not brittle -
>> significant energy is absorbed as the fracture interface progresses
>> [depending on fabrication and constituent materials of course].
>
> Every time we've seen a CFRP bike part that has been hit or loaded
> hard enough to break it, it has been broken completely through. That
> seems to indicate the the energy to complete a fracture isn't much, at
> least for carbon-epoxy such as we see in bikes.
This is both true and incredibly misleading. There are a lot of people out
there riding on damaged (broken) carbon frames & forks that aren't aware of
it. Few know what to look for, and even fewer *want* to look for the damage,
preferring instead to think "phew, looks like it came out OK, I don't have
to shell out a ton of money!"
So yes, it's true that few have "seen" a carbon fiber product that's broken
and not yet completely failed, but that doesn't mean they're not out there.
It just means that people don't know what to look for, or prefer not to. We
find damage to bikes frequently that the owner missed. There's this
common-sense thing that's sometimes lacking. If an impact was nasty enough
to have likely caused serious damage, it probably did. You just didn't look
hard enough, or in the right places, to find it. A huge number of "just
riding along" failures happen due to damage from a prior incident, and that
small pothole just happened to be the final straw.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | |
Date: 13 Sep 2007 03:38:03
From: bjw@mambo.ucolick.org
Subject: Re: "brittle" vs. non-ductile
|
On Sep 12, 8:05 pm, Ryan Cousineau <rcous...@sfu.ca > wrote:
> Chalo <chalo.col...@gmail.com> wrote:
> > Ryan Cousineau wrote:
> > > Wait a decade, and some rather cheap bikes will have CFRP frames.
>
> > If anybody can figure out how to injection-mold a frame that contains
> > sufficiently long fibers, you will most definitely be correct in
> > this. I rather doubt that hand-laid fabric-based CFRP bikes will ever
> > be cost-effective, though.
For mid-low-end bike store bikes, expect CFRP to become more
common, but for the lowest end and for big-box-store bikes, CFRP
won't be there unless it's actually cheaper than aluminum, since
buyers of those bikes are buying more strictly on price than on
price/performance. Aluminum is in dept store bikes now because
it's cheaper to assemble than steel, not because it's lighter.
> The number of processes that have proven amenable to automation is
> staggering. I would have never thought that you could automate
> wheel-building in a cost-effective fashion, e pur si muove.
People used to think that posting to rec.bicycles.* couldn't be
automated, and now practically everyone on both r.b.r. and
r.b.t is a bot, so there you go.
Ben
Now SMP compliant
|
| | | |
Date: 12 Sep 2007 01:02:35
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Michael Warner wrote:
>
> Chalo wrote:
> >
> > It's a serious problem for cyclists that such a wide segment of the
> > non-cycling public regards bikes as toys. That perception costs some
> > cyclists' lives, and robs many others of the pleasure of sharing the
> > road in peace. Folks who take up cycling the way one might take up
> > paintball are a major impediment to growing the credibility of cycling
> > as a mode of transportation.
>
> People who resent other people getting out and having fun riding
> unless they pay their dues (presumably by plodding along on some
> fat-tyred boat anchor to work or the shops at least 90% of the time)
> are a major impediment to the credibility of the human race.
>
> Most of the people I ride with also commute or shop by bike, at
> least some of the time.
How do you feel about people who drive "recreationally" in sports cars
on public streets, rather than keeping their sport on the track and
closed courses?
I don't dispute the right of lycras to use the streets as their gym
and playground, I just find it bothersome that most of them will do
that without returning the favor to their communities by using their
bikes as transportation on those same streets.
Chalo
|
| | | | |
Date: 15 Sep 2007 01:03:45
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 14, 6:30 pm, "Bill Sornson" <as...@ask.me > wrote:
> Peter Cole wrote:
> > Bill Sornson wrote:
> >> Peter Cole wrote:
> >>> Bill Sornson wrote:
> >>>> Michael Press wrote:
> >>>>> The great thing here in the USA is
> >>>>> that food labels must list ingredients, and I have read
> >>>>> them from the time I could read at all.
> >>>> Exactly.
> >>> Not exactly.
>
> >> Exactly NOT what I was replying to, but nicely misleading!
>
> >> Bill "can see why poor ol' jim beam gets so exasperated" S.
>
> > Kind of hard to know what your "exactly" was referring to since you
> > tacked it to a long paragraph.
>
> I see these endless back & forth arguments between you and beam, and neither
> of you trim ANYTHING. (Makes them all but unreadable, BTW, but then no one
> else is interested anyway.)
>
> Yet here you decided to trim the "meat" (intended) of what Press wrote and
> with which I agreed and left instead some off-hand remark about labels,
> implying that that was what prompted my comment.
>
> I repeat: nicely misleading.
>
> Bill "almost Floggeresque" S.
Yet again, Bill Sornson complains about people trimming Usenet posts!
I'm continually astounded that such a standard practice confuses him!
Does he not realize that context is always available on Usenet? Does
he think nobody can remember a previous post when they read the
subsequent post? Is it because _he_ can't remember context for that
long?
Bill, if you think the context has been irreparably destroyed, don't
whine; just copy the missing phrase and restore it. But the chances
are even that is unnecessary.
- Frank Krygowski
|
| | | | |
Date: 11 Sep 2007 21:04:59
From: Mike Jacoubowsky
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
>> People who resent other people getting out and having fun riding
>> unless they pay their dues (presumably by plodding along on some
>> fat-tyred boat anchor to work or the shops at least 90% of the time)
>> are a major impediment to the credibility of the human race.
>>
>> Most of the people I ride with also commute or shop by bike, at
>> least some of the time.
>
> How do you feel about people who drive "recreationally" in sports cars
> on public streets, rather than keeping their sport on the track and
> closed courses?
>
> I don't dispute the right of lycras to use the streets as their gym
> and playground, I just find it bothersome that most of them will do
> that without returning the favor to their communities by using their
> bikes as transportation on those same streets.
So you can't ride for fun unless you also commute by bike?
It's not a guess.. A huge percentage of those lycra-clad racer types ride
their bikes to the start of their group ride, and then ride back home
afterward (I'm talking about regularly-scheduled rides, not centuries). In
other words, for their chosen form of recreation, they're not using their
cars to get there. Can you say that for most others? Those, for example,
heading to the gym? Even most runners I see seem to drive out to their
favorite places and run from there, instead of from their houses. Does this
count for nothing?
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Chalo" <chalo.colina@gmail.com > wrote in message
news:1189558955.721601.129150@w3g2000hsg.googlegroups.com...
> Michael Warner wrote:
>>
>> Chalo wrote:
>> >
>> > It's a serious problem for cyclists that such a wide segment of the
>> > non-cycling public regards bikes as toys. That perception costs some
>> > cyclists' lives, and robs many others of the pleasure of sharing the
>> > road in peace. Folks who take up cycling the way one might take up
>> > paintball are a major impediment to growing the credibility of cycling
>> > as a mode of transportation.
>>
>> People who resent other people getting out and having fun riding
>> unless they pay their dues (presumably by plodding along on some
>> fat-tyred boat anchor to work or the shops at least 90% of the time)
>> are a major impediment to the credibility of the human race.
>>
>> Most of the people I ride with also commute or shop by bike, at
>> least some of the time.
>
> How do you feel about people who drive "recreationally" in sports cars
> on public streets, rather than keeping their sport on the track and
> closed courses?
>
> I don't dispute the right of lycras to use the streets as their gym
> and playground, I just find it bothersome that most of them will do
> that without returning the favor to their communities by using their
> bikes as transportation on those same streets.
>
> Chalo
>
|
| | | | | |
Date: 16 Sep 2007 03:05:36
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
>
> And yet military families remain supportive of the war effort and the
> administration. Go figger.
Bred to be tractable livestock.
|
| | | | | | |
Date: 16 Sep 2007 07:37:26
From: Jay Hill
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo wrote:
> Bill Sornson wrote:
>> And yet military families remain supportive of the war effort and the
>> administration. Go figger.
>
> Bred to be tractable livestock.
>
Hey, don't let Sornson bait you into bashing the soldiers themselves.
Sornson's generalized statement that "military families remain
supportive of the war effort" is easily disproven, from Colin Powell
down. Some do, of course, but I personally know many current and
ex-military that are disgusted with the neocons' waste of good soldiers.
It's also important to note that the vast majority of the neocons that
were behind the invasion of Iraq have never served in the military;
pointedly, Bush, Chaney, Wolfowitz, and others. Elite ruling members of
societies sending the middle and poor classes off to be cannon fodder
while they, the elites, avoid danger, then strut and wrap themselves in
their flags, has been going on for thousands of years.
http://www.vaiw.org/vet/index.php
http://tribes.tribe.net/marinesvetsagainstbush
|
| | | | | | | |
Date: 16 Sep 2007 07:56:51
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Hill wrote:
> Chalo wrote:
>> Bill Sornson wrote:
>>> And yet military families remain supportive of the war effort and
>>> the administration. Go figger.
>>
>> Bred to be tractable livestock.
>>
> Hey, don't let Sornson bait you into bashing the soldiers themselves.
Chalo doesn't need baiting (even his breath indicates that). He HATES the
military. (And the fat slob traitorous blob didn't wait for /Iraq/ to show
it.)
> Sornson's generalized statement that "military families remain
> supportive of the war effort" is easily disproven, from Colin Powell
> down. Some do, of course, but I personally know many current and
> ex-military that are disgusted with the neocons' waste of good
> soldiers.
Take a poll. Why do you think the Dems try every year to prevent the
troops' votes from counting?
In the '60s, at least the anti-war crowd were true peaceniks. Today it's
ALL about political power; they don't give a shit about soldiers, civilians,
Iraqis or anyone else. "Peace" is merely convenient.
Bill "Hillary Lied; People Died" S.
|
| | | | | |
Date: 16 Sep 2007 02:24:54
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 15, 9:33 pm, "Bill Sornson" <as...@ask.me > wrote:
> andresm...@aol.com wrote:
> > On Sep 15, 4:39 pm, r15...@aol.com wrote:
> >> On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> >>> r15...@aol.com wrote:
> >>>> On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> >>>>> ALARMISTS
>
> >>>> Like the folks who insist we're in the fight of our lives against a
> >>>> bunch of retarded jihadis?
>
> >>> Yeah, you're right. Let's just relax.
>
> >> So those are our two choices? 'Just relax' or endless war for our
> >> very survival. Check.
>
> >> Seriously, the current path is creating more retarded jihadis than it
> >> does kill or capture them. You can't kill your way out of this mess.
>
> > Actually most Americans are pretty relaxed about the whole thing. They
> > drink beer, go riding, get the latest on Paris Hilton or Britney
> > Spears, etc. When I go to work, go riding or walk down the streets, I
> > don't see many people walking tense or worried about whatever the hell
> > is happening in Iraq, or wherever the hell young soldier kids and
> > tons of civilians are getting killed. The only ones that are not
> > relaxed are the poor kids that are getting killed and seriously
> > injured over there,their families and the civilian population over
> > there.
>
> And yet military families remain supportive of the war effort and the
> administration. Go figger.
Perhaps some do. But not most.
My extended family just got one of our kids back from his second
forced tour in Iraq. We've got an ex Army and ex Marine among the
older generation. Not one person in this extended family thinks the
Iraq invasion and occupation made any sense at all. That especially
includes the guy who just returned.
- Frank Krygowski
|
| | | | | |
Date: 15 Sep 2007 19:22:32
From: andresmuro@aol.com
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 15, 7:33 pm, "Bill Sornson" <as...@ask.me > wrote:
> andresm...@aol.com wrote:
> > On Sep 15, 4:39 pm, r15...@aol.com wrote:
> >> On Sep 15, 1:15 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> >>> r15...@aol.com wrote:
> >>>> On Sep 13, 6:49 pm, "Bill Sornson" <as...@ask.me> wrote:
>
> >>>>> ALARMISTS
>
> >>>> Like the folks who insist we're in the fight of our lives against a
> >>>> bunch of retarded jihadis?
>
> >>> Yeah, you're right. Let's just relax.
>
> >> So those are our two choices? 'Just relax' or endless war for our
> >> very survival. Check.
>
> >> Seriously, the current path is creating more retarded jihadis than it
> >> does kill or capture them. You can't kill your way out of this mess.
>
> > Actually most Americans are pretty relaxed about the whole thing. They
> > drink beer, go riding, get the latest on Paris Hilton or Britney
> > Spears, etc. When I go to work, go riding or walk down the streets, I
> > don't see many people walking tense or worried about whatever the hell
> > is happening in Iraq, or wherever the hell young soldier kids and
> > tons of civilians are getting killed. The only ones that are not
> > relaxed are the poor kids that are getting killed and seriously
> > injured over there,their families and the civilian population over
> > there.
>
> And yet military families remain supportive of the war effort and the
> administration. Go figger.
They do?
Last week seven soldiers wrote a piece against the war. three of them
died. its been all over the news. The Tillman family is overwhelmingly
against the war. Its been all over the news. Most people that have
families over in Iraq want them back safe ASAP.
A friend of mine just came back from her second tour. She is a captain
and nurse anesthetist. I can give you her email and she can personally
tell you how she, her family, her other military colleagues, the
soldiers under her and their families feel about the war.
another friend of mine who is a Mayor is a psychologist for the
soldiers returning from the war and for their families while they are
gone. I can get you in contact with him and he can also tell you how
the soldiers and the families feel.
I live in El Paso. What is so significant about El Paso? It is were
fort Bliss is located. It is one of the main deployment centers in the
US. Thousands of families get stationed in El Paso. El Paso also has
several FBI and Border Patrol buildings. I ride with FBI agents,
military personnel, and border patrol agents every weekend. Actually,
I haven't for the last couple of weeks cause I've been sick. But,
these people are traditionally Republicans. I talk to them regularly
and know how they feel about the war.
