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Main
Date: 29 Oct 2007 21:55:39
From: Jas51
Subject: Spoke tension Question
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Using the rim taco-method of setting spoke tension, should a tire be
mounted and inflated beforehand? Ive always brung the spokes up to tension
with no tire mounted, but the 160 psi thread got me wondering. What's the
proper technique?
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Date: 10 Nov 2007 11:25:46
From:
Subject: Re: Spoke tension Question
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On Oct 30, 12:55 am, Jas51 <ja...@emord.net > wrote:
> Using the rim taco-method of setting spoke tension, should a tire be
> mounted and inflated beforehand? Ive always brung the spokes up to tension
> with no tire mounted, but the 160 psi thread got me wondering. What's the
> proper technique?
yes set the wheels without pressure. the tube acts like an air bladder
so the pressure will be distributed evenly. if there is a problem on
set up and it is pressurized, it is only going to make it worse
regards,
carlos
www.bikingthings.com
Get Faster, Enjoy Cycling, Get Fit, Live Better.
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Date: 04 Nov 2007 13:54:57
From: Joe Riel
Subject: Re: Spoke tension Question
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Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > writes:
> For as many times as I need to post it, the one making the contention
> should provide the proof.
That sword has two edges. However, considering that the
straightforward test requires a certain amount of risk, I'd think that
the burden is on the party who claims it safe.
Make it appear sufficiently dangerous, and involve some incendaries
(these posts don't count), and maybe we could outsource the work
to MythBusters.
--
Joe Riel
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Date: 04 Nov 2007 16:02:55
From: Tom Sherman
Subject: Re: Spoke tension Question
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Joe Riel wrote:
> Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> writes:
>
>> For as many times as I need to post it, the one making the contention
>> should provide the proof.
>
> That sword has two edges. However, considering that the
> straightforward test requires a certain amount of risk, I'd think that
> the burden is on the party who claims it safe....
Yes, going over the bars of an upright bicycle onto pavement is
something I have done twice in my life and do not wish to repeat.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
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Date: 04 Nov 2007 13:37:30
From: Ozark Bicycle
Subject: Re: Spoke tension Question
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On Nov 4, 3:09 pm, Michael Press <rub...@pacbell.net > wrote:
> In article <472dd7dd$0$20608$4c368...@roadrunner.com>,
>
>
>
> "Sandy" <leur...@free.fr> wrote:
> > Dans le message denews:slrnfircjc.d6c.spamspam@bowser.marioworld,
> > Ben C <spams...@spam.eggs> a r=E9fl=E9chi, et puis a d=E9clar=E9 :
> > > On 2007-11-04, Tom Sherman <sunsetss0...@REMOVETHISyahoo.com> wrote:
>
> > >> Do you have data showing that higher spoke tensions lead to more
> > >> flat-spotting of rims?
>
> > > No. But all I'm doing here is disputing the claim that a rim whose
> > > spoke bed cracks when built to just-sub-taco tension is necessarily
> > > sub-optimally engineered.
>
> > It could be expressed differently. A rim meeting the taco test satisfi=
es
> > the taco test, yet that is not necessarily an optimum design, save for
> > meeting that test's criteria. Your idea, harmony and equilibrium makes=
more
> > sense.
>
> > The taco test favors spoke design over rim design. Favoring either one
> > separately fails to properly measure wheel design. After all, you woul=
dn't
> > fault spokes, necessarily, should they explode while tightening them. =
Each
> > material has limits. You wouldn't say that a curry is not well composed
> > unless the roof of your mouth melted, a "design" which would favor one
> > specific element of the composition over others.
>
> > The taco test is just another macho-feather-spreading myth, not a relia=
ble
> > index. I have never heard that taking something _over_ the limit to ac=
hieve
> > the limit is a sensible approach. When a manufacturer specifies a limi=
t,
> > and one regularly exceeds it, it's hard to understand how the design wo=
uld
> > have been at fault.
>
> It is not a test.
No, it is suggested as methodology. That's worse, IMO.
> When attempted on the type of rim
> for which it is explicitly meant, it shows the builder
> what a fully tensioned wheel is like. It need be done
> at most once. After that, the builder knows what
> a fully tensioned wheel is and brings subsequent
> wheels to that tension level.
And just how is a casual, home-mechanic wheelbuilder (the vast
majority of Brandt's 'faithful') supposed to repeat this sans a
tensionmeter or another *identical* wheel (if you already have one,
why build another?). Does drinking the Jobstian Kool-Aid imbue one
with calibrated fingers?
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Date: 03 Nov 2007 10:09:06
From: landotter
Subject: Re: Spoke tension Question
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On Nov 2, 11:42 pm, Tim McNamara <tim...@bitstream.net > wrote:
> Tom Sherman wrote:
> > Jas51 who? wrote:
> >> On Mon, 29 Oct 2007 21:55:39 -0800, Jas51 wrote:
>
> >> Bump
>
> > This is Usenet, not a web based message board.
>
> Perhaps he's a Google Groups user and has no clue about this.
I use GG, as I dual boot Linux/Xp on two computers for a total of four
logins--but find there to be no reason Google usage would encourage
"bumping" as it doesn't benefit this format either. More likely an
Invision Power Board habit.
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Date: 02 Nov 2007 19:07:54
From: Jay Beattie
Subject: Re: Spoke tension Question
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On Nov 2, 5:28 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Nov 2, 7:04 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Tom Sherman wrote:
> >>> Ozark Bicycle wrote:
> >>>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
> >>>>> Ozark Bicycle skrev:
> >>>>>> "The Jobst taco method" is way outta date and not applicable to modern
> >>>>>> rims (which are more resistant to 'doing the taco' than are box shape
> >>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
> >>>>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
> >>>>> 105, he specifically says that the "taco" method only applies to
> >>>>> conventional road rims under 430 grams with 36 spokes (perhaps 32
> >>>>> spokes too).
> >>>>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
> >>>>> "Taco" method.
> >>>>> I see the "Taco" method as an easy, practical way to get the safe
> >>>>> maximum tension on a standard wheel set. The method is in no way
> >>>>> "outdated", on the contrary,
> >>>> IME, many modern profile rims will have their recommended spoke
> >>>> tension maximum before fhey 'deform' per the method recommended by
> >>>> Jobst Brandt....
> >>> Then these rims are poorly designed,
> >> eh? so by that rationale, rims are also poorly designed because they
> >> dent when you ride up 6" curbs? because that's well within the range of
> >> daily experience.
>
> >>> since there is excess material that
> >>> creates stiffness in bending that is greater than the wheel needs to
> >>> remain true at maximum allowable spoke tension. The rim could be made
> >>> lighter for a given WHEEL strength, or the same weight rim could be
> >>> redesigned to allow for a stronger overall WHEEL.
> >> er....
>
> > Why argue with an idiot, mr. beam?
>
> tom's not an idiot - he's just laboring a point that i'm still not sure
> he fully understands. there /is/ no point in seeking higher and higher
> spoke tension, so there /is/ no point in redesigning rims for it. and
> there /is/ no point designing rims to abused by underinformed
> neanderthals, just like there /is/ no point designing frames to
> withstand dropped hammers.- Hide quoted text -
There is a point in designing a rim strong enough to accept spoke
tensions that will keep the wheel true without goobering the threads,
e.g., linseed oil, Locktite, etc. I will use that stuff if I have to,
but I would prefer not to. As for hammers dropping on my bike, well,
it would be nice to have a light frame that was also resistant to
mechanical damage. I don't know about CF explolding if it gets
nicked, but even apart from that, I wish my beer-can-thickness
aluminum frame were tougher -- if only so I could squeeze it in my old
Park stand. I liked the old days of squeezing my steel frames in my
"jaws of death" Park shop stand. No fuss, no muss. You could pound
nails with my old SP frames. I could live without the boat-anchor
weight of those things, though. I wonder why we don't see a true
plastic frame made out of some of that super tough plastic they use to
experiment with making engine blocks. No Carl, I'm not talking about
this one: blockshttp://www.firstflightbikes.com/plstbke.JPG I mean
something super-cool-modern. -- Jay Beattie.
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Date: 02 Nov 2007 19:34:18
From: jim beam
Subject: Re: Spoke tension Question
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Jay Beattie wrote:
> On Nov 2, 5:28 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Nov 2, 7:04 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> Tom Sherman wrote:
>>>>> Ozark Bicycle wrote:
>>>>>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
>>>>>>> Ozark Bicycle skrev:
>>>>>>>> "The Jobst taco method" is way outta date and not applicable to modern
>>>>>>>> rims (which are more resistant to 'doing the taco' than are box shape
>>>>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>>>>>>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
>>>>>>> 105, he specifically says that the "taco" method only applies to
>>>>>>> conventional road rims under 430 grams with 36 spokes (perhaps 32
>>>>>>> spokes too).
>>>>>>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
>>>>>>> "Taco" method.
>>>>>>> I see the "Taco" method as an easy, practical way to get the safe
>>>>>>> maximum tension on a standard wheel set. The method is in no way
>>>>>>> "outdated", on the contrary,
>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>>> Jobst Brandt....
>>>>> Then these rims are poorly designed,
>>>> eh? so by that rationale, rims are also poorly designed because they
>>>> dent when you ride up 6" curbs? because that's well within the range of
>>>> daily experience.
>>>>> since there is excess material that
>>>>> creates stiffness in bending that is greater than the wheel needs to
>>>>> remain true at maximum allowable spoke tension. The rim could be made
>>>>> lighter for a given WHEEL strength, or the same weight rim could be
>>>>> redesigned to allow for a stronger overall WHEEL.
>>>> er....
>>> Why argue with an idiot, mr. beam?
>> tom's not an idiot - he's just laboring a point that i'm still not sure
>> he fully understands. there /is/ no point in seeking higher and higher
>> spoke tension, so there /is/ no point in redesigning rims for it. and
>> there /is/ no point designing rims to abused by underinformed
>> neanderthals, just like there /is/ no point designing frames to
>> withstand dropped hammers.- Hide quoted text -
>
> There is a point in designing a rim strong enough to accept spoke
> tensions that will keep the wheel true without goobering the threads,
> e.g., linseed oil, Locktite, etc. I will use that stuff if I have to,
> but I would prefer not to.
actually, that's debatable. since the lateral stiffness afforded by a
bracing spoke is proportional to 1/sin theta, the angle of incidence,
you can see that as the angle gets shallower, it becomes infinitely hard
for the spoke to do its job. so the next best thing is to allow for a
reasonable range of service conditions known to exist, recognize that
the wheel won't collapse if a few spokes go momentarily slack, and deal
with the consequences, i.e. use threadlock.
> As for hammers dropping on my bike, well,
> it would be nice to have a light frame that was also resistant to
> mechanical damage. I don't know about CF explolding if it gets
> nicked,
don't worry, it doesn't. despite what the fudsters may say.
>, but even apart from that, I wish my beer-can-thickness
> aluminum frame were tougher -- if only so I could squeeze it in my old
> Park stand. I liked the old days of squeezing my steel frames in my
> "jaws of death" Park shop stand. No fuss, no muss. You could pound
> nails with my old SP frames. I could live without the boat-anchor
> weight of those things, though.
so really, performance prevails over abuse tolerance.
> I wonder why we don't see a true
> plastic frame made out of some of that super tough plastic they use to
> experiment with making engine blocks.
how much do you want to pay?
> No Carl, I'm not talking about
> this one: blockshttp://www.firstflightbikes.com/plstbke.JPG I mean
> something super-cool-modern. -- Jay Beattie.
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Date: 02 Nov 2007 18:37:40
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 2, 7:28 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Nov 2, 7:04 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Tom Sherman wrote:
> >>> Ozark Bicycle wrote:
> >>>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
> >>>>> Ozark Bicycle skrev:
> >>>>>> "The Jobst taco method" is way outta date and not applicable to modern
> >>>>>> rims (which are more resistant to 'doing the taco' than are box shape
> >>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
> >>>>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
> >>>>> 105, he specifically says that the "taco" method only applies to
> >>>>> conventional road rims under 430 grams with 36 spokes (perhaps 32
> >>>>> spokes too).
> >>>>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
> >>>>> "Taco" method.
> >>>>> I see the "Taco" method as an easy, practical way to get the safe
> >>>>> maximum tension on a standard wheel set. The method is in no way
> >>>>> "outdated", on the contrary,
> >>>> IME, many modern profile rims will have their recommended spoke
> >>>> tension maximum before fhey 'deform' per the method recommended by
> >>>> Jobst Brandt....
> >>> Then these rims are poorly designed,
> >> eh? so by that rationale, rims are also poorly designed because they
> >> dent when you ride up 6" curbs? because that's well within the range of
> >> daily experience.
>
> >>> since there is excess material that
> >>> creates stiffness in bending that is greater than the wheel needs to
> >>> remain true at maximum allowable spoke tension. The rim could be made
> >>> lighter for a given WHEEL strength, or the same weight rim could be
> >>> redesigned to allow for a stronger overall WHEEL.
> >> er....
>
> > Why argue with an idiot, mr. beam?
>
> tom's not an idiot -
We differ on this point......
> he's just laboring a point that i'm still not sure
> he fully understands. there /is/ no point in seeking higher and higher
> spoke tension, so there /is/ no point in redesigning rims for it. and
> there /is/ no point designing rims to abused by underinformed
> neanderthals, just like there /is/ no point designing frames to
> withstand dropped hammers.
IMO, Sherman is arguing for the sake of arguing; it relieves the
crushing boredom of his life.
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Date: 02 Nov 2007 18:21:16
From: Ozark Bicycle
Subject: Re: Spoke tension Question
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On Nov 2, 7:04 pm, jim beam <spamvor...@bad.example.net > wrote:
> Tom Sherman wrote:
> > Ozark Bicycle wrote:
> >> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
> >>> Ozark Bicycle skrev:
>
> >>>> "The Jobst taco method" is way outta date and not applicable to modern
> >>>> rims (which are more resistant to 'doing the taco' than are box shape
> >>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
> >>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
> >>> 105, he specifically says that the "taco" method only applies to
> >>> conventional road rims under 430 grams with 36 spokes (perhaps 32
> >>> spokes too).
> >>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
> >>> "Taco" method.
>
> >>> I see the "Taco" method as an easy, practical way to get the safe
> >>> maximum tension on a standard wheel set. The method is in no way
> >>> "outdated", on the contrary,
>
> >> IME, many modern profile rims will have their recommended spoke
> >> tension maximum before fhey 'deform' per the method recommended by
> >> Jobst Brandt....
>
> > Then these rims are poorly designed,
>
> eh? so by that rationale, rims are also poorly designed because they
> dent when you ride up 6" curbs? because that's well within the range of
> daily experience.
>
> > since there is excess material that
> > creates stiffness in bending that is greater than the wheel needs to
> > remain true at maximum allowable spoke tension. The rim could be made
> > lighter for a given WHEEL strength, or the same weight rim could be
> > redesigned to allow for a stronger overall WHEEL.
>
> er....
Why argue with an idiot, mr. beam?
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Date: 02 Nov 2007 18:28:24
From: jim beam
Subject: Re: Spoke tension Question
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Ozark Bicycle wrote:
> On Nov 2, 7:04 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Tom Sherman wrote:
>>> Ozark Bicycle wrote:
>>>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
>>>>> Ozark Bicycle skrev:
>>>>>> "The Jobst taco method" is way outta date and not applicable to modern
>>>>>> rims (which are more resistant to 'doing the taco' than are box shape
>>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>>>>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
>>>>> 105, he specifically says that the "taco" method only applies to
>>>>> conventional road rims under 430 grams with 36 spokes (perhaps 32
>>>>> spokes too).
>>>>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
>>>>> "Taco" method.
>>>>> I see the "Taco" method as an easy, practical way to get the safe
>>>>> maximum tension on a standard wheel set. The method is in no way
>>>>> "outdated", on the contrary,
>>>> IME, many modern profile rims will have their recommended spoke
>>>> tension maximum before fhey 'deform' per the method recommended by
>>>> Jobst Brandt....
>>> Then these rims are poorly designed,
>> eh? so by that rationale, rims are also poorly designed because they
>> dent when you ride up 6" curbs? because that's well within the range of
>> daily experience.
>>
>>> since there is excess material that
>>> creates stiffness in bending that is greater than the wheel needs to
>>> remain true at maximum allowable spoke tension. The rim could be made
>>> lighter for a given WHEEL strength, or the same weight rim could be
>>> redesigned to allow for a stronger overall WHEEL.
>> er....
>
>
> Why argue with an idiot, mr. beam?
>
tom's not an idiot - he's just laboring a point that i'm still not sure
he fully understands. there /is/ no point in seeking higher and higher
spoke tension, so there /is/ no point in redesigning rims for it. and
there /is/ no point designing rims to abused by underinformed
neanderthals, just like there /is/ no point designing frames to
withstand dropped hammers.
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Date: 02 Nov 2007 18:03:04
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 2, 4:50 pm, landotter <landot...@gmail.com > wrote:
> On Nov 2, 4:30 pm, Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Nov 2, 12:12 pm, Ron Ruff <rruffrr...@yahoo.com> wrote:
>
> > > On Nov 2, 4:40 am, Ozark Bicycle
>
> > > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > > If the wheel stays true, and spokes don't break - all is well.
>
> > > Yes... but most likely the threadlock wasn't necessary. What do you
> > > use for a threadlock?
>
> > I've used linseed oil since 1989. IMO, with 130mm 8/9/10sp rear wheels
> > built on mom-offset rims, it most likely *is* a benefit. Aside from a
> > few more minutes prep time, there is no downside - none- nada- zip.
>
> Do ya let it set up for a while, or just dip and use? I suppose you
> could use Danish or Tung oil oil if you really want to upsell!
I dip the spoke threads and build the wheel. I do prefer to let it
'set up' for a couple of days before the wheel is used - if possible
(some people are in such a damn hurry!).
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Date: 02 Nov 2007 15:50:18
From: landotter
Subject: Re: Spoke tension Question
|
On Nov 2, 4:30 pm, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Nov 2, 12:12 pm, Ron Ruff <rruffrr...@yahoo.com> wrote:
>
> > On Nov 2, 4:40 am, Ozark Bicycle
>
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > If the wheel stays true, and spokes don't break - all is well.
>
> > Yes... but most likely the threadlock wasn't necessary. What do you
> > use for a threadlock?
>
> I've used linseed oil since 1989. IMO, with 130mm 8/9/10sp rear wheels
> built on mom-offset rims, it most likely *is* a benefit. Aside from a
> few more minutes prep time, there is no downside - none- nada- zip.
Do ya let it set up for a while, or just dip and use? I suppose you
could use Danish or Tung oil oil if you really want to upsell!
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Date: 02 Nov 2007 14:30:45
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 2, 12:12 pm, Ron Ruff <rruffrr...@yahoo.com > wrote:
> On Nov 2, 4:40 am, Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > If the wheel stays true, and spokes don't break - all is well.
>
> Yes... but most likely the threadlock wasn't necessary. What do you
> use for a threadlock?
I've used linseed oil since 1989. IMO, with 130mm 8/9/10sp rear wheels
built on mom-offset rims, it most likely *is* a benefit. Aside from a
few more minutes prep time, there is no downside - none- nada- zip.
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Date: 02 Nov 2007 17:03:50
From: A Muzi
Subject: Re: Spoke tension Question
|
>> Ozark Bicycle
>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>> If the wheel stays true, and spokes don't break - all is well.
> Ron Ruff <rruffrr...@yahoo.com> wrote:
>> Yes... but most likely the threadlock wasn't necessary. What do you
>> use for a threadlock?
Ozark Bicycle wrote:
> I've used linseed oil since 1989. IMO, with 130mm 8/9/10sp rear wheels
> built on mom-offset rims, it most likely *is* a benefit. Aside from a
> few more minutes prep time, there is no downside - none- nada- zip.
Agreed. For even longer, we've seen no reason to change. Works well, no
downside, a quart goes about a year here.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 02 Nov 2007 11:12:15
From: Ron Ruff
Subject: Re: Spoke tension Question
|
On Nov 2, 4:40 am, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> If the wheel stays true, and spokes don't break - all is well.
Yes... but most likely the threadlock wasn't necessary. What do you
use for a threadlock?
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Date: 02 Nov 2007 03:40:41
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 1, 8:19 pm, Ron Ruff <rruffrr...@yahoo.com > wrote:
> On Nov 1, 1:28 pm, Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > Hmmmm.....if the NDS spokes are tensioned (i.e., not slack) when the
> > wheel is built, and the threadlock "keeps them from unscrewing" during
> > use........
>
> They go slack under load... like when you are riding the bike.
If the wheel stays true, and spokes don't break - all is well.
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Date: 01 Nov 2007 23:21:34
From: Jas51
Subject: Re: Spoke tension Question
|
On Mon, 29 Oct 2007 21:55:39 -0800, Jas51 wrote:
Bump
> Using the rim taco-method of setting spoke tension, should a tire be
> mounted and inflated beforehand? Ive always brung the spokes up to tension
> with no tire mounted, but the 160 psi thread got me wondering. What's the
> proper technique?
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Date: 02 Nov 2007 19:25:51
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Jas51 who? wrote:
> On Mon, 29 Oct 2007 21:55:39 -0800, Jas51 wrote:
>
>
> Bump
This is Usenet, not a web based message board.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | |
Date: 02 Nov 2007 23:42:13
From: Tim McNamara
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Jas51 who? wrote:
>> On Mon, 29 Oct 2007 21:55:39 -0800, Jas51 wrote:
>>
>>
>> Bump
>
> This is Usenet, not a web based message board.
Perhaps he's a Google Groups user and has no clue about this.
|
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Date: 01 Nov 2007 19:19:40
From: Ron Ruff
Subject: Re: Spoke tension Question
|
On Nov 1, 1:28 pm, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> Hmmmm.....if the NDS spokes are tensioned (i.e., not slack) when the
> wheel is built, and the threadlock "keeps them from unscrewing" during
> use........
