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Main
Date: 03 Sep 2007 14:49:27
From: George
Subject: Question About Cranks
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This is a question about cranks, but it is not a crank question.
I learned about cotterless cranks around 1978.
Today, I saw a bike with an interesting crank set. On the right side
(i.e. on the chain ring side), there was no crank bolt. The area where
there would be a crank bolt was completely smooth. On the left side,
there was also no crank bolt, but the end of the crank arm near the
bottom bracket axle was slit and the crank arm was (apparently) held
on with an Allen screw "tangent" to the bottom bracket axle. (i.e.,
The crank arm was held in place in manner similar to the way a
seatpost is held in place by a bolt.)
Who makes this type of bottom bracket assembly? Does it work well? Why
is it made this way?
To reply directly to me, replace all 'z' with 'a' in email address.
Thanks.
George
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Date: 09 Sep 2007 03:43:22
From: Ozark Bicycle
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
On Sep 9, 1:22 am, Michael Press <rub...@pacbell.net > wrote:
> In article
> <1189274677.066395.237...@50g2000hsm.googlegroups.com>,
> Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Sep 8, 12:46 pm, "Jambo" <-...@-.-> wrote:
> > > "jim beam" <spamvor...@bad.example.net> wrote in message
>
> > >news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
>
> > > > the great jobst brand knows more about bearings than skf!!! classic.
>
> > > More than you'll know, that's for sure.
>
> > Beam's knowledge of bearings wasn't even under discussion, was it?
>
> Yes, it is. Do you know why? ....
>
>
|
| | |
Date: 09 Sep 2007 13:18:52
From: Michael Press
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
In article
<1189334602.879139.58150@57g2000hsv.googlegroups.com >,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com > wrote:
> On Sep 9, 1:22 am, Michael Press <rub...@pacbell.net> wrote:
> > In article
> > <1189274677.066395.237...@50g2000hsm.googlegroups.com>,
> > Ozark Bicycle
> >
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > On Sep 8, 12:46 pm, "Jambo" <-...@-.-> wrote:
> > > > "jim beam" <spamvor...@bad.example.net> wrote in message
> >
> > > >news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
> >
> > > > > the great jobst brand knows more about bearings than skf!!! classic.
> >
> > > > More than you'll know, that's for sure.
> >
> > > Beam's knowledge of bearings wasn't even under discussion, was it?
> >
> > Yes, it is. Do you know why? ....
> >
> >
|
| | | |
Date: 09 Sep 2007 21:09:07
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Michael Press wrote:
> In article
> <1189334602.879139.58150@57g2000hsv.googlegroups.com>,
> Ozark Bicycle
> <bicycleatelier@ozarkbicycleservice.com> wrote:
>
>> On Sep 9, 1:22 am, Michael Press <rub...@pacbell.net> wrote:
>>> In article
>>> <1189274677.066395.237...@50g2000hsm.googlegroups.com>,
>>> Ozark Bicycle
>>>
>>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>>> On Sep 8, 12:46 pm, "Jambo" <-...@-.-> wrote:
>>>>> "jim beam" <spamvor...@bad.example.net> wrote in message
>>>>> news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
>>>>>> the great jobst brand knows more about bearings than skf!!! classic.
>>>>> More than you'll know, that's for sure.
>>>> Beam's knowledge of bearings wasn't even under discussion, was it?
>>> Yes, it is. Do you know why? ....
>>>
>>>
|
| | | | |
Date: 10 Sep 2007 13:22:12
From: Jambo
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:Z_ednRRDG8X4XnnbnZ2dnUVZ_jqdnZ2d@speakeasy.net...
>
> no numbers, just typical underinformed jobstian opinion masquerading as
> fact. to say that sfk are "missing the point" is a damned bold
> assertion - one that the author had better be prepared to prove with hard
> data.
As if you have numbers yourself, you lying fucktard. Like you have hard
data of your "materials lecture over 30 years ago", when it's clear you made
that story up. Like you have stress-strain ratio for CF is 10x higher than
for Al.
> it's ridiculous that jobst urgently trots out the specter of sub-micron
> elastic bearing shell distortion when it comes to non-failure of bb
> bearings, yet happily ignores elastic distortion when it comes to very
> real spoke failures.
It's ridiculous that you know nothing about Hertzian stress, and then try to
tie in a totally different issue for spoke failures! You lying fucktard!
> oh, wait, he claims to be able to cure one, not
> the other and tries to sell books accordingly...
Oh wait, CF forks talk to you before they fail, and try to get people to
believe you.....
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| |
Date: 08 Sep 2007 11:04:37
From: Ozark Bicycle
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
On Sep 8, 12:46 pm, "Jambo" <-...@-.- > wrote:
> "jim beam" <spamvor...@bad.example.net> wrote in message
>
> news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
>
> > the great jobst brand knows more about bearings than skf!!! classic.
>
> More than you'll know, that's for sure.
Beam's knowledge of bearings wasn't even under discussion, was it?
|
| | |
Date: 08 Sep 2007 23:22:31
From: Michael Press
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
In article
<1189274677.066395.237010@50g2000hsm.googlegroups.com >,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com > wrote:
> On Sep 8, 12:46 pm, "Jambo" <-...@-.-> wrote:
> > "jim beam" <spamvor...@bad.example.net> wrote in message
> >
> > news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
> >
> > > the great jobst brand knows more about bearings than skf!!! classic.
> >
> > More than you'll know, that's for sure.
>
> Beam's knowledge of bearings wasn't even under discussion, was it?
Yes, it is. Do you know why? ....
|
| |
Date: 08 Sep 2007 09:39:40
From: Ozark Bicycle
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
On Sep 8, 11:01 am, jim beam <spamvor...@bad.example.net > wrote:
> jobst.bra...@stanfordalumni.org wrote:
> > Thomas Hood writes:
>
> >>>> I'm surprised no-one has mentioned that 2008 will see the external
> >>>> bearing start to disappear.
>
> >>> Shimano:http://preview.tinyurl.com/yth9j3
> >>> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>
> >>>> The difference between the two systems is that the Trek 'drops' a
> >>>> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
> >>>> surprised if special tools were actually _needed_ to fit remove
> >>>> the Shimano effort though. I wonder what seals -- if any --
> >>>> either system use.
>
> >>> As I mentioned when the Shimano design was first shown, an aluminum
> >>> outboard bearing cup is too weak to withstand fretting damage in
> >>> its threads and keep a solid hold to the BB. One of my riding pals
> >>> has one of these and it creaks with standing hill climbing... as
> >>> expected. I came to my assessment because steel internal cups with
> >>> English threading fret enough to erode BB threads to zero, the BB
> >>> being softer steel than the right bearing cup.
>
> >>> If internal steel cups experience failure, external aluminum cups
> >>> cannot be reliable. Either their threads will fail or the cups
> >>> will break off at the BB face. That's why I say, I have no easy
> >>> solution to the bearing problem although the crank attachment seems
> >>> to be well taken care of. As you see, Shimano realized that
> >>> bearings need a press fit or they will fret themselves into a loose
> >>> fit.
>
> >>> If these guys would only test their stuff on real riders before
> >>> going to market, we could be spared the task of field testing at
> >>> our expense. At least Campagnolo replaced failed parts in the days
> >>> of Tullio.
>
> >> I think you may have missed the significance of what I posted.
>
> >> The bearing designs I linked to are not 'external'. They use a new
> >> 'standard' ~80mm wide (and some unspecified diameter) bottom bracket
> >> shell that places the bearings in the same place as they would be on
> >> a traditional 68mm bottom bracket with external cups.
>
> >> Please look at the pictures:
>
> > http://preview.tinyurl.com/39bhjj
> > http://preview.tinyurl.com/3453m9
> > http://preview.tinyurl.com/yujcqm
> > http://preview.tinyurl.com/2zmeou
>
> > I don't know why these guys cannot show a cross section drawing
> > including all parts. These photos do not show how the parts fit and
> > the 3D model from TREK glosses over the essentials. I don't see how
> > one inserts and removes the "press fit" Shimano bearings or even what
> > they are. Just relying on seal lips on a BB bearing doesn't insure
> > exclusion of water either.
>
> > As I mentioned, "The seal that doesn't leak, leaks." That is, for a
> > seal lip to work, it must weep and that means slight leakage. Without
> > that the lip goes dry and fries, making it no longer a seal. By this
> > rule, no to fluids can be separated by a single seal lip. There must
> > be one for each fluid and if the outer one is wet only rarely, it is
> > running dry most of the time.
>
> > That is why automotive wheel bearing and drive shaft seals keep the
> > lubricant in and a labyrinth seal keeps the water off the seals.
>
> >> Haven't the canting loads been greatly reduced -- the loads now
> >> being borne radially by the wider BB shell?. I wonder if the
> >> composite retainer Shimano are using is a safeguard against
> >> creaking?
>
> > I don't understand how that bearing works and how it is installed.
>
> >> Whilst the distance between the pedal attachments remain as always,
> >> we now have a system where the bearings are of significantly greater
> >> diameter and situated as close to the arms as practicable.
> >> Furthermore, we no longer need specialist, shop tools to fit/ remove
> >> them.
>
> > That's fine but how is the bearing retained in the BB? That is a
> > difficult interface and I didn't see how it is done.
>
> >> It looks like this design is an improvement to the square taper on
> >> every front.
>
> > The square taper is a crank to spindle problem that the current
> > Shimano design solved, but the bearings and how they are held is
> > unclear to me so I cannot comment.
>
> >> Now if a company with real bearing knowledge -- like SKF -- could
> >> produce compatible bearings with 'automotive grade' seals (no
> >> 'aerospace' tech needed!) we might get the fit and forget BB that
> >> should have existed 20 years ago. The bottom bracket must be the
> >> single greatest cause of irritating squeaks and creaks on the modern
> >> bicycle.
>
> > It isn't a bearing problem. We have had adequate bearings for a long
> > time. It is a challenge of assembly, stresses between bearing races
> > and spindle and housing, and sealing. None of these require SKF but
> > rather someone with understanding of the problems specific to bicycle
> > BB's.
>
> > http://www.skf.com/portal/skf/home/industries?contentId=517237 =en
> > http://www.skf.com/portal/skf/home/industries?contentId=517236 =en
> > http://www.skf.com/cmimages/190967.jpg
> > http://www.skf.com/portal/skf/home/industries?contentId=517230 =en
> > 10yr guarantee speaks volumes, as, unfortunately does the price...
>
> > The stress picture of the ISIS spindle missed a point. There is a
> > notch at the shoulder of this spindle that has caused failures and
> > high stress in that notch does not show on their diagram. The ISIS
> > spindle has a taper spine that presents unfavorable stress gradients
> > over its length. It is not easily formed on the steel spindle and has
> > cumbersome installation of the cranks in contrast to the Shimano
> > pinch-bolt attachment.
>
> > In addition, SKF claims that rollers are better, missing the point
>
> the great jobst brand knows more about bearings than skf!!! classic.
I was thinking just that myself.
Jobst Brandt: the only thing bigger than the man himself is his ego.
|
| |
Date: 08 Sep 2007 10:37:16
From: Thomas Hood
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
On Sep 8, 12:14 am, jobst.bra...@stanfordalumni.org wrote:
> Thomas Hood writes:
> >>> I didn't look at the advertising material, but I think that one
> >>> problem Campagnolo was trying to solve has to do with the loose
> >>> fit between the inner bearing races and the spindle on Shimano
> >>> cranks which, according to some, causes wear on the spindle.
> >>> Campagnolo has bearings that are press fit on to the spindle. I
> >>> have an Ultegra that seems to be doing fine so far.
>
> But are you goofy footed?
Not my text, I'm afraid.
> >> As I have mentioned in earlier discussion about BB design, it's a huge
> >> can of worms and I don't see an easy solution to the bearing problem
> >> although I believe the crank attachment that Shimano has is a clean
> >> one that should work reliably. Their outboard bearing can't be good
> >> considering that inboard cups have failed on the right side from
> >> fretting, fretting that has a red flag on it because it requires a
> >> left hand thread, the best indicator of micro-motion.
> >> The point you mention is another headache for which I see no solution
> >> with the present design. This is such a high load interface that a
> >> slip fit bearing has got to fret and leave rouge traces from wear. I
> >> haven't worked with this BB but just looking at it at InterBike gave
> >> me reason to stay clear of it, considering how many cranks and
> >> spindles have withered under my feet.
> >> We'll have to wait and see.
> > I'm surprised no-one has mentioned that 2008 will see the external
> > bearing start to disappear.
>
> Shimano:http://preview.tinyurl.com/yth9j3
> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>
> > The difference between the two systems is that the Trek 'drops' a
> > bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
> > surprised if special tools were actually _needed_ to fit remove the
> > Shimano effort though. I wonder what seals -- if any -- either
> > system use.