I also happen to ride with very wealthy real estate developers,
corporate owners, business owners, etc. These are not connected with
soldiers much and have never seen a battle field. While they don't
speak in support of the war they do support the administration.
Andres
|
| | | | | |
Date: 13 Sep 2007 08:41:06
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 15:56:14 GMT, Mike Jacoubowsky wrote:
> The biggest reason I rarely mountain bike is that I have very little spare
> time to ride, and I'd have to waste half an hour each way getting to the
> places to ride. That's time I could be out on my bike, and time I don't have
> to be in my car spewing out whatever it spews.
I'd rather not think about what my old Corolla spews on the infrequent
occasions when I use it. Bits of the engine, most likely. I haven't changed
the oil for a couple of years :-)
> There's a reason they like ski runs that operate their lifts in the summer
> for mountain bikes... personally, I like climbing as much as descending,
> probably more so.
I see descending as the reward for a good solid climb. Unfortunately, some
of the racers I ride with go harder down than up, just for the adrenaline
rush. And they do it in a tight group! I just hang back and shake my
head in disbelief :-)
|
| | | | | | |
Date: 13 Sep 2007 00:52:11
From: Mike Jacoubowsky
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
>> There's a reason they like ski runs that operate their lifts in the
>> summer
>> for mountain bikes... personally, I like climbing as much as descending,
>> probably more so.
>
> I see descending as the reward for a good solid climb. Unfortunately, some
> of the racers I ride with go harder down than up, just for the adrenaline
> rush. And they do it in a tight group! I just hang back and shake my
> head in disbelief :-)
The guys I ride with are getting steadily faster in their climbing, and I'm
doing my very best to keep from getting slower. The average age of the group
continues to climb as well, so in theory, they should be getting slower. I
feel fortunate that last year, at 50, I was in better shape than I was at
35. Unfortunately, there's a slight downward trend as I've been spending
more and more time working with my 14 year old, getting him into shape (two
years ago he was 5'2 and 220+lbs; now he's 5'7 and 200, and we're going to
keep moving in the right direction). It means I don't get to do the AltoVelo
"A" ride on Sundays anymore (50-85 hilly/mountainous miles at 17-20mph
average speed, sometimes more), but instead much slower rides with my son.
But that's OK; he's up to 73 miles now, and his speeds *are* increasing as
well. Hills no longer scare him; he actually looks forward to the challenge.
In two years, he'll (hopefully) be kicking Dad's butt!
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | |
Date: 11 Sep 2007 22:15:18
From: Wayne Pein
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo wrote:
> I don't dispute the right of lycras to use the streets as their gym
> and playground, I just find it bothersome that most of them will do
> that without returning the favor to their communities by using their
> bikes as transportation on those same streets.
>
You believe that transportation is more important or a greater good than
recreational cycling. I do both, and can make the argument that
recreation is as or more important. At the least, I'd hate to be reduced
to being only a commuter.
If transportation cycling is doing the community a favor, can
recreational cycling be characterized as doing society a favor?
Wayne
|
| | | | | |
Date: 12 Sep 2007 20:24:49
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 02:41:44 -0000, Chalo wrote:
> But I'd say it's society that's doing play cyclists a bigger favor, by
> letting them play in the streets from which most other kinds of play
> have been banned.
I had no idea that there were cyclists who felt this much resentment
toward some other cyclists. Unless they're breaking road rules or riding
dangerously, I'm always pleased to see other people out on bikes.
|
| | | |
Date: 04 Sep 2007 20:35:54
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Mike Jacoubowsky wrote:
>>> fracture energy absorption is what determines whether a material is
>>> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
>>> [the apparent, er, "confusion"] but it is typically not brittle -
>>> significant energy is absorbed as the fracture interface progresses
>>> [depending on fabrication and constituent materials of course].
>> Every time we've seen a CFRP bike part that has been hit or loaded
>> hard enough to break it, it has been broken completely through. That
>> seems to indicate the the energy to complete a fracture isn't much, at
>> least for carbon-epoxy such as we see in bikes.
>
> This is both true and incredibly misleading. There are a lot of people out
> there riding on damaged (broken) carbon frames & forks that aren't aware of
> it. Few know what to look for, and even fewer *want* to look for the damage,
> preferring instead to think "phew, looks like it came out OK, I don't have
> to shell out a ton of money!"
indeed.
>
> So yes, it's true that few have "seen" a carbon fiber product that's broken
> and not yet completely failed, but that doesn't mean they're not out there.
absolutely - the warning signs are there but are frequently ignored.
> It just means that people don't know what to look for, or prefer not to.
indeed.
> We
> find damage to bikes frequently that the owner missed. There's this
> common-sense thing that's sometimes lacking. If an impact was nasty enough
> to have likely caused serious damage, it probably did. You just didn't look
> hard enough, or in the right places, to find it. A huge number of "just
> riding along" failures happen due to damage from a prior incident, and that
> small pothole just happened to be the final straw.
well said.
|
| | | | |
Date: 05 Sep 2007 09:31:18
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Mike Jacoubowsky wrote:
>> Someone wrote:
>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>> hard enough to break it, it has been broken completely through. That
>>> seems to indicate the the energy to complete a fracture isn't much, at
>>> least for carbon-epoxy such as we see in bikes.
>>
>> This is both true and incredibly misleading. There are a lot of people
>> out there riding on damaged (broken) carbon frames & forks that aren't
>> aware of it. Few know what to look for, and even fewer *want* to look
>> for the damage, preferring instead to think "phew, looks like it came
>> out OK, I don't have to shell out a ton of money!"
>
> indeed.
This is probably the best demonstration of why CF is bad for "prime time".
>> So yes, it's true that few have "seen" a carbon fiber product that's
>> broken and not yet completely failed, but that doesn't mean they're
>> not out there.
First you say that there are lots of people riding damaged CF without
knowing, then few have seen these (unless you're splitting "damaged" and
"broken" and "failed"). Seems contradictory, unless you mean there are
lots of damaged frames and forks that don't have symptoms? (something I
have no trouble believing).
> absolutely - the warning signs are there but are frequently ignored.
He seems to say there aren't any.
|
| | | | | |
Date: 12 Sep 2007 02:41:44
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Wayne Pein wrote:
>
> Chalo wrote:
> > I don't dispute the right of lycras to use the streets as their gym
> > and playground, I just find it bothersome that most of them will do
> > that without returning the favor to their communities by using their
> > bikes as transportation on those same streets.
>
> You believe that transportation is more important or a greater good than
> recreational cycling. I do both, and can make the argument that
> recreation is as or more important. At the least, I'd hate to be reduced
> to being only a commuter.
>
> If transportation cycling is doing the community a favor, can
> recreational cycling be characterized as doing society a favor?
I don't know. Is paintball a favor to society? If it keeps you from
shooting people with lead balls instead, or if it prevents you from
having a heart attack at 42 from too much TV and fast food and
lethargy, then maybe.
But I'd say it's society that's doing play cyclists a bigger favor, by
letting them play in the streets from which most other kinds of play
have been banned.
Chalo
|
| | | | | | |
Date: 12 Sep 2007 11:56:33
From: Wayne Pein
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo wrote:
> But I'd say it's society that's doing play cyclists a bigger favor, by
> letting them play in the streets from which most other kinds of play
> have been banned.
>
I think you greatly underestimate the amount of motor vehicle "play"
that society endorses/encourages/embraces.
Wayne
|
| | | | | | | |
Date: 13 Sep 2007 14:35:57
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 02:18:58 -0000, Chalo wrote:
> You're right about that. And any kind of cycling is categorically
> more wholesome. I just don't see why for some folks, cycling has
> degenerated into something just about as shallow and materialistic as
> cruising in your hoopty rolling on 22" spinners while rattling the
> doors off with your loud subwoofers. To me, it seems like the
> activity of cycling intrinsically promotes enough introspection to
> grow folks out of that mindset.
The activity of cycling on a bike like yours, that is. Plastic bikes
clearly promote selfish, undesirable extroversion :-)
|
| | | | | |
Date: 12 Sep 2007 01:29:34
From: Chalo
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
Michael Press wrote:
>
> Ben C <spams...@spam.eggs> wrote:
> >
> > On 2007-09-11, Jambo <-...@-.-> wrote:
> > >
> > > Put it this way - imagine one carbon fiber as a pencil. It's very strong in
> > > compression and tension, as long as the load is parallel to its length (or
> > > axis). However, put a load perpendicular to its axis, and you can easily
> > > break the pencil.
> >
> > I think that's a herring.
>
> Wood is a composite material, so the analogy is
> excellent. No fishy smell. Wood easier to crush
> transversely than longitudinally. That is why good
> cutting blocks are made with the end grain on the
> surface of the block. Wood is optimized to carry an
> axial load. Tall timber. When wood is called upon act
> as a beam as in a limb, it puts more material on the
> side of the neutral axis that is in compression, the
> underside.
I've noticed jb likes to use the CFRP-wood analogy. I think it bears
pointing out that wood is a pretty terrible material for structural
tubing, which is why nobody uses it that way. It's also worth noting
that aerospace industries, brought up so often in this context, don't
seem to be going out of their way to use CFRP as tubing or framework
anywhere.
Wooden bicycle frames have been tried time and time again and always
found lacking. CFRP, being comparable to a very hard, very strong
wood, should be subject to many of wood's shortcomings-- which looks
to be true.
Chalo
|
| | | | | | |
Date: 11 Sep 2007 23:40:46
From: A Muzi
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
>>> Jambo <-...@-.-> wrote:
>>>> Put it this way - imagine one carbon fiber as a pencil. It's very strong in
>>>> compression and tension, as long as the load is parallel to its length (or
>>>> axis). However, put a load perpendicular to its axis, and you can easily
>>>> break the pencil.
>> Ben C <spams...@spam.eggs> wrote:
>>> I think that's a herring.
> Michael Press wrote:
>> Wood is a composite material, so the analogy is
>> excellent. No fishy smell. Wood easier to crush
>> transversely than longitudinally. That is why good
>> cutting blocks are made with the end grain on the
>> surface of the block. Wood is optimized to carry an
>> axial load. Tall timber. When wood is called upon act
>> as a beam as in a limb, it puts more material on the
>> side of the neutral axis that is in compression, the
>> underside.
Chalo wrote:
> I've noticed jb likes to use the CFRP-wood analogy. I think it bears
> pointing out that wood is a pretty terrible material for structural
> tubing, which is why nobody uses it that way. It's also worth noting
> that aerospace industries, brought up so often in this context, don't
> seem to be going out of their way to use CFRP as tubing or framework
> anywhere.
>
> Wooden bicycle frames have been tried time and time again and always
> found lacking. CFRP, being comparable to a very hard, very strong
> wood, should be subject to many of wood's shortcomings-- which looks
> to be true.
In fairness, true monocoque (some Kestrels for example) designs use the
material to its best advantage, obviating tube-to-tube jointing issues.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | |
Date: 11 Sep 2007 22:02:31
From: jim beam
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
A Muzi wrote:
>>>> Jambo <-...@-.-> wrote:
>>>>> Put it this way - imagine one carbon fiber as a pencil. It's very
>>>>> strong in
>>>>> compression and tension, as long as the load is parallel to its
>>>>> length (or
>>>>> axis). However, put a load perpendicular to its axis, and you can
>>>>> easily
>>>>> break the pencil.
>
>>> Ben C <spams...@spam.eggs> wrote:
>>>> I think that's a herring.
>
>> Michael Press wrote:
>>> Wood is a composite material, so the analogy is
>>> excellent. No fishy smell. Wood easier to crush
>>> transversely than longitudinally. That is why good
>>> cutting blocks are made with the end grain on the
>>> surface of the block. Wood is optimized to carry an
>>> axial load. Tall timber. When wood is called upon act
>>> as a beam as in a limb, it puts more material on the
>>> side of the neutral axis that is in compression, the
>>> underside.
>
> Chalo wrote:
>> I've noticed jb likes to use the CFRP-wood analogy. I think it bears
>> pointing out that wood is a pretty terrible material for structural
>> tubing, which is why nobody uses it that way. It's also worth noting
>> that aerospace industries, brought up so often in this context, don't
>> seem to be going out of their way to use CFRP as tubing or framework
>> anywhere.
>>
>> Wooden bicycle frames have been tried time and time again and always
>> found lacking. CFRP, being comparable to a very hard, very strong
>> wood, should be subject to many of wood's shortcomings-- which looks
>> to be true.
>
> In fairness, true monocoque (some Kestrels for example) designs use the
> material to its best advantage, obviating tube-to-tube jointing issues.
personally, i'm not so convinced about this. and few are true monocoque
- giant aren't from what i've seen.
integrity of crfp depends on compaction during cure. enclosed
structures like a true monocoque are very hard to get truly compacted.
if not, then extra weight is required to build in more safety. while
mistakes can be made, epoxied cfrp componentry like forks are proven
quantities. when i get around to buying a full carbon frame, i'll
probably go for a lugged frame like look.
|
| | | | | | | | |
Date: 12 Sep 2007 00:15:00
From: A Muzi
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
>>>>> Jambo <-...@-.-> wrote:
>>>>>> Put it this way - imagine one carbon fiber as a pencil. It's very
>>>>>> strong in
>>>>>> compression and tension, as long as the load is parallel to its
>>>>>> length (or
>>>>>> axis). However, put a load perpendicular to its axis, and you can
>>>>>> easily
>>>>>> break the pencil.
>>
>>>> Ben C <spams...@spam.eggs> wrote:
>>>>> I think that's a herring.
>>
>>> Michael Press wrote:
>>>> Wood is a composite material, so the analogy is
>>>> excellent. No fishy smell. Wood easier to crush
>>>> transversely than longitudinally. That is why good
>>>> cutting blocks are made with the end grain on the
>>>> surface of the block. Wood is optimized to carry an
>>>> axial load. Tall timber. When wood is called upon act
>>>> as a beam as in a limb, it puts more material on the
>>>> side of the neutral axis that is in compression, the
>>>> underside.