They go slack under load... like when you are riding the bike.
|
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Date: 01 Nov 2007 12:28:26
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 1, 1:06 pm, Ron Ruff <rruffrr...@yahoo.com > wrote:
> On Oct 31, 2:28 pm, Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > And, when the DS tension is too high, the spoke bed cracks around the
> > DS spokeholes. The solution to keeping the NDS spokes from going slack
> > is a mild threadlock.
>
> Doesn't keep them from going slack... just keeps them from unscrewing.
> You still have the spoke fatigue and greater chance of rim buckling
> when a spoke goes slack.
Hmmmm.....if the NDS spokes are tensioned (i.e., not slack) when the
wheel is built, and the threadlock "keeps them from unscrewing" during
use........
|
| |
Date: 01 Nov 2007 12:06:41
From: Ron Ruff
Subject: Re: Spoke tension Question
|
On Oct 31, 2:28 pm, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> And, when the DS tension is too high, the spoke bed cracks around the
> DS spokeholes. The solution to keeping the NDS spokes from going slack
> is a mild threadlock.
Doesn't keep them from going slack... just keeps them from unscrewing.
You still have the spoke fatigue and greater chance of rim buckling
when a spoke goes slack.
|
| |
Date: 01 Nov 2007 12:04:10
From: Ron Ruff
Subject: Re: Spoke tension Question
|
On Oct 31, 6:16 pm, Jay Beattie <jbeat...@lindsayhart.com > wrote:
> That's true -- or even higher spoke tensions. The CPX 33 seems to fit
> the bill as well as some of the heavier Velocity rims. IMO, the
> optimal rim would be an Aerohead OC with more metal at the eyelets or
> sockets -- maybe a 450g rim instead of nominal 400g. I like the OC
> design.
Aeroheads seem to weigh 420-430g at the moment... but then they
usually vary a lot. Has anyone got stories of Aeroheads cracking
around the eyelets? Or Fusions or Deep Vs?
> The market is pushing for lighter prefab wheels, though, and
> we'll be lucky if we can eveny buy bare rims in five years -- let
> alone get new entrants to the rim-only market. -- Jay Beattie.
Some are getting out of the game (like Mavic) but others are coming in
(like Kinlin). I think the wheel parts (build your own) market has
already hit bottom. Custom wheels in the $500+ range can be lighter,
more aerodynamic, and less expensive than the factory alternatives,
and have easily replaceable and less expensive parts. There will
always be some people who appreciate those qualities.
|
| |
Date: 01 Nov 2007 08:57:14
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 1, 8:55 am, "Sandy" <leur...@free.fr > wrote:
> Dans le message denews:1193808134.652190.268030@z24g2000prh.googlegroups.=
com,
> Jay Beattie <jbeat...@lindsayhart.com> a r=E9fl=E9chi, et puis a d=E9clar=
=E9 :
>
>
>
> > On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> Ozark Bicycle wrote:
> >>> On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> >>>> On Oct 30, 11:29 am, Ozark Bicycle
>
> >>>> <bicycleatel...@ozarkbicycleservice.com> wrote:
> >>>>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> >>>>>> Ozark Bicycle wrote:
> >>>>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> >>>>>>>> Jas51 wrote:
> >>>>>>>>> Using the rim taco-method of setting spoke tension, should a
> >>>>>>>>> tire be mounted and inflated beforehand? Ive always brung
> >>>>>>>>> the spokes up to tension with no tire mounted, but the 160
> >>>>>>>>> psi thread got me wondering. What's the proper technique?
> >>>>>>>> Bare rim. Using a really shitty spoke wrench you got carded at
> >>>>>>>> a Kmart in 1988, as you can't find your Park model, tension
> >>>>>>>> each spoke till your index finger hurts and it goes "twinnng!"
> >>>>>>>> instead of "twooong!" when plucked. Make sure to have your
> >>>>>>>> ears calibrated beforehand.
> >>>>>>> Next step: Use Google to find the best price on a new rim.
> >>>>>>> Rinse and repeat. ;-)
> >>>>>> All kidding aside, I do have a general pitch which I true around,
> >>>>>> dished wheels getting an average of that tone. It doesn't
> >>>>>> distinguish between specific brands of rims, some which can take
> >>>>>> more tension--but the wheels stay true, and that's all that
> >>>>>> matters in the end. ;-) I've only had one rim ever go bad on me,
> >>>>>> and that was a cracked MA3 a couple years ago--which I doubt had
> >>>>>> to do with spoke tension. As long as the tension is good enough,
> >>>>>> the spokes seated in the flanges, and the overall tension
> >>>>>> even--you're still miles ahead of factory tuned junk.
> >>>>>> The Jobst taco method strikes me as a bit more dangerous than my
> >>>>>> rather plebian ways, seeing as he's a proponent of socketed rims,
> >>>>>> which I assume are going to be a bit more resistant to cracking
> >>>>>> compared to eyeletted or plain hole stoff.
> >>>>> "The Jobst taco method" is way outta date and not applicable to
> >>>>> modern
> >>>>> rims (which are more resistant to 'doing the taco' than are box
> >>>>> shape
> >>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.-
> >>>>> Hide quoted text -
> >>>>http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=3D'2539-00' I
> >>>> think $54 is a reasonable investment -- less than a Open Pro rim
> >>>> full price. -- Jay Beattie
>
> >>> Considering the investment in a pair of hubs, pair of rims, 60+
> >>> spokes, etc., it seems foolish to "cheap out" and not buy a Park
> >>> Tensiometer.
>
> >> yeahbut some individuals think their psychic powers make them exempt
> >> from the physics of earthly matter. they "don't need no steenkin'
> >> tensiometer", remember?- Hide quoted text -
>
> > I think the Book has to abandon the MA2/6 speed paradigm. It is no
> > longer the real world. -- Jay Beattie.
>
> I'm sure I read it's being updated to 7V - not true??
> --
Apparently, Jobst the Great and Mighty is now using 7sp Shimano
freehubs. He's moved right into the heart of 1980s technology. What's
next, crossover front gearing????
|
| |
Date: 01 Nov 2007 05:23:49
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> >> On Oct 30, 11:29 am, Ozark Bicycle
>
> >> <bicycleatel...@ozarkbicycleservice.com> wrote:
> >>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> >>>> Ozark Bicycle wrote:
> >>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> >>>>>> Jas51 wrote:
> >>>>>>> Using the rim taco-method of setting spoke tension, should a tire be
> >>>>>>> mounted and inflated beforehand? Ive always brung the spokes up to tension
> >>>>>>> with no tire mounted, but the 160 psi thread got me wondering. What's the
> >>>>>>> proper technique?
> >>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> >>>>>> in 1988, as you can't find your Park model, tension each spoke till
> >>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
> >>>>>> when plucked. Make sure to have your ears calibrated beforehand.
> >>>>> Next step: Use Google to find the best price on a new rim. Rinse and
> >>>>> repeat. ;-)
> >>>> All kidding aside, I do have a general pitch which I true around,
> >>>> dished wheels getting an average of that tone. It doesn't distinguish
> >>>> between specific brands of rims, some which can take more tension--but
> >>>> the wheels stay true, and that's all that matters in the end. ;-) I've
> >>>> only had one rim ever go bad on me, and that was a cracked MA3 a
> >>>> couple years ago--which I doubt had to do with spoke tension. As long
> >>>> as the tension is good enough, the spokes seated in the flanges, and
> >>>> the overall tension even--you're still miles ahead of factory tuned
> >>>> junk.
> >>>> The Jobst taco method strikes me as a bit more dangerous than my
> >>>> rather plebian ways, seeing as he's a proponent of socketed rims,
> >>>> which I assume are going to be a bit more resistant to cracking
> >>>> compared to eyeletted or plain hole stoff.
> >>> "The Jobst taco method" is way outta date and not applicable to modern
> >>> rims (which are more resistant to 'doing the taco' than are box shape
> >>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
> >>http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> >> think $54 is a reasonable investment -- less than a Open Pro rim full
> >> price. -- Jay Beattie
>
> > Considering the investment in a pair of hubs, pair of rims, 60+
> > spokes, etc., it seems foolish to "cheap out" and not buy a Park
> > Tensiometer.
>
> yeahbut some individuals think their psychic powers make them exempt
> from the physics of earthly matter. they "don't need no steenkin'
> tensiometer", remember?- Hide quoted text -
I think the Book has to abandon the MA2/6 speed paradigm. It is no
longer the real world. -- Jay Beattie.
|
| | |
Date: 01 Nov 2007 10:55:02
From: Sandy
Subject: Re: Spoke tension Question
|
Dans le message de
news:1193808134.652190.268030@z24g2000prh.googlegroups.com,
Jay Beattie <jbeattie@lindsayhart.com > a réfléchi, et puis a déclaré :
> On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
>>>> On Oct 30, 11:29 am, Ozark Bicycle
>>
>>>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>>>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>>>>>> Ozark Bicycle wrote:
>>>>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
>>>>>>>> Jas51 wrote:
>>>>>>>>> Using the rim taco-method of setting spoke tension, should a
>>>>>>>>> tire be mounted and inflated beforehand? Ive always brung
>>>>>>>>> the spokes up to tension with no tire mounted, but the 160
>>>>>>>>> psi thread got me wondering. What's the proper technique?
>>>>>>>> Bare rim. Using a really shitty spoke wrench you got carded at
>>>>>>>> a Kmart in 1988, as you can't find your Park model, tension
>>>>>>>> each spoke till your index finger hurts and it goes "twinnng!"
>>>>>>>> instead of "twooong!" when plucked. Make sure to have your
>>>>>>>> ears calibrated beforehand.
>>>>>>> Next step: Use Google to find the best price on a new rim.
>>>>>>> Rinse and repeat. ;-)
>>>>>> All kidding aside, I do have a general pitch which I true around,
>>>>>> dished wheels getting an average of that tone. It doesn't
>>>>>> distinguish between specific brands of rims, some which can take
>>>>>> more tension--but the wheels stay true, and that's all that
>>>>>> matters in the end. ;-) I've only had one rim ever go bad on me,
>>>>>> and that was a cracked MA3 a couple years ago--which I doubt had
>>>>>> to do with spoke tension. As long as the tension is good enough,
>>>>>> the spokes seated in the flanges, and the overall tension
>>>>>> even--you're still miles ahead of factory tuned junk.
>>>>>> The Jobst taco method strikes me as a bit more dangerous than my
>>>>>> rather plebian ways, seeing as he's a proponent of socketed rims,
>>>>>> which I assume are going to be a bit more resistant to cracking
>>>>>> compared to eyeletted or plain hole stoff.
>>>>> "The Jobst taco method" is way outta date and not applicable to
>>>>> modern
>>>>> rims (which are more resistant to 'doing the taco' than are box
>>>>> shape
>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.-
>>>>> Hide quoted text -
>>>> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
>>>> think $54 is a reasonable investment -- less than a Open Pro rim
>>>> full price. -- Jay Beattie
>>
>>> Considering the investment in a pair of hubs, pair of rims, 60+
>>> spokes, etc., it seems foolish to "cheap out" and not buy a Park
>>> Tensiometer.
>>
>> yeahbut some individuals think their psychic powers make them exempt
>> from the physics of earthly matter. they "don't need no steenkin'
>> tensiometer", remember?- Hide quoted text -
>
> I think the Book has to abandon the MA2/6 speed paradigm. It is no
> longer the real world. -- Jay Beattie.
I'm sure I read it's being updated to 7V - not true??
--
Sandy
Verneuil-sur-Seine FR
"Le Vin est la plus saine et la plus hygiénique des boissons."
- Louis Pasteur
|
| |
Date: 31 Oct 2007 18:55:25
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Oct 31, 5:43 pm, Michael Press <rub...@pacbell.net > wrote:
> In article
> <1193862515.970812.83...@o80g2000hse.googlegroups.com>,
> Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > And, when the DS tension is too high, the spoke bed cracks around the
> > DS spokeholes. The solution to keeping the NDS spokes from going slack
> > is a mild threadlock.
>
> The solution is to buy only rims whose spoke beds can
> sustain 110 kgf.
The post to which I was replying was implying DS spoke tensions far in
excess of 110 kgf (in order to keep the NDS spokes from going slack).
|
| | |
Date: 31 Oct 2007 22:14:22
From: Michael Press
Subject: Re: Spoke tension Question
|
In article
<1193882125.240250.34150@k79g2000hse.googlegroups.com >,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com > wrote:
> On Oct 31, 5:43 pm, Michael Press <rub...@pacbell.net> wrote:
> > In article
> > <1193862515.970812.83...@o80g2000hse.googlegroups.com>,
> > Ozark Bicycle
> >
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > And, when the DS tension is too high, the spoke bed cracks around the
> > > DS spokeholes. The solution to keeping the NDS spokes from going slack
> > > is a mild threadlock.
> >
> > The solution is to buy only rims whose spoke beds can
> > sustain 110 kgf.
>
> The post to which I was replying was implying DS spoke tensions far in
> excess of 110 kgf (in order to keep the NDS spokes from going slack).
I have not paid particularly close attention. Is it the
case that at least one builder here had spoke beds crack
at less than 110 kgF?
--
Michael Press
|
| |
Date: 31 Oct 2007 17:16:26
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 31, 4:43 pm, Michael Press <rub...@pacbell.net > wrote:
> In article
> <1193862515.970812.83...@o80g2000hse.googlegroups.com>,
> Ozark Bicycle
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > And, when the DS tension is too high, the spoke bed cracks around the
> > DS spokeholes. The solution to keeping the NDS spokes from going slack
> > is a mild threadlock.
>
> The solution is to buy only rims whose spoke beds can
> sustain 110 kgf. Then the manufacturers would make
> more of them. There are rims now that can sustain
> the whole nine yards.
That's true -- or even higher spoke tensions. The CPX 33 seems to fit
the bill as well as some of the heavier Velocity rims. IMO, the
optimal rim would be an Aerohead OC with more metal at the eyelets or
sockets -- maybe a 450g rim instead of nominal 400g. I like the OC
design. The market is pushing for lighter prefab wheels, though, and
we'll be lucky if we can eveny buy bare rims in five years -- let
alone get new entrants to the rim-only market. -- Jay Beattie.
|
| |
Date: 31 Oct 2007 14:56:01
From:
Subject: Re: Spoke tension Question
|
Ozark Bicycle skrev:
> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
> IME, many modern profile rims will have their recommended spoke
> tension maximum before fhey 'deform' per the method recommended by
> Jobst Brandt.
The point is that these profile rims (if by that you mean deep section
aero rims) probably weighs more than 430 g., and furthermore are
excluded from the "Taco" method by being deep section rims. Again,
according to JB's book (3. ed, p. 105) only conventional 36h rims
below 430 g. can use the "Taco" method. When reading page 105 it
becomes clear that JB never claims that the "Taco" method is a
universal rule for all the rims in the world, but a usefull rule for a
specific class of rims.
> And, when the DS tension is too high, the spoke bed cracks around the
> DS spokeholes. The solution to keeping the NDS spokes from going slack
> is a mild threadlock.
My wheels are made with Sapim swaged spokes (2/1.8mm) and Mavic CXP 33
rims (semi deep v, 460 grams) on 36 hole 10 spd. Shimano and
Campagnolo hubs. DS spoke tension is around 155 Kgf according to my
Park Tool tensiometer. Never had a rim crack around the spoke hole
since I started building my own wheels some years ago. Never needed
any threadlock either even though I am a heavy guy that often commute
with two heavy loaded panniers.
> > So not only are you wrong about what Jobst Brandt's "Taco" method is,
> > you are also wrong about it being outdated.
>
> Bullshit, pal.
Well, I do think you that you don't know what rims JB's book claims
can use the "Taco" method.
--
Regards
|
| | |
Date: 31 Oct 2007 21:58:48
From: jim beam
Subject: Re: Spoke tension Question
|
phs123@gmail.com wrote:
> Ozark Bicycle skrev:
>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
>
>> IME, many modern profile rims will have their recommended spoke
>> tension maximum before fhey 'deform' per the method recommended by
>> Jobst Brandt.
>
> The point is that these profile rims (if by that you mean deep section
> aero rims) probably weighs more than 430 g., and furthermore are
> excluded from the "Taco" method by being deep section rims. Again,
> according to JB's book (3. ed, p. 105) only conventional 36h rims
> below 430 g. can use the "Taco" method. When reading page 105 it
> becomes clear that JB never claims that the "Taco" method is a
> universal rule for all the rims in the world, but a usefull rule for a
> specific class of rims.
>
>> And, when the DS tension is too high, the spoke bed cracks around the
>> DS spokeholes. The solution to keeping the NDS spokes from going slack
>> is a mild threadlock.
>
> My wheels are made with Sapim swaged spokes
d.t. swage their spokes [hammering process].
sapim use a [die] drawing process.
jobst is incorrect when he uses the word "swaged". the correct term is
"butted", which includes the results of /all/ the different spoke
narrowing processes.
> (2/1.8mm) and Mavic CXP 33
> rims (semi deep v, 460 grams) on 36 hole 10 spd. Shimano and
> Campagnolo hubs. DS spoke tension is around 155 Kgf according to my
> Park Tool tensiometer. Never had a rim crack around the spoke hole
> since I started building my own wheels some years ago. Never needed
> any threadlock either even though I am a heavy guy that often commute
> with two heavy loaded panniers.
>
>>> So not only are you wrong about what Jobst Brandt's "Taco" method is,
>>> you are also wrong about it being outdated.
>> Bullshit, pal.
>
> Well, I do think you that you don't know what rims JB's book claims
> can use the "Taco" method.
when jobst formulated his "taco" theory, he didn't understand that
increasing spoke tension diminished available rim strength. he further
didn't understand the nature of the materials used either. bottom line,
he makes /many/ mistakes in his writings and misleads the uninformed
accordingly. see above.
|
| |
Date: 31 Oct 2007 13:28:35
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Oct 31, 12:45 pm, phs...@gmail.com wrote:
> Ozark Bicycle skrev:
>
> > "The Jobst taco method" is way outta date and not applicable to modern
> > rims (which are more resistant to 'doing the taco' than are box shape
> > rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>
> If people bothered to look up in Jobst Brandt's book (3. ed.) page
> 105, he specifically says that the "taco" method only applies to
> conventional road rims under 430 grams with 36 spokes (perhaps 32
> spokes too).
> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
> "Taco" method.
>
> I see the "Taco" method as an easy, practical way to get the safe
> maximum tension on a standard wheel set. The method is in no way
> "outdated", on the contrary,
IME, many modern profile rims will have their recommended spoke
tension maximum before fhey 'deform' per the method recommended by
Jobst Brandt.
> since highly dished wheels often require
> very high DS tension so that the NDS tension becomes sufficiently
> high.
And, when the DS tension is too high, the spoke bed cracks around the
DS spokeholes. The solution to keeping the NDS spokes from going slack
is a mild threadlock.
>
> So not only are you wrong about what Jobst Brandt's "Taco" method is,
> you are also wrong about it being outdated.
Bullshit, pal.
>
|
| | |
Date: 02 Nov 2007 19:20:04
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ozark Bicycle wrote:
> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
>> Ozark Bicycle skrev:
>>
>>> "The Jobst taco method" is way outta date and not applicable to modern
>>> rims (which are more resistant to 'doing the taco' than are box shape
>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
>> 105, he specifically says that the "taco" method only applies to
>> conventional road rims under 430 grams with 36 spokes (perhaps 32
>> spokes too).
>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
>> "Taco" method.
>>
>> I see the "Taco" method as an easy, practical way to get the safe
>> maximum tension on a standard wheel set. The method is in no way
>> "outdated", on the contrary,
>
> IME, many modern profile rims will have their recommended spoke
> tension maximum before fhey 'deform' per the method recommended by
> Jobst Brandt....
Then these rims are poorly designed, since there is excess material that
creates stiffness in bending that is greater than the wheel needs to
remain true at maximum allowable spoke tension. The rim could be made
lighter for a given WHEEL strength, or the same weight rim could be
redesigned to allow for a stronger overall WHEEL.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | |
Date: 03 Nov 2007 05:25:52
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > wrote:
> Ozark Bicycle wrote:
[...]
>> IME, many modern profile rims will have their recommended spoke
>> tension maximum before fhey 'deform' per the method recommended by
>> Jobst Brandt....
>
> Then these rims are poorly designed, since there is excess material that
> creates stiffness in bending that is greater than the wheel needs to
> remain true at maximum allowable spoke tension. The rim could be made
> lighter for a given WHEEL strength, or the same weight rim could be
> redesigned to allow for a stronger overall WHEEL.
I hear this a lot but isn't this based on the premise that the
performance of a wheel is solely a function of how much spoke tension it
can support?
That seems to leave yield strength of the rim itself completely out of
the equation.
|
| | | | |
Date: 03 Nov 2007 13:20:19
From: Tim McNamara
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ozark Bicycle wrote:
> [...]
>>> IME, many modern profile rims will have their recommended spoke
>>> tension maximum before fhey 'deform' per the method recommended by
>>> Jobst Brandt....
>>
>> Then these rims are poorly designed, since there is excess material that
>> creates stiffness in bending that is greater than the wheel needs to
>> remain true at maximum allowable spoke tension. The rim could be made
>> lighter for a given WHEEL strength, or the same weight rim could be
>> redesigned to allow for a stronger overall WHEEL.
>
> I hear this a lot but isn't this based on the premise that the
> performance of a wheel is solely a function of how much spoke tension it
> can support?
>
> That seems to leave yield strength of the rim itself completely out of
> the equation.
Not necessarily, but there comes a point when increased rim strength is
just a waste of material. Rims routinely weigh lots more than they did
30 years ago, but try to make up for that by having fewer spokes. It's
goofy as hell.
|
| | | | |
Date: 03 Nov 2007 06:26:36
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ozark Bicycle wrote:
> [...]
>>> IME, many modern profile rims will have their recommended spoke
>>> tension maximum before fhey 'deform' per the method recommended by
>>> Jobst Brandt....