>
> As I mentioned when the Shimano design was first shown, an aluminum
> outboard bearing cup is too weak to withstand fretting damage in its
> threads and keep a solid hold to the BB. One of my riding pals has
> one of these and it creaks with standing hill climbing... as expected.
> I came to my assessment because steel internal cups with English
> threading fret enough to erode BB threads to zero, the BB being softer
> steel than the right bearing cup.
>
> If internal steel cups experience failure, external aluminum cups
> cannot be reliable. Either their threads will fail or the cups will
> break off at the BB face. That's why I say, I have no easy solution
> to the bearing problem although the crank attachment seems to be well
> taken care of. As you see, Shimano realized that bearings need a
> press fit or they will fret themselves into a loose fit.
>
> If these guys would only test their stuff on real riders before going
> to market, we could be spared the task of field testing at our
> expense. At least Campagnolo replaced failed parts in the days of
> Tullio.
>
> Jobst Brandt
Jobst,
I think you may have missed the significance of what I posted.
The bearing designs I linked to are not 'external'. They use a new
'standard' ~80mm wide (and some unspecified diameter) bottom bracket
shell that places the bearings in the same place as they would be on a
traditional 68mm bottom bracket with external cups.
Please look at the pictures:
http://preview.tinyurl.com/39bhjj
http://preview.tinyurl.com/3453m9
http://preview.tinyurl.com/yujcqm
http://preview.tinyurl.com/2zmeou
Haven't the canting loads been greatly reduced -- the loads now being
borne radially by the wider BB shell?. I wonder if the composite
retainer Shimano are using is a safeguard against creaking?
Whist the distance between the pedal attachments remain as always, we
now have a system where the bearings are of significantly greater
diameter and situated as close to the arms as practicable.
Furthermore, we no longer need specialist, shop tools to fit/ remove
them.
It looks like this design is an improvement to the square taper on
every front.
Now if a company with real bearing knowledge -- like SKF -- could
produce compatible bearings with 'automotive grade' seals (no
'aerospace' tech needed!) we might get the fit and forget BB that
should have existed 20 years ago. The bottom bracket must be the
single greatest cause of irritating squeaks and creaks on the modern
bicycle.
http://www.skf.com/portal/skf/home/industries?contentId=517237&lang=en
http://www.skf.com/portal/skf/home/industries?contentId=517236&lang=en
http://www.skf.com/cmimages/190967.jpg
http://www.skf.com/portal/skf/home/industries?contentId=517230&lang=en
10yr guarantee speaks volumes, as, unfortunately does the price...
Thomas Hood
|
| | |
Date: 08 Sep 2007 23:13:59
From: Michael Press
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
In article
<1189247836.047063.283540@19g2000hsx.googlegroups.com >,
Thomas Hood <thomas.hood@gmail.com > wrote:
> It looks like this design is an improvement to the square taper on
> every front.
The square taper fit is not a problem. The replacement
spline fit has more reported failures than the square
taper fit.
Bigger problems are inward bending of the crank arm at
the bottom of the standing pedal stroke, pedal eye
fretting, and the undersized bottom bracket shell.
Yes, the pinch bolt on the crank to spindle attachment
is effective, but who builds a crank that supports the
load of a rider bearing down on the pedal at the bottom
of the stroke? I think steel cranks are in order.
--
Michael Press
|
| | | |
Date: 09 Sep 2007 06:42:50
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Michael Press wrote:
> In article
> <1189247836.047063.283540@19g2000hsx.googlegroups.com>,
> Thomas Hood <thomas.hood@gmail.com> wrote:
>
>> It looks like this design is an improvement to the square taper on
>> every front.
>
> The square taper fit is not a problem. The replacement
> spline fit has more reported failures than the square
> taper fit.
eh? no it doesn't! square taper is a regular problem for a crank arm
working its way loose. it's something i've dealt with many times on
bikes i owned and friends bikes [previously "professionally" serviced].
otoh, neither i nor any riding buddy have ever had a problem with the
allegedly loosening octalink crank. outside of brandt, i can recall
only /one/ incident of reported octalink loosening here on r.b.t, and
that boiled down to not following manufacturer torque spec and
subsequent permanent damage to the spline interface.
>
> Bigger problems are inward bending of the crank arm at
> the bottom of the standing pedal stroke, pedal eye
> fretting, and the undersized bottom bracket shell.
more preposterous jobstian fud - r.b.t has seen only finger-of-one-hand
incidence of crank failure in those modes in the last decade for campy
and shimano - the guys that bothered to do their fatigue homework.
other cranks from manufacturers that still use I-beam crank arms are
another matter - a jobstian redesign still wouldn't help them.
>
> Yes, the pinch bolt on the crank to spindle attachment
> is effective, but who builds a crank that supports the
> load of a rider bearing down on the pedal at the bottom
> of the stroke? I think steel cranks are in order.
easy there charlie - yes, we all want a safe ride, but steel is no
guarantee of fatigue elimination. especially a steel that's been
welded, chrome plated or that has rusted.
|
| | |
Date: 08 Sep 2007 15:54:56
From:
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Thomas Hood writes:
>>> I'm surprised no-one has mentioned that 2008 will see the external
>>> bearing start to disappear.
>> Shimano: http://preview.tinyurl.com/yth9j3
>> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>>> The difference between the two systems is that the Trek 'drops' a
>>> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
>>> surprised if special tools were actually _needed_ to fit remove
>>> the Shimano effort though. I wonder what seals -- if any --
>>> either system use.
>> As I mentioned when the Shimano design was first shown, an aluminum
>> outboard bearing cup is too weak to withstand fretting damage in
>> its threads and keep a solid hold to the BB. One of my riding pals
>> has one of these and it creaks with standing hill climbing... as
>> expected. I came to my assessment because steel internal cups with
>> English threading fret enough to erode BB threads to zero, the BB
>> being softer steel than the right bearing cup.
>> If internal steel cups experience failure, external aluminum cups
>> cannot be reliable. Either their threads will fail or the cups
>> will break off at the BB face. That's why I say, I have no easy
>> solution to the bearing problem although the crank attachment seems
>> to be well taken care of. As you see, Shimano realized that
>> bearings need a press fit or they will fret themselves into a loose
>> fit.
>> If these guys would only test their stuff on real riders before
>> going to market, we could be spared the task of field testing at
>> our expense. At least Campagnolo replaced failed parts in the days
>> of Tullio.
> I think you may have missed the significance of what I posted.
> The bearing designs I linked to are not 'external'. They use a new
> 'standard' ~80mm wide (and some unspecified diameter) bottom bracket
> shell that places the bearings in the same place as they would be on
> a traditional 68mm bottom bracket with external cups.
> Please look at the pictures:
http://preview.tinyurl.com/39bhjj
http://preview.tinyurl.com/3453m9
http://preview.tinyurl.com/yujcqm
http://preview.tinyurl.com/2zmeou
I don't know why these guys cannot show a cross section drawing
including all parts. These photos do not show how the parts fit and
the 3D model from TREK glosses over the essentials. I don't see how
one inserts and removes the "press fit" Shimano bearings or even what
they are. Just relying on seal lips on a BB bearing doesn't insure
exclusion of water either.
As I mentioned, "The seal that doesn't leak, leaks." That is, for a
seal lip to work, it must weep and that means slight leakage. Without
that the lip goes dry and fries, making it no longer a seal. By this
rule, no to fluids can be separated by a single seal lip. There must
be one for each fluid and if the outer one is wet only rarely, it is
running dry most of the time.
That is why automotive wheel bearing and drive shaft seals keep the
lubricant in and a labyrinth seal keeps the water off the seals.
> Haven't the canting loads been greatly reduced -- the loads now
> being borne radially by the wider BB shell?. I wonder if the
> composite retainer Shimano are using is a safeguard against
> creaking?
I don't understand how that bearing works and how it is installed.
> Whilst the distance between the pedal attachments remain as always,
> we now have a system where the bearings are of significantly greater
> diameter and situated as close to the arms as practicable.
> Furthermore, we no longer need specialist, shop tools to fit/ remove
> them.
That's fine but how is the bearing retained in the BB? That is a
difficult interface and I didn't see how it is done.
> It looks like this design is an improvement to the square taper on
> every front.
The square taper is a crank to spindle problem that the current
Shimano design solved, but the bearings and how they are held is
unclear to me so I cannot comment.
> Now if a company with real bearing knowledge -- like SKF -- could
> produce compatible bearings with 'automotive grade' seals (no
> 'aerospace' tech needed!) we might get the fit and forget BB that
> should have existed 20 years ago. The bottom bracket must be the
> single greatest cause of irritating squeaks and creaks on the modern
> bicycle.
It isn't a bearing problem. We have had adequate bearings for a long
time. It is a challenge of assembly, stresses between bearing races
and spindle and housing, and sealing. None of these require SKF but
rather someone with understanding of the problems specific to bicycle
BB's.
http://www.skf.com/portal/skf/home/industries?contentId=517237&lang=en
http://www.skf.com/portal/skf/home/industries?contentId=517236&lang=en
http://www.skf.com/cmimages/190967.jpg
http://www.skf.com/portal/skf/home/industries?contentId=517230&lang=en
10yr guarantee speaks volumes, as, unfortunately does the price...
The stress picture of the ISIS spindle missed a point. There is a
notch at the shoulder of this spindle that has caused failures and
high stress in that notch does not show on their diagram. The ISIS
spindle has a taper spine that presents unfavorable stress gradients
over its length. It is not easily formed on the steel spindle and has
cumbersome installation of the cranks in contrast to the Shimano
pinch-bolt attachment.
In addition, SKF claims that rollers are better, missing the point
that bicycle BB's have such high stress that flexing is a concern and
that rollers work only where parts run concentric and parallel. In
automotive use, ball bearings are used in places where, in theory,
rollers would be able to do better, but because rollers do not work
with elastic skewing, balls are used. For this reason rollers are
ever so slightly barrel shaped to accommodate slight skewing, but that
isn't enough for BB's.
As I said, durable BB design is not simple and most designs that have
been offered have feet of clay.
Jobst Brandt
|
| | | |
Date: 08 Sep 2007 13:13:16
From: A Muzi
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
jobst.brandt@stanfordalumni.org wrote:
> Thomas Hood writes:
>
>>>> I'm surprised no-one has mentioned that 2008 will see the external
>>>> bearing start to disappear.
>
>>> Shimano: http://preview.tinyurl.com/yth9j3
>>> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>
>>>> The difference between the two systems is that the Trek 'drops' a
>>>> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
>>>> surprised if special tools were actually _needed_ to fit remove
>>>> the Shimano effort though. I wonder what seals -- if any --
>>>> either system use.
>
>>> As I mentioned when the Shimano design was first shown, an aluminum
>>> outboard bearing cup is too weak to withstand fretting damage in
>>> its threads and keep a solid hold to the BB. One of my riding pals
>>> has one of these and it creaks with standing hill climbing... as
>>> expected. I came to my assessment because steel internal cups with
>>> English threading fret enough to erode BB threads to zero, the BB
>>> being softer steel than the right bearing cup.
>
>>> If internal steel cups experience failure, external aluminum cups
>>> cannot be reliable. Either their threads will fail or the cups
>>> will break off at the BB face. That's why I say, I have no easy
>>> solution to the bearing problem although the crank attachment seems
>>> to be well taken care of. As you see, Shimano realized that
>>> bearings need a press fit or they will fret themselves into a loose
>>> fit.
>
>>> If these guys would only test their stuff on real riders before
>>> going to market, we could be spared the task of field testing at
>>> our expense. At least Campagnolo replaced failed parts in the days
>>> of Tullio.
>
>> I think you may have missed the significance of what I posted.
>
>> The bearing designs I linked to are not 'external'. They use a new
>> 'standard' ~80mm wide (and some unspecified diameter) bottom bracket
>> shell that places the bearings in the same place as they would be on
>> a traditional 68mm bottom bracket with external cups.
>
>> Please look at the pictures:
>
> http://preview.tinyurl.com/39bhjj
> http://preview.tinyurl.com/3453m9
> http://preview.tinyurl.com/yujcqm
> http://preview.tinyurl.com/2zmeou
>
> I don't know why these guys cannot show a cross section drawing
> including all parts. These photos do not show how the parts fit and
> the 3D model from TREK glosses over the essentials. I don't see how
> one inserts and removes the "press fit" Shimano bearings or even what
> they are. Just relying on seal lips on a BB bearing doesn't insure
> exclusion of water either.
>
> As I mentioned, "The seal that doesn't leak, leaks." That is, for a
> seal lip to work, it must weep and that means slight leakage. Without
> that the lip goes dry and fries, making it no longer a seal. By this
> rule, no to fluids can be separated by a single seal lip. There must
> be one for each fluid and if the outer one is wet only rarely, it is
> running dry most of the time.