>>
>> Chalo wrote:
>>> I've noticed jb likes to use the CFRP-wood analogy. I think it bears
>>> pointing out that wood is a pretty terrible material for structural
>>> tubing, which is why nobody uses it that way. It's also worth noting
>>> that aerospace industries, brought up so often in this context, don't
>>> seem to be going out of their way to use CFRP as tubing or framework
>>> anywhere.
>>>
>>> Wooden bicycle frames have been tried time and time again and always
>>> found lacking. CFRP, being comparable to a very hard, very strong
>>> wood, should be subject to many of wood's shortcomings-- which looks
>>> to be true.
> A Muzi wrote:
>> In fairness, true monocoque (some Kestrels for example) designs use
>> the material to its best advantage, obviating tube-to-tube jointing
>> issues.
jim beam wrote:
> personally, i'm not so convinced about this. and few are true monocoque
> - giant aren't from what i've seen.
>
> integrity of crfp depends on compaction during cure. enclosed
> structures like a true monocoque are very hard to get truly compacted.
> if not, then extra weight is required to build in more safety. while
> mistakes can be made, epoxied cfrp componentry like forks are proven
> quantities. when i get around to buying a full carbon frame, i'll
> probably go for a lugged frame like look.
Kestrel's patent (expired now?) is a pressurized internal bladder and a
rigid separable outer mold case. No longer used for an entire frame,
just sections, for a few reasons including overly complex and expensive
tooling which makes frequent 'model year' changes prohibitive.
We occasionally see moisture problems in glued joints of all material
combinations and a one-piece at least doesn't do that. I'm no expert
but, looking at other industries' use of the material, many
multi-layered directional fiber carbon designs look like those frames
(then again, fishing rods don't... ).
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | | |
Date: 11 Sep 2007 22:36:09
From: jim beam
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
A Muzi wrote:
>>>>>> Jambo <-...@-.-> wrote:
>>>>>>> Put it this way - imagine one carbon fiber as a pencil. It's
>>>>>>> very strong in
>>>>>>> compression and tension, as long as the load is parallel to its
>>>>>>> length (or
>>>>>>> axis). However, put a load perpendicular to its axis, and you
>>>>>>> can easily
>>>>>>> break the pencil.
>>>
>>>>> Ben C <spams...@spam.eggs> wrote:
>>>>>> I think that's a herring.
>>>
>>>> Michael Press wrote:
>>>>> Wood is a composite material, so the analogy is
>>>>> excellent. No fishy smell. Wood easier to crush
>>>>> transversely than longitudinally. That is why good
>>>>> cutting blocks are made with the end grain on the
>>>>> surface of the block. Wood is optimized to carry an
>>>>> axial load. Tall timber. When wood is called upon act
>>>>> as a beam as in a limb, it puts more material on the
>>>>> side of the neutral axis that is in compression, the
>>>>> underside.
>>>
>>> Chalo wrote:
>>>> I've noticed jb likes to use the CFRP-wood analogy. I think it bears
>>>> pointing out that wood is a pretty terrible material for structural
>>>> tubing, which is why nobody uses it that way. It's also worth noting
>>>> that aerospace industries, brought up so often in this context, don't
>>>> seem to be going out of their way to use CFRP as tubing or framework
>>>> anywhere.
>>>>
>>>> Wooden bicycle frames have been tried time and time again and always
>>>> found lacking. CFRP, being comparable to a very hard, very strong
>>>> wood, should be subject to many of wood's shortcomings-- which looks
>>>> to be true.
>
>> A Muzi wrote:
>>> In fairness, true monocoque (some Kestrels for example) designs use
>>> the material to its best advantage, obviating tube-to-tube jointing
>>> issues.
>
> jim beam wrote:
>> personally, i'm not so convinced about this. and few are true
>> monocoque - giant aren't from what i've seen.
>>
>> integrity of crfp depends on compaction during cure. enclosed
>> structures like a true monocoque are very hard to get truly compacted.
>> if not, then extra weight is required to build in more safety. while
>> mistakes can be made, epoxied cfrp componentry like forks are proven
>> quantities. when i get around to buying a full carbon frame, i'll
>> probably go for a lugged frame like look.
>
> Kestrel's patent (expired now?) is a pressurized internal bladder
right, but for a true monocoque, that's still a pita.
> and a
> rigid separable outer mold case. No longer used for an entire frame,
> just sections, for a few reasons including overly complex and expensive
> tooling which makes frequent 'model year' changes prohibitive.
>
> We occasionally see moisture problems in glued joints of all material
> combinations and a one-piece at least doesn't do that. I'm no expert
> but, looking at other industries' use of the material, many
> multi-layered directional fiber carbon designs look like those frames
> (then again, fishing rods don't... ).
i've seen sectioned giant "monocoque" frames, and they're made in large
sections which can be layed up and compacted properly, then the sections
are joined so it looks seamless. the joins are supposed to be strong,
and i believe giant take their business seriously.
otoh, i believe others are less rigorous and the monocoque look is more
for appearances than anything else.
what i like about the lugged design, at least in theory, is the ability
to not only fully compact and q.c. each tube and lug because you can
access it properly, but you can have each tube and lug individually
composed for its position and function in the frame - short fiber for
road buzz attenuation, long fiber for stiffness, etc.
|
| | | | | | |
Date: 11 Sep 2007 20:56:21
From: jim beam
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
Chalo wrote:
> Michael Press wrote:
>> Ben C <spams...@spam.eggs> wrote:
>>> On 2007-09-11, Jambo <-...@-.-> wrote:
>>>> Put it this way - imagine one carbon fiber as a pencil. It's very strong in
>>>> compression and tension, as long as the load is parallel to its length (or
>>>> axis). However, put a load perpendicular to its axis, and you can easily
>>>> break the pencil.
>>> I think that's a herring.
>> Wood is a composite material, so the analogy is
>> excellent. No fishy smell. Wood easier to crush
>> transversely than longitudinally. That is why good
>> cutting blocks are made with the end grain on the
>> surface of the block. Wood is optimized to carry an
>> axial load. Tall timber. When wood is called upon act
>> as a beam as in a limb, it puts more material on the
>> side of the neutral axis that is in compression, the
>> underside.
>
> I've noticed jb likes to use the CFRP-wood analogy.
yes you have.
> I think it bears
> pointing out that wood is a pretty terrible material for structural
> tubing, which is why nobody uses it that way. It's also worth noting
> that aerospace industries, brought up so often in this context, don't
> seem to be going out of their way to use CFRP as tubing or framework
> anywhere.
but planes used to be made of wood. even a relatively modern one like
this one i saw in england one time:
http://www.warbirdalley.com/mossie.htm
construction:
http://www.mossie.org/articles/CWD/Mos.html
>
> Wooden bicycle frames have been tried time and time again and always
> found lacking. CFRP, being comparable to a very hard, very strong
> wood, should be subject to many of wood's shortcomings-- which looks
> to be true.
that's because amateurs are trying to reverse engineer a metal frame.
jointing is a significant problem. adequate stiffness and strength with
metal-sized componentry is a significant problem. if it were designed
from the ground up /for/ that material, like an old wooden plane, then
you'd see different results.
|
| | | | | | |
Date: 11 Sep 2007 22:39:02
From: Doug Taylor
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
On Wed, 12 Sep 2007 01:29:34 -0000, Chalo <chalo.colina@gmail.com >
wrote:
> CFRP, being comparable to a very hard, very strong
>wood, should be subject to many of wood's shortcomings-- which looks
>to be true.
Unless you race bikes, in which case it the state of the art
frame/fork material. If you don't believe that, then ask such
erstwhile boutique frame builders as Litespeed, Merlin, Moots, Dean,
Seven et al. what their profit margin looks like over the past 3 -5
years, and whether anybody at all buys their titanium bikes for racing
anymore. In 5 short years, ti goes from top of the line to just
another durable but expensive and hard to work frame material boutique
bikes used to be made of.
|
| | | | | | | |
Date: 12 Sep 2007 15:57:17
From: Jambo
Subject: Re: "brittle" vs. non-ductile - getting through the jb rubbish
|
"Doug Taylor" <dtaylor@dreamscape.com > wrote in message
news:hljee3ltug0ur14q7k2n81banbea6v3d4m@4ax.com...
> On Wed, 12 Sep 2007 01:29:34 -0000, Chalo <chalo.colina@gmail.com>
> wrote:
>
>> CFRP, being comparable to a very hard, very strong
>>wood, should be subject to many of wood's shortcomings-- which looks
>>to be true.
>
> Unless you race bikes, in which case it the state of the art
> frame/fork material.
> If you don't believe that, then ask sucherstwhile boutique frame builders
> as Litespeed, Merlin, Moots, Dean,
> Seven et al. what their profit margin looks like over the past 3 -5
> years, and whether anybody at all buys their titanium bikes for racing
> anymore.
Profit margins, exactly.
> In 5 short years, ti goes from top of the line to just
> another durable but expensive and hard to work frame material boutique
> bikes used to be made of.
Boutique bikes, exactly. Say no more.....
|
| | | | | |
Date: 05 Sep 2007 21:01:44
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Mike Jacoubowsky wrote:
>>> Someone wrote:
>>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>>> hard enough to break it, it has been broken completely through. That
>>>> seems to indicate the the energy to complete a fracture isn't much, at
>>>> least for carbon-epoxy such as we see in bikes.
>>>
>>> This is both true and incredibly misleading. There are a lot of
>>> people out there riding on damaged (broken) carbon frames & forks
>>> that aren't aware of it. Few know what to look for, and even fewer
>>> *want* to look for the damage, preferring instead to think "phew,
>>> looks like it came out OK, I don't have to shell out a ton of money!"
>>
>> indeed.
>
> This is probably the best demonstration of why CF is bad for "prime time".
er, you ought to let boeing into your secret then...
>
>
>>> So yes, it's true that few have "seen" a carbon fiber product that's
>>> broken and not yet completely failed, but that doesn't mean they're
>>> not out there.
>
> First you say that there are lots of people riding damaged CF without
> knowing, then few have seen these (unless you're splitting "damaged" and
> "broken" and "failed"). Seems contradictory, unless you mean there are
> lots of damaged frames and forks that don't have symptoms? (something I
> have no trouble believing).
misconstruction.
>
>
>> absolutely - the warning signs are there but are frequently ignored.
>
> He seems to say there aren't any.
putting words into peoples mouths...
|
| | | | | | |
Date: 12 Sep 2007 11:25:56
From: Jay Beattie
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 3:48 am, Michael Warner <m...@westnet.com.au > wrote:
> On Tue, 11 Sep 2007 21:04:59 -0700, Mike Jacoubowsky wrote:
> > It's not a guess.. A huge percentage of those lycra-clad racer types ride
> > their bikes to the start of their group ride, and then ride back home
> > afterward (I'm talking about regularly-scheduled rides, not centuries). In
> > other words, for their chosen form of recreation, they're not using their
> > cars to get there.
>
> One of the reasons I don't race is that I'd have to drive about 70km (round
> trip) to do it with the guys who keep pestering me to come along. If I have
> to drive just to get to a ride, I rarely bother.
In Oregon and Washington you get a lot of races out of the
metropolitan areas and can drive a long way to ride a short race. My
brother is an avid masters MTB racer and state champ who lives in
Washington. He may drive hours to do a five minute down-hill race.
Usually there is a cross-country race, too, but he has driven a long
way to do only a brief down-hill event -- usually as a required event
in some points series. As my racing career wound down, I started to
think that it was pretty stupid to drive three or four hours just to
be pack-filler. It was not like I was enjoying the scenery as I
gulped for air. -- Jay Beattie.
|
| | | | | | | |
Date: 17 Sep 2007 05:30:53
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Hill wrote:
>
> Elite ruling members of
> societies sending the middle and poor classes off to be cannon fodder
> while they, the elites, avoid danger, then strut and wrap themselves in
> their flags, has been going on for thousands of years.
Nobody is poor enough to excuse being murderously stupid. The
ingrained cultural habit of supporting the soldier but not the war is
the equivalent of supporting the rapist but not a particular rape.
We'll not be free of corrupt wars until we lose that habit.
Chalo
|
| | | | | | | |
Date: 14 Sep 2007 13:42:02
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 21:02:19 GMT, Mike Jacoubowsky wrote:
> Obviously, there's some motivation for those guys to be there. It's not
> something I could relate to, and possibly not you either. I never could
> quite figure out why they were there back in the day, but I feel a bit
> differently about it now. I can see the point to being in a race that you
> have no chance of finishing in the top-10, because maybe it's a way of
> testing yourself to see where you are. Maybe you came in 10 minutes behind
> the winners this race, but you were 15 last time. That's progress, and
> progress can keep a dream fueled.
The racers I ride with all regularly win or place in their grades - I know
this because detailed post-mortems of last weekend's races are always
a favourite topic! - so I don't have any insight into the amateur "pack
fodder" lifestyle.
For me there's both co-operative and competitive fun to be had in road
riding, particularly when you often ride the same courses with the same
people. There's an unspoken agreement that some of us will race each other
up certain hills or sprint for certain markers, but then we reassemble,
don't race downhill or dodge and weave on the flat. So we keep track of
our strengths and have something to stir each other over, but without the
danger or group breakups of real racing.
That's the balance of social and competitive benefits I like. If I was
racing for money, I think I'd feel pressure to buy flimsy wheels and other
light components, go out training when I didn't want to, waste money on
petrol and showy clothing, and intimidate others in order to get an
advantage. None of that appeals to me, not least because I'm not
particularly wealthy :-)
|
| | | | | | | |
Date: 13 Sep 2007 14:45:08
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 18:31:32 -0700, Bill Sornson wrote:
> None of your (not at all humble) business.