>> Then these rims are poorly designed, since there is excess material that
>> creates stiffness in bending that is greater than the wheel needs to
>> remain true at maximum allowable spoke tension. The rim could be made
>> lighter for a given WHEEL strength, or the same weight rim could be
>> redesigned to allow for a stronger overall WHEEL.
>
> I hear this a lot but isn't this based on the premise that the
> performance of a wheel is solely a function of how much spoke tension it
> can support?
well said.
>
> That seems to leave yield strength of the rim itself completely out of
> the equation.
put another way, it's strange that "wheel strength" is considered to be
solely a function of spoke tension!
|
| | | | |
Date: 03 Nov 2007 06:14:45
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ben C? wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ozark Bicycle wrote:
> [...]
>>> IME, many modern profile rims will have their recommended spoke
>>> tension maximum before fhey 'deform' per the method recommended by
>>> Jobst Brandt....
>> Then these rims are poorly designed, since there is excess material that
>> creates stiffness in bending that is greater than the wheel needs to
>> remain true at maximum allowable spoke tension. The rim could be made
>> lighter for a given WHEEL strength, or the same weight rim could be
>> redesigned to allow for a stronger overall WHEEL.
>
> I hear this a lot but isn't this based on the premise that the
> performance of a wheel is solely a function of how much spoke tension it
> can support?
>
> That seems to leave yield strength of the rim itself completely out of
> the equation.
There are several different ways a rim can yield. Which of these are you
referring to?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | |
Date: 03 Nov 2007 13:46:10
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > wrote:
> Ben C? wrote:
>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ozark Bicycle wrote:
>> [...]
>>>> IME, many modern profile rims will have their recommended spoke
>>>> tension maximum before fhey 'deform' per the method recommended by
>>>> Jobst Brandt....
>>> Then these rims are poorly designed, since there is excess material that
>>> creates stiffness in bending that is greater than the wheel needs to
>>> remain true at maximum allowable spoke tension. The rim could be made
>>> lighter for a given WHEEL strength, or the same weight rim could be
>>> redesigned to allow for a stronger overall WHEEL.
>>
>> I hear this a lot but isn't this based on the premise that the
>> performance of a wheel is solely a function of how much spoke tension it
>> can support?
>>
>> That seems to leave yield strength of the rim itself completely out of
>> the equation.
>
> There are several different ways a rim can yield. Which of these are you
> referring to?
Probably flat-spotting. We had a thread recently where we discussed how
tension might affect propensity to flat-spot. With high tensions the rim
will flat spot more easily if it reaches yield stress before the spokes
go slack.
This would be an interesting experiment to do: build a wheel with high
tension, and keep loading it (weight downwards on the hub, the same
thing it gets in use). Measure spoke tension in the bottom spokes. Keep
adding weights until the tension goes to almost but not quite zero.
Remove weights. Check rim for permanent deformation. If it has deformed
permanently, then reduction in rim yield strength due to spoke tension
is a real issue.
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Date: 05 Nov 2007 07:07:26
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> Probably flat-spotting. We had a thread recently where we discussed how
> tension might affect propensity to flat-spot. With high tensions the rim
> will flat spot more easily if it reaches yield stress before the spokes
> go slack.
But it won't, as you can see if you use numbers. There's a reason that
low spoke count wheels spec higher spoke tensions.
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Date: 06 Nov 2007 20:33:55
From: jim beam
Subject: Re: Spoke tension Question
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Peter Cole wrote:
> Ben C wrote:
>
>> Probably flat-spotting. We had a thread recently where we discussed how
>> tension might affect propensity to flat-spot. With high tensions the rim
>> will flat spot more easily if it reaches yield stress before the spokes
>> go slack.
>
> But it won't, as you can see if you use numbers. There's a reason that
> low spoke count wheels spec higher spoke tensions.
but they don't, as you can see if you use numbers.
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Date: 05 Nov 2007 08:06:01
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-05, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>
>> Probably flat-spotting. We had a thread recently where we discussed how
>> tension might affect propensity to flat-spot. With high tensions the rim
>> will flat spot more easily if it reaches yield stress before the spokes
>> go slack.
>
> But it won't, as you can see if you use numbers.
Maybe you can see that, but I don't find it so easy to work out.
I don't know how to work out how many spokes go slack and by how much
for a given load except with an FEA, or, better still, trying it on an
actual wheel.
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Date: 05 Nov 2007 15:34:22
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-05, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>
>>> Probably flat-spotting. We had a thread recently where we discussed how
>>> tension might affect propensity to flat-spot. With high tensions the rim
>>> will flat spot more easily if it reaches yield stress before the spokes
>>> go slack.
>> But it won't, as you can see if you use numbers.
>
> Maybe you can see that, but I don't find it so easy to work out.
>
> I don't know how to work out how many spokes go slack and by how much
> for a given load except with an FEA, or, better still, trying it on an
> actual wheel.
Well, then perhaps you shouldn't be making such claims.
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Date: 05 Nov 2007 15:59:19
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-05, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-05, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>>>
>>>> Probably flat-spotting. We had a thread recently where we discussed how
>>>> tension might affect propensity to flat-spot. With high tensions the rim
>>>> will flat spot more easily if it reaches yield stress before the spokes
>>>> go slack.
>>> But it won't, as you can see if you use numbers.
>>
>> Maybe you can see that, but I don't find it so easy to work out.
>>
>> I don't know how to work out how many spokes go slack and by how much
>> for a given load except with an FEA, or, better still, trying it on an
>> actual wheel.
>
> Well, then perhaps you shouldn't be making such claims.
What claims exactly did I make?
I was trying to discuss with Tom Sherman his proposal that a rim whose
spoke bed cracks when built to just-sub-taco tension is sub-optimally
designed.
I thought perhaps he hadn't thought of the possibility of rim yield, or
that, if he had, perhaps he had some more light to shed on the subject
of why it might not be a factor.
I got the impression from the next few posts that he hadn't thought of
it, so I think I was right to bring it up.
I suspect that it is a factor until I see evidence or a convincing
explanation why it is likely not to be.
You have quoted me out of context above. Tom asked something like "a rim
can yield in many ways, which one are you thinking of?". I replied
"probably flat-spotting" meaning that that was the failure mode related
to rim yield that I considered most likely (and easiest to explain) out
of all failure modes to be promoted by excessive spoke tension.
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Date: 06 Nov 2007 07:24:18
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-05, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-05, Peter Cole <peter_cole@comcast.net> wrote:
>>>> Ben C wrote:
>>>>
>>>>> Probably flat-spotting. We had a thread recently where we discussed how
>>>>> tension might affect propensity to flat-spot. With high tensions the rim
>>>>> will flat spot more easily if it reaches yield stress before the spokes
>>>>> go slack.
>>>> But it won't, as you can see if you use numbers.
>>> Maybe you can see that, but I don't find it so easy to work out.
>>>
>>> I don't know how to work out how many spokes go slack and by how much
>>> for a given load except with an FEA, or, better still, trying it on an
>>> actual wheel.
>> Well, then perhaps you shouldn't be making such claims.
>
> What claims exactly did I make?
>
> I was trying to discuss with Tom Sherman his proposal that a rim whose
> spoke bed cracks when built to just-sub-taco tension is sub-optimally
> designed.
>
> I thought perhaps he hadn't thought of the possibility of rim yield, or
> that, if he had, perhaps he had some more light to shed on the subject
> of why it might not be a factor.
>
> I got the impression from the next few posts that he hadn't thought of
> it, so I think I was right to bring it up.
>
> I suspect that it is a factor until I see evidence or a convincing
> explanation why it is likely not to be.
>
> You have quoted me out of context above. Tom asked something like "a rim
> can yield in many ways, which one are you thinking of?". I replied
> "probably flat-spotting" meaning that that was the failure mode related
> to rim yield that I considered most likely (and easiest to explain) out
> of all failure modes to be promoted by excessive spoke tension.
"With high tensions the rim
>>>>> will flat spot more easily if it reaches yield stress before the
spokes
>>>>> go slack."
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Date: 06 Nov 2007 06:42:27
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-06, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
[...]
> "With high tensions the rim
> >>>>> will flat spot more easily if it reaches yield stress before the
> spokes
> >>>>> go slack."
Well that's true isn't it? What's wrong with it?
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Date: 06 Nov 2007 10:34:48
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
> [...]
>> "With high tensions the rim
>>>>>>> will flat spot more easily if it reaches yield stress before the
>> spokes
>>>>>>> go slack."
>
> Well that's true isn't it? What's wrong with it?
As I said, it just doesn't happen. Look at the numbers, spokes go slack
with a displacement of around 1mm.
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Date: 06 Nov 2007 10:17:56
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-06, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>> [...]
>>> "With high tensions the rim
>>>>>>>> will flat spot more easily if it reaches yield stress before the
>>> spokes
>>>>>>>> go slack."
>>
>> Well that's true isn't it? What's wrong with it?
>
> As I said, it just doesn't happen. Look at the numbers, spokes go slack
> with a displacement of around 1mm.
Well I said _if_ it reaches yield stress before the spokes go slack.
You're saying it won't, which isn't quite the same as saying my
statement was false. But never mind, let's not quibble.
Your figure of 1mm is based on Ian Smith's FEA I think
(http://www.astounding.org.uk/ian/wheel/index.html).
He's modelling a rim with a similar section to an MA-2 with 36 spokes.
It's not obvious how things change when you use a stiffer rim with a
deeper cross-section.
But I have another question:
That displacement doesn't tell you anything about the total stress on
the rim. It tells you what the change in stress was when loading was
applied (if you know the stiffness).
If the whole rim is highly precompressed by spoke tension almost to the
point of yielding, then a 1mm displacement _will_ be enough to flat-spot
it?
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Date: 06 Nov 2007 13:31:06
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>>> Ben C wrote:
>>> [...]
>>>> "With high tensions the rim
>>>>>>>>> will flat spot more easily if it reaches yield stress before the
>>>> spokes
>>>>>>>>> go slack."
>>> Well that's true isn't it? What's wrong with it?
>> As I said, it just doesn't happen. Look at the numbers, spokes go slack
>> with a displacement of around 1mm.
>
> Well I said _if_ it reaches yield stress before the spokes go slack.
> You're saying it won't, which isn't quite the same as saying my
> statement was false. But never mind, let's not quibble.
Your statement assumes it can happen, it can't.
> Your figure of 1mm is based on Ian Smith's FEA I think
> (http://www.astounding.org.uk/ian/wheel/index.html).
>
> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
> It's not obvious how things change when you use a stiffer rim with a
> deeper cross-section.
It's not that complicated, you just have to know the elasticity of a spoke.
> But I have another question:
>
> That displacement doesn't tell you anything about the total stress on
> the rim. It tells you what the change in stress was when loading was
> applied (if you know the stiffness).
Doesn't matter, spoke will be slack at ~1mm, the most a rim can be
permanently bent after that will be much less than 1mm.
> If the whole rim is highly precompressed by spoke tension almost to the
> point of yielding, then a 1mm displacement _will_ be enough to flat-spot
> it?
No.
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Date: 06 Nov 2007 14:37:09
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-06, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
[...]
>> Your figure of 1mm is based on Ian Smith's FEA I think
>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>
>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>> It's not obvious how things change when you use a stiffer rim with a
>> deeper cross-section.
>
> It's not that complicated, you just have to know the elasticity of a
> spoke.
I would have thought the stiffness of the rim would also influence how
many spokes went slack, and therefore by how much, for a given load.
[...]
>> But I have another question:
>>
>> That displacement doesn't tell you anything about the total stress on
>> the rim. It tells you what the change in stress was when loading was
>> applied (if you know the stiffness).
>
> Doesn't matter, spoke will be slack at ~1mm, the most a rim can be
> permanently bent after that will be much less than 1mm.
Well I think I'd still rather not have a flat spot, even if it were only
1mm, than have one.
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Date: 06 Nov 2007 16:19:53
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
> [...]
>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>
>>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>>> It's not obvious how things change when you use a stiffer rim with a
>>> deeper cross-section.
>> It's not that complicated, you just have to know the elasticity of a
>> spoke.
>
> I would have thought the stiffness of the rim would also influence how
> many spokes went slack, and therefore by how much, for a given load.
Well, that wasn't your initial issue. In any case, it doesn't really
matter, the spokes will go slack before the rim deforms, how much load
that takes is proportional to spoke tension.
>
> [...]
>>> But I have another question:
>>>
>>> That displacement doesn't tell you anything about the total stress on
>>> the rim. It tells you what the change in stress was when loading was
>>> applied (if you know the stiffness).
>> Doesn't matter, spoke will be slack at ~1mm, the most a rim can be
>> permanently bent after that will be much less than 1mm.
>
> Well I think I'd still rather not have a flat spot, even if it were only
> 1mm, than have one.
Then make your spokes tight.
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Date: 06 Nov 2007 15:56:42
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-06, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>> [...]
>>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>>
>>>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>>>> It's not obvious how things change when you use a stiffer rim with a
>>>> deeper cross-section.
>>> It's not that complicated, you just have to know the elasticity of a
>>> spoke.
>>
>> I would have thought the stiffness of the rim would also influence how
>> many spokes went slack, and therefore by how much, for a given load.
>
> Well, that wasn't your initial issue. In any case, it doesn't really
> matter, the spokes will go slack before the rim deforms, how much load
> that takes is proportional to spoke tension.
The rim deforms _as_ the spokes go slack, or they wouldn't go slack.
If you meant to say "before the rim deforms plastically", then I don't
believe you know that. Or if you do you aren't sharing your calculations
with the rest of us.
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Date: 06 Nov 2007 20:15:23
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>>> Ben C wrote:
>>> [...]
>>>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>>>
>>>>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>>>>> It's not obvious how things change when you use a stiffer rim with a
>>>>> deeper cross-section.
>>>> It's not that complicated, you just have to know the elasticity of a
>>>> spoke.
>>> I would have thought the stiffness of the rim would also influence how
>>> many spokes went slack, and therefore by how much, for a given load.
>> Well, that wasn't your initial issue. In any case, it doesn't really
>> matter, the spokes will go slack before the rim deforms, how much load
>> that takes is proportional to spoke tension.
>
> The rim deforms _as_ the spokes go slack, or they wouldn't go slack.
absolutely right!
>
> If you meant to say "before the rim deforms plastically", then I don't
> believe you know that. Or if you do you aren't sharing your calculations
> with the rest of us.
he's badly confused. elasticity precedes plasticity. if the rim is
compressed to its elastic limit, plasticity follows, and does do at the
tiniest of additional displacements.
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Date: 07 Nov 2007 02:08:53
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-07, jim beam <spamvortex@bad.example.net > wrote:
> Ben C wrote:
[...]
>> If you meant to say "before the rim deforms plastically", then I don't
>> believe you know that. Or if you do you aren't sharing your calculations
>> with the rest of us.
>
> he's badly confused. elasticity precedes plasticity. if the rim is
> compressed to its elastic limit, plasticity follows, and does do at the
> tiniest of additional displacements.
Yes, that's what I thought.
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Date: 06 Nov 2007 19:05:38
From: Peter Cole
Subject: Re: Spoke tension Question
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Ben C wrote:
> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>>> Ben C wrote:
>>> [...]
>>>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>>>
>>>>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>>>>> It's not obvious how things change when you use a stiffer rim with a
>>>>> deeper cross-section.
>>>> It's not that complicated, you just have to know the elasticity of a
>>>> spoke.
>>> I would have thought the stiffness of the rim would also influence how
>>> many spokes went slack, and therefore by how much, for a given load.
>> Well, that wasn't your initial issue. In any case, it doesn't really
>> matter, the spokes will go slack before the rim deforms, how much load
>> that takes is proportional to spoke tension.
>
> The rim deforms _as_ the spokes go slack, or they wouldn't go slack.
>
> If you meant to say "before the rim deforms plastically", then I don't
> believe you know that. Or if you do you aren't sharing your calculations
> with the rest of us.
The most a rim can deform before spokes slack is ~1mm. That's not enough
to permanently deform.
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Date: 07 Nov 2007 02:06:52
From: Ben C
Subject: Re: Spoke tension Question
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On 2007-11-07, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>>>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>>>> Ben C wrote:
>>>> [...]
>>>>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>>>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>>>>
>>>>>> He's modelling a rim with a similar section to an MA-2 with 36 spokes.
>>>>>> It's not obvious how things change when you use a stiffer rim with a
>>>>>> deeper cross-section.
>>>>> It's not that complicated, you just have to know the elasticity of a
>>>>> spoke.
>>>> I would have thought the stiffness of the rim would also influence how
>>>> many spokes went slack, and therefore by how much, for a given load.
>>> Well, that wasn't your initial issue. In any case, it doesn't really
>>> matter, the spokes will go slack before the rim deforms, how much load
>>> that takes is proportional to spoke tension.
>>
>> The rim deforms _as_ the spokes go slack, or they wouldn't go slack.
>>
>> If you meant to say "before the rim deforms plastically", then I don't
>> believe you know that. Or if you do you aren't sharing your calculations
>> with the rest of us.
>
> The most a rim can deform before spokes slack is ~1mm. That's not enough
> to permanently deform.
That ~1mm is the _change in deformation_, not the total deformation. The
rim is already precompressed. That extra ~1mm could bring it to yield if
it has enough precompression.
And ~1mm is not an upper bound. It's an estimate based on an FEA of a
particular rim. In particular the tyre wasn't simulated-- Ian says:
"The only possibly significant simplification in this (I believe) is
that the loading distribution is just a fudge which I guessed to be
vaguely similar to the real situation for a touring type tyre. I've
discussed this with someone who's actually measured some contact
patches (loaded inked wheels on panes on glass and so on), who told
me that my guess was pretty good."
Note also what the stated purpose of that analysis was:
"The purpose of this page is to consider a common question about
bicycle type wheels: does the hub hang from the top spokes, or press
on the lower spokes. Alternatively, does it do something
in-between?"
It answers that question very well. But that doesn't mean the actual
numbers are all that accurate.
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Date: 07 Nov 2007 08:55:53
From: Peter Cole
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>> to permanently deform.
>
> That ~1mm is the _change in deformation_, not the total deformation. The
> rim is already precompressed.
Spoke tension causes a circumferential force, load/impact a radial
force, they are orthogonal.
The stress from spoke tension is the circumferential force divided by
the rim cross section area, nominally estimated to be <1/4 of yield.
> That extra ~1mm could bring it to yield if
> it has enough precompression.
Theoretically, but if you consider it would require ~4x nominal spoke
tension to get that rim compression, that would be very difficult. Worst
case, that would only give a conceivable maximum 1mm yield.
>
> And ~1mm is not an upper bound. It's an estimate based on an FEA of a
> particular rim. In particular the tyre wasn't simulated-- Ian says:
Again, the actual deflection before the spoke goes slack is easily
determined from the spoke elasticity, that's all you need to know. The
actual number for a thin spoke at 100kgf is 0.75mm, more tension means
more deflection (linear), thicker spokes mean less, 1mm is a
conservative estimate. You don't need the FEA.
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Date: 07 Nov 2007 08:52:28
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-07, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>
>>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>>> to permanently deform.
>>
>> That ~1mm is the _change in deformation_, not the total deformation. The
>> rim is already precompressed.
>
> Spoke tension causes a circumferential force, load/impact a radial
> force, they are orthogonal.
But the spokes are pulling radially so isn't that also a radial force?
> The stress from spoke tension is the circumferential force divided by
> the rim cross section area, nominally estimated to be <1/4 of yield.
Now I'm lost. How do you get that estimate?
>> That extra ~1mm could bring it to yield if
>> it has enough precompression.
>
> Theoretically, but if you consider it would require ~4x nominal spoke
> tension to get that rim compression, that would be very difficult. Worst
> case, that would only give a conceivable maximum 1mm yield.
Not sure what you mean by ~4x nominal spoke tension.
But anyway, if the rim is flimsy enough that 1500N spoke tension brings
it right up to yield, then yes, there is a maximum ~1mm deep
deformation.
>> And ~1mm is not an upper bound. It's an estimate based on an FEA of a
>> particular rim. In particular the tyre wasn't simulated-- Ian says:
>
> Again, the actual deflection before the spoke goes slack is easily
> determined from the spoke elasticity, that's all you need to know. The
> actual number for a thin spoke at 100kgf is 0.75mm, more tension means
> more deflection (linear), thicker spokes mean less, 1mm is a
> conservative estimate. You don't need the FEA.
Yes, I figured that out eventually.
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Date: 07 Nov 2007 11:22:40
From: Peter Cole
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>>>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>>>> to permanently deform.
>>> That ~1mm is the _change in deformation_, not the total deformation. The
>>> rim is already precompressed.
>> Spoke tension causes a circumferential force, load/impact a radial
>> force, they are orthogonal.
>
> But the spokes are pulling radially so isn't that also a radial force?
Yes, but (locally) when the spoke goes slake, that component is gone.
>> The stress from spoke tension is the circumferential force divided by
>> the rim cross section area, nominally estimated to be <1/4 of yield.
>
> Now I'm lost. How do you get that estimate?
From Jobst's book -- it gives the circumferential force. Stress is
force/area, so it's easy (if you have the cross section area) to compute
the stress (which is uniform across the cross section).
>>> That extra ~1mm could bring it to yield if
>>> it has enough precompression.
>> Theoretically, but if you consider it would require ~4x nominal spoke
>> tension to get that rim compression, that would be very difficult. Worst
>> case, that would only give a conceivable maximum 1mm yield.
>
> Not sure what you mean by ~4x nominal spoke tension.
If you calculate the stress from rim compression, you get somewhere
around 70MPa, about 1/4 yield, you'd have to increase the spoke tension
4x to bring the cross section into the region of yield (but the spokes
would snap, and/or the rim would buckle long before that).
> But anyway, if the rim is flimsy enough that 1500N spoke tension brings
> it right up to yield, then yes, there is a maximum ~1mm deep
> deformation.