>
> That is why automotive wheel bearing and drive shaft seals keep the
> lubricant in and a labyrinth seal keeps the water off the seals.
>
>> Haven't the canting loads been greatly reduced -- the loads now
>> being borne radially by the wider BB shell?. I wonder if the
>> composite retainer Shimano are using is a safeguard against
>> creaking?
>
> I don't understand how that bearing works and how it is installed.
>
>> Whilst the distance between the pedal attachments remain as always,
>> we now have a system where the bearings are of significantly greater
>> diameter and situated as close to the arms as practicable.
>> Furthermore, we no longer need specialist, shop tools to fit/ remove
>> them.
>
> That's fine but how is the bearing retained in the BB? That is a
> difficult interface and I didn't see how it is done.
>
>> It looks like this design is an improvement to the square taper on
>> every front.
>
> The square taper is a crank to spindle problem that the current
> Shimano design solved, but the bearings and how they are held is
> unclear to me so I cannot comment.
>
>> Now if a company with real bearing knowledge -- like SKF -- could
>> produce compatible bearings with 'automotive grade' seals (no
>> 'aerospace' tech needed!) we might get the fit and forget BB that
>> should have existed 20 years ago. The bottom bracket must be the
>> single greatest cause of irritating squeaks and creaks on the modern
>> bicycle.
>
> It isn't a bearing problem. We have had adequate bearings for a long
> time. It is a challenge of assembly, stresses between bearing races
> and spindle and housing, and sealing. None of these require SKF but
> rather someone with understanding of the problems specific to bicycle
> BB's.
>
> http://www.skf.com/portal/skf/home/industries?contentId=517237&lang=en
> http://www.skf.com/portal/skf/home/industries?contentId=517236&lang=en
> http://www.skf.com/cmimages/190967.jpg
> http://www.skf.com/portal/skf/home/industries?contentId=517230&lang=en
> 10yr guarantee speaks volumes, as, unfortunately does the price...
>
> The stress picture of the ISIS spindle missed a point. There is a
> notch at the shoulder of this spindle that has caused failures and
> high stress in that notch does not show on their diagram. The ISIS
> spindle has a taper spine that presents unfavorable stress gradients
> over its length. It is not easily formed on the steel spindle and has
> cumbersome installation of the cranks in contrast to the Shimano
> pinch-bolt attachment.
>
> In addition, SKF claims that rollers are better, missing the point
> that bicycle BB's have such high stress that flexing is a concern and
> that rollers work only where parts run concentric and parallel. In
> automotive use, ball bearings are used in places where, in theory,
> rollers would be able to do better, but because rollers do not work
> with elastic skewing, balls are used. For this reason rollers are
> ever so slightly barrel shaped to accommodate slight skewing, but that
> isn't enough for BB's.
>
> As I said, durable BB design is not simple and most designs that have
> been offered have feet of clay.
Yes, we remember the Stronglight 63 double-needle bearing BB with its
own unique failures. Balls on curved races are more tolerant of the
inherent misalignments.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 08 Sep 2007 09:01:23
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
jobst.brandt@stanfordalumni.org wrote:
> Thomas Hood writes:
>
>>>> I'm surprised no-one has mentioned that 2008 will see the external
>>>> bearing start to disappear.
>
>>> Shimano: http://preview.tinyurl.com/yth9j3
>>> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>
>>>> The difference between the two systems is that the Trek 'drops' a
>>>> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
>>>> surprised if special tools were actually _needed_ to fit remove
>>>> the Shimano effort though. I wonder what seals -- if any --
>>>> either system use.
>
>>> As I mentioned when the Shimano design was first shown, an aluminum
>>> outboard bearing cup is too weak to withstand fretting damage in
>>> its threads and keep a solid hold to the BB. One of my riding pals
>>> has one of these and it creaks with standing hill climbing... as
>>> expected. I came to my assessment because steel internal cups with
>>> English threading fret enough to erode BB threads to zero, the BB
>>> being softer steel than the right bearing cup.
>
>>> If internal steel cups experience failure, external aluminum cups
>>> cannot be reliable. Either their threads will fail or the cups
>>> will break off at the BB face. That's why I say, I have no easy
>>> solution to the bearing problem although the crank attachment seems
>>> to be well taken care of. As you see, Shimano realized that
>>> bearings need a press fit or they will fret themselves into a loose
>>> fit.
>
>>> If these guys would only test their stuff on real riders before
>>> going to market, we could be spared the task of field testing at
>>> our expense. At least Campagnolo replaced failed parts in the days
>>> of Tullio.
>
>> I think you may have missed the significance of what I posted.
>
>> The bearing designs I linked to are not 'external'. They use a new
>> 'standard' ~80mm wide (and some unspecified diameter) bottom bracket
>> shell that places the bearings in the same place as they would be on
>> a traditional 68mm bottom bracket with external cups.
>
>> Please look at the pictures:
>
> http://preview.tinyurl.com/39bhjj
> http://preview.tinyurl.com/3453m9
> http://preview.tinyurl.com/yujcqm
> http://preview.tinyurl.com/2zmeou
>
> I don't know why these guys cannot show a cross section drawing
> including all parts. These photos do not show how the parts fit and
> the 3D model from TREK glosses over the essentials. I don't see how
> one inserts and removes the "press fit" Shimano bearings or even what
> they are. Just relying on seal lips on a BB bearing doesn't insure
> exclusion of water either.
>
> As I mentioned, "The seal that doesn't leak, leaks." That is, for a
> seal lip to work, it must weep and that means slight leakage. Without
> that the lip goes dry and fries, making it no longer a seal. By this
> rule, no to fluids can be separated by a single seal lip. There must
> be one for each fluid and if the outer one is wet only rarely, it is
> running dry most of the time.
>
> That is why automotive wheel bearing and drive shaft seals keep the
> lubricant in and a labyrinth seal keeps the water off the seals.
>
>> Haven't the canting loads been greatly reduced -- the loads now
>> being borne radially by the wider BB shell?. I wonder if the
>> composite retainer Shimano are using is a safeguard against
>> creaking?
>
> I don't understand how that bearing works and how it is installed.
>
>> Whilst the distance between the pedal attachments remain as always,
>> we now have a system where the bearings are of significantly greater
>> diameter and situated as close to the arms as practicable.
>> Furthermore, we no longer need specialist, shop tools to fit/ remove
>> them.
>
> That's fine but how is the bearing retained in the BB? That is a
> difficult interface and I didn't see how it is done.
>
>> It looks like this design is an improvement to the square taper on
>> every front.
>
> The square taper is a crank to spindle problem that the current
> Shimano design solved, but the bearings and how they are held is
> unclear to me so I cannot comment.
>
>> Now if a company with real bearing knowledge -- like SKF -- could
>> produce compatible bearings with 'automotive grade' seals (no
>> 'aerospace' tech needed!) we might get the fit and forget BB that
>> should have existed 20 years ago. The bottom bracket must be the
>> single greatest cause of irritating squeaks and creaks on the modern
>> bicycle.
>
> It isn't a bearing problem. We have had adequate bearings for a long
> time. It is a challenge of assembly, stresses between bearing races
> and spindle and housing, and sealing. None of these require SKF but
> rather someone with understanding of the problems specific to bicycle
> BB's.
>
> http://www.skf.com/portal/skf/home/industries?contentId=517237&lang=en
> http://www.skf.com/portal/skf/home/industries?contentId=517236&lang=en
> http://www.skf.com/cmimages/190967.jpg
> http://www.skf.com/portal/skf/home/industries?contentId=517230&lang=en
> 10yr guarantee speaks volumes, as, unfortunately does the price...
>
> The stress picture of the ISIS spindle missed a point. There is a
> notch at the shoulder of this spindle that has caused failures and
> high stress in that notch does not show on their diagram. The ISIS
> spindle has a taper spine that presents unfavorable stress gradients
> over its length. It is not easily formed on the steel spindle and has
> cumbersome installation of the cranks in contrast to the Shimano
> pinch-bolt attachment.
>
> In addition, SKF claims that rollers are better, missing the point
the great jobst brand knows more about bearings than skf!!! classic.
> that bicycle BB's have such high stress that flexing is a concern and
> that rollers work only where parts run concentric and parallel. In
> automotive use, ball bearings are used in places where, in theory,
> rollers would be able to do better, but because rollers do not work
> with elastic skewing, balls are used. For this reason rollers are
> ever so slightly barrel shaped to accommodate slight skewing, but that
> isn't enough for BB's.
>
> As I said, durable BB design is not simple and most designs that have
> been offered have feet of clay.
>
> Jobst Brandt
|
| | | | |
Date: 08 Sep 2007 13:22:03
From: A Muzi
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
> jobst.brandt@stanfordalumni.org wrote:
>> In addition, SKF claims that rollers are better, missing the point
jim beam wrote:
> the great jobst brand knows more about bearings than skf!!! classic.
Perhaps SKF has not given these specific problems as much attention. All
of SKF's bicycle related revenues are likely smaller than SKF's
over/short rounding.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | |
Date: 09 Sep 2007 06:43:34
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
A Muzi wrote:
>> jobst.brandt@stanfordalumni.org wrote:
>>> In addition, SKF claims that rollers are better, missing the point
>
> jim beam wrote:
>> the great jobst brand knows more about bearings than skf!!! classic.
>
> Perhaps SKF has not given these specific problems as much attention.
have you ever read any of their tech lit? those guys are so freakin'
anal and pedantic about getting everything "just so", i doubt they take
a pee without calculating flow trajectory.
> All
> of SKF's bicycle related revenues are likely smaller than SKF's
> over/short rounding.
|
| | | | |
Date: 08 Sep 2007 13:46:09
From: Jambo
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
> the great jobst brand knows more about bearings than skf!!! classic.
More than you'll know, that's for sure.
|
| | | | | |
Date: 08 Sep 2007 11:04:22
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Jambo wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:Bp-dndT6xffOWn_bnZ2dnUVZ_hadnZ2d@speakeasy.net...
>> the great jobst brand knows more about bearings than skf!!! classic.
>
> More than you'll know, that's for sure.
>
>
so that's why he thinks bike bearings are elasto-hydrodynamically separated?
you need to get your facts straight kiddo.
|
| |
Date: 07 Sep 2007 21:14:44
From: Thomas Hood
Subject: Shimano Press fit bottom-brackets, was Question About Cranks
|
On Sep 5, 4:34 am, jobst.bra...@stanfordalumni.org wrote:
> Jay Beattie writes:
> > I didn't look at the advertising material, but I think that one
> > problem Campagnolo was trying to solve has to do with the loose fit
> > between the inner bearing races and the spindle on Shimano cranks
> > which, according to some, causes wear on the spindle. Campagnolo has
> > bearings that are press fit on to the spindle. I have an Ultegra
> > that seems to be doing fine so far.
>
> As I have mentioned in earlier discussion about BB design, it's a huge
> can of worms and I don't see an easy solution to the bearing problem
> although I believe the crank attachment that Shimano has is a clean
> one that should work reliably. Their outboard bearing can't be good
> considering that inboard cups have failed on the right side from
> fretting, fretting that has a red flag on it because it requires a
> left hand thread, the best indicator of micro-motion.
>
> The point you mention is another headache for which I see no solution
> with the present design. This is such a high load interface that a
> slip fit bearing has got to fret and leave rouge traces from wear. I
> haven't worked with this BB but just looking at it at InterBike gave
> me reason to stay clear of it, considering how many cranks and
> spindles have withered under my feet.
>
> We'll have to wait and see.
>
> Jobst Brandt
I'm surprised no-one has mentioned that 2008 will see the external
bearing start to disappear.
Shimano: http://preview.tinyurl.com/yth9j3
Trek: http://www.trekbikes.com/madone/technology/efficiency/
The differernce between the two systems is that the Trek 'drops' a
bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
surprised if special tools were actually _needed_ to fit remove the
Shimano effort though. I wonder what seals -- if any -- either system
use.
Thomas Hood
|
| | |
Date: 07 Sep 2007 23:14:27
From:
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Thomas Hood writes:
>>> I didn't look at the advertising material, but I think that one
>>> problem Campagnolo was trying to solve has to do with the loose
>>> fit between the inner bearing races and the spindle on Shimano
>>> cranks which, according to some, causes wear on the spindle.
>>> Campagnolo has bearings that are press fit on to the spindle. I
>>> have an Ultegra that seems to be doing fine so far.
But are you goofy footed?
>> As I have mentioned in earlier discussion about BB design, it's a huge
>> can of worms and I don't see an easy solution to the bearing problem
>> although I believe the crank attachment that Shimano has is a clean
>> one that should work reliably. Their outboard bearing can't be good
>> considering that inboard cups have failed on the right side from
>> fretting, fretting that has a red flag on it because it requires a
>> left hand thread, the best indicator of micro-motion.