If you post something here, you're inviting opinions about it. And given
what we're doing to the world's oil supply and atmosphere, spending
hours driving somewhere just to roll down a hill and go home again is
certainly something I have an opinion about.
|
| | | | | | | | |
Date: 12 Sep 2007 22:31:38
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Michael Warner wrote:
> On Wed, 12 Sep 2007 18:31:32 -0700, Bill Sornson wrote:
>
>> None of your (not at all humble) business.
>
> If you post something here, you're inviting opinions about it. And
> given what we're doing to the world's oil supply and atmosphere,
> spending hours driving somewhere just to roll down a hill and go home
> again is certainly something I have an opinion about.
That why you deleted your comment (and its context) that prompted mine?
What about a parent that drives a kid an hour and a half for a recital or
audition? What about Hollywood film productions that spew crap in the air
24-7 for months and months while pampered stars sit idling in their opulent
trailers?
But you choose to express faux concern and genuine disdain for a
(world-class, apparently) cyclist who travels to competitions?
I repeat: IT'S NONE OF YOUR BUSINESS. (Just a guess: you're in favor of
banning transfats and fast-food restaurants, too, right?)
Bill "stop do-gooder control, dammit" S.
|
| | | | | | | | | |
Date: 17 Sep 2007 00:30:33
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 17, 12:58 am, "Bill Sornson" <as...@ask.me > wrote:
> r15...@aol.com wrote:
> > On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>
> >> Bill "Hillary Lied; People Died" S.
>
> > True ... she was complicit along with so many others.
>
> Hillary didn't merely vote for the war; she went /beyond/ administration
> claims in making the CASE for war. (For instance, she claimed a direct
> connection between Saddam Hussein and A.Q.: " He has also given aid,
> comfort, and sanctuary to terrorists, including Al Qaida members.")
>
> Of course, she was probably right, but...
Like many others, she clamored on board the troopship because she
thought invading Iraq would be an easy endeavor.
This for her was some seriously poor judgment.
|
| | | | | | | | | | |
Date: 17 Sep 2007 08:38:34
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
r15757@aol.com wrote:
> On Sep 17, 12:58 am, "Bill Sornson" <as...@ask.me> wrote:
>> r15...@aol.com wrote:
>>> On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>>
>>>> Bill "Hillary Lied; People Died" S.
>>
>>> True ... she was complicit along with so many others.
>>
>> Hillary didn't merely vote for the war; she went /beyond/
>> administration claims in making the CASE for war. (For instance,
>> she claimed a direct connection between Saddam Hussein and A.Q.: "
>> He has also given aid, comfort, and sanctuary to terrorists,
>> including Al Qaida members.")
>>
>> Of course, she was probably right, but...
>
> Like many others, she clamored on board the troopship because she
> thought invading Iraq would be an easy endeavor.
>
> This for her was some seriously poor judgment.
Today she says she was against it from the start. And none of her opponents
(except a wife or two) OR the press will press her on it.
Do they fear for their kneecaps or what? (Of course, that "Shoe Guy" --
Hsu? -- was /supposed/ to wind up dead. Even wrote a suicide note -- or
someone did -- but he screwed 'em by not dying. Yet.)
Bill "maybe Sandy Burglar will do the deed...he owes people, you know" S.
|
| | | | | | | | | |
Date: 13 Sep 2007 06:21:09
From: Jay Hill
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Bill Sornson wrote:
>
> Bill "stop do-gooder control, dammit" S.
Which is its own kind of do-gooder control.
PS. You should learn-up about trans fats, there, Homer.
|
| | | | | | | | | | |
Date: 13 Sep 2007 08:31:58
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Hill wrote:
> Bill Sornson wrote:
>>
>> Bill "stop do-gooder control, dammit" S.
> Which is its own kind of do-gooder control.
Bull. Let people do what they choose. (The more information the better,
but not regulation.)
> PS. You should learn-up about trans fats, there, Homer.
Lard Police. What's next?!?
|
| | | | | | | | | | | |
Date: 17 Sep 2007 09:00:26
From: andresmuro@aol.com
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 17, 9:38 am, "Bill Sornson" <as...@ask.me > wrote:
> r15...@aol.com wrote:
> > On Sep 17, 12:58 am, "Bill Sornson" <as...@ask.me> wrote:
> >> r15...@aol.com wrote:
> >>> On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>
> >>>> Bill "Hillary Lied; People Died" S.
>
> >>> True ... she was complicit along with so many others.
>
> >> Hillary didn't merely vote for the war; she went /beyond/
> >> administration claims in making the CASE for war. (For instance,
> >> she claimed a direct connection between Saddam Hussein and A.Q.: "
> >> He has also given aid, comfort, and sanctuary to terrorists,
> >> including Al Qaida members.")
>
> >> Of course, she was probably right, but...
>
> > Like many others, she clamored on board the troopship because she
> > thought invading Iraq would be an easy endeavor.
>
> > This for her was some seriously poor judgment.
>
> Today she says she was against it from the start. And none of her opponents
> (except a wife or two) OR the press will press her on it.
>
> Do they fear for their kneecaps or what? (Of course, that "Shoe Guy" --
> Hsu? -- was /supposed/ to wind up dead. Even wrote a suicide note -- or
> someone did -- but he screwed 'em by not dying. Yet.)
>
> Bill "maybe Sandy Burglar will do the deed...he owes people, you know" S.
That's because the liberal media is owned by the liberal corporations,
namely aol time warner, viacom, fox/clear channel, disney, etc. They
area also funded through advertisement by ATT, Pfizer, Nabisco,
Sasetru, Magnolia, Chevron, Exxon, all state, etc.
All these liberal corporation have ordered their employees not to
question H Clinton. These liberal corporations feel that it is unfair
for the Republicans not to tax them, to give them subsidies and to
spend lots of money in the war. So, they want a morel liberal
government that will tax them more, end all corporate subsidies, offer
socialized medicine and spend more on education, less in the military
and less in huge corporate contracts. So, to that end, these
corporations are supporting a liberal.
Makes perfect sense to me.
Andres
|
| | | | | | | | | | | | |
Date: 17 Sep 2007 09:27:08
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
andresmuro@aol.com wrote:
> On Sep 17, 9:38 am, "Bill Sornson" <as...@ask.me> wrote:
>> r15...@aol.com wrote:
>>> On Sep 17, 12:58 am, "Bill Sornson" <as...@ask.me> wrote:
>>>> r15...@aol.com wrote:
>>>>> On Sep 16, 8:56 am, "Bill Sornson" <as...@ask.me> wrote:
>>
>>>>>> Bill "Hillary Lied; People Died" S.
>>
>>>>> True ... she was complicit along with so many others.
>>
>>>> Hillary didn't merely vote for the war; she went /beyond/
>>>> administration claims in making the CASE for war. (For instance,
>>>> she claimed a direct connection between Saddam Hussein and A.Q.: "
>>>> He has also given aid, comfort, and sanctuary to terrorists,
>>>> including Al Qaida members.")
>>
>>>> Of course, she was probably right, but...
>>
>>> Like many others, she clamored on board the troopship because she
>>> thought invading Iraq would be an easy endeavor.
>>
>>> This for her was some seriously poor judgment.
>>
>> Today she says she was against it from the start. And none of her
>> opponents (except a wife or two) OR the press will press her on it.
>>
>> Do they fear for their kneecaps or what? (Of course, that "Shoe
>> Guy" -- Hsu? -- was /supposed/ to wind up dead. Even wrote a
>> suicide note -- or someone did -- but he screwed 'em by not dying.
>> Yet.)
>>
>> Bill "maybe Sandy Burglar will do the deed...he owes people, you
>> know" S.
>
> That's because the liberal media is owned by the liberal corporations,
> namely aol time warner, viacom, fox/clear channel, disney, etc. They
> area also funded through advertisement by ATT, Pfizer, Nabisco,
> Sasetru, Magnolia, Chevron, Exxon, all state, etc.
>
> All these liberal corporation have ordered their employees not to
> question H Clinton. These liberal corporations feel that it is unfair
> for the Republicans not to tax them, to give them subsidies and to
> spend lots of money in the war. So, they want a morel liberal
> government that will tax them more, end all corporate subsidies, offer
> socialized medicine and spend more on education, less in the military
> and less in huge corporate contracts. So, to that end, these
> corporations are supporting a liberal.
>
> Makes perfect sense to me.
So why won't they ask her tough questions? (Like, other than the above, how
she can claim to be pro-woman yet helped destroy the women who accused her
hubby of abuse, lewd behavior and even rape? Were they ALL liars???)
Kneecaps, I tells ya. Kneecaps.
|
| | | | | | |
Date: 06 Sep 2007 15:50:07
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Mike Jacoubowsky wrote:
>>>> Someone wrote:
>>>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>>>> hard enough to break it, it has been broken completely through. That
>>>>> seems to indicate the the energy to complete a fracture isn't much, at
>>>>> least for carbon-epoxy such as we see in bikes.
>>>>
>>>> This is both true and incredibly misleading. There are a lot of
>>>> people out there riding on damaged (broken) carbon frames & forks
>>>> that aren't aware of it. Few know what to look for, and even fewer
>>>> *want* to look for the damage, preferring instead to think "phew,
>>>> looks like it came out OK, I don't have to shell out a ton of money!"
>>>
>>> indeed.
>>
>> This is probably the best demonstration of why CF is bad for "prime
>> time".
>
> er, you ought to let boeing into your secret then...
The aircraft industry works to higher standards than joe (jim) consumer.
That's the point.
>
>
>>
>>
>>>> So yes, it's true that few have "seen" a carbon fiber product that's
>>>> broken and not yet completely failed, but that doesn't mean they're
>>>> not out there.
>>
>> First you say that there are lots of people riding damaged CF without
>> knowing, then few have seen these (unless you're splitting "damaged"
>> and "broken" and "failed"). Seems contradictory, unless you mean there
>> are lots of damaged frames and forks that don't have symptoms?
>> (something I have no trouble believing).
>
> misconstruction.
>
>>
>>
>>> absolutely - the warning signs are there but are frequently ignored.
>>
>> He seems to say there aren't any.
>
> putting words into peoples mouths...
Then how (if there are "warning signs") could there be:
"a lot of people out there riding on damaged (broken) carbon frames &
forks that aren't aware of it." ?
|
| | | | | | | |
Date: 13 Sep 2007 02:18:58
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Wayne Pein wrote:
>
> Chalo wrote:
> > But I'd say it's society that's doing play cyclists a bigger favor, by
> > letting them play in the streets from which most other kinds of play
> > have been banned.
>
> I think you greatly underestimate the amount of motor vehicle "play"
> that society endorses/encourages/embraces.
You're right about that. And any kind of cycling is categorically
more wholesome. I just don't see why for some folks, cycling has
degenerated into something just about as shallow and materialistic as
cruising in your hoopty rolling on 22" spinners while rattling the
doors off with your loud subwoofers. To me, it seems like the
activity of cycling intrinsically promotes enough introspection to
grow folks out of that mindset.
Chalo
|
| | | | | | | |
Date: 12 Sep 2007 10:58:42
From: Jay Beattie
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 11, 7:41 pm, Chalo <chalo.col...@gmail.com > wrote:
> Wayne Pein wrote:
>
> > Chalo wrote:
> > > I don't dispute the right of lycras to use the streets as their gym
> > > and playground, I just find it bothersome that most of them will do
> > > that without returning the favor to their communities by using their
> > > bikes as transportation on those same streets.
>
> > You believe that transportation is more important or a greater good than
> > recreational cycling. I do both, and can make the argument that
> > recreation is as or more important. At the least, I'd hate to be reduced
> > to being only a commuter.
>
> > If transportation cycling is doing the community a favor, can
> > recreational cycling be characterized as doing society a favor?
>
> I don't know. Is paintball a favor to society? If it keeps you from
> shooting people with lead balls instead, or if it prevents you from
> having a heart attack at 42 from too much TV and fast food and
> lethargy, then maybe.
>
> But I'd say it's society that's doing play cyclists a bigger favor, by
> letting them play in the streets from which most other kinds of play
> have been banned.
Gawd, Chalo, really! What about people like me who commute to work
and then ride the long way home for fun and exercise. Is there some
point at which I convert from being Mr. Socially Responsible to bad
fun cyclist? I think it probably happens somewhere in the hills --
where I am working so hard that wearing cleated shoes, padded shorts
and a breathable jersey actually has a benefit. Now, on the weekends,
I am pure bad fun cyclist -- unless I stop at the hardware store on
the way home, then, for a breif and fleeting moment, I am Mr. Socially
Responsible -- unless I am buying killer drain cleaner or lead based
solder for joining copper pipe. -- Jay Beattie.
|
| | | | | | | |
Date: 06 Sep 2007 20:57:50
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Mike Jacoubowsky wrote:
>>>>> Someone wrote:
>>>>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>>>>> hard enough to break it, it has been broken completely through. That
>>>>>> seems to indicate the the energy to complete a fracture isn't
>>>>>> much, at
>>>>>> least for carbon-epoxy such as we see in bikes.
>>>>>
>>>>> This is both true and incredibly misleading. There are a lot of
>>>>> people out there riding on damaged (broken) carbon frames & forks
>>>>> that aren't aware of it. Few know what to look for, and even fewer
>>>>> *want* to look for the damage, preferring instead to think "phew,
>>>>> looks like it came out OK, I don't have to shell out a ton of money!"
>>>>
>>>> indeed.
>>>
>>> This is probably the best demonstration of why CF is bad for "prime
>>> time".
>>
>> er, you ought to let boeing into your secret then...
>
> The aircraft industry works to higher standards than joe (jim) consumer.
> That's the point.
i /hate/ to point this out, but the people that /started/ using cfrp in
bikes used experience /from/ the aerospace industry. damn.
>
>
>>
>>
>>>
>>>
>>>>> So yes, it's true that few have "seen" a carbon fiber product
>>>>> that's broken and not yet completely failed, but that doesn't mean
>>>>> they're not out there.