No rim is that flimsy, not even the old school ones.
>
>>> And ~1mm is not an upper bound. It's an estimate based on an FEA of a
>>> particular rim. In particular the tyre wasn't simulated-- Ian says:
>> Again, the actual deflection before the spoke goes slack is easily
>> determined from the spoke elasticity, that's all you need to know. The
>> actual number for a thin spoke at 100kgf is 0.75mm, more tension means
>> more deflection (linear), thicker spokes mean less, 1mm is a
>> conservative estimate. You don't need the FEA.
>
> Yes, I figured that out eventually.
Keep going.
|
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Date: 07 Nov 2007 11:15:58
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-07, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>>>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>>>>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>>>>> to permanently deform.
>>>> That ~1mm is the _change in deformation_, not the total deformation. The
>>>> rim is already precompressed.
>>> Spoke tension causes a circumferential force, load/impact a radial
>>> force, they are orthogonal.
>>
>> But the spokes are pulling radially so isn't that also a radial force?
>
> Yes, but (locally) when the spoke goes slake, that component is gone.
I was talking about the rim yielding due to the radial tension + load,
i.e. yielding that might happen _before_ the spoke above the contact
patch has gone slack.
But I see your point-- the spokes directly above the bit that's
potentially flat-spotting may be slack, but the other spokes are still
contributing a bit of compressive stress because of the circumferential
force. I hadn't even considered that.
[...]
>> Not sure what you mean by ~4x nominal spoke tension.
>
> If you calculate the stress from rim compression, you get somewhere
> around 70MPa, about 1/4 yield, you'd have to increase the spoke tension
> 4x to bring the cross section into the region of yield (but the spokes
> would snap, and/or the rim would buckle long before that).
I see.
Perhaps I can use this: http://en.wikipedia.org/wiki/Pressure_vessel,
thinking of the wheel as a cylinder and the spokes collectively as a
sort of gas inside it.
36 spokes, 1500N each: 54000N
Radius (r): 0.3m
Thickness of wall (t): 0.02m
Width of rim: 0.02m
Area of rim: 2*pi*r * 0.02m = 0.037 m^2
Pressure on inside of rim (p): 54000 / 0.037 = 1430000 N/m^2
hoop stress = pr / t = 21MPa.
Hmm, not quite right, but then the rim is actually a box section, for
one thing.
>> But anyway, if the rim is flimsy enough that 1500N spoke tension brings
>> it right up to yield, then yes, there is a maximum ~1mm deep
>> deformation.
>
> No rim is that flimsy, not even the old school ones.
Yes, and certainly not if normal spoke tension brings the rim to 1/4
yield.
|
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Date: 08 Nov 2007 21:13:30
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>> Ben C wrote:
>>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>>>> Ben C wrote:
>>>>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
>>>>>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>>>>>> to permanently deform.
>>>>> That ~1mm is the _change in deformation_, not the total deformation. The
>>>>> rim is already precompressed.
>>>> Spoke tension causes a circumferential force, load/impact a radial
>>>> force, they are orthogonal.
>>> But the spokes are pulling radially so isn't that also a radial force?
>> Yes, but (locally) when the spoke goes slake, that component is gone.
>
> I was talking about the rim yielding due to the radial tension + load,
> i.e. yielding that might happen _before_ the spoke above the contact
> patch has gone slack.
>
> But I see your point-- the spokes directly above the bit that's
> potentially flat-spotting may be slack, but the other spokes are still
> contributing a bit of compressive stress because of the circumferential
> force. I hadn't even considered that.
>
> [...]
>>> Not sure what you mean by ~4x nominal spoke tension.
>> If you calculate the stress from rim compression, you get somewhere
>> around 70MPa, about 1/4 yield, you'd have to increase the spoke tension
>> 4x to bring the cross section into the region of yield (but the spokes
>> would snap, and/or the rim would buckle long before that).
>
> I see.
>
> Perhaps I can use this: http://en.wikipedia.org/wiki/Pressure_vessel,
> thinking of the wheel as a cylinder and the spokes collectively as a
> sort of gas inside it.
>
> 36 spokes, 1500N each: 54000N
> Radius (r): 0.3m
> Thickness of wall (t): 0.02m
>
> Width of rim: 0.02m
> Area of rim: 2*pi*r * 0.02m = 0.037 m^2
> Pressure on inside of rim (p): 54000 / 0.037 = 1430000 N/m^2
>
> hoop stress = pr / t = 21MPa.
>
> Hmm, not quite right, but then the rim is actually a box section, for
> one thing.
>
>>> But anyway, if the rim is flimsy enough that 1500N spoke tension brings
>>> it right up to yield, then yes, there is a maximum ~1mm deep
>>> deformation.
>> No rim is that flimsy, not even the old school ones.
>
> Yes, and certainly not if normal spoke tension brings the rim to 1/4
> yield.
the above assumes bulk yielding. the actual deformation zone is small,
and caused by bending - leverage alone causes significant stress. 21MPa
could be 10% of yield, but that's 10% less load required to cause a flat
spot.
|
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Date: 09 Nov 2007 02:22:46
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-09, jim beam <spamvortex@bad.example.net > wrote:
> Ben C wrote:
>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
[...]
>>>> Not sure what you mean by ~4x nominal spoke tension.
>>> If you calculate the stress from rim compression, you get somewhere
>>> around 70MPa, about 1/4 yield, you'd have to increase the spoke tension
>>> 4x to bring the cross section into the region of yield (but the spokes
>>> would snap, and/or the rim would buckle long before that).
>>
>> I see.
>>
>> Perhaps I can use this: http://en.wikipedia.org/wiki/Pressure_vessel,
>> thinking of the wheel as a cylinder and the spokes collectively as a
>> sort of gas inside it.
>>
>> 36 spokes, 1500N each: 54000N
>> Radius (r): 0.3m
>> Thickness of wall (t): 0.02m
>>
>> Width of rim: 0.02m
>> Area of rim: 2*pi*r * 0.02m = 0.037 m^2
>> Pressure on inside of rim (p): 54000 / 0.037 = 1430000 N/m^2
>>
>> hoop stress = pr / t = 21MPa.
>>
>> Hmm, not quite right, but then the rim is actually a box section, for
>> one thing.
>>
>>>> But anyway, if the rim is flimsy enough that 1500N spoke tension brings
>>>> it right up to yield, then yes, there is a maximum ~1mm deep
>>>> deformation.
>>> No rim is that flimsy, not even the old school ones.
>>
>> Yes, and certainly not if normal spoke tension brings the rim to 1/4
>> yield.
>
> the above assumes bulk yielding. the actual deformation zone is small,
> and caused by bending - leverage alone causes significant stress. 21MPa
> could be 10% of yield, but that's 10% less load required to cause a flat
> spot.
70MPa is likely to be a better figure than my probably incorrect
estimate of 21MPa.
But you're right: if it's hoop compression we're talking about, that's
still there (reduced a bit but still there) even when spokes above the
contact patch have gone slack. So the limit of ~1mm doesn't apply.
In this scenario the rim flat spots with slack spokes above it but
bending is assisted by the hoop compression contributed by other spokes
whose length is changing very little.
The problem is you have to set that against the number of spokes that go
slack. With tighter spokes fewer will go slack for a given load and so
the rim will be supported better-- less bending leverage.
|
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Date: 09 Nov 2007 05:48:34
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-09, jim beam <spamvortex@bad.example.net> wrote:
>> Ben C wrote:
>>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
> [...]
>>>>> Not sure what you mean by ~4x nominal spoke tension.
>>>> If you calculate the stress from rim compression, you get somewhere
>>>> around 70MPa, about 1/4 yield, you'd have to increase the spoke tension
>>>> 4x to bring the cross section into the region of yield (but the spokes
>>>> would snap, and/or the rim would buckle long before that).
>>> I see.
>>>
>>> Perhaps I can use this: http://en.wikipedia.org/wiki/Pressure_vessel,
>>> thinking of the wheel as a cylinder and the spokes collectively as a
>>> sort of gas inside it.
>>>
>>> 36 spokes, 1500N each: 54000N
>>> Radius (r): 0.3m
>>> Thickness of wall (t): 0.02m
>>>
>>> Width of rim: 0.02m
>>> Area of rim: 2*pi*r * 0.02m = 0.037 m^2
>>> Pressure on inside of rim (p): 54000 / 0.037 = 1430000 N/m^2
>>>
>>> hoop stress = pr / t = 21MPa.
>>>
>>> Hmm, not quite right, but then the rim is actually a box section, for
>>> one thing.
>>>
>>>>> But anyway, if the rim is flimsy enough that 1500N spoke tension brings
>>>>> it right up to yield, then yes, there is a maximum ~1mm deep
>>>>> deformation.
>>>> No rim is that flimsy, not even the old school ones.
>>> Yes, and certainly not if normal spoke tension brings the rim to 1/4
>>> yield.
>> the above assumes bulk yielding. the actual deformation zone is small,
>> and caused by bending - leverage alone causes significant stress. 21MPa
>> could be 10% of yield, but that's 10% less load required to cause a flat
>> spot.
>
> 70MPa is likely to be a better figure than my probably incorrect
> estimate of 21MPa.
>
> But you're right: if it's hoop compression we're talking about, that's
> still there (reduced a bit but still there) even when spokes above the
> contact patch have gone slack. So the limit of ~1mm doesn't apply.
>
> In this scenario the rim flat spots with slack spokes above it but
> bending is assisted by the hoop compression contributed by other spokes
> whose length is changing very little.
>
> The problem is you have to set that against the number of spokes that go
> slack. With tighter spokes fewer will go slack for a given load and so
> the rim will be supported better-- less bending leverage.
if the rim was infinitely stiff, the spoke tension distribution deltas
would be completely different. so, if you look at spoke slacking as a
function of rim deformation, you can start to see why modern wheels use
deeper rims and lower spoke counts with spoke tension remaining about
the same.
|
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Date: 09 Nov 2007 08:40:59
From: Peter Cole
Subject: Re: Spoke tension Question
|
Ben C wrote:
> But you're right: if it's hoop compression we're talking about, that's
> still there (reduced a bit but still there) even when spokes above the
> contact patch have gone slack. So the limit of ~1mm doesn't apply.
>
> In this scenario the rim flat spots with slack spokes above it but
> bending is assisted by the hoop compression contributed by other spokes
> whose length is changing very little.
>
> The problem is you have to set that against the number of spokes that go
> slack. With tighter spokes fewer will go slack for a given load and so
> the rim will be supported better-- less bending leverage.
Flat spotting is caused by striking a hole edge or some other uneven
surface, causing very local deformation. Under normal (flat surface)
loading, a 36 spoke wheel will see 1/2 the spoke change in tension in
adjacent spokes compared to the spoke directly above the contact patch
(from FEA). One could only assume that an uneven surface would cause
even more concentrated deformation.
The salient point is that when the spoke at load center becomes slack
(~1mm), the rim is no longer supported in this area, but will be still
supported by adjacent spokes. This causes a dramatic change in local
stiffness, with additional force causing proportionally greater rim
deflection.
The circumferential compression from spoke tension causes a uniform
stress across the rim cross section, estimated to be in the order of
70Mpa for a nominal wheel (36x100kgf). Bending force will superimpose an
additional compression on the outer part of the rim (tension inner)
reaching a maximum at the outer skin.
My very rough estimate of bending stress for the nominal wheel in
Jobst's book gives perhaps 20MPa for 50kg load. Given that yield is at
least 250MPa, 70Mpa static stress gives an additional >180MPa of bending
stress before yield, or ~9x load (assuming no spoke slacking). The spoke
at the load point will go slack at approximately 5x load. It's not clear
that a 50% increase in spoke tension from the nominal 100kgf wouldn't
make a wheel that was less prone to flat spotting, it would approach
yield at around the same point as spoke slack, or about 7.5x load,
whereas the nominal wheel would slack at 5x, change stiffness at that
point, and be unsupported for the further 2.5x load. It's likely that
that greater bending stress (from loss of stiffness) would exceed the
additional static rim compression stress from increasing spoke tension 50%.
For rims significantly stiffer than the nominal, the change in stiffness
at spoke slack load may not be as large, but I'd guess the difference is
small when such rims are used with fewer (and stiffer) spokes.
|
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Date: 10 Nov 2007 12:11:44
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-09, Peter Cole <peter_cole@comcast.net > wrote:
> Ben C wrote:
>
>> But you're right: if it's hoop compression we're talking about, that's
>> still there (reduced a bit but still there) even when spokes above the
>> contact patch have gone slack. So the limit of ~1mm doesn't apply.
>>
>> In this scenario the rim flat spots with slack spokes above it but
>> bending is assisted by the hoop compression contributed by other spokes
>> whose length is changing very little.
>>
>> The problem is you have to set that against the number of spokes that go
>> slack. With tighter spokes fewer will go slack for a given load and so
>> the rim will be supported better-- less bending leverage.
>
> Flat spotting is caused by striking a hole edge or some other uneven
> surface, causing very local deformation. Under normal (flat surface)
> loading, a 36 spoke wheel will see 1/2 the spoke change in tension in
> adjacent spokes compared to the spoke directly above the contact patch
> (from FEA).
Is that from Jobst's FEA? I think Ian was saying he had to guesstimate a
bit how the load distributes, since it depends on the tyre which is
difficult to model.
> One could only assume that an uneven surface would cause even more
> concentrated deformation.
Generally yes, although I suppose if the tyre were striking a concave
deformation that approximated its own radius the deformation might be
less concentrated.
> (~1mm), the rim is no longer supported in this area, but will be still
> supported by adjacent spokes. This causes a dramatic change in local
> stiffness, with additional force causing proportionally greater rim
> deflection.
>
> The circumferential compression from spoke tension causes a uniform
> stress across the rim cross section, estimated to be in the order of
> 70Mpa for a nominal wheel (36x100kgf). Bending force will superimpose an
> additional compression on the outer part of the rim (tension inner)
> reaching a maximum at the outer skin.
>
> My very rough estimate of bending stress for the nominal wheel in
> Jobst's book gives perhaps 20MPa for 50kg load. Given that yield is at
> least 250MPa, 70Mpa static stress gives an additional >180MPa of bending
> stress before yield, or ~9x load (assuming no spoke slacking). The spoke
> at the load point will go slack at approximately 5x load. It's not clear
> that a 50% increase in spoke tension from the nominal 100kgf wouldn't
> make a wheel that was less prone to flat spotting, it would approach
> yield at around the same point as spoke slack, or about 7.5x load,
> whereas the nominal wheel would slack at 5x, change stiffness at that
> point, and be unsupported for the further 2.5x load. It's likely that
> that greater bending stress (from loss of stiffness) would exceed the
> additional static rim compression stress from increasing spoke tension 50%.
Why does loss of stiffness result in greater bending stress?
I think you get greater bending moment (and therefore stress) as a
result of losing the support of some of the spokes as they go slack
(railroad ties). Is that what you mean or are you talking about
something else?
> For rims significantly stiffer than the nominal, the change in stiffness
> at spoke slack load may not be as large, but I'd guess the difference is
> small when such rims are used with fewer (and stiffer) spokes.
|
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Date: 07 Nov 2007 04:06:45
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-07, Ben C <spamspam@spam.eggs > wrote:
> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
[...]
>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>> to permanently deform.
>
> That ~1mm is the _change in deformation_, not the total deformation. The
> rim is already precompressed. That extra ~1mm could bring it to yield if
> it has enough precompression.
>
> And ~1mm is not an upper bound. It's an estimate based on an FEA of a
> particular rim. In particular the tyre wasn't simulated-- Ian says:
>
> "The only possibly significant simplification in this (I believe) is
> that the loading distribution is just a fudge which I guessed to be
> vaguely similar to the real situation for a touring type tyre. I've
> discussed this with someone who's actually measured some contact
> patches (loaded inked wheels on panes on glass and so on), who told
> me that my guess was pretty good."
>
> Note also what the stated purpose of that analysis was:
>
> "The purpose of this page is to consider a common question about
> bicycle type wheels: does the hub hang from the top spokes, or press
> on the lower spokes. Alternatively, does it do something
> in-between?"
>
> It answers that question very well. But that doesn't mean the actual
> numbers are all that accurate.
These unknowns mostly relate to how many spokes the load is distributed
between. That tells you how long the flat spot is, not how deep.
The maximum depth of the flat spot can be estimated pretty well from
spoke elasticity (which I think Peter Cole said in an earlier post).
So, if the spoke is 293mm long, has a diameter of 2mm, a Young's modulus
of 205GPa, and is at a tension of 1500N, I make it only a 0.68mm
reduction in length before it's gone slack.
That is an upper bound for the depth of the flat spot that can be
precipitated by excessive spoke tension. In other words: very small.
|
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Date: 07 Nov 2007 09:17:41
From: Peter Cole
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-07, Ben C <spamspam@spam.eggs> wrote:
>> On 2007-11-07, Peter Cole <peter_cole@comcast.net> wrote:
> [...]
>>> The most a rim can deform before spokes slack is ~1mm. That's not enough
>>> to permanently deform.
>> That ~1mm is the _change in deformation_, not the total deformation. The
>> rim is already precompressed. That extra ~1mm could bring it to yield if
>> it has enough precompression.
>>
>> And ~1mm is not an upper bound. It's an estimate based on an FEA of a
>> particular rim. In particular the tyre wasn't simulated-- Ian says:
>>
>> "The only possibly significant simplification in this (I believe) is
>> that the loading distribution is just a fudge which I guessed to be
>> vaguely similar to the real situation for a touring type tyre. I've
>> discussed this with someone who's actually measured some contact
>> patches (loaded inked wheels on panes on glass and so on), who told
>> me that my guess was pretty good."
>>
>> Note also what the stated purpose of that analysis was:
>>
>> "The purpose of this page is to consider a common question about
>> bicycle type wheels: does the hub hang from the top spokes, or press
>> on the lower spokes. Alternatively, does it do something
>> in-between?"
>>
>> It answers that question very well. But that doesn't mean the actual
>> numbers are all that accurate.
>
> These unknowns mostly relate to how many spokes the load is distributed
> between. That tells you how long the flat spot is, not how deep.
>
> The maximum depth of the flat spot can be estimated pretty well from
> spoke elasticity (which I think Peter Cole said in an earlier post).
>
> So, if the spoke is 293mm long, has a diameter of 2mm, a Young's modulus
> of 205GPa, and is at a tension of 1500N, I make it only a 0.68mm
> reduction in length before it's gone slack.
>
> That is an upper bound for the depth of the flat spot that can be
> precipitated by excessive spoke tension. In other words: very small.
It's the theoretical upper bound, the practical is much lower. This also
sets the limit for the possible deleterious effect of "borrowing" rim
strength. This "borrowing" is, of course, offset by the advantage gained
by supporting the rim with the spokes, elements which are 2-4x as stiff.
Spokes do serve a purpose.
|
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Date: 06 Nov 2007 20:15:06
From: jim beam
Subject: Re: Spoke tension Question
|
Peter Cole wrote:
> Ben C wrote:
>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>> Ben C wrote:
>>>> On 2007-11-06, Peter Cole <peter_cole@comcast.net> wrote:
>>>>> Ben C wrote:
>>>> [...]
>>>>>> Your figure of 1mm is based on Ian Smith's FEA I think
>>>>>> (http://www.astounding.org.uk/ian/wheel/index.html).
>>>>>>
>>>>>> He's modelling a rim with a similar section to an MA-2 with 36
>>>>>> spokes.
>>>>>> It's not obvious how things change when you use a stiffer rim with a
>>>>>> deeper cross-section.
>>>>> It's not that complicated, you just have to know the elasticity of a
>>>>> spoke.
>>>> I would have thought the stiffness of the rim would also influence how
>>>> many spokes went slack, and therefore by how much, for a given load.
>>> Well, that wasn't your initial issue. In any case, it doesn't really
>>> matter, the spokes will go slack before the rim deforms, how much
>>> load that takes is proportional to spoke tension.
>>
>> The rim deforms _as_ the spokes go slack, or they wouldn't go slack.
>>
>> If you meant to say "before the rim deforms plastically", then I don't
>> believe you know that. Or if you do you aren't sharing your calculations
>> with the rest of us.
>
> The most a rim can deform before spokes slack is ~1mm. That's not enough
> to permanently deform.
you're scary. such an ignorant blanket statement, in a thread where,
yet again, you evidence not understanding the distinction between
elasticity and plasticity, is just ridiculous.
|
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Date: 03 Nov 2007 15:59:19
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ben C? wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ozark Bicycle wrote:
>>> [...]
>>>>> IME, many modern profile rims will have their recommended spoke
>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>> Jobst Brandt....
>>>> Then these rims are poorly designed, since there is excess material that
>>>> creates stiffness in bending that is greater than the wheel needs to
>>>> remain true at maximum allowable spoke tension. The rim could be made
>>>> lighter for a given WHEEL strength, or the same weight rim could be
>>>> redesigned to allow for a stronger overall WHEEL.
>>> I hear this a lot but isn't this based on the premise that the
>>> performance of a wheel is solely a function of how much spoke tension it
>>> can support?
>>>
>>> That seems to leave yield strength of the rim itself completely out of
>>> the equation.
>> There are several different ways a rim can yield. Which of these are you
>> referring to?
>
> Probably flat-spotting. We had a thread recently where we discussed how
> tension might affect propensity to flat-spot. With high tensions the rim
> will flat spot more easily if it reaches yield stress before the spokes
> go slack.
>
> This would be an interesting experiment to do: build a wheel with high
> tension, and keep loading it (weight downwards on the hub, the same
> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
> adding weights until the tension goes to almost but not quite zero.
> Remove weights. Check rim for permanent deformation. If it has deformed
> permanently, then reduction in rim yield strength due to spoke tension
> is a real issue.