>> The point you mention is another headache for which I see no solution
>> with the present design. This is such a high load interface that a
>> slip fit bearing has got to fret and leave rouge traces from wear. I
>> haven't worked with this BB but just looking at it at InterBike gave
>> me reason to stay clear of it, considering how many cranks and
>> spindles have withered under my feet.
>> We'll have to wait and see.
> I'm surprised no-one has mentioned that 2008 will see the external
> bearing start to disappear.
Shimano: http://preview.tinyurl.com/yth9j3
Trek: http://www.trekbikes.com/madone/technology/efficiency/
> The difference between the two systems is that the Trek 'drops' a
> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
> surprised if special tools were actually _needed_ to fit remove the
> Shimano effort though. I wonder what seals -- if any -- either
> system use.
As I mentioned when the Shimano design was first shown, an aluminum
outboard bearing cup is too weak to withstand fretting damage in its
threads and keep a solid hold to the BB. One of my riding pals has
one of these and it creaks with standing hill climbing... as expected.
I came to my assessment because steel internal cups with English
threading fret enough to erode BB threads to zero, the BB being softer
steel than the right bearing cup.
If internal steel cups experience failure, external aluminum cups
cannot be reliable. Either their threads will fail or the cups will
break off at the BB face. That's why I say, I have no easy solution
to the bearing problem although the crank attachment seems to be well
taken care of. As you see, Shimano realized that bearings need a
press fit or they will fret themselves into a loose fit.
If these guys would only test their stuff on real riders before going
to market, we could be spared the task of field testing at our
expense. At least Campagnolo replaced failed parts in the days of
Tullio.
Jobst Brandt
|
| | | |
Date: 10 Sep 2007 10:36:22
From: Larry Dickman
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
In article <46e1db53$0$14090$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> As I mentioned when the Shimano design was first shown, an aluminum
> outboard bearing cup is too weak to withstand fretting damage in its
> threads and keep a solid hold to the BB. One of my riding pals has
> one of these and it creaks with standing hill climbing... as expected.
> I came to my assessment because steel internal cups with English
> threading fret enough to erode BB threads to zero, the BB being softer
> steel than the right bearing cup.
So what happens? You have to replace the aluminum cups after so many
years. Being softer than the steel bottom bracket shell threads, they
get sacrificed and save the steel threads, correct? As for creaking,
anti-seize compound and/or teflon tape ought to correct that, at least
I've not experienced any creaking in the three years I've had my bike
with external bearing cranks.
|
| | | | |
Date: 10 Sep 2007 19:08:47
From:
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
Larry Dickman writes:
>> As I mentioned when the Shimano design was first shown, an aluminum
>> outboard bearing cup is too weak to withstand fretting damage in
>> its threads and keep a solid hold to the BB. One of my riding pals
>> has one of these and it creaks with standing hill climbing... as
>> expected. I came to my assessment because steel internal cups with
>> English threading fret enough to erode BB threads to zero, the BB
>> being softer steel than the right bearing cup.
> So what happens? You have to replace the aluminum cups after so
> many years. Being softer than the steel bottom bracket shell
> threads, they get sacrificed and save the steel threads, correct? As
> for creaking, anti-seize compound and/or teflon tape ought to
> correct that, at least I've not experienced any creaking in the
> three years I've had my bike with external bearing cranks.
Neither anti-seize or Teflon tape will arrest bearing cup motion, both
being lubricants. I think you are tossing out bad advice to those who
are having problems. The advice suggests the problem is with the
observer, rather than the design.
Because you have not experienced problems with your BB is no proof
that it does not occur, whereas the occurrences are evidence that the
design can and does fail to work properly. Your reply is similar to
people who don't believe clinchers can be blown off rims by brake
heating because they never had it happened. Even though most people
on wreck.bike have not had such an experience, those that have are not
imagining it.
Jobst Brandt
|
| | | | | |
Date: 10 Sep 2007 16:46:09
From: Larry Dickman
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
In article <46e5963f$0$14095$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> Larry Dickman writes:
>
> >> As I mentioned when the Shimano design was first shown, an aluminum
> >> outboard bearing cup is too weak to withstand fretting damage in
> >> its threads and keep a solid hold to the BB. One of my riding pals
> >> has one of these and it creaks with standing hill climbing... as
> >> expected. I came to my assessment because steel internal cups with
> >> English threading fret enough to erode BB threads to zero, the BB
> >> being softer steel than the right bearing cup.
>
> > So what happens? You have to replace the aluminum cups after so
> > many years. Being softer than the steel bottom bracket shell
> > threads, they get sacrificed and save the steel threads, correct? As
> > for creaking, anti-seize compound and/or teflon tape ought to
> > correct that, at least I've not experienced any creaking in the
> > three years I've had my bike with external bearing cranks.
>
> Neither anti-seize or Teflon tape will arrest bearing cup motion, both
> being lubricants. I think you are tossing out bad advice to those who
> are having problems. The advice suggests the problem is with the
> observer, rather than the design.
My point was that anti-seize or Teflon tape will alleviate the creaking.
Frankly, I think that is good advice and you should have told that to
your riding buddy instead of having to listen to that cacophony when
riding along side of him.
Bottom brackets are a wear item and eventually need to be replaced. You
seem to chasing the Holy Grail of a component that never wears out or
fails. Basically, there is no economic incentive for a component
manufacturer to produce an item that lasts forever unless there is a
safety consideration or they can sell the product with a huge markup
like Chris Bling.
|
| | | |
Date: 07 Sep 2007 18:21:38
From: jim beam
Subject: Re: Shimano Press fit bottom-brackets, was Question About Cranks
|
jobst.brandt@stanfordalumni.org wrote:
> Thomas Hood writes:
>
>>>> I didn't look at the advertising material, but I think that one
>>>> problem Campagnolo was trying to solve has to do with the loose
>>>> fit between the inner bearing races and the spindle on Shimano
>>>> cranks which, according to some, causes wear on the spindle.
>>>> Campagnolo has bearings that are press fit on to the spindle. I
>>>> have an Ultegra that seems to be doing fine so far.
>
> But are you goofy footed?
>
>>> As I have mentioned in earlier discussion about BB design, it's a huge
>>> can of worms and I don't see an easy solution to the bearing problem
>>> although I believe the crank attachment that Shimano has is a clean
>>> one that should work reliably. Their outboard bearing can't be good
>>> considering that inboard cups have failed on the right side from
>>> fretting, fretting that has a red flag on it because it requires a
>>> left hand thread, the best indicator of micro-motion.
>
>>> The point you mention is another headache for which I see no solution
>>> with the present design. This is such a high load interface that a
>>> slip fit bearing has got to fret and leave rouge traces from wear. I
>>> haven't worked with this BB but just looking at it at InterBike gave
>>> me reason to stay clear of it, considering how many cranks and
>>> spindles have withered under my feet.
>
>>> We'll have to wait and see.
>
>> I'm surprised no-one has mentioned that 2008 will see the external
>> bearing start to disappear.
>
> Shimano: http://preview.tinyurl.com/yth9j3
> Trek: http://www.trekbikes.com/madone/technology/efficiency/
>
>> The difference between the two systems is that the Trek 'drops' a
>> bare bearing in, whereas the Shimano needs a 'press fit'. I'd be
>> surprised if special tools were actually _needed_ to fit remove the
>> Shimano effort though. I wonder what seals -- if any -- either
>> system use.
>
> As I mentioned when the Shimano design was first shown, an aluminum
> outboard bearing cup is too weak to withstand fretting damage in its
> threads and keep a solid hold to the BB. One of my riding pals has
> one of these and it creaks with standing hill climbing... as expected.
> I came to my assessment because steel internal cups with English
> threading fret enough to erode BB threads to zero, the BB being softer
> steel than the right bearing cup.
>
> If internal steel cups experience failure, external aluminum cups
> cannot be reliable. Either their threads will fail or the cups will
> break off at the BB face. That's why I say, I have no easy solution
> to the bearing problem although the crank attachment seems to be well
> taken care of. As you see, Shimano realized that bearings need a
> press fit or they will fret themselves into a loose fit.
>
> If these guys would only test their stuff on real riders before going
> to market, we could be spared the task of field testing at our
> expense. At least Campagnolo replaced failed parts in the days of
> Tullio.
>
fud.
|
| |
Date: 05 Sep 2007 22:18:54
From: velodancer
Subject: Re: Question About Cranks
|
On Sep 5, 11:07 am, Chalo <chalo.col...@gmail.com > wrote:
> Ryan Cousineau wrote:
>
> > JeffWills wrote:
>
> > > Sheldon Brown wrote:
>
> > > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > > now most of the major crank manufacturers have followed suit.
>
> > > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > > two-piece cranks somewhere around the Cretaceous era:
> > >http://www.bikepro.com/products/cranks/bullseye.html
>
> > I think external bearings may have been what Sheldon was referring to,
> > along with the application to road bikes and MTBs.
>
> Magic Motorcycle made their cranks with big-tube spindles and external
> bearings a long time ago (early '90s?). http://patineto.smugmug.com/photos/53289989-O.jpg
>
> I made an external bearing BB for my own bike in 1999:http://picasaweb.google.com/chalo.colina/RedBike/photo#51067828464183...
>
> Shimano not only used the patented Bullseye design for their cranks,
> but they waited a long time to let Roger Durham's patent expire while
> producing a variety of inferior, sometimes defective alternatives.
> Saying Shimano pioneered any part of the Hollowtech II system is
> giving them far too much credit, and is unfair to real innovators in
> the business.
>
> Chalo
Bulleye pioneered tubular steel tig welded cranks. Magic Motorcycle
pioneered glued aluminum CNC'd clamshells. Shimano's innovation was
forged U shaped cranks (similar to many others) but with an aluminum
plate welded on teh backside to close the U. Thus hollow forged welded
cranks and I think that was a true first in production. The only
innovation they all shared/copied is the integrated spindle.
|
| | |
Date: 06 Sep 2007 06:04:27
From: jim beam
Subject: Re: Question About Cranks
|
velodancer wrote:
> On Sep 5, 11:07 am, Chalo <chalo.col...@gmail.com> wrote:
>> Ryan Cousineau wrote:
>>
>>> JeffWills wrote:
>>>> Sheldon Brown wrote:
>>>>> Shimano pioneered this style, with their "Hollowtech II" system, but
>>>>> now most of the major crank manufacturers have followed suit.
>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye created
>>>> two-piece cranks somewhere around the Cretaceous era:
>>>> http://www.bikepro.com/products/cranks/bullseye.html
>>> I think external bearings may have been what Sheldon was referring to,
>>> along with the application to road bikes and MTBs.
>> Magic Motorcycle made their cranks with big-tube spindles and external
>> bearings a long time ago (early '90s?). http://patineto.smugmug.com/photos/53289989-O.jpg
>>
>> I made an external bearing BB for my own bike in 1999:http://picasaweb.google.com/chalo.colina/RedBike/photo#51067828464183...
>>
>> Shimano not only used the patented Bullseye design for their cranks,
>> but they waited a long time to let Roger Durham's patent expire while
>> producing a variety of inferior, sometimes defective alternatives.
>> Saying Shimano pioneered any part of the Hollowtech II system is
>> giving them far too much credit, and is unfair to real innovators in
>> the business.
>>
>> Chalo
>
>
> Bulleye pioneered tubular steel tig welded cranks. Magic Motorcycle
> pioneered glued aluminum CNC'd clamshells. Shimano's innovation was
> forged U shaped cranks (similar to many others) but with an aluminum
> plate welded on teh backside to close the U.
i don't agree that that is the fabrication route. shimano may have a
protective patent on that fab route for legal purposes, but that doesn't
mean they actually use it. and the ones i saw at a shop in berkeley, ca
contradict that fab route too. they had 3 different crank blanks
showing stages of fabrication:
1. solid flat - wide in the middle.
2. bent around
3. cold pressure "welded" closed.
but the most compelling argument against is that the most fatigue
resistant aluminum fabrication route is cold forging - fusion welding
destroys the microstructure that the cold forging creates. and 2000
series alloys, which shimano say they use on dura-ace for instance, is
/not/ typically weldable.
> Thus hollow forged welded
> cranks and I think that was a true first in production. The only
> innovation they all shared/copied is the integrated spindle.
>
|
| |
Date: 05 Sep 2007 22:18:17
From: velodancer
Subject: Re: Question About Cranks
|
On Sep 5, 11:07 am, Chalo <chalo.col...@gmail.com > wrote:
> Ryan Cousineau wrote:
>
> > JeffWills wrote:
>
> > > Sheldon Brown wrote:
>
> > > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > > now most of the major crank manufacturers have followed suit.