>>>
>>> First you say that there are lots of people riding damaged CF without
>>> knowing, then few have seen these (unless you're splitting "damaged"
>>> and "broken" and "failed"). Seems contradictory, unless you mean
>>> there are lots of damaged frames and forks that don't have symptoms?
>>> (something I have no trouble believing).
>>
>> misconstruction.
>>
>>>
>>>
>>>> absolutely - the warning signs are there but are frequently ignored.
>>>
>>> He seems to say there aren't any.
>>
>> putting words into peoples mouths...
>
> Then how (if there are "warning signs") could there be:
> "a lot of people out there riding on damaged (broken) carbon frames &
> forks that aren't aware of it." ?
simply pay attention big guy.
1. the bike comes with an owners manual outlining inspection and
warnings. or
2. ask advice on this forum from people that are familiar with the
material and its failures. or even, if sufficiently desperate,
3. ask bike shop owners that are familiar with the material and its
failures.
as a guy that doesn't understand the difference between elasticity and
plasticity, you're not exactly well positioned to try spreading fud. at
least, not to people that aren't gullible fools.
|
| | | | | | | | |
Date: 12 Sep 2007 18:37:35
From: Jay Beattie
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 4:14 pm, Michael Warner <m...@westnet.com.au > wrote:
> On Wed, 12 Sep 2007 11:25:56 -0700, Jay Beattie wrote:
> > In Oregon and Washington you get a lot of races out of the
> > metropolitan areas and can drive a long way to ride a short race. My
> > brother is an avid masters MTB racer and state champ who lives in
> > Washington. He may drive hours to do a five minute down-hill race.
> > Usually there is a cross-country race, too, but he has driven a long
> > way to do only a brief down-hill event -- usually as a required event
> > in some points series.
>
> That's ridiculous. When your recreation turns into that sort of expensive
> grind, it's time to take a good look at yourself IMHO.
You certainly could make that argument. But when two points separate
you from first and second place -- and that coveted old-guy state
title (and cool jersey) -- then you make the drive to pick up the
points -- or at least that is the logic. I don't bust his chops about
it. That's between him and his family. -- Jay Beattie.
|
| | | | | | | | | |
Date: 12 Sep 2007 20:25:25
From: Bill Sornson
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Beattie wrote:
> On Sep 12, 4:14 pm, Michael Warner <m...@westnet.com.au> wrote:
>> On Wed, 12 Sep 2007 11:25:56 -0700, Jay Beattie wrote:
>>> In Oregon and Washington you get a lot of races out of the
>>> metropolitan areas and can drive a long way to ride a short race.
>>> My brother is an avid masters MTB racer and state champ who lives in
>>> Washington. He may drive hours to do a five minute down-hill race.
>>> Usually there is a cross-country race, too, but he has driven a long
>>> way to do only a brief down-hill event -- usually as a required
>>> event in some points series.
>>
>> That's ridiculous. When your recreation turns into that sort of
>> expensive grind, it's time to take a good look at yourself IMHO.
>
> You certainly could make that argument. But when two points separate
> you from first and second place -- and that coveted old-guy state
> title (and cool jersey) -- then you make the drive to pick up the
> points -- or at least that is the logic. I don't bust his chops about
> it. That's between him and his family. -- Jay Beattie.
What about Little Miss Sunshine?!? Driving all that way for a 3-minute
routine.
Bill "oh, the planetary humanity!" S.
|
| | | | | | | | |
Date: 12 Sep 2007 15:56:24
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 9:56 am, "Mike Jacoubowsky" <mik...@ix.netcom.com > wrote:
> The biggest reason I rarely mountain bike is that I have very little spare
> time to ride, and I'd have to waste half an hour each way getting to the
> places to ride. ...
Just a half hour? Consider yourself lucky. An hour of driving for a
several-hour long trail ride is well worth it.
Robert
|
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Date: 13 Sep 2007 14:39:19
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 00:47:05 GMT, Mike Jacoubowsky wrote:
> It's all a matter of degree. If that's the worst way in which he impacts
> "the planet", it could be worse.
Of course it could be, but I wasn't previously aware that amateurs could
chew through so much petrol for so little riding, purely in the name of
competition. That bothers me a lot more than the conspicuous consumption of
riding a CF bike in a team outfit.
> "Carbon neutral." That's the buzz-phrase these days. The idea that you can
> somehow mitigate the damage you're doing by paying someone off.
Yeah. The fact that dirty industries have warmed to the idea worries me.
They must have figured out how to twist the rules to their advantage.
|
| | | | | | | | | | |
Date: 13 Sep 2007 00:14:46
From: A Muzi
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
> Mike Jacoubowsky wrote:
>> It's all a matter of degree. If that's the worst way in which he impacts
>> "the planet", it could be worse.
Michael Warner wrote:
> Of course it could be, but I wasn't previously aware that amateurs could
> chew through so much petrol for so little riding, purely in the name of
> competition. That bothers me a lot more than the conspicuous consumption of
> riding a CF bike in a team outfit.
> Mike Jacoubowsky wrote:
>> "Carbon neutral." That's the buzz-phrase these days. The idea that you can
>> somehow mitigate the damage you're doing by paying someone off.
Michael Warner wrote:
> Yeah. The fact that dirty industries have warmed to the idea worries me.
> They must have figured out how to twist the rules to their advantage.
All regulation shares that aspect. If not at the outset, regulated and
regulators wise up later.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
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Date: 13 Sep 2007 09:11:57
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Wed, 12 Sep 2007 15:56:24 -0700, r15757@aol.com wrote:
> Just a half hour? Consider yourself lucky. An hour of driving for a
> several-hour long trail ride is well worth it.
Worth it to you, maybe, but what does the planet think about it?
|
| | | | | | | | | | |
Date: 13 Sep 2007 00:47:05
From: Mike Jacoubowsky
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
>> Just a half hour? Consider yourself lucky. An hour of driving for a
>> several-hour long trail ride is well worth it.
>
> Worth it to you, maybe, but what does the planet think about it?
It's all a matter of degree. If that's the worst way in which he impacts
"the planet", it could be worse. What about people whose living requires
that they're constantly flying across the continent? How much damage is that
doing? What if the person driving an hour to his or her favorite trail has a
reasonably-eco-not-quite-so-unfriendly vehicle, vs the person who would
never think to drive an hour to a trail but drives to the grocery store in a
Hummer?
We make choices, usually unintentional, that make an impact on the
environment in just about everything we do. I seriously doubt that many
people consider the impact on the environment of their jobs, or, for that
matter, their vacations. Maybe I shouldn't be flying to France each July? I
try in most other ways to be sensitive to the planet and not too
conspicuously-consumptive, but I could definitely do better. Having a kid in
college is helping, as the negative cash flow I'll have for the next 9 years
(another kid after that) keeps the urge to buy things way, way down!
"Carbon neutral." That's the buzz-phrase these days. The idea that you can
somehow mitigate the damage you're doing by paying someone off. Essentially
taxing yourself a small amount to help make it more practical for someone
else to fix your mistakes. I guess that's a variant of what I'm
suggesting... that if you work hard at trying to minimize your footprint on
the planet, you're off-setting things to a certain extent. Obviously, better
yet would be to not have to off-set at all. But that's carrying things
further than most would feel comfortable doing.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | | | | | | | | |
Date: 13 Sep 2007 15:18:22
From: Michael Warner
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Thu, 13 Sep 2007 00:14:46 -0500, A Muzi wrote:
> All regulation shares that aspect. If not at the outset, regulated and
> regulators wise up later.
The supposedly regulated usually end up the winners, because they're
able to buy off the regulator and/or hire better lawyers to find lucrative
loopholes in the regulations. Until there's a disaster on the order of what
Enron did to California's power supply, anyway.
|
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Date: 13 Sep 2007 16:09:04
From: A Muzi
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
> A Muzi wrote:
>> All regulation shares that aspect. If not at the outset, regulated and
>> regulators wise up later.
Michael Warner wrote:
> The supposedly regulated usually end up the winners, because they're
> able to buy off the regulator and/or hire better lawyers to find lucrative
> loopholes in the regulations. Until there's a disaster on the order of what
> Enron did to California's power supply, anyway.
Taxi drivers, surgeons, land developers, endlessly by its nature.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | |
Date: 07 Sep 2007 11:24:47
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:2sadndNsqIKiUX3bnZ2dnUVZ_r2nnZ2d@speakeasy.net...
> Peter Cole wrote:
>> The aircraft industry works to higher standards than joe (jim) consumer.
>> That's the point.
>
> i /hate/ to point this out, but the people that /started/ using cfrp in
> bikes used experience /from/ the aerospace industry. damn.
This is your say so, not fact. Geez, you're incredibly gullible.
|
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Date: 12 Sep 2007 12:40:23
From: Jay Beattie
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 11:44 am, Chalo <chalo.col...@gmail.com > wrote:
> On Sep 12, 12:58 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
>
>
>
> > Is there some
> > point at which I convert from being Mr. Socially Responsible to bad
> > fun cyclist? I think it probably happens somewhere in the hills --
> > where I am working so hard that wearing cleated shoes, padded shorts
> > and a breathable jersey actually has a benefit. Now, on the weekends,
> > I am pure bad fun cyclist -- unless I stop at the hardware store on
> > the way home, then, for a breif and fleeting moment, I am Mr. Socially
> > Responsible -- unless I am buying killer drain cleaner or lead based
> > solder for joining copper pipe.
>
> I ride for fun, lots.
>
> I'm not saying cycling shouldn't be fun. I'm not saying that lycras
> shouldn't have their own kind of fun. I'm not even objecting to folks
> using the streets however the law will let them. I'm just saying that
> a certain kind of cyclist-- team kit, this year's plastic bike, silly
> shoes, sillier shades, point-A-to-point-A, conspicuous consumption to
> the hilt-- annoys me. That's all.
I feel the same way, although I am perhaps a little less sensitive to
poseurs because I pose a little myself. I wear lycra and old team
jerseys (teams that I rode on) -- but I do not wear trade team
outfits, let alone matching (down to the socks) trade team outfits.
That is the new thing in PDX -- droves of cyclists wearing matching
trade team outfits. It only happend this year -- its like the pretty
butterflies hatched all at once.
The butterflies also have a weird spin-class fitness -- some are
really pretty strong (and look far better than me in lycra), but they
cannot ride straight and cannot descend. They also look clumsy
climbing out of the saddle -- maybe they are looking down for the
friction knob. -- Jay Beattie.
|
| | | | | | | | | | |
Date: 12 Sep 2007 17:12:06
From: Peter Cole
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Jay Beattie wrote:
> On Sep 12, 11:44 am, Chalo <chalo.col...@gmail.com> wrote:
>> On Sep 12, 12:58 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
>>
>>
>>
>>> Is there some
>>> point at which I convert from being Mr. Socially Responsible to bad
>>> fun cyclist? I think it probably happens somewhere in the hills --
>>> where I am working so hard that wearing cleated shoes, padded shorts
>>> and a breathable jersey actually has a benefit. Now, on the weekends,
>>> I am pure bad fun cyclist -- unless I stop at the hardware store on
>>> the way home, then, for a breif and fleeting moment, I am Mr. Socially
>>> Responsible -- unless I am buying killer drain cleaner or lead based
>>> solder for joining copper pipe.
>> I ride for fun, lots.
>>
>> I'm not saying cycling shouldn't be fun. I'm not saying that lycras
>> shouldn't have their own kind of fun. I'm not even objecting to folks
>> using the streets however the law will let them. I'm just saying that
>> a certain kind of cyclist-- team kit, this year's plastic bike, silly
>> shoes, sillier shades, point-A-to-point-A, conspicuous consumption to
>> the hilt-- annoys me. That's all.
>
> I feel the same way, although I am perhaps a little less sensitive to
> poseurs because I pose a little myself. I wear lycra and old team
> jerseys (teams that I rode on) -- but I do not wear trade team
> outfits, let alone matching (down to the socks) trade team outfits.
> That is the new thing in PDX -- droves of cyclists wearing matching
> trade team outfits. It only happend this year -- its like the pretty
> butterflies hatched all at once.
>
> The butterflies also have a weird spin-class fitness -- some are
> really pretty strong (and look far better than me in lycra), but they
> cannot ride straight and cannot descend. They also look clumsy
> climbing out of the saddle -- maybe they are looking down for the
> friction knob. -- Jay Beattie.
>
OK, I was holding back, but... There's a group of well-heeled, mostly
over 50, professionals I sometimes ride with who have had a rather
spectacular run of crashes over the past few years. It seems like
virtually every one (perhaps of 30) is a member of the "broken
collarbone club". This is not from racing. The latest incident was a
broken rib and punctured lung from a crash when the rider lost control
while fishing in a jersey pocket (airlifted out). Other recent ones
were: accidentally jamming a water bottle into the tire/fork when
replacing it in the cage (few days hospital), jamming fingers in the
fork when clearing a leaf (few days hospital), fixed gear pedal strike
(collarbone), jacket around waist fouling rear wheel (2 crashed,
collarbone), etc., etc. Their ride reports sound like combat missions.
These guys do tons of miles, are really fit, always have the latest
high-end zoot (including matching outfits), but ride with disaster
hanging in the air like LA smog.
One guy in another group I ride with agonized for months over a high-end
Madone (not as well-heeled as the other guys, apparently). He was
crushed after he bought it because he was no faster than on his old
steel clunker. He was really scary to ride with for months after that
because, although he was pretty sketchy to begin with, he started to
ride really hard to make the bike work -- too hard, if you know what I
mean. He finally did get a little faster and is probably now convinced
it was the bike. It was really trying to live up to the bike.
I have ridden with the same group, same course, 52 Saturdays a year for
over 10 years now. New bikes have never changed anything. I, too, have a
problem with conspicuous over consumption -- it just seems crude and
tasteless, not to mention snobbish. From a performance POV, it really
comes down to paying a few thousand to shave a few pounds. Considering
pudge on many of these guys that borders on obscene. It's high tech
liposuction.