But if the spoke tension were less, the rim would permanently deform
with the bottom spokes in a slack condition in this test? What would
lower spoke tension gain in return for its known demerits?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
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Date: 04 Nov 2007 09:52:05
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Nov 4, 9:47 am, jim beam <spamvor...@bad.example.net > wrote:
> Tom Sherman wrote:
> > "jim beam" wrote:
> >> Tom Sherman wrote:
> >>> "jim beam" wrote:
> >>>> Tom Sherman wrote:
> >>>> <snip obstinate crap>
>
> >>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>
> >>> "jim beam" has proved that a wheel missing a few spokes can support a
> >>> static load in one (1) orientation. Very useful.
>
> >> in the *worst* orientation. any other is easier. go ahead and do
> >> your own research big guy. you have the components. put your money
> >> where your [bored and useless] mouth is.
>
> > Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
> > contentions? Inquiring minds want to know!
>
> ok, now you're being stupid. instead of sitting behind that screen
> where it's safe, /you/ put some skin in the game and try to prove me
> wrong.
Sherman will never do such a thing. He actually has no interest in
anything other than an endless arguement. Remember, this is the guy
who dragged Ed Dolan to RBT after they (Dolan and Sherman) laid waste
to the ARBR group.
The best way to deal with Sherman is to just ignore him and let him
post into a void the way Dolan does these days. Eventually, he'll
inflict himself somewhere else ( rec.bicycles.mental-masturbation?).
|
| | | | | | | | |
Date: 04 Nov 2007 12:01:05
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ozark Bicycle wrote:
> On Nov 4, 9:47 am, jim beam <spamvor...@bad.example.net> wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>> <snip obstinate crap>
>>>>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>>>> "jim beam" has proved that a wheel missing a few spokes can support a
>>>>> static load in one (1) orientation. Very useful.
>>>> in the *worst* orientation. any other is easier. go ahead and do
>>>> your own research big guy. you have the components. put your money
>>>> where your [bored and useless] mouth is.
>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
>>> contentions? Inquiring minds want to know!
>> ok, now you're being stupid. instead of sitting behind that screen
>> where it's safe, /you/ put some skin in the game and try to prove me
>> wrong.
>
> Sherman will never do such a thing. He actually has no interest in
> anything other than an endless arguement. Remember, this is the guy
> who dragged Ed Dolan to RBT after they (Dolan and Sherman) laid waste
> to the ARBR group.
No Zarkie, Mr. Ed followed me around.
> The best way to deal with Sherman is to just ignore him and let him
> post into a void the way Dolan does these days. Eventually, he'll
> inflict himself somewhere else ( rec.bicycles.mental-masturbation?).
Not following your own advice, Zarkie?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | |
Date: 03 Nov 2007 18:30:57
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Ben C? wrote:
>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> Ozark Bicycle wrote:
>>>> [...]
>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>>> Jobst Brandt....
>>>>> Then these rims are poorly designed, since there is excess material
>>>>> that creates stiffness in bending that is greater than the wheel
>>>>> needs to remain true at maximum allowable spoke tension. The rim
>>>>> could be made lighter for a given WHEEL strength, or the same
>>>>> weight rim could be redesigned to allow for a stronger overall WHEEL.
>>>> I hear this a lot but isn't this based on the premise that the
>>>> performance of a wheel is solely a function of how much spoke
>>>> tension it
>>>> can support?
>>>>
>>>> That seems to leave yield strength of the rim itself completely out of
>>>> the equation.
>>> There are several different ways a rim can yield. Which of these are
>>> you referring to?
>>
>> Probably flat-spotting. We had a thread recently where we discussed how
>> tension might affect propensity to flat-spot. With high tensions the rim
>> will flat spot more easily if it reaches yield stress before the spokes
>> go slack.
>>
>> This would be an interesting experiment to do: build a wheel with high
>> tension, and keep loading it (weight downwards on the hub, the same
>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>> adding weights until the tension goes to almost but not quite zero.
>> Remove weights. Check rim for permanent deformation. If it has deformed
>> permanently, then reduction in rim yield strength due to spoke tension
>> is a real issue.
>
> But if the spoke tension were less, the rim would permanently deform
> with the bottom spokes in a slack condition in this test?
that's not my experience.
http://www.flickr.com/photos/38636024@N00/417157612/
> What would
> lower spoke tension gain in return for its known demerits?
"known demerits"? like the presumption that wheels collapse as soon as
a spoke goes loose?
http://www.flickr.com/photos/38636024@N00/417157612/
|
| | | | | | | | |
Date: 03 Nov 2007 20:36:17
From: Tom Sherman
Subject: Re: Spoke tension Question
|
jim beam wrote:
> Tom Sherman wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>> Ozark Bicycle wrote:
>>>>> [...]
>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>>>> Jobst Brandt....
>>>>>> Then these rims are poorly designed, since there is excess
>>>>>> material that creates stiffness in bending that is greater than
>>>>>> the wheel needs to remain true at maximum allowable spoke tension.
>>>>>> The rim could be made lighter for a given WHEEL strength, or the
>>>>>> same weight rim could be redesigned to allow for a stronger
>>>>>> overall WHEEL.
>>>>> I hear this a lot but isn't this based on the premise that the
>>>>> performance of a wheel is solely a function of how much spoke
>>>>> tension it
>>>>> can support?
>>>>>
>>>>> That seems to leave yield strength of the rim itself completely out of
>>>>> the equation.
>>>> There are several different ways a rim can yield. Which of these are
>>>> you referring to?
>>>
>>> Probably flat-spotting. We had a thread recently where we discussed how
>>> tension might affect propensity to flat-spot. With high tensions the rim
>>> will flat spot more easily if it reaches yield stress before the spokes
>>> go slack.
>>>
>>> This would be an interesting experiment to do: build a wheel with high
>>> tension, and keep loading it (weight downwards on the hub, the same
>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>> adding weights until the tension goes to almost but not quite zero.
>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>> permanently, then reduction in rim yield strength due to spoke tension
>>> is a real issue.
>>
>> But if the spoke tension were less, the rim would permanently deform
>> with the bottom spokes in a slack condition in this test?
>
> that's not my experience.
>
> http://www.flickr.com/photos/38636024@N00/417157612/
>
>> What would lower spoke tension gain in return for its known demerits?
>
> "known demerits"? like the presumption that wheels collapse as soon as
> a spoke goes loose?
>
> http://www.flickr.com/photos/38636024@N00/417157612/
Where is the video of that wheel being ridden, including some pothole
hits and hard braking?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | |
Date: 03 Nov 2007 18:45:42
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> jim beam wrote:
>> Tom Sherman wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> Ben C? wrote:
>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>> Ozark Bicycle wrote:
>>>>>> [...]
>>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>>>>> Jobst Brandt....
>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>> strength, or the same weight rim could be redesigned to allow for
>>>>>>> a stronger overall WHEEL.
>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>> tension it
>>>>>> can support?
>>>>>>
>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>> out of
>>>>>> the equation.
>>>>> There are several different ways a rim can yield. Which of these
>>>>> are you referring to?
>>>>
>>>> Probably flat-spotting. We had a thread recently where we discussed how
>>>> tension might affect propensity to flat-spot. With high tensions the
>>>> rim
>>>> will flat spot more easily if it reaches yield stress before the spokes
>>>> go slack.
>>>>
>>>> This would be an interesting experiment to do: build a wheel with high
>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>>> adding weights until the tension goes to almost but not quite zero.
>>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>> is a real issue.
>>>
>>> But if the spoke tension were less, the rim would permanently deform
>>> with the bottom spokes in a slack condition in this test?
>>
>> that's not my experience.
>>
>> http://www.flickr.com/photos/38636024@N00/417157612/
>>
>>> What would lower spoke tension gain in return for its known demerits?
>>
>> "known demerits"? like the presumption that wheels collapse as soon
>> as a spoke goes loose?
>>
>> http://www.flickr.com/photos/38636024@N00/417157612/
>
> Where is the video of that wheel being ridden, including some pothole
> hits and hard braking?
>
feel free to replicate tom. and include the video of the wheel
collapsing as soon as the spokes go slack.
|
| | | | | | | | | | |
Date: 03 Nov 2007 20:49:37
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> jim beam wrote:
>>> Tom Sherman wrote:
>>>> Ben C? wrote:
>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>> Ben C? wrote:
>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>> Ozark Bicycle wrote:
>>>>>>> [...]
>>>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>>>> tension maximum before fhey 'deform' per the method recommended by
>>>>>>>>> Jobst Brandt....
>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>>> strength, or the same weight rim could be redesigned to allow
>>>>>>>> for a stronger overall WHEEL.
>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>> tension it
>>>>>>> can support?
>>>>>>>
>>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>>> out of
>>>>>>> the equation.
>>>>>> There are several different ways a rim can yield. Which of these
>>>>>> are you referring to?
>>>>>
>>>>> Probably flat-spotting. We had a thread recently where we discussed
>>>>> how
>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>> the rim
>>>>> will flat spot more easily if it reaches yield stress before the
>>>>> spokes
>>>>> go slack.
>>>>>
>>>>> This would be an interesting experiment to do: build a wheel with high
>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>> thing it gets in use). Measure spoke tension in the bottom spokes.
>>>>> Keep
>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>> deformed
>>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>>> is a real issue.
>>>>
>>>> But if the spoke tension were less, the rim would permanently deform
>>>> with the bottom spokes in a slack condition in this test?
>>>
>>> that's not my experience.
>>>
>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>
>>>> What would lower spoke tension gain in return for its known demerits?
>>>
>>> "known demerits"? like the presumption that wheels collapse as soon
>>> as a spoke goes loose?
>>>
>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>
>> Where is the video of that wheel being ridden, including some pothole
>> hits and hard braking?
>>
>
> feel free to replicate tom. and include the video of the wheel
> collapsing as soon as the spokes go slack.
[Yawn] Here we go again. "jim beam" is making a claim, yet wants others
to (dis)prove it for him.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | |
Date: 03 Nov 2007 18:51:50
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> jim beam wrote:
>>>> Tom Sherman wrote:
>>>>> Ben C? wrote:
>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>> Ben C? wrote:
>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>> wrote:
>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>> [...]
>>>>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>> recommended by
>>>>>>>>>> Jobst Brandt....
>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>>>> strength, or the same weight rim could be redesigned to allow
>>>>>>>>> for a stronger overall WHEEL.
>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>>> tension it
>>>>>>>> can support?
>>>>>>>>
>>>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>>>> out of
>>>>>>>> the equation.
>>>>>>> There are several different ways a rim can yield. Which of these
>>>>>>> are you referring to?
>>>>>>
>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>> discussed how
>>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>>> the rim
>>>>>> will flat spot more easily if it reaches yield stress before the
>>>>>> spokes
>>>>>> go slack.
>>>>>>
>>>>>> This would be an interesting experiment to do: build a wheel with
>>>>>> high
>>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>>> thing it gets in use). Measure spoke tension in the bottom spokes.
>>>>>> Keep
>>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>> deformed
>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>> tension
>>>>>> is a real issue.
>>>>>
>>>>> But if the spoke tension were less, the rim would permanently
>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>
>>>> that's not my experience.
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>
>>>>> What would lower spoke tension gain in return for its known demerits?
>>>>
>>>> "known demerits"? like the presumption that wheels collapse as soon
>>>> as a spoke goes loose?
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>
>>> Where is the video of that wheel being ridden, including some pothole
>>> hits and hard braking?
>>>
>>
>> feel free to replicate tom. and include the video of the wheel
>> collapsing as soon as the spokes go slack.
>
> [Yawn] Here we go again. "jim beam" is making a claim, yet wants others
> to (dis)prove it for him.
>
i've posted the frigging data dude. /you/ want to expand the experiment
- /you/ do the frigging work!!!! geeze - it's not like you don't have
the time on your hands.
|
| | | | | | | | | | | | |
Date: 03 Nov 2007 21:55:07
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> jim beam wrote:
>>>>> Tom Sherman wrote:
>>>>>> Ben C? wrote:
>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>> Ben C? wrote:
>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>> wrote:
>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>> [...]
>>>>>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>> recommended by
>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>>> material that creates stiffness in bending that is greater
>>>>>>>>>> than the wheel needs to remain true at maximum allowable spoke
>>>>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>>>>> strength, or the same weight rim could be redesigned to allow
>>>>>>>>>> for a stronger overall WHEEL.
>>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>>>> tension it
>>>>>>>>> can support?
>>>>>>>>>
>>>>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>>>>> out of
>>>>>>>>> the equation.
>>>>>>>> There are several different ways a rim can yield. Which of these
>>>>>>>> are you referring to?
>>>>>>>
>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>> discussed how
>>>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>>>> the rim
>>>>>>> will flat spot more easily if it reaches yield stress before the
>>>>>>> spokes
>>>>>>> go slack.
>>>>>>>
>>>>>>> This would be an interesting experiment to do: build a wheel with
>>>>>>> high
>>>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>> spokes. Keep
>>>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>>> deformed
>>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>>> tension
>>>>>>> is a real issue.
>>>>>>
>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>
>>>>> that's not my experience.
>>>>>
>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>
>>>>>> What would lower spoke tension gain in return for its known demerits?
>>>>>
>>>>> "known demerits"? like the presumption that wheels collapse as
>>>>> soon as a spoke goes loose?
>>>>>
>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>
>>>> Where is the video of that wheel being ridden, including some
>>>> pothole hits and hard braking?
>>>>
>>>
>>> feel free to replicate tom. and include the video of the wheel
>>> collapsing as soon as the spokes go slack.
>>
>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>> others to (dis)prove it for him.
>>
>
> i've posted the frigging data dude. /you/ want to expand the experiment
> - /you/ do the frigging work!!!! geeze - it's not like you don't have
> the time on your hands.
No "jim", you are the one that claims the wheel with the missing spokes
is a functional wheel, not I. Post proof that this wheel can survive
normal use.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | |
Date: 03 Nov 2007 20:16:12
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> jim beam wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> Ben C? wrote:
>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>> wrote:
>>>>>>>>> Ben C? wrote:
>>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>>> wrote:
>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>> [...]
>>>>>>>>>>>> IME, many modern profile rims will have their recommended spoke
>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>> recommended by
>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>>>> material that creates stiffness in bending that is greater
>>>>>>>>>>> than the wheel needs to remain true at maximum allowable
>>>>>>>>>>> spoke tension. The rim could be made lighter for a given
>>>>>>>>>>> WHEEL strength, or the same weight rim could be redesigned to
>>>>>>>>>>> allow for a stronger overall WHEEL.
>>>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>>>>> tension it
>>>>>>>>>> can support?
>>>>>>>>>>
>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>> completely out of
>>>>>>>>>> the equation.
>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>> these are you referring to?
>>>>>>>>
>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>> discussed how
>>>>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>>>>> the rim
>>>>>>>> will flat spot more easily if it reaches yield stress before the
>>>>>>>> spokes
>>>>>>>> go slack.
>>>>>>>>
>>>>>>>> This would be an interesting experiment to do: build a wheel
>>>>>>>> with high
>>>>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>> spokes. Keep
>>>>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>>>> deformed
>>>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>>>> tension
>>>>>>>> is a real issue.
>>>>>>>
>>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>>
>>>>>> that's not my experience.
>>>>>>
>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>
>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>> demerits?
>>>>>>
>>>>>> "known demerits"? like the presumption that wheels collapse as
>>>>>> soon as a spoke goes loose?
>>>>>>
>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>
>>>>> Where is the video of that wheel being ridden, including some
>>>>> pothole hits and hard braking?
>>>>>
>>>>
>>>> feel free to replicate tom. and include the video of the wheel
>>>> collapsing as soon as the spokes go slack.
>>>
>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>> others to (dis)prove it for him.
>>>
>>
>> i've posted the frigging data dude. /you/ want to expand the
>> experiment - /you/ do the frigging work!!!! geeze - it's not like you
>> don't have the time on your hands.
>
> No "jim", you are the one that claims the wheel with the missing spokes
> is a functional wheel, not I. Post proof that this wheel can survive
> normal use.
>
since it seems to have escaped the analysis of your laser-sharp
engineering mind, i've done more than that - 205# is well above front
wheel "normal use" loading.
|
| | | | | | | | | | | | | | |
Date: 03 Nov 2007 22:45:18
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> jim beam wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> Ben C? wrote:
>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>> wrote:
>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>>> [...]
>>>>>>>>>>>>> IME, many modern profile rims will have their recommended
>>>>>>>>>>>>> spoke
>>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>>> recommended by
>>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>>>>> material that creates stiffness in bending that is greater
>>>>>>>>>>>> than the wheel needs to remain true at maximum allowable
>>>>>>>>>>>> spoke tension. The rim could be made lighter for a given
>>>>>>>>>>>> WHEEL strength, or the same weight rim could be redesigned
>>>>>>>>>>>> to allow for a stronger overall WHEEL.
>>>>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>>>>>> tension it
>>>>>>>>>>> can support?
>>>>>>>>>>>
>>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>>> completely out of
>>>>>>>>>>> the equation.
>>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>>> these are you referring to?
>>>>>>>>>
>>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>>> discussed how
>>>>>>>>> tension might affect propensity to flat-spot. With high
>>>>>>>>> tensions the rim
>>>>>>>>> will flat spot more easily if it reaches yield stress before
>>>>>>>>> the spokes
>>>>>>>>> go slack.
>>>>>>>>>
>>>>>>>>> This would be an interesting experiment to do: build a wheel
>>>>>>>>> with high
>>>>>>>>> tension, and keep loading it (weight downwards on the hub, the
>>>>>>>>> same
>>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>>> spokes. Keep
>>>>>>>>> adding weights until the tension goes to almost but not quite
>>>>>>>>> zero.
>>>>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>>>>> deformed
>>>>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>>>>> tension
>>>>>>>>> is a real issue.
>>>>>>>>
>>>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>>>
>>>>>>> that's not my experience.
>>>>>>>
>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>
>>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>>> demerits?
>>>>>>>
>>>>>>> "known demerits"? like the presumption that wheels collapse as
>>>>>>> soon as a spoke goes loose?
>>>>>>>
>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>
>>>>>> Where is the video of that wheel being ridden, including some
>>>>>> pothole hits and hard braking?
>>>>>>
>>>>>
>>>>> feel free to replicate tom. and include the video of the wheel
>>>>> collapsing as soon as the spokes go slack.
>>>>
>>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>>> others to (dis)prove it for him.
>>>>
>>>
>>> i've posted the frigging data dude. /you/ want to expand the
>>> experiment - /you/ do the frigging work!!!! geeze - it's not like
>>> you don't have the time on your hands.
>>
>> No "jim", you are the one that claims the wheel with the missing
>> spokes is a functional wheel, not I. Post proof that this wheel can
>> survive normal use.
>>
>
> since it seems to have escaped the analysis of your laser-sharp
> engineering mind, i've done more than that - 205# is well above front
> wheel "normal use" loading.
As an engineer, I will tell you that the wheel will be subjected to
significantly different loads during riding than during your static test
at one orientation.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | |
Date: 03 Nov 2007 20:49:10
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> jim beam wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>>> Ben C? wrote:
>>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>>> wrote:
>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>>>> [...]
>>>>>>>>>>>>>> IME, many modern profile rims will have their recommended
>>>>>>>>>>>>>> spoke
>>>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>>>> recommended by
>>>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>>>>>> material that creates stiffness in bending that is greater
>>>>>>>>>>>>> than the wheel needs to remain true at maximum allowable
>>>>>>>>>>>>> spoke tension. The rim could be made lighter for a given
>>>>>>>>>>>>> WHEEL strength, or the same weight rim could be redesigned
>>>>>>>>>>>>> to allow for a stronger overall WHEEL.
>>>>>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>>>>>> performance of a wheel is solely a function of how much
>>>>>>>>>>>> spoke tension it
>>>>>>>>>>>> can support?
>>>>>>>>>>>>
>>>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>>>> completely out of
>>>>>>>>>>>> the equation.
>>>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>>>> these are you referring to?
>>>>>>>>>>
>>>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>>>> discussed how
>>>>>>>>>> tension might affect propensity to flat-spot. With high
>>>>>>>>>> tensions the rim
>>>>>>>>>> will flat spot more easily if it reaches yield stress before
>>>>>>>>>> the spokes
>>>>>>>>>> go slack.
>>>>>>>>>>
>>>>>>>>>> This would be an interesting experiment to do: build a wheel
>>>>>>>>>> with high
>>>>>>>>>> tension, and keep loading it (weight downwards on the hub, the
>>>>>>>>>> same
>>>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>>>> spokes. Keep
>>>>>>>>>> adding weights until the tension goes to almost but not quite
>>>>>>>>>> zero.
>>>>>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>>>>>> deformed
>>>>>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>>>>>> tension
>>>>>>>>>> is a real issue.
>>>>>>>>>
>>>>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>>>>
>>>>>>>> that's not my experience.
>>>>>>>>
>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>
>>>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>>>> demerits?
>>>>>>>>
>>>>>>>> "known demerits"? like the presumption that wheels collapse as
>>>>>>>> soon as a spoke goes loose?
>>>>>>>>
>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>
>>>>>>> Where is the video of that wheel being ridden, including some
>>>>>>> pothole hits and hard braking?
>>>>>>>
>>>>>>
>>>>>> feel free to replicate tom. and include the video of the wheel
>>>>>> collapsing as soon as the spokes go slack.
>>>>>
>>>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>>>> others to (dis)prove it for him.
>>>>>
>>>>
>>>> i've posted the frigging data dude. /you/ want to expand the
>>>> experiment - /you/ do the frigging work!!!! geeze - it's not like
>>>> you don't have the time on your hands.
>>>
>>> No "jim", you are the one that claims the wheel with the missing
>>> spokes is a functional wheel, not I. Post proof that this wheel can
>>> survive normal use.
>>>
>>
>> since it seems to have escaped the analysis of your laser-sharp
>> engineering mind, i've done more than that - 205# is well above front
>> wheel "normal use" loading.
>
> As an engineer, I will tell you that the wheel will be subjected to
> significantly different loads during riding than during your static test
> at one orientation.