>
> > > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > > two-piece cranks somewhere around the Cretaceous era:
> > >http://www.bikepro.com/products/cranks/bullseye.html
>
> > I think external bearings may have been what Sheldon was referring to,
> > along with the application to road bikes and MTBs.
>
> Magic Motorcycle made their cranks with big-tube spindles and external
> bearings a long time ago (early '90s?). http://patineto.smugmug.com/photos/53289989-O.jpg
>
> I made an external bearing BB for my own bike in 1999:http://picasaweb.google.com/chalo.colina/RedBike/photo#51067828464183...
>
> Shimano not only used the patented Bullseye design for their cranks,
> but they waited a long time to let Roger Durham's patent expire while
> producing a variety of inferior, sometimes defective alternatives.
> Saying Shimano pioneered any part of the Hollowtech II system is
> giving them far too much credit, and is unfair to real innovators in
> the business.
>
> Chalo
Bulleye pioneered tubular steel tig welded cranks. Magic Motorcycle
pioneered glued aluminum CNC'd clamshells. Shimano's innovation was
forged U shaped cranks (similar to many others) but with an aluminum
plate welded on teh backside to close the U. Thus hollow forged welded
cranks and I think that was a true first in production. The only
innovation they all shared is the integrated spindle.
|
| |
Date: 05 Sep 2007 20:09:45
From: Hank Wirtz
Subject: Re: Question About Cranks
|
On Sep 5, 8:05 pm, Ryan Cousineau <rcous...@sfu.ca > wrote:
> In article <46df2ab2$0$14088$742ec...@news.sonic.net>,
> Those rings are the only purely orphan part I can think of. I had
> falsely assumed that XTR was the only group that used the Dual-Control
> system (basically, shifting is incorporated into the brake lever; this
> is more weird on an MTB than on a road bike), but that has trickled down
> two groups to Deore LX and XT.
Three. Deore got them this year. I think these are gonna go the way of
Biopace rings: some people love them, most don't, so they're gonna go
away after this last push.
|
| |
Date: 05 Sep 2007 19:46:25
From: Hank Wirtz
Subject: Re: Question About Cranks
|
On Sep 5, 2:50 pm, A Muzi <a...@yellowjersey.org > wrote:
> > "russellseat...@yahoo.com" <russellseat...@yahoo.com> wrote:
> >> Not paying to use a patent and thus not making a product is a Shimano
> >> trait.
> Hank Wirtz wrote:
> > Frank Berto talks about this in The Dancing Chain, how SIS's
> > introduction coincided with and was dependent upon the expiration of
> > Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
> > geometry with dual pivot springs to maintain constant jockey pulley
> > distance. That enabled shifting without overshifting, which is
> > necessary for good indexing.
>
> The first DA SIS, even later New 600EX SIS were not
> slant-parallelogram. But, yes it was a big improvement.
> I think chain snap links make another instance.
> --
> Andrew Muziwww.yellowjersey.org
> Open every day since 1 April, 1971
I have the book open, and the exploded diagram sure looks like a slant
parallelogram; Berto also makes a big deal about what a breakthrough
the RD-7400 was, and how every RD made today is rooted in its design.
I'm gonna side with Berto, here.
|
| | |
Date: 05 Sep 2007 21:56:56
From: A Muzi
Subject: Re: Question About Cranks
|
>>> "russellseat...@yahoo.com" <russellseat...@yahoo.com> wrote:
>>>> Not paying to use a patent and thus not making a product is a Shimano
>>>> trait.
>> Hank Wirtz wrote:
>>> Frank Berto talks about this in The Dancing Chain, how SIS's
>>> introduction coincided with and was dependent upon the expiration of
>>> Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
>>> geometry with dual pivot springs to maintain constant jockey pulley
>>> distance. That enabled shifting without overshifting, which is
>>> necessary for good indexing.
> A Muzi <a...@yellowjersey.org> erred:
>> The first DA SIS, even later New 600EX SIS were not
>> slant-parallelogram. But, yes it was a big improvement.
>> I think chain snap links make another instance.
Hank Wirtz wrote:
> I have the book open, and the exploded diagram sure looks like a slant
> parallelogram; Berto also makes a big deal about what a breakthrough
> the RD-7400 was, and how every RD made today is rooted in its design.
> I'm gonna side with Berto, here.
mea culpa, I was in the 1983 book and you're right.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 05 Sep 2007 18:10:00
From: Ozark Bicycle
Subject: Re: Question About Cranks
|
On Sep 5, 4:50 pm, A Muzi <a...@yellowjersey.org > wrote:
> > "russellseat...@yahoo.com" <russellseat...@yahoo.com> wrote:
> >> Not paying to use a patent and thus not making a product is a Shimano
> >> trait.
> Hank Wirtz wrote:
> > Frank Berto talks about this in The Dancing Chain, how SIS's
> > introduction coincided with and was dependent upon the expiration of
> > Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
> > geometry with dual pivot springs to maintain constant jockey pulley
> > distance. That enabled shifting without overshifting, which is
> > necessary for good indexing.
>
> The first DA SIS, even later New 600EX SIS were not
> slant-parallelogram.
But they *were* slant parallelogram. I had a D-A RD-7400 from '85 to
'90. It was basically identical to the D-A RD-7402 that is still on
one of my bikes.
|
| | |
Date: 05 Sep 2007 21:40:21
From: A Muzi
Subject: Re: Question About Cranks
|
>>> "russellseat...@yahoo.com" <russellseat...@yahoo.com> wrote:
>>>> Not paying to use a patent and thus not making a product is a Shimano
>>>> trait.
>> Hank Wirtz wrote:
>>> Frank Berto talks about this in The Dancing Chain, how SIS's
>>> introduction coincided with and was dependent upon the expiration of
>>> Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
>>> geometry with dual pivot springs to maintain constant jockey pulley
>>> distance. That enabled shifting without overshifting, which is
>>> necessary for good indexing.
> A Muzi <a...@yellowjersey.org> screwed up:
>> The first DA SIS, even later New 600EX SIS were not
>> slant-parallelogram.
Ozark Bicycle wrote:
> But they *were* slant parallelogram. I had a D-A RD-7400 from '85 to
> '90. It was basically identical to the D-A RD-7402 that is still on
> one of my bikes.
I was off a by a year. Earlier I looked at the 1983 New 600 6207 which
like all Shimano rears though 1983 (Deore XT too) are "Servo Pantograph"
not slanted.
I just found the later book. The autumn 1983 for 1984 model year book
shows the first SIS system 7400, as Hank noted, Slant bodied. The New
600 moves to a slant 6208 design along with everything else after that.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 05 Sep 2007 17:52:09
From: Gary Young
Subject: Re: Question About Cranks
|
On Wed, 05 Sep 2007 05:04:40 +0000, Ryan Cousineau wrote:
<snip >
> As if to baffle us all, the latest XTR design uses a non pinch-bolt
> attachment, as most clearly shown in this exploded diagram PDF:
>
> http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC
> /EV-FC-M970-2592_v1_m56577569830608898.pdf
>
> Basically, there's a "crank arm fixing bolt unit" that screws into the
> end of the spindle, along with an "adjust nut" that apparently goes
> between the crank arm and the BB shell, and which itself is held in
> place with a pinch bolt. But note that the adjust nut is threaded
> to...the inside of the left crank arm?!
>
> Deeply worrying installation instructions here:
>
> http://bike.shimano.com/media/techdocs/content/cycle/SI/XTR/FC-M970/15H0A
> _EN_v1_m56577569830600538.PDF
>
> For those of you who aren't MTBers, note that XT has historically
> suffered from some of the same sorts of unique-bits weirdness that
> Dura-Ace occasionally experiences.
>
I'm not sure where I saw this, but one of the sites covering Eurobike said
that Shimano's new carbon-fiber crank is going to use the same setup as
the new XTR.
|
| |
Date: 05 Sep 2007 14:05:39
From: Hank Wirtz
Subject: Re: Question About Cranks
|
On Sep 5, 1:22 pm, "russellseat...@yahoo.com"
<russellseat...@yahoo.com > wrote:
> Not paying to use a patent and thus not making a product is a Shimano
> trait.
Frank Berto talks about this in The Dancing Chain, how SIS's
introduction coincided with and was dependent upon the expiration of
Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
geometry with dual pivot springs to maintain constant jockey pulley
distance. That enabled shifting without overshifting, which is
necessary for good indexing.
|
| | |
Date: 10 Sep 2007 16:22:04
From: Larry Dickman
Subject: Re: Question About Cranks
|
In article <1189026339.071940.235700@d55g2000hsg.googlegroups.com >,
Hank Wirtz <hank@wirtznet.net > wrote:
> On Sep 5, 1:22 pm, "russellseat...@yahoo.com"
> <russellseat...@yahoo.com> wrote:
>
> > Not paying to use a patent and thus not making a product is a Shimano
> > trait.
>
> Frank Berto talks about this in The Dancing Chain, how SIS's
> introduction coincided with and was dependent upon the expiration of
> Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
> geometry with dual pivot springs to maintain constant jockey pulley
> distance. That enabled shifting without overshifting, which is
> necessary for good indexing.
SRAM derailleurs seem to shift just as well without dual pivot springs.
|
| | |
Date: 05 Sep 2007 16:50:13
From: A Muzi
Subject: Re: Question About Cranks
|
> "russellseat...@yahoo.com" <russellseat...@yahoo.com> wrote:
>> Not paying to use a patent and thus not making a product is a Shimano
>> trait.
Hank Wirtz wrote:
> Frank Berto talks about this in The Dancing Chain, how SIS's
> introduction coincided with and was dependent upon the expiration of
> Suntour's patent on Slant-Parallellogram RDs. Shimano combined SP
> geometry with dual pivot springs to maintain constant jockey pulley
> distance. That enabled shifting without overshifting, which is
> necessary for good indexing.
The first DA SIS, even later New 600EX SIS were not
slant-parallelogram. But, yes it was a big improvement.
I think chain snap links make another instance.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 05 Sep 2007 13:22:11
From: russellseaton1@yahoo.com
Subject: Re: Question About Cranks
|
On Sep 5, 1:07 pm, Chalo <chalo.col...@gmail.com > wrote:
> Ryan Cousineau wrote:
>
> > JeffWills wrote:
>
> > > Sheldon Brown wrote:
>
> > > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > > now most of the major crank manufacturers have followed suit.
>
> > > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > > two-piece cranks somewhere around the Cretaceous era:
> > >http://www.bikepro.com/products/cranks/bullseye.html
>
> > I think external bearings may have been what Sheldon was referring to,
> > along with the application to road bikes and MTBs.
>
> Magic Motorcycle made their cranks with big-tube spindles and external
> bearings a long time ago (early '90s?). http://patineto.smugmug.com/photos/53289989-O.jpg
>
> I made an external bearing BB for my own bike in 1999:http://picasaweb.google.com/chalo.colina/RedBike/photo#51067828464183...
>
> Shimano not only used the patented Bullseye design for their cranks,
> but they waited a long time to let Roger Durham's patent expire while
> producing a variety of inferior, sometimes defective alternatives.
Not paying to use a patent and thus not making a product is a Shimano
trait. No Shimano threadless headset. Until the DiaCompe(?) patent
expires. Shimano stopped licensing the Look pedal/cleat patent and
came up with SPD-R for awhile. Until the patent expired and then they
pioneered their SPD-SL Look copy.
I use the SPD-SL pedals and they are very good. I'm a Campagnolo man
but Shimano does make good pedals. Shimano brand SPD or SPD-SL are
the ones I use. The Shimano under bottom bracket cable guide works
well too.
> Saying Shimano pioneered any part of the Hollowtech II system is
> giving them far too much credit, and is unfair to real innovators in
> the business.
>
> Chalo
|
| |
Date: 05 Sep 2007 18:07:30
From: Chalo
Subject: Re: Question About Cranks
|
Ryan Cousineau wrote:
>
> JeffWills wrote:
> >
> > Sheldon Brown wrote:
> > >
> > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > now most of the major crank manufacturers have followed suit.
> >
> > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > two-piece cranks somewhere around the Cretaceous era:
> >http://www.bikepro.com/products/cranks/bullseye.html
>
> I think external bearings may have been what Sheldon was referring to,
> along with the application to road bikes and MTBs.
Magic Motorcycle made their cranks with big-tube spindles and external
bearings a long time ago (early '90s?). http://patineto.smugmug.com/photos/53289989-O.jpg
I made an external bearing BB for my own bike in 1999:
http://picasaweb.google.com/chalo.colina/RedBike/photo#5106782846418368274
Shimano not only used the patented Bullseye design for their cranks,
but they waited a long time to let Roger Durham's patent expire while
producing a variety of inferior, sometimes defective alternatives.
Saying Shimano pioneered any part of the Hollowtech II system is
giving them far too much credit, and is unfair to real innovators in
the business.