I showed up on one ride with a new bike. One of the regulars asked what
it was, I said a Nash-Bay. He didn't get it. Another guy complimented my
(14 yo) son on beating him, saying how amazing it was given he had all
the "wrong stuff" (jerk). My wife is frequently annoyed when riders tell
her she should get "a faster bike".
I used to think it was funny when Trek used Lance, all the while he had
a book out "It's Not About the Bike".
|
| | | | | | | | | |
Date: 12 Sep 2007 18:44:50
From: Chalo
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
On Sep 12, 12:58 pm, Jay Beattie <jbeat...@lindsayhart.com > wrote:
>
> Is there some
> point at which I convert from being Mr. Socially Responsible to bad
> fun cyclist? I think it probably happens somewhere in the hills --
> where I am working so hard that wearing cleated shoes, padded shorts
> and a breathable jersey actually has a benefit. Now, on the weekends,
> I am pure bad fun cyclist -- unless I stop at the hardware store on
> the way home, then, for a breif and fleeting moment, I am Mr. Socially
> Responsible -- unless I am buying killer drain cleaner or lead based
> solder for joining copper pipe.
I ride for fun, lots.
I'm not saying cycling shouldn't be fun. I'm not saying that lycras
shouldn't have their own kind of fun. I'm not even objecting to folks
using the streets however the law will let them. I'm just saying that
a certain kind of cyclist-- team kit, this year's plastic bike, silly
shoes, sillier shades, point-A-to-point-A, conspicuous consumption to
the hilt-- annoys me. That's all.
Chalo
|
| | | | | | | | | | |
Date: 12 Sep 2007 20:15:43
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo Colina writes:
>> Is there some point at which I convert from being Mr. Socially
>> Responsible to bad fun cyclist? I think it probably happens
>> somewhere in the hills -- where I am working so hard that wearing
>> cleated shoes, padded shorts and a breathable jersey actually has a
>> benefit. Now, on the weekends, I am pure bad fun cyclist -- unless
>> I stop at the hardware store on the way home, then, for a brief and
>> fleeting moment, I am Mr. Socially Responsible -- unless I am
>> buying killer drain cleaner or lead based solder for joining copper
>> pipe.
> I ride for fun, lots.
> I'm not saying cycling shouldn't be fun. I'm not saying that lycras
> shouldn't have their own kind of fun. I'm not even objecting to
> folks using the streets however the law will let them. I'm just
> saying that a certain kind of cyclist-- team kit, this year's
> plastic bike, silly shoes, sillier shades, point-A-to-point-A,
> conspicuous consumption to the hilt-- annoys me. That's all.
The world is full of poseurs although bicyclists may show it most
glaringly with their paraphenalia. No less conspicuous are baggy
(cargo) pants teens or the middle aged "truck" drivers in their black
pickup trucks or SUV's with blackened windows, protruding chrome
wheels and multiple exhaust pipes. You could get excited about the
"sports car" drivers who rumble around in low gears so you can hear
the roar of their powerful motors, or the Harley riders with their
shotgun exhaust.
Humans are beasts with frail egos and an insensitivity to their own
machinations. I often wonder why the guy in a truck with huge wheels
and jacked up chassis is not embarrassed to be seen that way. The
same goes for drivers of pseudo racing cars with giant air foils.
http://i1.tinypic.com/505ukc2.jpg
Jobst Brandt
|
| | | | | | | | | | | |
Date: 12 Sep 2007 13:18:48
From: Tom Nakashima
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
<jobst.brandt@stanfordalumni.org > wrote in message
news:46e848ef$0$14064$742ec2ed@news.sonic.net...
>
> http://i1.tinypic.com/505ukc2.jpg
>
> Jobst Brandt
Jobst,
that was nice of you to assist the driver into his vehicle.
-tom
|
| | | | | | | | | | |
Date: 12 Sep 2007 19:58:14
From:
Subject: Re: Play cyclists, was Re: "brittle" vs. non-ductile
|
Chalo Colina writes:
>> Is there some point at which I convert from being Mr. Socially
>> Responsible to bad fun cyclist? I think it probably happens
>> somewhere in the hills -- where I am working so hard that wearing
>> cleated shoes, padded shorts and a breathable jersey actually has a
>> benefit. Now, on the weekends, I am pure bad fun cyclist -- unless
>> I stop at the hardware store on the way home, then, for a brief and
>> fleeting moment, I am Mr. Socially Responsible -- unless I am
>> buying killer drain cleaner or lead based solder for joining copper
>> pipe.
> I ride for fun, lots.
> I'm not saying cycling shouldn't be fun. I'm not saying that lycras
> shouldn't have their own kind of fun. I'm not even objecting to
> folks using the streets however the law will let them. I'm just
> saying that a certain kind of cyclist-- team kit, this year's
> plastic bike, silly shoes, sillier shades, point-A-to-point-A,
> conspicuous consumption to the hilt-- annoys me. That's all.
The world is full o poseurs although the may show it most glaringly
with bicycling paraphenalia. No less conspicuous are the baggy
(cargo) pants teens or the middle aged "truck" drivers in their black
pickup trucks and SUV's with blackened windows, protruding chrome
wheels and multiple exhaust pipes. You could get excited about the
"sports car" drivers who rumble around in low gears so you can hear
the roar of the motors, or the Harley riders with their shotgun
exhaust.
Humans are beasts with frail egos and insensitivity to their own
machinations. I often wonder why the guy in a truck with huge wheels
and jacked up chassis is not embarrassed to be seen that way. The
same goes for drivers of pseudo racing cars with giant air foils.
http://i1.tinypic.com/505ukc2.jpg
Jobst Brandt
|
| | | | | | | | |
Date: 07 Sep 2007 08:50:54
From: Peter Cole
Subject: Re: "brittle" vs. non-ductile
|
jim beam wrote:
> Peter Cole wrote:
>> Then how (if there are "warning signs") could there be:
>> "a lot of people out there riding on damaged (broken) carbon frames &
>> forks that aren't aware of it." ?
>
> simply pay attention big guy.
>
> 1. the bike comes with an owners manual outlining inspection and
> warnings. or
I have. They (Trek) essentially say "if you suspect damage, bring it
in". What if you don't suspect damage? The material I've found asserts
that "tap, squeeze and peek" often won't find existing damage.
> 2. ask advice on this forum from people that are familiar with the
> material and its failures. or even, if sufficiently desperate,
The few on this forum that seem to have some level of expertise of CF
agree with what I've dug up (and cited).
> 3. ask bike shop owners that are familiar with the material and its
> failures.
I wouldn't for 2 reasons: they're not (in most cases) technically
qualified and they have a conflict of interest.
> as a guy that doesn't understand the difference between elasticity and
> plasticity, you're not exactly well positioned to try spreading fud. at
> least, not to people that aren't gullible fools.
You can repeat that claim ad nauseam, it doesn't make it true.
|
| | | | | | | | | |
Date: 07 Sep 2007 06:33:29
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>
>>> Then how (if there are "warning signs") could there be:
>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>> forks that aren't aware of it." ?
>>
>> simply pay attention big guy.
>>
>> 1. the bike comes with an owners manual outlining inspection and
>> warnings. or
>
> I have. They (Trek) essentially say "if you suspect damage, bring it
> in". What if you don't suspect damage? The material I've found asserts
> that "tap, squeeze and peek" often won't find existing damage.
now that is presumptive bullshit!!!! but it sure is great to fabricate
something to be frightened of!!!
>
>
>> 2. ask advice on this forum from people that are familiar with the
>> material and its failures. or even, if sufficiently desperate,
>
> The few on this forum that seem to have some level of expertise of CF
> agree with what I've dug up (and cited).
no they don't. you've got the usual retards competing for the stupidity
prize, and one other joker that dismisses the very aerospace standards
he tried to espouse.
>
>
>> 3. ask bike shop owners that are familiar with the material and its
>> failures.
>
> I wouldn't for 2 reasons: they're not (in most cases) technically
> qualified and they have a conflict of interest.
ah, the jobstian dodge - insult, question competence and make false
accusation. nice.
>
>
>> as a guy that doesn't understand the difference between elasticity and
>> plasticity, you're not exactly well positioned to try spreading fud.
>> at least, not to people that aren't gullible fools.
>
> You can repeat that claim ad nauseam, it doesn't make it true.
but we have your own words and they're on archive!!! "plasticity",
"elasticity", "ductility", "fracture energy absorption" are all terms
with which you're on record as being hopelessly "confused".
|
| | | | | | | |
Date: 06 Sep 2007 16:40:09
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
> Then how (if there are "warning signs") could there be:
> "a lot of people out there riding on damaged (broken) carbon frames &
> forks that aren't aware of it." ?
Because, as pointed out previously, people either don't know what to look
for, or don't want to look for it (wishful thinking, wanting to believe
everything's OK since the bike can be ridden) or a combination of the two.
The statement is factual. That it's difficult for some to comprehend is
obvious, but that doesn't change that it's true.
I'm even guilty of it myself. My son & I took a trip to France with our
bikes in July, and due to restrictions regarding what can be taken on the
TGV, we had to transport them in bags, not boxes. From the outside of the
bag it was quite obvious my bike had been through a lot, but whatever damage
might have happened, I didn't want to know about, because it still rode OK
and ignorance is bliss (didn't want to wreck the trip). One of these days
I'll be going over it carefully, preferably before the rain comes (since it
was my rain bike I brought with me).
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Peter Cole" <peter_cole@comcast.net > wrote in message
news:Y7OdnamzzZhtxH3bnZ2dnUVZ_qqgnZ2d@comcast.com...
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Mike Jacoubowsky wrote:
>>>>> Someone wrote:
>>>>>> Every time we've seen a CFRP bike part that has been hit or loaded
>>>>>> hard enough to break it, it has been broken completely through. That
>>>>>> seems to indicate the the energy to complete a fracture isn't much,
>>>>>> at
>>>>>> least for carbon-epoxy such as we see in bikes.
>>>>>
>>>>> This is both true and incredibly misleading. There are a lot of people
>>>>> out there riding on damaged (broken) carbon frames & forks that aren't
>>>>> aware of it. Few know what to look for, and even fewer *want* to look
>>>>> for the damage, preferring instead to think "phew, looks like it came
>>>>> out OK, I don't have to shell out a ton of money!"
>>>>
>>>> indeed.
>>>
>>> This is probably the best demonstration of why CF is bad for "prime
>>> time".
>>
>> er, you ought to let boeing into your secret then...
>
> The aircraft industry works to higher standards than joe (jim) consumer.
> That's the point.
>
>
>>
>>
>>>
>>>
>>>>> So yes, it's true that few have "seen" a carbon fiber product that's
>>>>> broken and not yet completely failed, but that doesn't mean they're
>>>>> not out there.
>>>
>>> First you say that there are lots of people riding damaged CF without
>>> knowing, then few have seen these (unless you're splitting "damaged" and
>>> "broken" and "failed"). Seems contradictory, unless you mean there are
>>> lots of damaged frames and forks that don't have symptoms? (something I
>>> have no trouble believing).
>>
>> misconstruction.
>>
>>>
>>>
>>>> absolutely - the warning signs are there but are frequently ignored.
>>>
>>> He seems to say there aren't any.
>>
>> putting words into peoples mouths...
>
> Then how (if there are "warning signs") could there be:
> "a lot of people out there riding on damaged (broken) carbon frames &
> forks that aren't aware of it." ?
|
| | | | | | | | |
Date: 06 Sep 2007 20:55:51
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <MikeJ@ChainReaction.com > wrote in message
news:td0Ei.1471$4J3.776@newssvr22.news.prodigy.net...
>> Then how (if there are "warning signs") could there be:
>> "a lot of people out there riding on damaged (broken) carbon frames &
>> forks that aren't aware of it." ?
>
> Because, as pointed out previously, people either don't know what to look
> for, or don't want to look for it (wishful thinking, wanting to believe
> everything's OK since the bike can be ridden) or a combination of the two.
>
> The statement is factual. That it's difficult for some to comprehend is
> obvious, but that doesn't change that it's true.
The point is that to rely only on visual inspection for CFRP damage is
foolish, since
1. as you say, people don't know what to look for or
2. don't wanna look; but also
3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
there.
It's also quite stupid to rely on any noise that CFRP may make when it gets
damaged. CFRP failure is catastrophic, and depending on the component, the
loud crack is the last thing you hear before things go not so nice. If it's
on a component like a handlebar, seatpost or fork, hope you have good health
cover.
If people want to use CFRP on bikes, fine and well, but it will do them good
to be aware of the pitfalls.
|
| | | | | | | | | |
Date: 07 Sep 2007 01:29:34
From: Mike Jacoubowsky
Subject: Re: "brittle" vs. non-ductile
|
> The point is that to rely only on visual inspection for CFRP damage is
> foolish, since
> 1. as you say, people don't know what to look for or
> 2. don't wanna look; but also
> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
> there.
Why do you insist that damage to carbon fiber cannot be seen? If that were
true, there'd be quite a few bikes still on the road that came in for crash
inspection, where we SAW damage to the tube. It's not uncommon to find an
area where the frame has a moderately-sized but hard-to-spot (unless you're
looking for it) crack. Usually it looks like a mild wrinkle in the tube. We
have seen such damage long after the crash happened (and after many
additional miles had been ridden), so it's not the case that a damaged
carbon tube allways instantaneously and catastrophically fails.
I should add that, if we don't find any visual damage, the next two steps
are to tap the tube with a coin and listen for any "dead" or buzzing areas,
and to squeeze the tubes by hand, feeling for any soft spots. The key to
successfully finding such things is to know how it crashed, and then figure
out where it may have been damaged.
> It's also quite stupid to rely on any noise that CFRP may make when it
> gets damaged. CFRP failure is catastrophic, and depending on the
> component, the loud crack is the last thing you hear before things go not
> so nice. If it's on a component like a handlebar, seatpost or fork, hope
> you have good health cover.