>
no shit. say, as an engineer, why didn't it collapse under excess
static loading?
|
| | | | | | | | | | | | | | | | |
Date: 03 Nov 2007 23:16:12
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> jim beam wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>>>>> [...]
>>>>>>>>>>>>>>> IME, many modern profile rims will have their recommended
>>>>>>>>>>>>>>> spoke
>>>>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>>>>> recommended by
>>>>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>>>>>>> material that creates stiffness in bending that is greater
>>>>>>>>>>>>>> than the wheel needs to remain true at maximum allowable
>>>>>>>>>>>>>> spoke tension. The rim could be made lighter for a given
>>>>>>>>>>>>>> WHEEL strength, or the same weight rim could be redesigned
>>>>>>>>>>>>>> to allow for a stronger overall WHEEL.
>>>>>>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>>>>>>> performance of a wheel is solely a function of how much
>>>>>>>>>>>>> spoke tension it
>>>>>>>>>>>>> can support?
>>>>>>>>>>>>>
>>>>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>>>>> completely out of
>>>>>>>>>>>>> the equation.
>>>>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>>>>> these are you referring to?
>>>>>>>>>>>
>>>>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>>>>> discussed how
>>>>>>>>>>> tension might affect propensity to flat-spot. With high
>>>>>>>>>>> tensions the rim
>>>>>>>>>>> will flat spot more easily if it reaches yield stress before
>>>>>>>>>>> the spokes
>>>>>>>>>>> go slack.
>>>>>>>>>>>
>>>>>>>>>>> This would be an interesting experiment to do: build a wheel
>>>>>>>>>>> with high
>>>>>>>>>>> tension, and keep loading it (weight downwards on the hub,
>>>>>>>>>>> the same
>>>>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>>>>> spokes. Keep
>>>>>>>>>>> adding weights until the tension goes to almost but not quite
>>>>>>>>>>> zero.
>>>>>>>>>>> Remove weights. Check rim for permanent deformation. If it
>>>>>>>>>>> has deformed
>>>>>>>>>>> permanently, then reduction in rim yield strength due to
>>>>>>>>>>> spoke tension
>>>>>>>>>>> is a real issue.
>>>>>>>>>>
>>>>>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>>>>>
>>>>>>>>> that's not my experience.
>>>>>>>>>
>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>>
>>>>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>>>>> demerits?
>>>>>>>>>
>>>>>>>>> "known demerits"? like the presumption that wheels collapse as
>>>>>>>>> soon as a spoke goes loose?
>>>>>>>>>
>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>
>>>>>>>> Where is the video of that wheel being ridden, including some
>>>>>>>> pothole hits and hard braking?
>>>>>>>>
>>>>>>>
>>>>>>> feel free to replicate tom. and include the video of the wheel
>>>>>>> collapsing as soon as the spokes go slack.
>>>>>>
>>>>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>>>>> others to (dis)prove it for him.
>>>>>>
>>>>>
>>>>> i've posted the frigging data dude. /you/ want to expand the
>>>>> experiment - /you/ do the frigging work!!!! geeze - it's not like
>>>>> you don't have the time on your hands.
>>>>
>>>> No "jim", you are the one that claims the wheel with the missing
>>>> spokes is a functional wheel, not I. Post proof that this wheel can
>>>> survive normal use.
>>>>
>>>
>>> since it seems to have escaped the analysis of your laser-sharp
>>> engineering mind, i've done more than that - 205# is well above front
>>> wheel "normal use" loading.
>>
>> As an engineer, I will tell you that the wheel will be subjected to
>> significantly different loads during riding than during your static
>> test at one orientation.
>>
>
> no shit.
Try more fiber and less Kentucky Bourbon in your diet.
> say, as an engineer, why didn't it collapse under excess
> static loading?
No torsional loading, no dynamic loading, only a single application of
the static load.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | |
Date: 03 Nov 2007 21:53:30
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>>> jim beam wrote:
>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>>>>>> [...]
>>>>>>>>>>>>>>>> IME, many modern profile rims will have their
>>>>>>>>>>>>>>>> recommended spoke
>>>>>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>>>>>> recommended by
>>>>>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>>>>>> Then these rims are poorly designed, since there is
>>>>>>>>>>>>>>> excess material that creates stiffness in bending that is
>>>>>>>>>>>>>>> greater than the wheel needs to remain true at maximum
>>>>>>>>>>>>>>> allowable spoke tension. The rim could be made lighter
>>>>>>>>>>>>>>> for a given WHEEL strength, or the same weight rim could
>>>>>>>>>>>>>>> be redesigned to allow for a stronger overall WHEEL.
>>>>>>>>>>>>>> I hear this a lot but isn't this based on the premise that
>>>>>>>>>>>>>> the
>>>>>>>>>>>>>> performance of a wheel is solely a function of how much
>>>>>>>>>>>>>> spoke tension it
>>>>>>>>>>>>>> can support?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>>>>>> completely out of
>>>>>>>>>>>>>> the equation.
>>>>>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>>>>>> these are you referring to?
>>>>>>>>>>>>
>>>>>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>>>>>> discussed how
>>>>>>>>>>>> tension might affect propensity to flat-spot. With high
>>>>>>>>>>>> tensions the rim
>>>>>>>>>>>> will flat spot more easily if it reaches yield stress before
>>>>>>>>>>>> the spokes
>>>>>>>>>>>> go slack.
>>>>>>>>>>>>
>>>>>>>>>>>> This would be an interesting experiment to do: build a wheel
>>>>>>>>>>>> with high
>>>>>>>>>>>> tension, and keep loading it (weight downwards on the hub,
>>>>>>>>>>>> the same
>>>>>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>>>>>> spokes. Keep
>>>>>>>>>>>> adding weights until the tension goes to almost but not
>>>>>>>>>>>> quite zero.
>>>>>>>>>>>> Remove weights. Check rim for permanent deformation. If it
>>>>>>>>>>>> has deformed
>>>>>>>>>>>> permanently, then reduction in rim yield strength due to
>>>>>>>>>>>> spoke tension
>>>>>>>>>>>> is a real issue.
>>>>>>>>>>>
>>>>>>>>>>> But if the spoke tension were less, the rim would permanently
>>>>>>>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>>>>>>>
>>>>>>>>>> that's not my experience.
>>>>>>>>>>
>>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>>>
>>>>>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>>>>>> demerits?
>>>>>>>>>>
>>>>>>>>>> "known demerits"? like the presumption that wheels collapse
>>>>>>>>>> as soon as a spoke goes loose?
>>>>>>>>>>
>>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>>
>>>>>>>>> Where is the video of that wheel being ridden, including some
>>>>>>>>> pothole hits and hard braking?
>>>>>>>>>
>>>>>>>>
>>>>>>>> feel free to replicate tom. and include the video of the wheel
>>>>>>>> collapsing as soon as the spokes go slack.
>>>>>>>
>>>>>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>>>>>> others to (dis)prove it for him.
>>>>>>>
>>>>>>
>>>>>> i've posted the frigging data dude. /you/ want to expand the
>>>>>> experiment - /you/ do the frigging work!!!! geeze - it's not like
>>>>>> you don't have the time on your hands.
>>>>>
>>>>> No "jim", you are the one that claims the wheel with the missing
>>>>> spokes is a functional wheel, not I. Post proof that this wheel can
>>>>> survive normal use.
>>>>>
>>>>
>>>> since it seems to have escaped the analysis of your laser-sharp
>>>> engineering mind, i've done more than that - 205# is well above
>>>> front wheel "normal use" loading.
>>>
>>> As an engineer, I will tell you that the wheel will be subjected to
>>> significantly different loads during riding than during your static
>>> test at one orientation.
>>>
>>
>> no shit.
>
> Try more fiber and less Kentucky Bourbon in your diet.
>
>> say, as an engineer, why didn't it collapse under excess static loading?
>
> No torsional loading,
eh? since when was torsion an issue for front wheels?
> no dynamic loading,
actually, i did. but i can't be bothered to "re-prove" it.
> only a single application of
> the static load.
yeah, a load that exceeds that of "normal use" and in the worst possible
orientation. if you want more, do it yourself.
|
| | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 00:07:56
From: Tom Sherman
Subject: Re: Spoke tension Question
|
jim beam wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> "jim beam" wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> jim beam wrote:
>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>>> Ben C? wrote:
>>>>>>>>>>>>>>> On 2007-11-03, Tom Sherman
>>>>>>>>>>>>>>> <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>>>>>>>>>>> Ozark Bicycle wrote:
>>>>>>>>>>>>>>> [...]
>>>>>>>>>>>>>>>>> IME, many modern profile rims will have their
>>>>>>>>>>>>>>>>> recommended spoke
>>>>>>>>>>>>>>>>> tension maximum before fhey 'deform' per the method
>>>>>>>>>>>>>>>>> recommended by
>>>>>>>>>>>>>>>>> Jobst Brandt....
>>>>>>>>>>>>>>>> Then these rims are poorly designed, since there is
>>>>>>>>>>>>>>>> excess material that creates stiffness in bending that
>>>>>>>>>>>>>>>> is greater than the wheel needs to remain true at
>>>>>>>>>>>>>>>> maximum allowable spoke tension. The rim could be made
>>>>>>>>>>>>>>>> lighter for a given WHEEL strength, or the same weight
>>>>>>>>>>>>>>>> rim could be redesigned to allow for a stronger overall
>>>>>>>>>>>>>>>> WHEEL.
>>>>>>>>>>>>>>> I hear this a lot but isn't this based on the premise
>>>>>>>>>>>>>>> that the
>>>>>>>>>>>>>>> performance of a wheel is solely a function of how much
>>>>>>>>>>>>>>> spoke tension it
>>>>>>>>>>>>>>> can support?
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> That seems to leave yield strength of the rim itself
>>>>>>>>>>>>>>> completely out of
>>>>>>>>>>>>>>> the equation.
>>>>>>>>>>>>>> There are several different ways a rim can yield. Which of
>>>>>>>>>>>>>> these are you referring to?
>>>>>>>>>>>>>
>>>>>>>>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>>>>>>>>> discussed how
>>>>>>>>>>>>> tension might affect propensity to flat-spot. With high
>>>>>>>>>>>>> tensions the rim
>>>>>>>>>>>>> will flat spot more easily if it reaches yield stress
>>>>>>>>>>>>> before the spokes
>>>>>>>>>>>>> go slack.
>>>>>>>>>>>>>
>>>>>>>>>>>>> This would be an interesting experiment to do: build a
>>>>>>>>>>>>> wheel with high
>>>>>>>>>>>>> tension, and keep loading it (weight downwards on the hub,
>>>>>>>>>>>>> the same
>>>>>>>>>>>>> thing it gets in use). Measure spoke tension in the bottom
>>>>>>>>>>>>> spokes. Keep
>>>>>>>>>>>>> adding weights until the tension goes to almost but not
>>>>>>>>>>>>> quite zero.
>>>>>>>>>>>>> Remove weights. Check rim for permanent deformation. If it
>>>>>>>>>>>>> has deformed
>>>>>>>>>>>>> permanently, then reduction in rim yield strength due to
>>>>>>>>>>>>> spoke tension
>>>>>>>>>>>>> is a real issue.
>>>>>>>>>>>>
>>>>>>>>>>>> But if the spoke tension were less, the rim would
>>>>>>>>>>>> permanently deform with the bottom spokes in a slack
>>>>>>>>>>>> condition in this test?
>>>>>>>>>>>
>>>>>>>>>>> that's not my experience.
>>>>>>>>>>>
>>>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>>>>
>>>>>>>>>>>> What would lower spoke tension gain in return for its known
>>>>>>>>>>>> demerits?
>>>>>>>>>>>
>>>>>>>>>>> "known demerits"? like the presumption that wheels collapse
>>>>>>>>>>> as soon as a spoke goes loose?
>>>>>>>>>>>
>>>>>>>>>>> http://www.flickr.com/photos/38636024@N00/417157612/
>>>>>>>>>>
>>>>>>>>>> Where is the video of that wheel being ridden, including some
>>>>>>>>>> pothole hits and hard braking?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> feel free to replicate tom. and include the video of the wheel
>>>>>>>>> collapsing as soon as the spokes go slack.
>>>>>>>>
>>>>>>>> [Yawn] Here we go again. "jim beam" is making a claim, yet wants
>>>>>>>> others to (dis)prove it for him.
>>>>>>>>
>>>>>>>
>>>>>>> i've posted the frigging data dude. /you/ want to expand the
>>>>>>> experiment - /you/ do the frigging work!!!! geeze - it's not
>>>>>>> like you don't have the time on your hands.
>>>>>>
>>>>>> No "jim", you are the one that claims the wheel with the missing
>>>>>> spokes is a functional wheel, not I. Post proof that this wheel
>>>>>> can survive normal use.
>>>>>>
>>>>>
>>>>> since it seems to have escaped the analysis of your laser-sharp
>>>>> engineering mind, i've done more than that - 205# is well above
>>>>> front wheel "normal use" loading.
>>>>
>>>> As an engineer, I will tell you that the wheel will be subjected to
>>>> significantly different loads during riding than during your static
>>>> test at one orientation.
>>>>
>>>
>>> no shit.
>>
>> Try more fiber and less Kentucky Bourbon in your diet.
>>
>>> say, as an engineer, why didn't it collapse under excess static loading?
>>
>> No torsional loading,
>
> eh? since when was torsion an issue for front wheels?
It is an issue for everyone with a front brake.
>> no dynamic loading,
>
> actually, i did. but i can't be bothered to "re-prove" it.
When did you prove that in the first place?
>> only a single application of the static load.
>
> yeah, a load that exceeds that of "normal use" and in the worst possible
> orientation. if you want more, do it yourself.
Why should I do it? I am not the one claiming that the wheel with
missing spokes is fully functional.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 05:48:43
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
<snip obstinate crap >
tom, you have the itch. you go scratch it. i've done my bit. bye.
|
| | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:01:52
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
> <snip obstinate crap>
>
> tom, you have the itch. you go scratch it. i've done my bit. bye.
"jim beam" has proved that a wheel missing a few spokes can support a
static load in one (1) orientation. Very useful.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:01:20
From: Tim McNamara
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>> <snip obstinate crap>
>>
>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>
> "jim beam" has proved that a wheel missing a few spokes can support a
> static load in one (1) orientation. Very useful.
"jim" can't be bothered to push his "proof" further because he knows
riding that wheel could disprove. It's as simple as that. He's not
interested in actually being right, only in "winning" the argument.
|
| | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:22:08
From: jim beam
Subject: Re: Spoke tension Question
|
Tim McNamara wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>> <snip obstinate crap>
>>>
>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>
>> "jim beam" has proved that a wheel missing a few spokes can support a
>> static load in one (1) orientation. Very useful.
>
> "jim" can't be bothered to push his "proof" further because he knows
> riding that wheel could disprove. It's as simple as that. He's not
> interested in actually being right, only in "winning" the argument.
says timmy the retard. it's /so/ much easier to sit about throwing
stones than to get off your lardy ass and prove me wrong, isn't it.
|
| | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 07:33:07
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>> <snip obstinate crap>
>>
>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>
> "jim beam" has proved that a wheel missing a few spokes can support a
> static load in one (1) orientation. Very useful.
>
in the *worst* orientation. any other is easier. go ahead and do your
own research big guy. you have the components. put your money where
your [bored and useless] mouth is.
|
| | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:36:40
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>> <snip obstinate crap>
>>>
>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>
>> "jim beam" has proved that a wheel missing a few spokes can support a
>> static load in one (1) orientation. Very useful.
>>
>
> in the *worst* orientation. any other is easier. go ahead and do your
> own research big guy. you have the components. put your money where
> your [bored and useless] mouth is.
Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
contentions? Inquiring minds want to know!
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 07:47:12
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>> <snip obstinate crap>
>>>>
>>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>>
>>> "jim beam" has proved that a wheel missing a few spokes can support a
>>> static load in one (1) orientation. Very useful.
>>>
>>
>> in the *worst* orientation. any other is easier. go ahead and do
>> your own research big guy. you have the components. put your money
>> where your [bored and useless] mouth is.
>
> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
> contentions? Inquiring minds want to know!
>
ok, now you're being stupid. instead of sitting behind that screen
where it's safe, /you/ put some skin in the game and try to prove me
wrong.
|
| | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 10:12:04
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>> <snip obstinate crap>
>>>>>
>>>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>>>
>>>> "jim beam" has proved that a wheel missing a few spokes can support
>>>> a static load in one (1) orientation. Very useful.
>>>>
>>>
>>> in the *worst* orientation. any other is easier. go ahead and do
>>> your own research big guy. you have the components. put your money
>>> where your [bored and useless] mouth is.
>>
>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
>> contentions? Inquiring minds want to know!
>>
>
> ok, now you're being stupid. instead of sitting behind that screen
> where it's safe, /you/ put some skin in the game and try to prove me wrong.
Why? I am not the one claiming a wheel with several contiguous missing
spokes is fully functional. Duh.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:04:08
From: Tim McNamara
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote: <snip obstinate crap>
>>>>>>
>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>> bit. bye.
>>>>>
>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>> support a static load in one (1) orientation. Very useful.
>>>>>
>>>>
>>>> in the *worst* orientation. any other is easier. go ahead and
>>>> do your own research big guy. you have the components. put
>>>> your money where your [bored and useless] mouth is.
>>>
>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>> own contentions? Inquiring minds want to know!
>>>
>>
>> ok, now you're being stupid. instead of sitting behind that screen
>> where it's safe, /you/ put some skin in the game and try to prove
>> me wrong.
>
> Why? I am not the one claiming a wheel with several contiguous
> missing spokes is fully functional. Duh.
Why?" Because "jim beam" doesn't understand scientific method or basic
logic, Tom. He is of the belief that facts don't matter, it's the
loudest opinion that wins the day.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:40:16
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Tim McNamara wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote: <snip obstinate crap>
>>>>>>>
>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>> bit. bye.
>>>>>>
>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>
>>>>>
>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>> do your own research big guy. you have the components. put
>>>>> your money where your [bored and useless] mouth is.
>>>>
>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>> own contentions? Inquiring minds want to know!
>>>>
>>>
>>> ok, now you're being stupid. instead of sitting behind that screen
>>> where it's safe, /you/ put some skin in the game and try to prove
>>> me wrong.
>>
>> Why? I am not the one claiming a wheel with several contiguous
>> missing spokes is fully functional. Duh.
>
> Why?" Because "jim beam" doesn't understand scientific method or basic
> logic, Tom. He is of the belief that facts don't matter, it's the
> loudest opinion that wins the day.
Well, at least Andres Muro finds that entertaining. ;)
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:20:34
From: jim beam
Subject: Re: Spoke tension Question
|
Tim McNamara wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote: <snip obstinate crap>
>>>>>>>
>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>> bit. bye.
>>>>>>
>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>
>>>>>
>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>> do your own research big guy. you have the components. put
>>>>> your money where your [bored and useless] mouth is.
>>>>
>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>> own contentions? Inquiring minds want to know!
>>>>
>>>
>>> ok, now you're being stupid. instead of sitting behind that screen
>>> where it's safe, /you/ put some skin in the game and try to prove
>>> me wrong.
>>
>> Why? I am not the one claiming a wheel with several contiguous
>> missing spokes is fully functional. Duh.
>
> Why?" Because "jim beam" doesn't understand scientific method or basic
> logic, Tom. He is of the belief that facts don't matter, it's the
> loudest opinion that wins the day.
says timmy the retard!
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:41:31
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tim McNamara wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote: <snip obstinate crap>
>>>>>>>>
>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>> bit. bye.
>>>>>>>
>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>
>>>>>>
>>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>>> do your own research big guy. you have the components. put
>>>>>> your money where your [bored and useless] mouth is.
>>>>>
>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>>> own contentions? Inquiring minds want to know!
>>>>>
>>>>
>>>> ok, now you're being stupid. instead of sitting behind that screen
>>>> where it's safe, /you/ put some skin in the game and try to prove
>>>> me wrong.
>>>
>>> Why? I am not the one claiming a wheel with several contiguous
>>> missing spokes is fully functional. Duh.
>>
>> Why?" Because "jim beam" doesn't understand scientific method or
>> basic logic, Tom. He is of the belief that facts don't matter, it's
>> the loudest opinion that wins the day.
>
> says timmy the retard!
Now that is a snappy comeback - NOT!
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 08:19:14
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>> <snip obstinate crap>
>>>>>>
>>>>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>>>>
>>>>> "jim beam" has proved that a wheel missing a few spokes can support
>>>>> a static load in one (1) orientation. Very useful.
>>>>>
>>>>
>>>> in the *worst* orientation. any other is easier. go ahead and do
>>>> your own research big guy. you have the components. put your money
>>>> where your [bored and useless] mouth is.
>>>
>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
>>> contentions? Inquiring minds want to know!
>>>
>>
>> ok, now you're being stupid. instead of sitting behind that screen
>> where it's safe, /you/ put some skin in the game and try to prove me
>> wrong.
>
> Why? I am not the one claiming a wheel with several contiguous missing
> spokes is fully functional. Duh.
>
but you're claiming that my results don't stand so you need to do your
own testing!!! [maybe this is a conceptual problem concept for you
civil engineering types - you don't destruction test your own product.]
|
| | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 10:29:35
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>> <snip obstinate crap>
>>>>>>>
>>>>>>> tom, you have the itch. you go scratch it. i've done my bit. bye.
>>>>>>
>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>
>>>>>
>>>>> in the *worst* orientation. any other is easier. go ahead and do
>>>>> your own research big guy. you have the components. put your
>>>>> money where your [bored and useless] mouth is.
>>>>
>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his own
>>>> contentions? Inquiring minds want to know!
>>>>
>>>
>>> ok, now you're being stupid. instead of sitting behind that screen
>>> where it's safe, /you/ put some skin in the game and try to prove me
>>> wrong.
>>
>> Why? I am not the one claiming a wheel with several contiguous missing
>> spokes is fully functional. Duh.