Chalo
|
| |
Date: 05 Sep 2007 09:16:25
From: Sheldon Brown
Subject: Re: Question About Cranks
|
On Sep 4, 2:19 pm, zencycle <zency...@bikerider.com > wrote:
> On Sep 3, 11:01 pm, JeffWills <jwi...@pacifier.com> wrote:
>
> > On Sep 3, 10:55 am,Sheldon Brown<CaptB...@sheldonbrown.com> wrote:
>
> > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > now most of the major crank manufacturers have followed suit.
>
> > > Sheldon "Progress" Brown
>
> > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > two-piece cranks somewhere around the Cretaceous era:http://www.bikepro.com/products/cranks/bullseye.html
>
> > Jeff
>
> There was a company making 'Sweet Wings" 15 years ago that did this
> too. As usual, shimano can't come up with an idea of their own.
> although what they make works quite well,
>
> http://pardo.net/pardo/bike/pic/fail/FAIL-006.html
+----------------------------------------------------+
|
| |
Date: 05 Sep 2007 07:12:08
From: Scott Gordo
Subject: Re: Question About Cranks
|
On Sep 3, 11:34 pm, Ryan Cousineau <rcous...@sfu.ca > wrote:
> In article <1188874909.791069.91...@o80g2000hse.googlegroups.com>,
>
> JeffWills <jwi...@pacifier.com> wrote:
> > On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
>
> > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > now most of the major crank manufacturers have followed suit.
>
> > > Sheldon "Progress" Brown
>
> > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > two-piece cranks somewhere around the Cretaceous era:
> >http://www.bikepro.com/products/cranks/bullseye.html
>
> > Jeff
>
> I think external bearings may have been what Sheldon was referring to,
> along with the application to road bikes and MTBs.
>
> That said, there's so much interesting weirdness happening in BMX parts,
> not to mention developments that sometimes seem to be at cross-purposes
> to that happening in road/MTB bikes, that it's worth checking their
> stuff out more often.
>
> For example, the trend in BMX is for the high-end stuff to use "Euro"
> BBs, which is to say bottom brackets based around the smaller, threaded
> MTB/road standards as opposed to the bigger, threadless, traditional BMX
> BB. This is ironic since every trend in road BBs is headed towards
> enlarging the BB one way (external bearings) or another (BB30,
> Overdrive, whatever the Pinarello and Trek standards are...).
>
> (BTW, Norco is currently selling their higher-end BMXs with something
> called "Spanish" BB. What is that?)
>
> For another thing, BMX is a neat source for oddball parts. You can get
> complete left-side drivetrains for those bikes (the practical purpose
> being for riders who prefer to do their grind tricks on the right side),
> which have a few uses in odd projects (one I saw was a guy who used a
> flip-flop hub and a LHD freewheel to run an auxiliary electric motor
> mounted on the rear rack. It was a pretty tidy home-brew).
>
> --
> Ryan Cousineau rcous...@sfu.cahttp://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
I've got a friend who rides the new-school bmx stuff with one of those
small bb shells. The rear freewheel is a different mechanism, allowing
you to run smaller rear sprockets than the old screw-on 16-tooth,
which thereby allows him to run smaller front rings for greater
clearance.
Still not sure I understand why the small bb shell is a benefit
though.
/s
|
| |
Date: 04 Sep 2007 20:01:46
From: Jay Beattie
Subject: Re: Question About Cranks
|
On Sep 4, 7:48 pm, jobst.bra...@stanfordalumni.org wrote:
> Michael Press writes:
> >>>> Shimano pioneered this style, with their "Hollowtech II" system,
> >>>> but now most of the major crank manufacturers have followed suit.
> >>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
> >>> created two-piece cranks somewhere around the Cretaceous era:
> >>>http://www.bikepro.com/products/cranks/bullseye.html
> >> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
> >> splined spindle. The Thun crank system has a spindle integral to
> >> the right crank like DA, a splined spindle like DA, a left slit
> >> crank with pinch bolt like DA, c. 1950s as well.
> > When you think about it the spindle should be integrated with the
> > non-drive sided (left) crank. It is the NDS to spindle attachment
> > that must transmit substantial pedaling torque, while the DS crank
> > attaches itself to the spider, and thence to the chain rings. Hey!
> > Who's in charge here?
>
> If you consider how to attach a spindle to a crank and what torque the
> spindle transmits you probably would do as others have and put pinch
> bolts on the left crank and permanently anchor the spindle in the
> right crank. The Campagnolo method is more complex and expensive. I
> think they ran into patent problems and came up with theirs as a way
> out.
I didn't look at the advertising material, but I think that one
problem Campagnolo was trying to solve has to do with the loose fit
between the inner bearing races and the spindle on Shimano cranks
which, according to some, causes wear on the spindle. Campagnolo has
bearings that are press fit on to the spindle. I have an Ultegra that
seems to be doing fine so far.-- Jay Beattie.
|
| | |
Date: 05 Sep 2007 03:34:42
From:
Subject: Re: Question About Cranks
|
Jay Beattie writes:
>>>>>> Shimano pioneered this style, with their "Hollowtech II"
>>>>>> system, but now most of the major crank manufacturers have
>>>>>> followed suit.
>>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
>>>>> created two-piece cranks somewhere around the Cretaceous era:
http://www.bikepro.com/products/cranks/bullseye.html
>>>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on
>>>> a splined spindle. The Thun crank system has a spindle integral
>>>> to the right crank like DA, a splined spindle like DA, a left
>>>> slit crank with pinch bolt like DA, c. 1950s as well.
>>> When you think about it the spindle should be integrated with the
>>> non-drive sided (left) crank. It is the NDS to spindle attachment
>>> that must transmit substantial pedaling torque, while the DS crank
>>> attaches itself to the spider, and thence to the chain rings.
>>> Hey! Who's in charge here?
>> If you consider how to attach a spindle to a crank and what torque
>> the spindle transmits you probably would do as others have and put
>> pinch bolts on the left crank and permanently anchor the spindle in
>> the right crank. The Campagnolo method is more complex and
>> expensive. I think they ran into patent problems and came up with
>> theirs as a way out.
> I didn't look at the advertising material, but I think that one
> problem Campagnolo was trying to solve has to do with the loose fit
> between the inner bearing races and the spindle on Shimano cranks
> which, according to some, causes wear on the spindle. Campagnolo has
> bearings that are press fit on to the spindle. I have an Ultegra
> that seems to be doing fine so far.
As I have mentioned in earlier discussion about BB design, it's a huge
can of worms and I don't see an easy solution to the bearing problem
although I believe the crank attachment that Shimano has is a clean
one that should work reliably. Their outboard bearing can't be good
considering that inboard cups have failed on the right side from
fretting, fretting that has a red flag on it because it requires a
left hand thread, the best indicator of micro-motion.
The point you mention is another headache for which I see no solution
with the present design. This is such a high load interface that a
slip fit bearing has got to fret and leave rouge traces from wear. I
haven't worked with this BB but just looking at it at InterBike gave
me reason to stay clear of it, considering how many cranks and
spindles have withered under my feet.
We'll have to wait and see.
Jobst Brandt
|
| | | |
Date: 04 Sep 2007 20:56:51
From: jim beam
Subject: Re: Question About Cranks
|
jobst.brandt@stanfordalumni.org wrote:
> Jay Beattie writes:
>
>>>>>>> Shimano pioneered this style, with their "Hollowtech II"
>>>>>>> system, but now most of the major crank manufacturers have
>>>>>>> followed suit.
>
>>>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
>>>>>> created two-piece cranks somewhere around the Cretaceous era:
>
> http://www.bikepro.com/products/cranks/bullseye.html
>
>>>>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on
>>>>> a splined spindle. The Thun crank system has a spindle integral
>>>>> to the right crank like DA, a splined spindle like DA, a left
>>>>> slit crank with pinch bolt like DA, c. 1950s as well.
>
>>>> When you think about it the spindle should be integrated with the
>>>> non-drive sided (left) crank. It is the NDS to spindle attachment
>>>> that must transmit substantial pedaling torque, while the DS crank
>>>> attaches itself to the spider, and thence to the chain rings.
>>>> Hey! Who's in charge here?
>
>>> If you consider how to attach a spindle to a crank and what torque
>>> the spindle transmits you probably would do as others have and put
>>> pinch bolts on the left crank and permanently anchor the spindle in
>>> the right crank. The Campagnolo method is more complex and
>>> expensive. I think they ran into patent problems and came up with
>>> theirs as a way out.
>
>> I didn't look at the advertising material, but I think that one
>> problem Campagnolo was trying to solve has to do with the loose fit
>> between the inner bearing races and the spindle on Shimano cranks
>> which, according to some, causes wear on the spindle. Campagnolo has
>> bearings that are press fit on to the spindle. I have an Ultegra
>> that seems to be doing fine so far.
>
> As I have mentioned in earlier discussion about BB design, it's a huge
> can of worms and I don't see an easy solution to the bearing problem
> although I believe the crank attachment that Shimano has is a clean
> one that should work reliably. Their outboard bearing can't be good
> considering that inboard cups have failed on the right side from
> fretting, fretting that has a red flag on it because it requires a
> left hand thread, the best indicator of micro-motion.
>
> The point you mention is another headache for which I see no solution
> with the present design. This is such a high load interface that a
> slip fit bearing has got to fret and leave rouge traces from wear. I
> haven't worked with this BB but just looking at it at InterBike gave
> me reason to stay clear of it, considering how many cranks and
> spindles have withered under my feet.
eh? how does metal fatigue in 1970's cranks cause fear of 2000's cranks
bearing frettage?
>
> We'll have to wait and see.
yes - it's much easier to criticize something from the comfort of the
sofa than is is to invest time, money and effort into physical testing
from which facts [and therefore valid opinions] could be drawn.
|
| |
Date: 04 Sep 2007 18:19:21
From: zencycle
Subject: Re: Question About Cranks
|
On Sep 3, 11:01 pm, JeffWills <jwi...@pacifier.com > wrote:
> On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
>
>
>
> > Shimano pioneered this style, with their "Hollowtech II" system, but
> > now most of the major crank manufacturers have followed suit.
>
> > Sheldon "Progress" Brown
>
> "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> two-piece cranks somewhere around the Cretaceous era:http://www.bikepro.com/products/cranks/bullseye.html
>
> Jeff
There was a company making 'Sweet Wings" 15 years ago that did this
too. As usual, shimano can't come up with an idea of their own.
although what they make works quite well,
http://pardo.net/pardo/bike/pic/fail/FAIL-006.html
|
| |
Date: 04 Sep 2007 01:31:07
From: Nate Knutson
Subject: Re: Question About Cranks
|
On Sep 3, 8:34 pm, Ryan Cousineau <rcous...@sfu.ca > wrote:
> In article <1188874909.791069.91...@o80g2000hse.googlegroups.com>,
>
> JeffWills <jwi...@pacifier.com> wrote:
> > On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
>
> > > Shimano pioneered this style, with their "Hollowtech II" system, but
> > > now most of the major crank manufacturers have followed suit.
>
> > > Sheldon "Progress" Brown
>
> > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > two-piece cranks somewhere around the Cretaceous era:
> >http://www.bikepro.com/products/cranks/bullseye.html
>
> > Jeff
>
> I think external bearings may have been what Sheldon was referring to,
> along with the application to road bikes and MTBs.
>
> That said, there's so much interesting weirdness happening in BMX parts,
> not to mention developments that sometimes seem to be at cross-purposes
> to that happening in road/MTB bikes, that it's worth checking their
> stuff out more often.
>
> For example, the trend in BMX is for the high-end stuff to use "Euro"
> BBs, which is to say bottom brackets based around the smaller, threaded
> MTB/road standards as opposed to the bigger, threadless, traditional BMX
> BB. This is ironic since every trend in road BBs is headed towards
> enlarging the BB one way (external bearings) or another (BB30,
> Overdrive, whatever the Pinarello and Trek standards are...).
it's not really accurate to say that euro is the trend for high end
bmx. it's been the most common in race bikes for some time now. it's
seriously lost favor to mid and spanish everywhere else. a lot of
people are of the feeling that the bearings are really too small and
not durable enough.
> (BTW, Norco is currently selling their higher-end BMXs with something
> called "Spanish" BB. What is that?)
It is a standard which uses a bearing somewhat larger than what lives
in a euro bb, but smaller than american. The bearing cartridges are
press fit directly into the frame.
Mid works on the same principle but uses larger bearings, either
similar or the same as what would be found in an american sealed bb.