I think I covered most of that in the prior paragraph, but beyond that
should point out that all materials used in forks, stems & handlebars are
known to have catastrophically fail at times. I've gone through three stems
myself; one titanium & two aluminum. I've also broken aluminum seatposts.
All sudden, "catastrophic" failures that gave, to the best of my knowledge
at the time, no prior warning.
> If people want to use CFRP on bikes, fine and well, but it will do them
> good to be aware of the pitfalls.
It will do them good to be aware of the limitations of *any* bicycle
component, regardless of material. Common sense prevails (or should
prevail). If it seems like the crash was bad enough to cause you to think
"Wow, how could it possibly have survived that intact?", you should consider
that it may not have.
To me, the main "danger" posed by use of carbon fiber in frames & forks etc
is that the expense of replacement is such that people may be willing to
take risks and make assumptions that are dangerous.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Jambo" <-@-.- > wrote in message
news:46e0a16b$0$18919$4c368faf@roadrunner.com...
>
> "Mike Jacoubowsky" <MikeJ@ChainReaction.com> wrote in message
> news:td0Ei.1471$4J3.776@newssvr22.news.prodigy.net...
>>> Then how (if there are "warning signs") could there be:
>>> "a lot of people out there riding on damaged (broken) carbon frames &
>>> forks that aren't aware of it." ?
>>
>> Because, as pointed out previously, people either don't know what to look
>> for, or don't want to look for it (wishful thinking, wanting to believe
>> everything's OK since the bike can be ridden) or a combination of the
>> two.
>>
>> The statement is factual. That it's difficult for some to comprehend is
>> obvious, but that doesn't change that it's true.
>
> The point is that to rely only on visual inspection for CFRP damage is
> foolish, since
> 1. as you say, people don't know what to look for or
> 2. don't wanna look; but also
> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
> there.
>
> It's also quite stupid to rely on any noise that CFRP may make when it
> gets damaged. CFRP failure is catastrophic, and depending on the
> component, the loud crack is the last thing you hear before things go not
> so nice. If it's on a component like a handlebar, seatpost or fork, hope
> you have good health cover.
>
> If people want to use CFRP on bikes, fine and well, but it will do them
> good to be aware of the pitfalls.
>
|
| | | | | | | | | | |
Date: 06 Sep 2007 22:25:16
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <MikeJ@ChainReaction.com > wrote in message
news:2Q1Ei.1930$FO2.1613@newssvr14.news.prodigy.net...
>> The point is that to rely only on visual inspection for CFRP damage is
>> foolish, since
>> 1. as you say, people don't know what to look for or
>> 2. don't wanna look; but also
>> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
>> there.
>
> Why do you insist that damage to carbon fiber cannot be seen? If that were
> true, there'd be quite a few bikes still on the road that came in for
> crash inspection, where we SAW damage to the tube. It's not uncommon to
> find an area where the frame has a moderately-sized but hard-to-spot
> (unless you're looking for it) crack. Usually it looks like a mild wrinkle
> in the tube. We have seen such damage long after the crash happened (and
> after many additional miles had been ridden),
I didn't say all damage to carbon components cannot be seen; but many types
of damage are not visible. Delamination is almost always not visible, and
any deformations where fibers have broken but the plastic matrix hasn't
plastically deformed (such as bumps). All damage aren't caused by crashes
where things become visible externally: I can overtorque a clamp on a carbon
handlebar, or overload my seatpost and not notice anything until it fails.
> so it's not the case that a damaged carbon tube allways instantaneously
> and catastrophically fails.
Sure, it depends on where the damage is, as I've also indicated before.
However, you've only mentioned frames - a cracked BB weld may take a while
to grow to noticeable size, but I've seen many CF handlebars and seatposts
fail catastrophically with almost no warning.
> I should add that, if we don't find any visual damage, the next two steps
> are to tap the tube with a coin and listen for any "dead" or buzzing
> areas, and to squeeze the tubes by hand, feeling for any soft spots. The
> key to successfully finding such things is to know how it crashed, and
> then figure out where it may have been damaged.
Your method may work for some damage, but not for all. I wouldn't ride a
crashed bike that has only been checked by your coin tap and squeeze tube
technique, and I wouldn't recommend anyone do so either: there are many
types of serious CF damage that are undetectable by these techniques.
Google the topic of NDI and carbon composites.
>> It's also quite stupid to rely on any noise that CFRP may make when it
>> gets damaged. CFRP failure is catastrophic, and depending on the
>> component, the loud crack is the last thing you hear before things go not
>> so nice. If it's on a component like a handlebar, seatpost or fork, hope
>> you have good health cover.
>
> I think I covered most of that in the prior paragraph, but beyond that
> should point out that all materials used in forks, stems & handlebars are
> known to have catastrophically fail at times. I've gone through three
> stems myself; one titanium & two aluminum. I've also broken aluminum
> seatposts. All sudden, "catastrophic" failures that gave, to the best of
> my knowledge at the time, no prior warning.
Of course, no one said that the other side is consequently true: that Al
alloys do not fail catastrophically. The fact is that CF will fail much
more readily after plastic deformation than Al, by a magnitude percent.
>> If people want to use CFRP on bikes, fine and well, but it will do them
>> good to be aware of the pitfalls.
>
> It will do them good to be aware of the limitations of *any* bicycle
> component, regardless of material. Common sense prevails (or should
> prevail). If it seems like the crash was bad enough to cause you to think
> "Wow, how could it possibly have survived that intact?", you should
> consider that it may not have.
Except that "common sense" isn't really all that common. Some may argue
that if it doesn't look damaged, doesn't feel damaged, then it must be ok -
common sense to the uninitiated.
> To me, the main "danger" posed by use of carbon fiber in frames & forks
> etc is that the expense of replacement is such that people may be willing
> to take risks and make assumptions that are dangerous.
That may be a factor, but the main danger is the failures experienced by
those who use CF in high-injury likelihood components such as stems,
handlebars, seatposts - as I've indicated before, check out the pictures and
stories at mtbr.com for examples.
|
| | | | | | | | | | | |
Date: 06 Sep 2007 20:49:05
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jambo wrote:
> "Mike Jacoubowsky" <MikeJ@ChainReaction.com> wrote in message
> news:2Q1Ei.1930$FO2.1613@newssvr14.news.prodigy.net...
>>> The point is that to rely only on visual inspection for CFRP damage is
>>> foolish, since
>>> 1. as you say, people don't know what to look for or
>>> 2. don't wanna look; but also
>>> 3. damage is likely to be sub-surface and CANNOT BE eyeballed, yet it's
>>> there.
>> Why do you insist that damage to carbon fiber cannot be seen? If that were
>> true, there'd be quite a few bikes still on the road that came in for
>> crash inspection, where we SAW damage to the tube. It's not uncommon to
>> find an area where the frame has a moderately-sized but hard-to-spot
>> (unless you're looking for it) crack. Usually it looks like a mild wrinkle
>> in the tube. We have seen such damage long after the crash happened (and
>> after many additional miles had been ridden),
>
> I didn't say all damage to carbon components cannot be seen; but many types
> of damage are not visible. Delamination is almost always not visible, and
> any deformations where fibers have broken but the plastic matrix hasn't
> plastically deformed (such as bumps). All damage aren't caused by crashes
> where things become visible externally: I can overtorque a clamp on a carbon
> handlebar, or overload my seatpost and not notice anything until it fails.
>
>> so it's not the case that a damaged carbon tube allways instantaneously
>> and catastrophically fails.
>
> Sure, it depends on where the damage is, as I've also indicated before.
> However, you've only mentioned frames - a cracked BB weld may take a while
> to grow to noticeable size, but I've seen many CF handlebars and seatposts
> fail catastrophically with almost no warning.
how convenient. and you must have abused a lot of personal equipment if
you have direct personal experience of this stuff failing with "no warning".
/or/, you're saying that you've seen other failures, and are /presuming/
there is no warning - something that those of us that have some
familiarity with this material don't believe, and which you'll have a
hard time convincing anybody of if it wasn't your own equipment.
>
>> I should add that, if we don't find any visual damage, the next two steps
>> are to tap the tube with a coin and listen for any "dead" or buzzing
>> areas, and to squeeze the tubes by hand, feeling for any soft spots. The
>> key to successfully finding such things is to know how it crashed, and
>> then figure out where it may have been damaged.
>
> Your method may work for some damage, but not for all. I wouldn't ride a
> crashed bike that has only been checked by your coin tap and squeeze tube
> technique, and I wouldn't recommend anyone do so either: there are many
> types of serious CF damage that are undetectable by these techniques.
> Google the topic of NDI and carbon composites.
here we go again - name a /single/ application outside aerospace where
that kind of testing is mandated. for any material. to claim it's
necessary fro cfrp bikes, but not for metals is a crock.
>
>>> It's also quite stupid to rely on any noise that CFRP may make when it
>>> gets damaged. CFRP failure is catastrophic, and depending on the
>>> component, the loud crack is the last thing you hear before things go not
>>> so nice. If it's on a component like a handlebar, seatpost or fork, hope
>>> you have good health cover.
>> I think I covered most of that in the prior paragraph, but beyond that
>> should point out that all materials used in forks, stems & handlebars are
>> known to have catastrophically fail at times. I've gone through three
>> stems myself; one titanium & two aluminum. I've also broken aluminum
>> seatposts. All sudden, "catastrophic" failures that gave, to the best of
>> my knowledge at the time, no prior warning.
>
> Of course, no one said that the other side is consequently true: that Al
> alloys do not fail catastrophically. The fact is that CF will fail much
> more readily after plastic deformation than Al, by a magnitude percent.
eh? cfrp doesn't plastically deform so don't confuse the two
deformation systems!!! and cfrp fails at a much higher limit than the
the al which is bent hopelessly long before the carbon.
>
>>> If people want to use CFRP on bikes, fine and well, but it will do them
>>> good to be aware of the pitfalls.
>> It will do them good to be aware of the limitations of *any* bicycle
>> component, regardless of material. Common sense prevails (or should
>> prevail). If it seems like the crash was bad enough to cause you to think
>> "Wow, how could it possibly have survived that intact?", you should
>> consider that it may not have.
>
> Except that "common sense" isn't really all that common. Some may argue
> that if it doesn't look damaged, doesn't feel damaged, then it must be ok -
> common sense to the uninitiated.
straw clutching.
>
>> To me, the main "danger" posed by use of carbon fiber in frames & forks
>> etc is that the expense of replacement is such that people may be willing
>> to take risks and make assumptions that are dangerous.
>
> That may be a factor, but the main danger is the failures experienced by
> those who use CF in high-injury likelihood components such as stems,
> handlebars, seatposts - as I've indicated before, check out the pictures and
> stories at mtbr.com for examples.
why not check r.b.t for examples? there's been over a decade of users,
and many many ned lud's bleating their fear of the unknown. and yet,
despite the many people just itching to criticize and millions of rider
miles on this "desperately dangerous" material, we have failures we can
count on the fingers of one hand. and all of them were preventable if
the rider had simply observed warning signs.
oh well, never let reality get in the way of a good fight - simply
bullshit your way along if people insist on pointing out the truth.
|
| | | | | | | | | | | | |
Date: 07 Sep 2007 11:49:07
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:peednfCgVemvV33bnZ2dnUVZ_hmtnZ2d@speakeasy.net...
> Jambo wrote:
>> Sure, it depends on where the damage is, as I've also indicated before.
>> However, you've only mentioned frames - a cracked BB weld may take a
>> while to grow to noticeable size, but I've seen many CF handlebars and
>> seatposts fail catastrophically with almost no warning.
>
> how convenient. and you must have abused a lot of personal equipment if
> you have direct personal experience of this stuff failing with "no
> warning".
Yes, I have, as opposed to your speculations. And they're not personal
equipment, but other people's.
> /or/, you're saying that you've seen other failures, and are /presuming/
> there is no warning - something that those of us that have some
> familiarity with this material don't believe, and which you'll have a hard
> time convincing anybody of if it wasn't your own equipment.
Well, people have related to me personally that there were no warnings, and
I've seen failures as they happened, with no warnings. So no, there are no
presumptions involved. And since it's obvious that you have no familiarity
whatsoever with CF components, your speculations are quite useless.
>> Your method may work for some damage, but not for all. I wouldn't ride a
>> crashed bike that has only been checked by your coin tap and squeeze tube
>> technique, and I wouldn't recommend anyone do so either: there are many
>> types of serious CF damage that are undetectable by these techniques.
>> Google the topic of NDI and carbon composites.
>
> here we go again - name a /single/ application outside aerospace where
> that kind of testing is mandated. for any material. to claim it's
> necessary fro cfrp bikes, but not for metals is a crock.
Eh, dood, you said the folks who use CF components on bikes used "aerospace
experience" - so to claim that NDI is necessary for aerospace but not for
bikes is stoopid. Contradict yourself much?
I suggest you learn more about CF and composites in general before you try
to engage in any kind of argument over it. Google is your friend.
>> Of course, no one said that the other side is consequently true: that Al
>> alloys do not fail catastrophically. The fact is that CF will fail much
>> more readily after plastic deformation than Al, by a magnitude percent.
>
> eh? cfrp doesn't plastically deform so don't confuse the two deformation
> systems!!! and cfrp fails at a much higher limit than the the al which is
> bent hopelessly long before the carbon.
How can you claim to be a "former metallurgist" when you're so clueless
about materials? CFRP does plastically deform - and elongation to failure
is 1.4%. Don't get confused now.
>> Except that "common sense" isn't really all that common. Some may argue
>> that if it doesn't look damaged, doesn't feel damaged, then it must be
>> ok - common sense to the uninitiated.
>
> straw clutching.
Another devastating retort from a "former metallurgist". How does that
work, by the way? You're either a metallurgist or you're not.