>>
>
> but you're claiming that my results don't stand so you need to do your
> own testing!!! [maybe this is a conceptual problem concept for you
> civil engineering types - you don't destruction test your own product.]
Should we extrapolate from a single static loading that a wheel with
missing spokes will function under the loads of normal use? An engineer
would be negligent (in a moral and legal sense) to make such an assumption.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:20:10
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>> <snip obstinate crap>
>>>>>>>>
>>>>>>>> tom, you have the itch. you go scratch it. i've done my bit.
>>>>>>>> bye.
>>>>>>>
>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>
>>>>>>
>>>>>> in the *worst* orientation. any other is easier. go ahead and do
>>>>>> your own research big guy. you have the components. put your
>>>>>> money where your [bored and useless] mouth is.
>>>>>
>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>>> own contentions? Inquiring minds want to know!
>>>>>
>>>>
>>>> ok, now you're being stupid. instead of sitting behind that screen
>>>> where it's safe, /you/ put some skin in the game and try to prove me
>>>> wrong.
>>>
>>> Why? I am not the one claiming a wheel with several contiguous
>>> missing spokes is fully functional. Duh.
>>>
>>
>> but you're claiming that my results don't stand so you need to do your
>> own testing!!! [maybe this is a conceptual problem concept for you
>> civil engineering types - you don't destruction test your own product.]
>
> Should we extrapolate from a single static loading that a wheel with
> missing spokes will function under the loads of normal use? An engineer
> would be negligent (in a moral and legal sense) to make such an assumption.
>
do your own testing tom. prove me wrong.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:40:53
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> "jim beam" wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>> <snip obstinate crap>
>>>>>>>>>
>>>>>>>>> tom, you have the itch. you go scratch it. i've done my bit.
>>>>>>>>> bye.
>>>>>>>>
>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>
>>>>>>>
>>>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>>>> do your own research big guy. you have the components. put your
>>>>>>> money where your [bored and useless] mouth is.
>>>>>>
>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>>>> own contentions? Inquiring minds want to know!
>>>>>>
>>>>>
>>>>> ok, now you're being stupid. instead of sitting behind that screen
>>>>> where it's safe, /you/ put some skin in the game and try to prove
>>>>> me wrong.
>>>>
>>>> Why? I am not the one claiming a wheel with several contiguous
>>>> missing spokes is fully functional. Duh.
>>>>
>>>
>>> but you're claiming that my results don't stand so you need to do
>>> your own testing!!! [maybe this is a conceptual problem concept for
>>> you civil engineering types - you don't destruction test your own
>>> product.]
>>
>> Should we extrapolate from a single static loading that a wheel with
>> missing spokes will function under the loads of normal use? An
>> engineer would be negligent (in a moral and legal sense) to make such
>> an assumption.
>>
>
> do your own testing tom. prove me wrong.
No, prove yourself right.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:53:40
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>>> "jim beam" wrote:
>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>
>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>> bit. bye.
>>>>>>>>>
>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>>
>>>>>>>>
>>>>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>>>>> do your own research big guy. you have the components. put
>>>>>>>> your money where your [bored and useless] mouth is.
>>>>>>>
>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>>>>> own contentions? Inquiring minds want to know!
>>>>>>>
>>>>>>
>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>> screen where it's safe, /you/ put some skin in the game and try to
>>>>>> prove me wrong.
>>>>>
>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>> missing spokes is fully functional. Duh.
>>>>>
>>>>
>>>> but you're claiming that my results don't stand so you need to do
>>>> your own testing!!! [maybe this is a conceptual problem concept for
>>>> you civil engineering types - you don't destruction test your own
>>>> product.]
>>>
>>> Should we extrapolate from a single static loading that a wheel with
>>> missing spokes will function under the loads of normal use? An
>>> engineer would be negligent (in a moral and legal sense) to make such
>>> an assumption.
>>>
>>
>> do your own testing tom. prove me wrong.
>
> No, prove yourself right.
>
i did. your contention is that i'm wrong. prove it.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 11:58:47
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> "jim beam" wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>>
>>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>>> bit. bye.
>>>>>>>>>>
>>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> in the *worst* orientation. any other is easier. go ahead and
>>>>>>>>> do your own research big guy. you have the components. put
>>>>>>>>> your money where your [bored and useless] mouth is.
>>>>>>>>
>>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove his
>>>>>>>> own contentions? Inquiring minds want to know!
>>>>>>>>
>>>>>>>
>>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>>> screen where it's safe, /you/ put some skin in the game and try
>>>>>>> to prove me wrong.
>>>>>>
>>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>>> missing spokes is fully functional. Duh.
>>>>>>
>>>>>
>>>>> but you're claiming that my results don't stand so you need to do
>>>>> your own testing!!! [maybe this is a conceptual problem concept
>>>>> for you civil engineering types - you don't destruction test your
>>>>> own product.]
>>>>
>>>> Should we extrapolate from a single static loading that a wheel with
>>>> missing spokes will function under the loads of normal use? An
>>>> engineer would be negligent (in a moral and legal sense) to make
>>>> such an assumption.
>>>>
>>>
>>> do your own testing tom. prove me wrong.
>>
>> No, prove yourself right.
>>
> i did. your contention is that i'm wrong. prove it.
Where did you prove the wheel will handle the normal dynamic loads
produced when riding?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 10:31:14
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>>> "jim beam" wrote:
>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>>>
>>>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>>>> bit. bye.
>>>>>>>>>>>
>>>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> in the *worst* orientation. any other is easier. go ahead
>>>>>>>>>> and do your own research big guy. you have the components.
>>>>>>>>>> put your money where your [bored and useless] mouth is.
>>>>>>>>>
>>>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove
>>>>>>>>> his own contentions? Inquiring minds want to know!
>>>>>>>>>
>>>>>>>>
>>>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>>>> screen where it's safe, /you/ put some skin in the game and try
>>>>>>>> to prove me wrong.
>>>>>>>
>>>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>>>> missing spokes is fully functional. Duh.
>>>>>>>
>>>>>>
>>>>>> but you're claiming that my results don't stand so you need to do
>>>>>> your own testing!!! [maybe this is a conceptual problem concept
>>>>>> for you civil engineering types - you don't destruction test your
>>>>>> own product.]
>>>>>
>>>>> Should we extrapolate from a single static loading that a wheel
>>>>> with missing spokes will function under the loads of normal use? An
>>>>> engineer would be negligent (in a moral and legal sense) to make
>>>>> such an assumption.
>>>>>
>>>>
>>>> do your own testing tom. prove me wrong.
>>>
>>> No, prove yourself right.
>>>
>> i did. your contention is that i'm wrong. prove it.
>
> Where did you prove the wheel will handle the normal dynamic loads
> produced when riding?
>
where did you prove it didn't? lightweight. do your own testing.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 13:15:46
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> "jim beam" wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>>>>
>>>>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>>>>> bit. bye.
>>>>>>>>>>>>
>>>>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> in the *worst* orientation. any other is easier. go ahead
>>>>>>>>>>> and do your own research big guy. you have the components.
>>>>>>>>>>> put your money where your [bored and useless] mouth is.
>>>>>>>>>>
>>>>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove
>>>>>>>>>> his own contentions? Inquiring minds want to know!
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>>>>> screen where it's safe, /you/ put some skin in the game and try
>>>>>>>>> to prove me wrong.
>>>>>>>>
>>>>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>>>>> missing spokes is fully functional. Duh.
>>>>>>>>
>>>>>>>
>>>>>>> but you're claiming that my results don't stand so you need to do
>>>>>>> your own testing!!! [maybe this is a conceptual problem concept
>>>>>>> for you civil engineering types - you don't destruction test your
>>>>>>> own product.]
>>>>>>
>>>>>> Should we extrapolate from a single static loading that a wheel
>>>>>> with missing spokes will function under the loads of normal use?
>>>>>> An engineer would be negligent (in a moral and legal sense) to
>>>>>> make such an assumption.
>>>>>>
>>>>>
>>>>> do your own testing tom. prove me wrong.
>>>>
>>>> No, prove yourself right.
>>>>
>>> i did. your contention is that i'm wrong. prove it.
>>
>> Where did you prove the wheel will handle the normal dynamic loads
>> produced when riding?
>>
> where did you prove it didn't? lightweight. do your own testing.
The burden of proof is on the individual claiming that it is a
functional wheel.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 12:39:17
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> "jim beam" wrote:
>>>>>>>> Tom Sherman wrote:
>>>>>>>>> "jim beam" wrote:
>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>>>>>> bit. bye.
>>>>>>>>>>>>>
>>>>>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes can
>>>>>>>>>>>>> support a static load in one (1) orientation. Very useful.
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> in the *worst* orientation. any other is easier. go ahead
>>>>>>>>>>>> and do your own research big guy. you have the components.
>>>>>>>>>>>> put your money where your [bored and useless] mouth is.
>>>>>>>>>>>
>>>>>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove
>>>>>>>>>>> his own contentions? Inquiring minds want to know!
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>>>>>> screen where it's safe, /you/ put some skin in the game and
>>>>>>>>>> try to prove me wrong.
>>>>>>>>>
>>>>>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>>>>>> missing spokes is fully functional. Duh.
>>>>>>>>>
>>>>>>>>
>>>>>>>> but you're claiming that my results don't stand so you need to
>>>>>>>> do your own testing!!! [maybe this is a conceptual problem
>>>>>>>> concept for you civil engineering types - you don't destruction
>>>>>>>> test your own product.]
>>>>>>>
>>>>>>> Should we extrapolate from a single static loading that a wheel
>>>>>>> with missing spokes will function under the loads of normal use?
>>>>>>> An engineer would be negligent (in a moral and legal sense) to
>>>>>>> make such an assumption.
>>>>>>>
>>>>>>
>>>>>> do your own testing tom. prove me wrong.
>>>>>
>>>>> No, prove yourself right.
>>>>>
>>>> i did. your contention is that i'm wrong. prove it.
>>>
>>> Where did you prove the wheel will handle the normal dynamic loads
>>> produced when riding?
>>>
>> where did you prove it didn't? lightweight. do your own testing.
>
> The burden of proof is on the individual claiming that it is a
> functional wheel.
>
this is the last time, lightweight.
http://www.flickr.com/photos/38636024@N00/417157612/
now fuck off and do your own homework.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 15:23:10
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> "jim beam" wrote:
>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>>>> "jim beam" wrote:
>>>>>>>>>>>>>>> Tom Sherman wrote:
>>>>>>>>>>>>>>> <snip obstinate crap>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> tom, you have the itch. you go scratch it. i've done my
>>>>>>>>>>>>>>> bit. bye.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> "jim beam" has proved that a wheel missing a few spokes
>>>>>>>>>>>>>> can support a static load in one (1) orientation. Very
>>>>>>>>>>>>>> useful.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> in the *worst* orientation. any other is easier. go ahead
>>>>>>>>>>>>> and do your own research big guy. you have the
>>>>>>>>>>>>> components. put your money where your [bored and useless]
>>>>>>>>>>>>> mouth is.
>>>>>>>>>>>>
>>>>>>>>>>>> Why won't "jim 'Kentucky Bourbon' beam" do the work to prove
>>>>>>>>>>>> his own contentions? Inquiring minds want to know!
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> ok, now you're being stupid. instead of sitting behind that
>>>>>>>>>>> screen where it's safe, /you/ put some skin in the game and
>>>>>>>>>>> try to prove me wrong.
>>>>>>>>>>
>>>>>>>>>> Why? I am not the one claiming a wheel with several contiguous
>>>>>>>>>> missing spokes is fully functional. Duh.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> but you're claiming that my results don't stand so you need to
>>>>>>>>> do your own testing!!! [maybe this is a conceptual problem
>>>>>>>>> concept for you civil engineering types - you don't destruction
>>>>>>>>> test your own product.]
>>>>>>>>
>>>>>>>> Should we extrapolate from a single static loading that a wheel
>>>>>>>> with missing spokes will function under the loads of normal use?
>>>>>>>> An engineer would be negligent (in a moral and legal sense) to
>>>>>>>> make such an assumption.
>>>>>>>>
>>>>>>>
>>>>>>> do your own testing tom. prove me wrong.
>>>>>>
>>>>>> No, prove yourself right.
>>>>>>
>>>>> i did. your contention is that i'm wrong. prove it.
>>>>
>>>> Where did you prove the wheel will handle the normal dynamic loads
>>>> produced when riding?
>>>>
>>> where did you prove it didn't? lightweight. do your own testing.
>>
>> The burden of proof is on the individual claiming that it is a
>> functional wheel.
>>
>
> this is the last time, lightweight.
For as many times as I need to post it, the one making the contention
should provide the proof.
> http://www.flickr.com/photos/38636024@N00/417157612/
>
> now fuck off and do your own homework.
"How shall we fuck off, O Lord?" - Arthur to Brian Cohen
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | |
Date: 03 Nov 2007 17:56:33
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > wrote:
> Ben C? wrote:
>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
[...]
>>>>> Then these rims are poorly designed, since there is excess material that
>>>>> creates stiffness in bending that is greater than the wheel needs to
>>>>> remain true at maximum allowable spoke tension. The rim could be made
>>>>> lighter for a given WHEEL strength, or the same weight rim could be
>>>>> redesigned to allow for a stronger overall WHEEL.
>>>> I hear this a lot but isn't this based on the premise that the
>>>> performance of a wheel is solely a function of how much spoke tension it
>>>> can support?
>>>>
>>>> That seems to leave yield strength of the rim itself completely out of
>>>> the equation.
>>> There are several different ways a rim can yield. Which of these are you
>>> referring to?
>>
>> Probably flat-spotting. We had a thread recently where we discussed how
>> tension might affect propensity to flat-spot. With high tensions the rim
>> will flat spot more easily if it reaches yield stress before the spokes
>> go slack.
>>
>> This would be an interesting experiment to do: build a wheel with high
>> tension, and keep loading it (weight downwards on the hub, the same
>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>> adding weights until the tension goes to almost but not quite zero.
>> Remove weights. Check rim for permanent deformation. If it has deformed
>> permanently, then reduction in rim yield strength due to spoke tension
>> is a real issue.
>
> But if the spoke tension were less, the rim would permanently deform
> with the bottom spokes in a slack condition in this test?
No, in this test, you stop before the spokes go slack.
> What would lower spoke tension gain in return for its known demerits?
If it's true that the rim deforms before the spokes go slack, then
loosening them a bit would have allowed it to bear more load before it
deformed.
When you crank up the spoke tension, you increase the load the wheel can
support before the spokes go slack (a good thing), but you reduce the
load the wheel can support before the rim yields plastically.
This is because the total stress on the rim is the load PLUS the
precompression from all that spoke tension.
So optimal spoke tension would seem to be whatever amount means that the
rim is just about to deform plastically at the load at which the spokes
are just going slack.
There are (at least) three variables: load the rim the can support
before it yields; load the wheel can support before the spokes go slack;
amount of tension the spoke bed can support without cracking after a few
thousand miles.
All three (plus others not thought of) one would expect to be matched on
an optimized rim; otherwise it's stronger than it needs to be or weaker
than it should be somewhere.
|
| | | | | | | | |
Date: 03 Nov 2007 18:24:28
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
> [...]
>>>>>> Then these rims are poorly designed, since there is excess material that
>>>>>> creates stiffness in bending that is greater than the wheel needs to
>>>>>> remain true at maximum allowable spoke tension. The rim could be made
>>>>>> lighter for a given WHEEL strength, or the same weight rim could be
>>>>>> redesigned to allow for a stronger overall WHEEL.
>>>>> I hear this a lot but isn't this based on the premise that the
>>>>> performance of a wheel is solely a function of how much spoke tension it
>>>>> can support?
>>>>>
>>>>> That seems to leave yield strength of the rim itself completely out of
>>>>> the equation.
>>>> There are several different ways a rim can yield. Which of these are you
>>>> referring to?
>>> Probably flat-spotting. We had a thread recently where we discussed how
>>> tension might affect propensity to flat-spot. With high tensions the rim
>>> will flat spot more easily if it reaches yield stress before the spokes
>>> go slack.
>>>
>>> This would be an interesting experiment to do: build a wheel with high
>>> tension, and keep loading it (weight downwards on the hub, the same
>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>> adding weights until the tension goes to almost but not quite zero.
>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>> permanently, then reduction in rim yield strength due to spoke tension
>>> is a real issue.
>> But if the spoke tension were less, the rim would permanently deform
>> with the bottom spokes in a slack condition in this test?
>
> No, in this test, you stop before the spokes go slack.
>
>> What would lower spoke tension gain in return for its known demerits?
>
> If it's true that the rim deforms before the spokes go slack, then
> loosening them a bit would have allowed it to bear more load before it
> deformed.
>
> When you crank up the spoke tension, you increase the load the wheel can
> support before the spokes go slack (a good thing), but you reduce the
> load the wheel can support before the rim yields plastically.
>
> This is because the total stress on the rim is the load PLUS the
> precompression from all that spoke tension.
>
> So optimal spoke tension would seem to be whatever amount means that the
> rim is just about to deform plastically at the load at which the spokes
> are just going slack.
while balanced against rim cracking...
>
> There are (at least) three variables: load the rim the can support
> before it yields; load the wheel can support before the spokes go slack;
> amount of tension the spoke bed can support without cracking after a few
> thousand miles.
indeed.
>
> All three (plus others not thought of) one would expect to be matched on
> an optimized rim; otherwise it's stronger than it needs to be or weaker
> than it should be somewhere.
indeed.
|
| | | | | | | | |
Date: 03 Nov 2007 19:03:13
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ben C? wrote:
> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
> [...]
>>>>>> Then these rims are poorly designed, since there is excess material that
>>>>>> creates stiffness in bending that is greater than the wheel needs to
>>>>>> remain true at maximum allowable spoke tension. The rim could be made
>>>>>> lighter for a given WHEEL strength, or the same weight rim could be
>>>>>> redesigned to allow for a stronger overall WHEEL.
>>>>> I hear this a lot but isn't this based on the premise that the
>>>>> performance of a wheel is solely a function of how much spoke tension it
>>>>> can support?
>>>>>
>>>>> That seems to leave yield strength of the rim itself completely out of
>>>>> the equation.
>>>> There are several different ways a rim can yield. Which of these are you
>>>> referring to?
>>> Probably flat-spotting. We had a thread recently where we discussed how
>>> tension might affect propensity to flat-spot. With high tensions the rim
>>> will flat spot more easily if it reaches yield stress before the spokes
>>> go slack.
>>>
>>> This would be an interesting experiment to do: build a wheel with high
>>> tension, and keep loading it (weight downwards on the hub, the same
>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>> adding weights until the tension goes to almost but not quite zero.
>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>> permanently, then reduction in rim yield strength due to spoke tension
>>> is a real issue.
>> But if the spoke tension were less, the rim would permanently deform
>> with the bottom spokes in a slack condition in this test?
>
> No, in this test, you stop before the spokes go slack.
But that is a different maximum load on the wheel, depending on original
spoke tension. How does that prove anything?
>> What would lower spoke tension gain in return for its known demerits?
>
> If it's true that the rim deforms before the spokes go slack, then
> loosening them a bit would have allowed it to bear more load before it
> deformed.
>
> When you crank up the spoke tension, you increase the load the wheel can
> support before the spokes go slack (a good thing), but you reduce the
> load the wheel can support before the rim yields plastically.
>
> This is because the total stress on the rim is the load PLUS the
> precompression from all that spoke tension.
Yes, but does this make a practical difference? If the spokes go slack
before the rim yields, then the wheel will fail from other causes. Do
you have data showing that higher spoke tensions lead to more
flat-spotting of rims?
> So optimal spoke tension would seem to be whatever amount means that the
> rim is just about to deform plastically at the load at which the spokes
> are just going slack.
>
> There are (at least) three variables: load the rim the can support
> before it yields; load the wheel can support before the spokes go slack;
> amount of tension the spoke bed can support without cracking after a few
> thousand miles.
>
> All three (plus others not thought of) one would expect to be matched on
> an optimized rim; otherwise it's stronger than it needs to be or weaker
> than it should be somewhere.
Remember that the buckling that occurs from excessive spoke tension
occurs along a different axis than the yielding that causes flat spots
on the rim.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | |
Date: 04 Nov 2007 05:51:26
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > wrote:
> Ben C? wrote:
>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ben C? wrote:
[...]
>>>> This would be an interesting experiment to do: build a wheel with high
>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>>> adding weights until the tension goes to almost but not quite zero.
>>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>> is a real issue.
>>> But if the spoke tension were less, the rim would permanently deform
>>> with the bottom spokes in a slack condition in this test?
>>
>> No, in this test, you stop before the spokes go slack.
>
> But that is a different maximum load on the wheel, depending on original
> spoke tension. How does that prove anything?
If the rim yields before the spokes go slack it shows that you probably
would have been better off with less spoke tension.
[...]
>> This is because the total stress on the rim is the load PLUS the
>> precompression from all that spoke tension.
>
> Yes, but does this make a practical difference?
I don't know. That's why it would be a good experiment to do.
> If the spokes go slack before the rim yields, then the wheel will fail
> from other causes.
You want to balance the two: as much spoke tension as you can get away
with without bringing the rim too close to yield.
> Do you have data showing that higher spoke tensions lead to more
> flat-spotting of rims?
No. But all I'm doing here is disputing the claim that a rim whose spoke
bed cracks when built to just-sub-taco tension is necessarily
sub-optimally engineered.
>> So optimal spoke tension would seem to be whatever amount means that the
>> rim is just about to deform plastically at the load at which the spokes
>> are just going slack.
>>
>> There are (at least) three variables: load the rim the can support
>> before it yields; load the wheel can support before the spokes go slack;
>> amount of tension the spoke bed can support without cracking after a few
>> thousand miles.
>>
>> All three (plus others not thought of) one would expect to be matched on
>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>> than it should be somewhere.
>
> Remember that the buckling that occurs from excessive spoke tension
> occurs along a different axis than the yielding that causes flat spots
> on the rim.