One thing going on right now in BMX that you don't hear much about is
all the mayhem ensuing from the rise of cheapo looseball BBs on lower
end bikes that use these standards. Some of them use proprietary
spindle sizes for which things like replacement sprocket adaptors,
locknuts, and lockwashers are straight up unavailable for. It sucks.
|
| |
Date: 03 Sep 2007 21:15:13
From: JeffWills
Subject: Re: Question About Cranks
|
On Sep 3, 7:34 pm, Ryan Cousineau <rcous...@sfu.ca > wrote:
> For another thing, BMX is a neat source for oddball parts. You can get
> complete left-side drivetrains for those bikes (the practical purpose
> being for riders who prefer to do their grind tricks on the right side),
> which have a few uses in odd projects (one I saw was a guy who used a
> flip-flop hub and a LHD freewheel to run an auxiliary electric motor
> mounted on the rear rack. It was a pretty tidy home-brew).
>
Indeed. If I ever get around to building a FWD recumbent like I keep
threatening to do, I'm going to model the drivetrain around Rob
English's Hachi:
http://www.kingcycle.co.uk/hpvs/Hachi3.html
but with the second chain going down the left side. John Tetz did this
by modifying a freehub:
http://www.recumbents.com/mars/pages/proj/tetz/VFS/projtetzVFS02lefthanddrive.html
but I figure if I can just buy the parts I might as well spend the
money.
Jeff
|
| |
Date: 03 Sep 2007 20:01:49
From: JeffWills
Subject: Re: Question About Cranks
|
On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com > wrote:
>
> Shimano pioneered this style, with their "Hollowtech II" system, but
> now most of the major crank manufacturers have followed suit.
>
> Sheldon "Progress" Brown
"Pioneered"??? Well, maybe the external bearings, but Bullseye created
two-piece cranks somewhere around the Cretaceous era:
http://www.bikepro.com/products/cranks/bullseye.html
Jeff
|
| | |
Date: 04 Sep 2007 02:33:49
From: A Muzi
Subject: Re: Question About Cranks
|
> On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
>> Shimano pioneered this style, with their "Hollowtech II" system, but
>> now most of the major crank manufacturers have followed suit.
>> Sheldon "Progress" Brown
JeffWills wrote:
> "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> two-piece cranks somewhere around the Cretaceous era:
> http://www.bikepro.com/products/cranks/bullseye.html
Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
splined spindle. The Thun crank system has a spindle integral to the
right crank like DA, a splined spindle like DA, a left slit crank with
pinch bolt like DA, c. 1950s as well.
I think Sheldon's choice of 'pioneered' wasn't the best word but his
meaning was otherwise clear.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 04 Sep 2007 15:10:22
From: Michael Press
Subject: Re: Question About Cranks
|
In article <13dq2h7k63oonad@corp.supernews.com >,
A Muzi <am@yellowjersey.org > wrote:
> > On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
> >> Shimano pioneered this style, with their "Hollowtech II" system, but
> >> now most of the major crank manufacturers have followed suit.
> >> Sheldon "Progress" Brown
>
> JeffWills wrote:
> > "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> > two-piece cranks somewhere around the Cretaceous era:
> > http://www.bikepro.com/products/cranks/bullseye.html
>
> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
> splined spindle. The Thun crank system has a spindle integral to the
> right crank like DA, a splined spindle like DA, a left slit crank with
> pinch bolt like DA, c. 1950s as well.
When you think about it the spindle should be integrated
with the non-drive sided (left) crank. It is the NDS to
spindle attachment that must transmit substantial pedaling
torque, while the DS crank attaches itself to the spider,
and thence to the chain rings. Hey! Who's in charge here?
> I think Sheldon's choice of 'pioneered' wasn't the best word but his
> meaning was otherwise clear.
--
Michael Press
|
| | | | |
Date: 05 Sep 2007 02:48:03
From:
Subject: Re: Question About Cranks
|
Michael Press writes:
>>>> Shimano pioneered this style, with their "Hollowtech II" system,
>>>> but now most of the major crank manufacturers have followed suit.
>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
>>> created two-piece cranks somewhere around the Cretaceous era:
>>> http://www.bikepro.com/products/cranks/bullseye.html
>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
>> splined spindle. The Thun crank system has a spindle integral to
>> the right crank like DA, a splined spindle like DA, a left slit
>> crank with pinch bolt like DA, c. 1950s as well.
> When you think about it the spindle should be integrated with the
> non-drive sided (left) crank. It is the NDS to spindle attachment
> that must transmit substantial pedaling torque, while the DS crank
> attaches itself to the spider, and thence to the chain rings. Hey!
> Who's in charge here?
If you consider how to attach a spindle to a crank and what torque the
spindle transmits you probably would do as others have and put pinch
bolts on the left crank and permanently anchor the spindle in the
right crank. The Campagnolo method is more complex and expensive. I
think they ran into patent problems and came up with theirs as a way
out.
You'll note that Shimano uses two pinch bolts, showing that they gave
this some thought and experimentation. I don't see how you propose to
locate such hardware on the right crank, and beyond that for what
reason. All torque that goes through the spindle is transmitted at
both ends equally. The V-shaped spline is used because it lends
itself to no-backlash attachment (something Octalink did not do) if
the mating part is clamped onto it.
>> I think Sheldon's choice of 'pioneered' wasn't the best word but
>> his meaning was otherwise clear.
This attachment was first used by Bullseye but they did it for a
different reason, having steel tubular welded cranks. That wouldn't
work well with the BB's of the day that were mostly square taper type.
I suspect the design was not lost in the memory of Shimano engineers,
because it has features that are ideal for steel tube to aluminum
crank attachment.
On the other hand, that Shimano took so long to recognize the flaw in
Octalink is a mystery to me.
Jobst Brandt
|
| | | | | |
Date: 07 Sep 2007 16:39:06
From: Paul Myron Hobson
Subject: Re: Question About Cranks
|
> Michael Press writes:
>> When you think about it the spindle should be integrated with the
>> non-drive sided (left) crank. It is the NDS to spindle attachment
>> that must transmit substantial pedaling torque, while the DS crank
>> attaches itself to the spider, and thence to the chain rings. Hey!
>> Who's in charge here?
Jobst Brandt wrote:
> If you consider how to attach a spindle to a crank and what torque the
> spindle transmits you probably would do as others have and put pinch
> bolts on the left crank and permanently anchor the spindle in the
> right crank. The Campagnolo method is more complex and expensive. I
> think they ran into patent problems and came up with theirs as a way
> out.
[snip]
Both of y'all should take a look and the new Crank Bros cranks:
Triple: http://tinyurl.com/39fdnf
Single: http://tinyurl.com/34r7jz
I can't quite tell how the non-drive side crank will secure itself on to
the bottom bracket. Should be interesting to see how these perform.
\\paul
|
| | | | | | |
Date: 07 Sep 2007 22:58:03
From:
Subject: Re: Question About Cranks
|
Paul Myron Hobson writes:
>>> When you think about it the spindle should be integrated with the
>>> non-drive sided (left) crank. It is the NDS to spindle attachment
>>> that must transmit substantial pedaling torque, while the DS crank
>>> attaches itself to the spider, and thence to the chain rings. Hey!
>>> Who's in charge here?
>> If you consider how to attach a spindle to a crank and what torque the
>> spindle transmits you probably would do as others have and put pinch
>> bolts on the left crank and permanently anchor the spindle in the
>> right crank. The Campagnolo method is more complex and expensive. I
>> think they ran into patent problems and came up with theirs as a way
>> out.
> Both of y'all should take a look and the new Crank Bros cranks:
Triple: http://tinyurl.com/39fdnf
Single: http://tinyurl.com/34r7jz
> I can't quite tell how the non-drive side crank will secure itself
> on to the bottom bracket. Should be interesting to see how these
> perform.
The single appears to be an ISIS interface, basically a multifaceted
square taper attached with a press fit. Are you sure the spindle is
permanently part of the left crank? I don't see what holds the right
crank on other than an axial ISIS attachment bolt. Other than that I
see nothing new.
Jobst Brandt
|
| | | | | | |
Date: 07 Sep 2007 18:08:46
From: Paul Myron Hobson
Subject: Re: Question About Cranks
|
Paul Myron Hobson wrote:
> I can't quite tell how the non-drive side crank will secure itself on to
xxxxxxxxxxxxxx
durrrrr. that should be *drive side*
|
| | | | | |
Date: 05 Sep 2007 05:04:40
From: Ryan Cousineau
Subject: Re: Question About Cranks
|
In article <46de18e3$0$14128$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> Michael Press writes:
>
> >>>> Shimano pioneered this style, with their "Hollowtech II" system,
> >>>> but now most of the major crank manufacturers have followed suit.
>
> >>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
> >>> created two-piece cranks somewhere around the Cretaceous era:
> >>> http://www.bikepro.com/products/cranks/bullseye.html
>
> >> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
> >> splined spindle. The Thun crank system has a spindle integral to
> >> the right crank like DA, a splined spindle like DA, a left slit
> >> crank with pinch bolt like DA, c. 1950s as well.
>
> > When you think about it the spindle should be integrated with the
> > non-drive sided (left) crank. It is the NDS to spindle attachment
> > that must transmit substantial pedaling torque, while the DS crank
> > attaches itself to the spider, and thence to the chain rings. Hey!
> > Who's in charge here?
>
> If you consider how to attach a spindle to a crank and what torque the
> spindle transmits you probably would do as others have and put pinch
> bolts on the left crank and permanently anchor the spindle in the
> right crank. The Campagnolo method is more complex and expensive. I
> think they ran into patent problems and came up with theirs as a way
> out.
>
> You'll note that Shimano uses two pinch bolts, showing that they gave
> this some thought and experimentation. I don't see how you propose to
> locate such hardware on the right crank, and beyond that for what
> reason. All torque that goes through the spindle is transmitted at
> both ends equally. The V-shaped spline is used because it lends
> itself to no-backlash attachment (something Octalink did not do) if
> the mating part is clamped onto it.
As if to baffle us all, the latest XTR design uses a non pinch-bolt
attachment, as most clearly shown in this exploded diagram PDF:
http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC
/EV-FC-M970-2592_v1_m56577569830608898.pdf
Basically, there's a "crank arm fixing bolt unit" that screws into the
end of the spindle, along with an "adjust nut" that apparently goes
between the crank arm and the BB shell, and which itself is held in
place with a pinch bolt. But note that the adjust nut is threaded
to...the inside of the left crank arm?!
Deeply worrying installation instructions here:
http://bike.shimano.com/media/techdocs/content/cycle/SI/XTR/FC-M970/15H0A
_EN_v1_m56577569830600538.PDF
For those of you who aren't MTBers, note that XT has historically
suffered from some of the same sorts of unique-bits weirdness that
Dura-Ace occasionally experiences.
> >> I think Sheldon's choice of 'pioneered' wasn't the best word but
> >> his meaning was otherwise clear.
--
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: 05 Sep 2007 22:16:18
From:
Subject: Re: Question About Cranks
|
Ryan Cousineau writes:
>>>>>> Shimano pioneered this style, with their "Hollowtech II" system,
>>>>>> but now most of the major crank manufacturers have followed suit.
>>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
>>>>> created two-piece cranks somewhere around the Cretaceous era:
>>>>> http://www.bikepro.com/products/cranks/bullseye.html
>>>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
>>>> splined spindle. The Thun crank system has a spindle integral to
>>>> the right crank like DA, a splined spindle like DA, a left slit
>>>> crank with pinch bolt like DA, c. 1950s as well.
>>> When you think about it the spindle should be integrated with the
>>> non-drive sided (left) crank. It is the NDS to spindle attachment
>>> that must transmit substantial pedaling torque, while the DS crank
>>> attaches itself to the spider, and thence to the chain rings. Hey!
>>> Who's in charge here?
>> If you consider how to attach a spindle to a crank and what torque the
>> spindle transmits you probably would do as others have and put pinch
>> bolts on the left crank and permanently anchor the spindle in the
>> right crank. The Campagnolo method is more complex and expensive. I
>> think they ran into patent problems and came up with theirs as a way
>> out.
>> You'll note that Shimano uses two pinch bolts, showing that they gave
>> this some thought and experimentation. I don't see how you propose to
>> locate such hardware on the right crank, and beyond that for what
>> reason. All torque that goes through the spindle is transmitted at
>> both ends equally. The V-shaped spline is used because it lends
>> itself to no-backlash attachment (something Octalink did not do) if
>> the mating part is clamped onto it.
> As if to baffle us all, the latest XTR design uses a non pinch-bolt
> attachment, as most clearly shown in this exploded diagram PDF:
> http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M970-2592_v1_m56577569830608898.pdf
This is an Octalink attachment that unscrews the retaining bolt and
shears the end of the 8-spline in the aluminum crank (for right foot
forward standees). That there are many such riders and that this
causes reverse torque in the spindle seems to have escaped the
originator of the Octalink.
Not only that, but the same designers assumed sheared spines were
caused by insufficient engagement length and made a second longer
version that suffers these same failures. The pinch bolt design for
attachment of the crank is superior because it has no elastic backlash
(that unscrews Octalinks) and can withstand recerse torqu that occurs
only when standing on both pedals with the right foot forward.