>> That may be a factor, but the main danger is the failures experienced by
>> those who use CF in high-injury likelihood components such as stems,
>> handlebars, seatposts - as I've indicated before, check out the pictures
>> and stories at mtbr.com for examples.
>
> why not check r.b.t for examples? there's been over a decade of users,
> and many many ned lud's bleating their fear of the unknown.
Why ignore mtbr.com, and any other fora where failures are reported?
Because it doesn't fit into your fantasy world, that's why!
> and yet, despite the many people just itching to criticize and millions of
> rider miles on this "desperately dangerous" material, we have failures we
> can count on the fingers of one hand.
That's with your discounting the other fora with reports of failures.
"La-la-la, if I close my eyes and hum loudly, all of these nasties will
disappear!"
> and all of them were preventable if the rider had simply observed warning
> signs.
Now we're back to user fault!
What a fool. You just keep breaking your lowest point every time you post.
> oh well, never let reality get in the way of a good fight - simply
> bullshit your way along if people insist on pointing out the truth.
You're very entertaining, at least you have that going for you!
|
| | | | | | | | | | | | | |
Date: 07 Sep 2007 18:22:14
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Jambo wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:peednfCgVemvV33bnZ2dnUVZ_hmtnZ2d@speakeasy.net...
>> Jambo wrote:
>>> Sure, it depends on where the damage is, as I've also indicated before.
>>> However, you've only mentioned frames - a cracked BB weld may take a
>>> while to grow to noticeable size, but I've seen many CF handlebars and
>>> seatposts fail catastrophically with almost no warning.
>> how convenient. and you must have abused a lot of personal equipment if
>> you have direct personal experience of this stuff failing with "no
>> warning".
>
> Yes, I have, as opposed to your speculations. And they're not personal
> equipment, but other people's.
<snip crap >
so, you're making presumptions about stuff you've not used, owned or
seen fail. what a fucking moron!
|
| | | | | | | | | | | | | | |
Date: 09 Sep 2007 12:14:11
From: Jambo
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:QPednTNFMevbZHzbnZ2dnUVZ_s_inZ2d@speakeasy.net...
> Jambo wrote:
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news:peednfCgVemvV33bnZ2dnUVZ_hmtnZ2d@speakeasy.net...
>>> Jambo wrote:
>>>> Sure, it depends on where the damage is, as I've also indicated before.
>>>> However, you've only mentioned frames - a cracked BB weld may take a
>>>> while to grow to noticeable size, but I've seen many CF handlebars and
>>>> seatposts fail catastrophically with almost no warning.
>>> how convenient. and you must have abused a lot of personal equipment if
>>> you have direct personal experience of this stuff failing with "no
>>> warning".
>>
>> Yes, I have, as opposed to your speculations. And they're not personal
>> equipment, but other people's.
> <snip crap>
>
> so, you're making presumptions about stuff you've not used, owned or seen
> fail. what a fucking moron!
Ah, so you can't understand English now? Did it not just say I saw,
observed, seen other people's failures occur?
HAHAHAHAHA! Weak even for you, lying fucktard!
|
| | | |
Date: 04 Sep 2007 06:00:30
From: Tim McTeague
Subject: Re: "brittle" vs. non-ductile
|
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message news:
>
> So yes, it's true that few have "seen" a carbon fiber product that's
> broken and not yet completely failed, but that doesn't mean they're not
> out there. It just means that people don't know what to look for, or
> prefer not to. We find damage to bikes frequently that the owner missed.
> There's this common-sense thing that's sometimes lacking. If an impact was
> nasty enough to have likely caused serious damage, it probably did. You
> just didn't look hard enough, or in the right places, to find it. A huge
> number of "just riding along" failures happen due to damage from a prior
> incident, and that small pothole just happened to be the final straw.
>
> --Mike-- Chain Reaction Bicycles
> www.ChainReactionBicycles.com
Ain't that the truth. I was hit by a car last month and my Reynolds Ouzo
Pro fork only had scratches on it and otherwise seemed fine. I am well
aware that carbon products can hide damage that will cause a future crash so
I replaced the fork. I still kept thinking "but it looks fine". The
thought of fork failure during a high speed descent allowed me to produce my
credit card. The LBS used the Park tool to remove the King baseplate so I
could move it to the new fork but it would not budge. They ended up bending
the plate edges and still it would not come off the fork. So, perhaps the
fork deformed a bit in that area. Anyway, I' glad I don't have to keep
wondering it my old fork is going to fail. Better save, and slightly
poorer, than sorry.
Tim McTeague
|
| | |
Date: 03 Sep 2007 09:50:52
From: jim beam
Subject: Re: "brittle" vs. non-ductile
|
Chalo wrote:
> jim beam wrote:
>> fracture energy absorption is what determines whether a material is
>> "brittle" or not. cfrp is not brittle like glass. it is not ductile,
>> [the apparent, er, "confusion"] but it is typically not brittle -
>> significant energy is absorbed as the fracture interface progresses
>> [depending on fabrication and constituent materials of course].
>
> Every time we've seen a CFRP bike part that has been hit or loaded
> hard enough to break it, it has been broken completely through. That
> seems to indicate the the energy to complete a fracture isn't much, at
> least for carbon-epoxy such as we see in bikes.
>
> Chalo
>
once metal starts to fracture, it usually breaks completely through as well.
|
| | | |
Date: 03 Sep 2007 19:53:57
From: Leo Lichtman
Subject: Re: "brittle" vs. non-ductile
|
"jim beam" wrote: once metal starts to fracture, it usually breaks
completely through as well.
^^^^^^^^^^^^^^^^^^^
If that were true, the term "fatigue failure" would not exist. Consider
also the case where the load exceeds the yield point, but is below the
ultimate strength. There is deformation without fracture, which is a form
of failure that does not occur in brittle materials.
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Date: 03 Sep 2007 13:28:13
From: jim beam
Subject: Re: "brittle" vs. non-ductile
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Leo Lichtman wrote:
> "jim beam" wrote: once metal starts to fracture, it usually breaks
> completely through as well.
> ^^^^^^^^^^^^^^^^^^^
> If that were true, the term "fatigue failure" would not exist.
but fatigue is different! and energy absorption by a metal once a
fatigue crack has grown to critical is minimal. hence the layman's
belief that metal "becomes brittle" when it fails in this way.
> Consider
> also the case where the load exceeds the yield point, but is below the
> ultimate strength. There is deformation without fracture, which is a form
> of failure that does not occur in brittle materials.
that's called ductility. it's not fracture energy absorption.
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Date: 04 Sep 2007 00:30:28
From: Leo Lichtman
Subject: Re: "brittle" vs. non-ductile
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"jim beam" wrote: (clip) but fatigue is different! and energy absorption
by a metal once a fatigue crack has grown to critical is minimal. (clip)
^^^^^^^^^^^^^^^^^^
Jim, you're answering a question different from the one I raised. Fatigure
failure begins with a microscopic crack, which acts as a stress raiser, and
grows gradually, until the remaining sound metal can no longer carry the
load. This is the interval I was thinking of in my response to:
"once metal starts to fracture, it usually breaks completely through as
well."
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Date: 03 Sep 2007 21:20:40
From: Tim McNamara
Subject: Re: "brittle" vs. non-ductile
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In article <EG1Di.66617$ax1.34082@bgtnsc05-news.ops.worldnet.att.net >,
"Leo Lichtman" <l.lichtman@worldnet.att.net > wrote:
> "jim beam" wrote: (clip) but fatigue is different! and energy absorption
> by a metal once a fatigue crack has grown to critical is minimal. (clip)
> ^^^^^^^^^^^^^^^^^^
>
> Jim, you're answering a question different from the one I raised.
> Fatigure failure begins with a microscopic crack, which acts as a
> stress raiser, and grows gradually, until the remaining sound metal
> can no longer carry the load. This is the interval I was thinking of
> in my response to: "once metal starts to fracture, it usually breaks
> completely through as well."
Here are some photos of metal failure, in this case an aluminum stem.
It would be interesting to discuss the failure mode of aluminum versus
CF in this type of application, since CF stems are available. This
might provide a concrete example to compare the qualities of the
material. How would CF versus Al endure this situation?
The cracks developed over an unknown period of time, but two days before
it was discovered the owner and I did a 104 mile ride that included
gravel roads, steep hills and rough pavement. The owner had noticed
some creaking for a couple of rides prior to the 104 miler. This stem
survived at least 150 miles of riding approaching this condition. It
was in service for five years seeing about 4000 miles of use a year.
The owner is 6 feet tall and about 160 pounds. The stem is a 3ttt
"Forge Ahead." The handlebar was a 3ttt road bar, 25.8 mm diameter at
the clamp area according to my calipers.
The stem was oriented so that the extension was flat (parallel to the
top tube). The major cracking is along the sides of the stem and
extending underneath, with another less-displaces crack extending around
the top. There is about 1 cm of intact metal separating the long cracks
on the side and the crack across the underside of the stem.
http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
http://www2.bitstream.net/~timmcn/stemphotos/stem_bottom.png
http://www2.bitstream.net/~timmcn/stemphotos/stem_clamp.png
http://www2.bitstream.net/~timmcn/stemphotos/stem_left.png
http://www2.bitstream.net/~timmcn/stemphotos/stem_left-under.png
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Date: 03 Sep 2007 19:59:47
From: jim beam
Subject: Re: "brittle" vs. non-ductile
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Tim McNamara wrote:
> In article <EG1Di.66617$ax1.34082@bgtnsc05-news.ops.worldnet.att.net>,
> "Leo Lichtman" <l.lichtman@worldnet.att.net> wrote:
>
>> "jim beam" wrote: (clip) but fatigue is different! and energy absorption
>> by a metal once a fatigue crack has grown to critical is minimal. (clip)
>> ^^^^^^^^^^^^^^^^^^
>>
>> Jim, you're answering a question different from the one I raised.
>> Fatigure failure begins with a microscopic crack, which acts as a
>> stress raiser, and grows gradually, until the remaining sound metal
>> can no longer carry the load. This is the interval I was thinking of
>> in my response to: "once metal starts to fracture, it usually breaks
>> completely through as well."
>
> Here are some photos of metal failure, in this case an aluminum stem.
> It would be interesting to discuss the failure mode of aluminum versus
> CF in this type of application, since CF stems are available. This
> might provide a concrete example to compare the qualities of the
> material. How would CF versus Al endure this situation?
that depends. if it's single-piece, there may be advantage, but the
cheapo "carbon" stems are aluminum ends with a bit of cfrp tube glued in
between. the aluminum ends will still fail.
>
> The cracks developed over an unknown period of time, but two days before
> it was discovered the owner and I did a 104 mile ride that included
> gravel roads, steep hills and rough pavement. The owner had noticed
> some creaking for a couple of rides prior to the 104 miler. This stem
> survived at least 150 miles of riding approaching this condition. It
> was in service for five years seeing about 4000 miles of use a year.
> The owner is 6 feet tall and about 160 pounds. The stem is a 3ttt
> "Forge Ahead." The handlebar was a 3ttt road bar, 25.8 mm diameter at
> the clamp area according to my calipers.
>
> The stem was oriented so that the extension was flat (parallel to the
> top tube). The major cracking is along the sides of the stem and
> extending underneath, with another less-displaces crack extending around
> the top. There is about 1 cm of intact metal separating the long cracks
> on the side and the crack across the underside of the stem.
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_right.png
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_bottom.png
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_clamp.png
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_left.png
>
> http://www2.bitstream.net/~timmcn/stemphotos/stem_left-under.png
it's possible the stem is defective in that the longitudinal cracking is
clearly taking advantage of an anisotropy weakness. other than that,
i'd question the stem clamp tightening torque, question handlebar
diameter and stick to 3t's user's manual/warranty guideline - in it, the
statement: "Replace the stem after 15/20000km intensive amateur use." is
quite unambiguous.
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Date: 04 Sep 2007 04:12:03
From: Leo Lichtman
Subject: Re: "brittle" vs. non-ductile
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"jim beam" wrote: it's possible the stem is defective in that the
longitudinal cracking is clearly taking advantage of an anisotropy
weakness.(clip)
^^^^^^^^^^^^^^^^^
Jim, what leads you to bring up anisotropy--is it that you need it to hold
up your end of the argument? If you hear hoofbeats, look for horses, not
zebras.
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Date: 04 Sep 2007 05:43:15
From: jim beam
Subject: Re: "brittle" vs. non-ductile
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Leo Lichtman wrote:
> "jim beam" wrote: it's possible the stem is defective in that the
> longitudinal cracking is clearly taking advantage of an anisotropy
> weakness.(clip)
> ^^^^^^^^^^^^^^^^^
> Jim, what leads you to bring up anisotropy--is it that you need it to hold
> up your end of the argument? If you hear hoofbeats, look for horses, not
> zebras.
>
>
look closely at the pictures - those surface marks you see running the
length of the stem are the result of the anisotropic substrate. if
you've never looked down a metallurgical microscope you may have
problems visualizing what i'm talking about.
http://www.mee-inc.com/gmet11.jpg
this is a stainless steel, but the highly anisotropic [directional]
nature of the material is evident. with the stem, you're simply seeing
crack growth propagate along the weakest path, along the grains.
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Date: 03 Sep 2007 18:21:30
From: jim beam
Subject: Re: "brittle" vs. non-ductile
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Leo Lichtman wrote:
> "jim beam" wrote: (clip) but fatigue is different! and energy absorption
> by a metal once a fatigue crack has grown to critical is minimal. (clip)
> ^^^^^^^^^^^^^^^^^^
> Jim, you're answering a question different from the one I raised. Fatigure
> failure begins with a microscopic crack, which acts as a stress raiser, and
> grows gradually, until the remaining sound metal can no longer carry the
> load. This is the interval I was thinking of in my response to:
> "once metal starts to fracture, it usually breaks completely through as
> well."
if you're considering the rupture that follows beyond the point of
ductility, that statement stands. you're right that fatigue is a
different matter, but fatigue is not the failure mode being considered.
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