> Basically, there's a "crank arm fixing bolt unit" that screws into the
> end of the spindle, along with an "adjust nut" that apparently goes
> between the crank arm and the BB shell, and which itself is held in
> place with a pinch bolt. But note that the adjust nut is threaded
> to...the inside of the left crank arm?!
> Deeply worrying installation instructions here:
http://bike.shimano.com/media/techdocs/content/cycle/SI/XTR/FC-M970/15H0A_EN_v1_m56577569830600538.PDF
> For those of you who aren't MTBers, note that XT has historically
> suffered from some of the same sorts of unique-bits weirdness that
> Dura-Ace occasionally experiences.
Sounds interesting. Please fill me in.
>>>> I think Sheldon's choice of 'pioneered' wasn't the best word but
>>>> his meaning was otherwise clear.
Jobst Brandt
|
| | | | | | | |
Date: 05 Sep 2007 21:09:09
From: jim beam
Subject: Re: Question About Cranks
|
jobst.brandt@stanfordalumni.org wrote:
> Ryan Cousineau writes:
>
>>>>>>> Shimano pioneered this style, with their "Hollowtech II" system,
>>>>>>> but now most of the major crank manufacturers have followed suit.
>
>>>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
>>>>>> created two-piece cranks somewhere around the Cretaceous era:
>>>>>> http://www.bikepro.com/products/cranks/bullseye.html
>
>>>>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
>>>>> splined spindle. The Thun crank system has a spindle integral to
>>>>> the right crank like DA, a splined spindle like DA, a left slit
>>>>> crank with pinch bolt like DA, c. 1950s as well.
>
>>>> When you think about it the spindle should be integrated with the
>>>> non-drive sided (left) crank. It is the NDS to spindle attachment
>>>> that must transmit substantial pedaling torque, while the DS crank
>>>> attaches itself to the spider, and thence to the chain rings. Hey!
>>>> Who's in charge here?
>
>>> If you consider how to attach a spindle to a crank and what torque the
>>> spindle transmits you probably would do as others have and put pinch
>>> bolts on the left crank and permanently anchor the spindle in the
>>> right crank. The Campagnolo method is more complex and expensive. I
>>> think they ran into patent problems and came up with theirs as a way
>>> out.
>
>>> You'll note that Shimano uses two pinch bolts, showing that they gave
>>> this some thought and experimentation. I don't see how you propose to
>>> locate such hardware on the right crank, and beyond that for what
>>> reason. All torque that goes through the spindle is transmitted at
>>> both ends equally. The V-shaped spline is used because it lends
>>> itself to no-backlash attachment (something Octalink did not do) if
>>> the mating part is clamped onto it.
>
>> As if to baffle us all, the latest XTR design uses a non pinch-bolt
>> attachment, as most clearly shown in this exploded diagram PDF:
>
>> http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M970-2592_v1_m56577569830608898.pdf
>
> This is an Octalink attachment that unscrews the retaining bolt and
> shears the end of the 8-spline in the aluminum crank (for right foot
> forward standees).
no it doesn't. not only does over a decade of usage prove you wrong in
practice, you failed to observe the radiused tooth roots on these
interfaces which prevent this in theory too.
> That there are many such riders and that this
> causes reverse torque in the spindle seems to have escaped the
> originator of the Octalink.
what? like fatigue not being eliminated in non strain-aging materials
you mean?
>
> Not only that, but the same designers assumed sheared spines were
> caused by insufficient engagement length and made a second longer
> version that suffers these same failures. The pinch bolt design for
> attachment of the crank is superior because it has no elastic backlash
> (that unscrews Octalinks) and can withstand recerse torqu that occurs
> only when standing on both pedals with the right foot forward.
but it doesn't.
>
>> Basically, there's a "crank arm fixing bolt unit" that screws into the
>> end of the spindle, along with an "adjust nut" that apparently goes
>> between the crank arm and the BB shell, and which itself is held in
>> place with a pinch bolt. But note that the adjust nut is threaded
>> to...the inside of the left crank arm?!
>
>> Deeply worrying installation instructions here:
>
> http://bike.shimano.com/media/techdocs/content/cycle/SI/XTR/FC-M970/15H0A_EN_v1_m56577569830600538.PDF
>
>> For those of you who aren't MTBers, note that XT has historically
>> suffered from some of the same sorts of unique-bits weirdness that
>> Dura-Ace occasionally experiences.
>
> Sounds interesting. Please fill me in.
>
>>>>> I think Sheldon's choice of 'pioneered' wasn't the best word but
>>>>> his meaning was otherwise clear.
>
same crap, different day.
|
| | | | | | | |
Date: 06 Sep 2007 03:05:03
From: Ryan Cousineau
Subject: Re: Question About Cranks
|
In article <46df2ab2$0$14088$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> Ryan Cousineau writes:
>
> >>>>>> Shimano pioneered this style, with their "Hollowtech II" system,
> >>>>>> but now most of the major crank manufacturers have followed suit.
>
> >>>>> "Pioneered"??? Well, maybe the external bearings, but Bullseye
> >>>>> created two-piece cranks somewhere around the Cretaceous era:
> >>>>> http://www.bikepro.com/products/cranks/bullseye.html
>
> >>>> Yeah, my 1950s Magistroni steel crank has a similar pinch bolt on a
> >>>> splined spindle. The Thun crank system has a spindle integral to
> >>>> the right crank like DA, a splined spindle like DA, a left slit
> >>>> crank with pinch bolt like DA, c. 1950s as well.
>
> >>> When you think about it the spindle should be integrated with the
> >>> non-drive sided (left) crank. It is the NDS to spindle attachment
> >>> that must transmit substantial pedaling torque, while the DS crank
> >>> attaches itself to the spider, and thence to the chain rings. Hey!
> >>> Who's in charge here?
>
> >> If you consider how to attach a spindle to a crank and what torque the
> >> spindle transmits you probably would do as others have and put pinch
> >> bolts on the left crank and permanently anchor the spindle in the
> >> right crank. The Campagnolo method is more complex and expensive. I
> >> think they ran into patent problems and came up with theirs as a way
> >> out.
>
> >> You'll note that Shimano uses two pinch bolts, showing that they gave
> >> this some thought and experimentation. I don't see how you propose to
> >> locate such hardware on the right crank, and beyond that for what
> >> reason. All torque that goes through the spindle is transmitted at
> >> both ends equally. The V-shaped spline is used because it lends
> >> itself to no-backlash attachment (something Octalink did not do) if
> >> the mating part is clamped onto it.
>
> > As if to baffle us all, the latest XTR design uses a non pinch-bolt
> > attachment, as most clearly shown in this exploded diagram PDF:
>
> > http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV
> > -FC-M970-2592_v1_m56577569830608898.pdf
>
> This is an Octalink attachment that unscrews the retaining bolt and
> shears the end of the 8-spline in the aluminum crank (for right foot
> forward standees). That there are many such riders and that this
> causes reverse torque in the spindle seems to have escaped the
> originator of the Octalink.
Well, it may be Octalink-style, but Shimano will assure you that it is
"XTR Hollowtech II" or some such.
> Not only that, but the same designers assumed sheared spines were
> caused by insufficient engagement length and made a second longer
> version that suffers these same failures. The pinch bolt design for
> attachment of the crank is superior because it has no elastic backlash
> (that unscrews Octalinks) and can withstand recerse torqu that occurs
> only when standing on both pedals with the right foot forward.
>
> > Basically, there's a "crank arm fixing bolt unit" that screws into the
> > end of the spindle, along with an "adjust nut" that apparently goes
> > between the crank arm and the BB shell, and which itself is held in
> > place with a pinch bolt. But note that the adjust nut is threaded
> > to...the inside of the left crank arm?!
>
> > Deeply worrying installation instructions here:
>
> http://bike.shimano.com/media/techdocs/content/cycle/SI/XTR/FC-M970/15H0A_EN_
> v1_m56577569830600538.PDF
>
> > For those of you who aren't MTBers, note that XT has historically
> > suffered from some of the same sorts of unique-bits weirdness that
> > Dura-Ace occasionally experiences.
>
> Sounds interesting. Please fill me in.
First off, I must correct myself: "XTR", not XT. When Deore XT was
introduced, it was the top MTB group. It was superseded by XTR (never
"Deore XTR" though "XT" is still nominally "Deore XT", not to be
confused with the lesser "Deore" and "Deore LX" groups. Even I would
have to look it up to tell you the order of precedence of the lesser
Altus, Acera, and Alivio groups...), which persists as the
light-and-pricey group.
Notable oddities:
http://www.retroraleighs.com/cribsheet-bcd.html
Note the XTR-only 112/68 4-bolt BCD, now superseded by a single BCD
standard for all Shimano 4-bolt (basically, all MTB) cranks, including
the latest XTR (think of the unique Dura-Ace triple BCD).
Those rings are the only purely orphan part I can think of. I had
falsely assumed that XTR was the only group that used the Dual-Control
system (basically, shifting is incorporated into the brake lever; this
is more weird on an MTB than on a road bike), but that has trickled down
two groups to Deore LX and XT.
XTR was also the
> >>>> I think Sheldon's choice of 'pioneered' wasn't the best word but
> >>>> his meaning was otherwise clear.
>
> Jobst Brandt
--
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: 04 Sep 2007 03:34:22
From: Ryan Cousineau
Subject: Re: Question About Cranks
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In article <1188874909.791069.91250@o80g2000hse.googlegroups.com >,
JeffWills <jwills@pacifier.com > wrote:
> On Sep 3, 10:55 am, Sheldon Brown <CaptB...@sheldonbrown.com> wrote:
> >
> > Shimano pioneered this style, with their "Hollowtech II" system, but
> > now most of the major crank manufacturers have followed suit.
> >
> > Sheldon "Progress" Brown
>
> "Pioneered"??? Well, maybe the external bearings, but Bullseye created
> two-piece cranks somewhere around the Cretaceous era:
> http://www.bikepro.com/products/cranks/bullseye.html
>
> Jeff
I think external bearings may have been what Sheldon was referring to,
along with the application to road bikes and MTBs.
That said, there's so much interesting weirdness happening in BMX parts,
not to mention developments that sometimes seem to be at cross-purposes
to that happening in road/MTB bikes, that it's worth checking their
stuff out more often.
For example, the trend in BMX is for the high-end stuff to use "Euro"
BBs, which is to say bottom brackets based around the smaller, threaded
MTB/road standards as opposed to the bigger, threadless, traditional BMX
BB. This is ironic since every trend in road BBs is headed towards
enlarging the BB one way (external bearings) or another (BB30,
Overdrive, whatever the Pinarello and Trek standards are...).
(BTW, Norco is currently selling their higher-end BMXs with something
called "Spanish" BB. What is that?)
For another thing, BMX is a neat source for oddball parts. You can get
complete left-side drivetrains for those bikes (the practical purpose
being for riders who prefer to do their grind tricks on the right side),
which have a few uses in odd projects (one I saw was a guy who used a
flip-flop hub and a LHD freewheel to run an auxiliary electric motor
mounted on the rear rack. It was a pretty tidy home-brew).
--
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: 04 Sep 2007 02:36:33
From: A Muzi
Subject: Re: Question About Cranks
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-snip cranks-
Ryan Cousineau wrote:
> (BTW, Norco is currently selling their higher-end BMXs with something
> called "Spanish" BB. What is that?)
It's relatively new, between BSC and OPC!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 03 Sep 2007 11:55:53
From: Sheldon Brown
Subject: Re: Question About Cranks
|
On Sep 3, 2:49 pm, George <g_czp...@yzhoo.com > wrote:
> This is a question about cranks, but it is not a crank question.
> I learned about cotterless cranks around 1978.
> Today, I saw a bike with an interesting crank set. On the right side
> (i.e. on the chain ring side), there was no crank bolt. The area where
> there would be a crank bolt was completely smooth. On the left side,
> there was also no crank bolt, but the end of the crank arm near the
> bottom bracket axle was slit and the crank arm was (apparently) held
> on with an Allen screw "tangent" to the bottom bracket axle. (i.e.,
> The crank arm was held in place in manner similar to the way a
> seatpost is held in place by a bolt.)
> Who makes this type of bottom bracket assembly? Does it work well? Why
> is it made this way?
This is a two-piece crank, seems to be the wave of the future...most
better quality bikes currently available use this system. These use
"external" bearings, permitting the use of a larger diameter, hollow
spindle, saving weight and increasing stiffness. The larger diameter
bearings should also be longer-lived than the smaller bearings that
have to fit inside the bottom bracket shell with older systems.
Shimano pioneered this style, with their "Hollowtech II" system, but
now most of the major crank manufacturers have followed suit.
Sheldon "Progress" Brown
+---------------------------------------------------------+
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