Indeed, I consider them to be different phenomena. How high tension
relates to buckling I don't know. At very high tensions we know the rim
tacos if you breathe on it. But at tensions people would actually use,
it might be more likely to buckle due to the big displacements that
happen when spokes go slack.
|
| | | | | | | | | | |
Date: 04 Nov 2007 09:00:11
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Ben C? wrote:
> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
> [...]
>>>>> This would be an interesting experiment to do: build a wheel with high
>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>>> is a real issue.
>>>> But if the spoke tension were less, the rim would permanently deform
>>>> with the bottom spokes in a slack condition in this test?
>>> No, in this test, you stop before the spokes go slack.
>> But that is a different maximum load on the wheel, depending on original
>> spoke tension. How does that prove anything?
>
> If the rim yields before the spokes go slack it shows that you probably
> would have been better off with less spoke tension.
Or, in use it could show that an inadequately strong rim was chosen.
> [...]
>>> This is because the total stress on the rim is the load PLUS the
>>> precompression from all that spoke tension.
>> Yes, but does this make a practical difference?
>
> I don't know. That's why it would be a good experiment to do.
>
>> If the spokes go slack before the rim yields, then the wheel will fail
>> from other causes.
>
> You want to balance the two: as much spoke tension as you can get away
> with without bringing the rim too close to yield.
Too add to this, a properly designed spoke bed that will not prematurely
fatigue from this degree of spoke tension.
>> Do you have data showing that higher spoke tensions lead to more
>> flat-spotting of rims?
>
> No. But all I'm doing here is disputing the claim that a rim whose spoke
> bed cracks when built to just-sub-taco tension is necessarily
> sub-optimally engineered.
Less material could have been used elsewhere for this lower tension
wheel, saving on weight. Is not weight savings one of the primary goals
of a certain class of bicycle components?
>>> So optimal spoke tension would seem to be whatever amount means that the
>>> rim is just about to deform plastically at the load at which the spokes
>>> are just going slack.
>>>
>>> There are (at least) three variables: load the rim the can support
>>> before it yields; load the wheel can support before the spokes go slack;
>>> amount of tension the spoke bed can support without cracking after a few
>>> thousand miles.
>>>
>>> All three (plus others not thought of) one would expect to be matched on
>>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>>> than it should be somewhere.
>> Remember that the buckling that occurs from excessive spoke tension
>> occurs along a different axis than the yielding that causes flat spots
>> on the rim.
>
> Indeed, I consider them to be different phenomena. How high tension
> relates to buckling I don't know. At very high tensions we know the rim
> tacos if you breathe on it. But at tensions people would actually use,
> it might be more likely to buckle due to the big displacements that
> happen when spokes go slack.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | |
Date: 04 Nov 2007 09:31:57
From: Sandy
Subject: Re: Spoke tension Question
|
Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
Ben C <spamspam@spam.eggs > a réfléchi, et puis a déclaré :
> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Do you have data showing that higher spoke tensions lead to more
>> flat-spotting of rims?
>
> No. But all I'm doing here is disputing the claim that a rim whose
> spoke bed cracks when built to just-sub-taco tension is necessarily
> sub-optimally engineered.
It could be expressed differently. A rim meeting the taco test satisfies
the taco test, yet that is not necessarily an optimum design, save for
meeting that test's criteria. Your idea, harmony and equilibrium makes more
sense.
The taco test favors spoke design over rim design. Favoring either one
separately fails to properly measure wheel design. After all, you wouldn't
fault spokes, necessarily, should they explode while tightening them. Each
material has limits. You wouldn't say that a curry is not well composed
unless the roof of your mouth melted, a "design" which would favor one
specific element of the composition over others.
The taco test is just another macho-feather-spreading myth, not a reliable
index. I have never heard that taking something _over_ the limit to achieve
the limit is a sensible approach. When a manufacturer specifies a limit,
and one regularly exceeds it, it's hard to understand how the design would
have been at fault.
--
Sandy
Verneuil-sur-Seine
*******
La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.
|
| | | | | | | | | | | |
Date: 04 Nov 2007 13:09:11
From: Michael Press
Subject: Re: Spoke tension Question
|
In article <472dd7dd$0$20608$4c368faf@roadrunner.com >,
"Sandy" <leurrre@free.fr > wrote:
> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
> Ben C <spamspam@spam.eggs> a réfléchi, et puis a déclaré :
> > On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>
> >> Do you have data showing that higher spoke tensions lead to more
> >> flat-spotting of rims?
> >
> > No. But all I'm doing here is disputing the claim that a rim whose
> > spoke bed cracks when built to just-sub-taco tension is necessarily
> > sub-optimally engineered.
>
> It could be expressed differently. A rim meeting the taco test satisfies
> the taco test, yet that is not necessarily an optimum design, save for
> meeting that test's criteria. Your idea, harmony and equilibrium makes more
> sense.
>
> The taco test favors spoke design over rim design. Favoring either one
> separately fails to properly measure wheel design. After all, you wouldn't
> fault spokes, necessarily, should they explode while tightening them. Each
> material has limits. You wouldn't say that a curry is not well composed
> unless the roof of your mouth melted, a "design" which would favor one
> specific element of the composition over others.
>
> The taco test is just another macho-feather-spreading myth, not a reliable
> index. I have never heard that taking something _over_ the limit to achieve
> the limit is a sensible approach. When a manufacturer specifies a limit,
> and one regularly exceeds it, it's hard to understand how the design would
> have been at fault.
It is not a test. When attempted on the type of rim
for which it is explicitly meant, it shows the builder
what a fully tensioned wheel is like. It need be done
at most once. After that, the builder knows what
a fully tensioned wheel is and brings subsequent
wheels to that tension level.
--
Michael Press
|
| | | | | | | | | | | | |
Date: 04 Nov 2007 23:44:25
From: Sandy
Subject: Re: Spoke tension Question
|
Dans le message de
news:rubrum-2C4AF5.13091104112007@newsclstr03.news.prodigy.net,
Michael Press <rubrum@pacbell.net > a réfléchi, et puis a déclaré :
> In article <472dd7dd$0$20608$4c368faf@roadrunner.com>,
> "Sandy" <leurrre@free.fr> wrote:
>
>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>> Ben C <spamspam@spam.eggs> a réfléchi, et puis a déclaré :
>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>
>>>> Do you have data showing that higher spoke tensions lead to more
>>>> flat-spotting of rims?
>>>
>>> No. But all I'm doing here is disputing the claim that a rim whose
>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>> sub-optimally engineered.
>>
>> It could be expressed differently. A rim meeting the taco test
>> satisfies the taco test, yet that is not necessarily an optimum
>> design, save for meeting that test's criteria. Your idea, harmony
>> and equilibrium makes more sense.
>>
>> The taco test favors spoke design over rim design. Favoring either
>> one separately fails to properly measure wheel design. After all,
>> you wouldn't fault spokes, necessarily, should they explode while
>> tightening them. Each material has limits. You wouldn't say that a
>> curry is not well composed unless the roof of your mouth melted, a
>> "design" which would favor one specific element of the composition
>> over others.
>>
>> The taco test is just another macho-feather-spreading myth, not a
>> reliable index. I have never heard that taking something _over_ the
>> limit to achieve the limit is a sensible approach. When a
>> manufacturer specifies a limit, and one regularly exceeds it, it's
>> hard to understand how the design would have been at fault.
>
> It is not a test. When attempted on the type of rim
> for which it is explicitly meant, it shows the builder
> what a fully tensioned wheel is like. It need be done
> at most once. After that, the builder knows what
> a fully tensioned wheel is and brings subsequent
> wheels to that tension level.
I guess you prefer literal to alliterative. Oh, well.
It's also no surprise. Could it just be that rim manufacturers try some
repetitions in a similar vein to provide the recommended tensions? Would it
not occur to them? I just think it may do.
So, rather than dealing with subsequent events (after all, front and rear
aren't the same, and ideally one does not repeat this monthly for new wheel
sets for a home builder), the likely application is to build a single wheel
set, one off, and be done. Much easier to achieve, following the published
tensions than going beyond them and backing off. I don't think the average
amateur wheelbuilder expects to pay for more than one set of rims per
exercise.
--
Bonne route !
Sandy
Verneuil-sur-Seine FR
|
| | | | | | | | | | | | | |
Date: 05 Nov 2007 20:31:38
From: jas51
Subject: Re: Spoke tension Question
|
On 06 Nov 2007 01:04:32 GMT, jobst.brandt@stanfordalumni.org wrote:
> Michael Press writes:
>
>> And yet, a lasting wheel can be built without measuring the tension.
>
> If you use a narrow definition of "measuring" that might be true, but
> the experienced wheel builder does not ignore the tension to which he
> builds and in effect is the tensiometer in person. That to me is
> "measuring tension".
>
> Jobst Brandt
Thanks, a bunch of replies and finally a good one. If I understand you
right, I can finalize the spoke tensions even on a wheel with 160 psi
inflated tire mounted!
You don't say! I'm almost there. Good thing tubes are cheap!
|
| | | | | | | | | | | | | |
Date: 05 Nov 2007 16:54:49
From: Michael Press
Subject: Re: Spoke tension Question
|
In article <472e9fa9$0$25688$4c368faf@roadrunner.com >,
"Sandy" <leurrre@free.fr > wrote:
> Dans le message de
> news:rubrum-2C4AF5.13091104112007@newsclstr03.news.prodigy.net,
> Michael Press <rubrum@pacbell.net> a réfléchi, et puis a déclaré :
> > In article <472dd7dd$0$20608$4c368faf@roadrunner.com>,
> > "Sandy" <leurrre@free.fr> wrote:
> >
> >> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
> >> Ben C <spamspam@spam.eggs> a réfléchi, et puis a déclaré :
> >>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
> >>
> >>>> Do you have data showing that higher spoke tensions lead to more
> >>>> flat-spotting of rims?
> >>>
> >>> No. But all I'm doing here is disputing the claim that a rim whose
> >>> spoke bed cracks when built to just-sub-taco tension is necessarily
> >>> sub-optimally engineered.
> >>
> >> It could be expressed differently. A rim meeting the taco test
> >> satisfies the taco test, yet that is not necessarily an optimum
> >> design, save for meeting that test's criteria. Your idea, harmony
> >> and equilibrium makes more sense.
> >>
> >> The taco test favors spoke design over rim design. Favoring either
> >> one separately fails to properly measure wheel design. After all,
> >> you wouldn't fault spokes, necessarily, should they explode while
> >> tightening them. Each material has limits. You wouldn't say that a
> >> curry is not well composed unless the roof of your mouth melted, a
> >> "design" which would favor one specific element of the composition
> >> over others.
> >>
> >> The taco test is just another macho-feather-spreading myth, not a
> >> reliable index. I have never heard that taking something _over_ the
> >> limit to achieve the limit is a sensible approach. When a
> >> manufacturer specifies a limit, and one regularly exceeds it, it's
> >> hard to understand how the design would have been at fault.
> >
> > It is not a test. When attempted on the type of rim
> > for which it is explicitly meant, it shows the builder
> > what a fully tensioned wheel is like. It need be done
> > at most once. After that, the builder knows what
> > a fully tensioned wheel is and brings subsequent
> > wheels to that tension level.
>
> I guess you prefer literal to alliterative. Oh, well.
>
> It's also no surprise. Could it just be that rim manufacturers try some
> repetitions in a similar vein to provide the recommended tensions? Would it
> not occur to them? I just think it may do.
>
> So, rather than dealing with subsequent events (after all, front and rear
> aren't the same, and ideally one does not repeat this monthly for new wheel
> sets for a home builder), the likely application is to build a single wheel
> set, one off, and be done. Much easier to achieve, following the published
> tensions than going beyond them and backing off. I don't think the average
> amateur wheelbuilder expects to pay for more than one set of rims per
> exercise.
And yet, a lasting wheel can be built without
measuring the tension.
--
Michael Press
|
| | | | | | | | | | | | | | |
Date: 06 Nov 2007 01:04:32
From:
Subject: Re: Spoke tension Question
|
Michael Press writes:
> And yet, a lasting wheel can be built without measuring the tension.
If you use a narrow definition of "measuring" that might be true, but
the experienced wheel builder does not ignore the tension to which he
builds and in effect is the tensiometer in person. That to me is
"measuring tension".
Jobst Brandt
|
| | | | | | | | | | | |
Date: 04 Nov 2007 07:26:44
From: jim beam
Subject: Re: Spoke tension Question
|
Sandy wrote:
> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
> Ben C <spamspam@spam.eggs> a r�fl�chi, et puis a d�clar� :
>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>
>>> Do you have data showing that higher spoke tensions lead to more
>>> flat-spotting of rims?
>> No. But all I'm doing here is disputing the claim that a rim whose
>> spoke bed cracks when built to just-sub-taco tension is necessarily
>> sub-optimally engineered.
>
> It could be expressed differently. A rim meeting the taco test satisfies
> the taco test, yet that is not necessarily an optimum design, save for
> meeting that test's criteria. Your idea, harmony and equilibrium makes more
> sense.
>
> The taco test favors spoke design over rim design.
absolutely!!!
> Favoring either one
> separately fails to properly measure wheel design.
indeed.
> After all, you wouldn't
> fault spokes, necessarily, should they explode while tightening them. Each
> material has limits. You wouldn't say that a curry is not well composed
> unless the roof of your mouth melted, a "design" which would favor one
> specific element of the composition over others.
>
> The taco test is just another macho-feather-spreading myth, not a reliable
> index. I have never heard that taking something _over_ the limit to achieve
> the limit is a sensible approach. When a manufacturer specifies a limit,
> and one regularly exceeds it, it's hard to understand how the design would
> have been at fault.
well said.
|
| | | | | | | | | | | |
Date: 04 Nov 2007 08:53:24
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Sandy Leurre wrote:
> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
> Ben C <spamspam@spam.eggs> a réfléchi, et puis a déclaré :
>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>
>>> Do you have data showing that higher spoke tensions lead to more
>>> flat-spotting of rims?
>> No. But all I'm doing here is disputing the claim that a rim whose
>> spoke bed cracks when built to just-sub-taco tension is necessarily
>> sub-optimally engineered.
>
> It could be expressed differently. A rim meeting the taco test satisfies
> the taco test, yet that is not necessarily an optimum design, save for
> meeting that test's criteria. Your idea, harmony and equilibrium makes more
> sense.
>
> The taco test favors spoke design over rim design. Favoring either one
> separately fails to properly measure wheel design. After all, you wouldn't
> fault spokes, necessarily, should they explode while tightening them. Each
> material has limits. You wouldn't say that a curry is not well composed
> unless the roof of your mouth melted, a "design" which would favor one
> specific element of the composition over others.
>
> The taco test is just another macho-feather-spreading myth, not a reliable
> index. I have never heard that taking something _over_ the limit to achieve
> the limit is a sensible approach. When a manufacturer specifies a limit,
> and one regularly exceeds it, it's hard to understand how the design would
> have been at fault.
Strange that the engineers who have to design things that work in real
life are on one side of this arguments, with the non-engineers on the
other. What can we learn from this?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
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Date: 04 Nov 2007 07:29:29
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Sandy Leurre wrote:
>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>> Ben C <spamspam@spam.eggs> a r�fl�chi, et puis a d�clar� :
>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>
>>>> Do you have data showing that higher spoke tensions lead to more
>>>> flat-spotting of rims?
>>> No. But all I'm doing here is disputing the claim that a rim whose
>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>> sub-optimally engineered.
>>
>> It could be expressed differently. A rim meeting the taco test
>> satisfies the taco test, yet that is not necessarily an optimum
>> design, save for meeting that test's criteria. Your idea, harmony and
>> equilibrium makes more sense.
>>
>> The taco test favors spoke design over rim design. Favoring either
>> one separately fails to properly measure wheel design. After all, you
>> wouldn't fault spokes, necessarily, should they explode while
>> tightening them. Each material has limits. You wouldn't say that a
>> curry is not well composed unless the roof of your mouth melted, a
>> "design" which would favor one specific element of the composition
>> over others.
>>
>> The taco test is just another macho-feather-spreading myth, not a
>> reliable index. I have never heard that taking something _over_ the
>> limit to achieve the limit is a sensible approach. When a
>> manufacturer specifies a limit, and one regularly exceeds it, it's
>> hard to understand how the design would have been at fault.
>
> Strange that the engineers who have to design things that work in real
> life are on one side of this arguments, with the non-engineers on the
> other. What can we learn from this?
>
we can learn that "engineers" that won't eat their own dog food are just
so much hot air. and bored.
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Date: 04 Nov 2007 11:21:02
From: Sandy
Subject: Re: Spoke tension Question
|
Dans le message de news:y-6dncHYDfvHeLDanZ2dnUVZ_qfinZ2d@speakeasy.net,
jim beam <spamvortex@bad.example.net > a réfléchi, et puis a déclaré :
> Tom Sherman wrote:
>> Sandy Leurre wrote:
>>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>>> Ben C <spamspam@spam.eggs> a r?fl?chi, et puis a d?clar? :
>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>> wrote:
>>>
>>>>> Do you have data showing that higher spoke tensions lead to more
>>>>> flat-spotting of rims?
>>>> No. But all I'm doing here is disputing the claim that a rim whose
>>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>>> sub-optimally engineered.
>>>
>>> It could be expressed differently. A rim meeting the taco test
>>> satisfies the taco test, yet that is not necessarily an optimum
>>> design, save for meeting that test's criteria. Your idea, harmony
>>> and equilibrium makes more sense.
>>>
>>> The taco test favors spoke design over rim design. Favoring either
>>> one separately fails to properly measure wheel design. After all,
>>> you wouldn't fault spokes, necessarily, should they explode while
>>> tightening them. Each material has limits. You wouldn't say that a
>>> curry is not well composed unless the roof of your mouth melted, a
>>> "design" which would favor one specific element of the composition
>>> over others.
>>>
>>> The taco test is just another macho-feather-spreading myth, not a
>>> reliable index. I have never heard that taking something _over_ the
>>> limit to achieve the limit is a sensible approach. When a
>>> manufacturer specifies a limit, and one regularly exceeds it, it's
>>> hard to understand how the design would have been at fault.
>>
>> Strange that the engineers who have to design things that work in
>> real life are on one side of this arguments, with the non-engineers
>> on the other. What can we learn from this?
>>
>
> we can learn that "engineers" that won't eat their own dog food are
> just so much hot air. and bored.
Perhaps Sherman thought he was not in my kill-file, or perhaps he does know.
Anyway, it proves the following: engineers who are trusted by the industry
to contribute to the success of product manufacture can find satisfactory
employment there. Those who have just made it to the late 20th century are
not welcome. And that non-eingineers can sort logic from dross.
--
Sandy
Verneuil-sur-Seine
*******
La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.
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Date: 04 Nov 2007 11:00:27
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Sandy Leurre wrote:
> Dans le message de news:y-6dncHYDfvHeLDanZ2dnUVZ_qfinZ2d@speakeasy.net,
> jim beam <spamvortex@bad.example.net> a réfléchi, et puis a déclaré :
>> Tom Sherman wrote:
>>> Sandy Leurre wrote:
>>>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>>>> Ben C <spamspam@spam.eggs> a r?fl?chi, et puis a d?clar? :
>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>> wrote:
>>>>>> Do you have data showing that higher spoke tensions lead to more
>>>>>> flat-spotting of rims?
>>>>> No. But all I'm doing here is disputing the claim that a rim whose
>>>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>>>> sub-optimally engineered.
>>>> It could be expressed differently. A rim meeting the taco test
>>>> satisfies the taco test, yet that is not necessarily an optimum
>>>> design, save for meeting that test's criteria. Your idea, harmony
>>>> and equilibrium makes more sense.
>>>>
>>>> The taco test favors spoke design over rim design. Favoring either
>>>> one separately fails to properly measure wheel design. After all,
>>>> you wouldn't fault spokes, necessarily, should they explode while
>>>> tightening them. Each material has limits. You wouldn't say that a
>>>> curry is not well composed unless the roof of your mouth melted, a
>>>> "design" which would favor one specific element of the composition
>>>> over others.
>>>>
>>>> The taco test is just another macho-feather-spreading myth, not a
>>>> reliable index. I have never heard that taking something _over_ the
>>>> limit to achieve the limit is a sensible approach. When a
>>>> manufacturer specifies a limit, and one regularly exceeds it, it's
>>>> hard to understand how the design would have been at fault.
>>> Strange that the engineers who have to design things that work in
>>> real life are on one side of this arguments, with the non-engineers
>>> on the other. What can we learn from this?
>>>
>> we can learn that "engineers" that won't eat their own dog food are
>> just so much hot air. and bored.
>
> Perhaps Sherman thought he was not in my kill-file, or perhaps he does know.
Oh damn, my heart is broken. [end sarcasm]
I was posting my message to the group, not to Sandy Leurre personally.
If I wanted to address him personally (I do not) I would use email, not
Usenet. Duh!
> Anyway, it proves the following: engineers who are trusted by the industry
> to contribute to the success of product manufacture can find satisfactory
> employment there. Those who have just made it to the late 20th century are
> not welcome.
What is the above supposed to mean? Leave it to a lawyer to obfuscate.
> And that non-eingineers can sort logic from dross.
What is an "eingineer" (sic)?
Several non-engineers on rec.bicycles.tech are not doing to well at
sorting dross from logic, however.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
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Date: 04 Nov 2007 09:31:27
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> Sandy Leurre wrote:
>>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>>> Ben C <spamspam@spam.eggs> a r�fl�chi, et puis a d�clar� :
>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>
>>>>> Do you have data showing that higher spoke tensions lead to more
>>>>> flat-spotting of rims?
>>>> No. But all I'm doing here is disputing the claim that a rim whose
>>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>>> sub-optimally engineered.
>>>
>>> It could be expressed differently. A rim meeting the taco test
>>> satisfies the taco test, yet that is not necessarily an optimum
>>> design, save for meeting that test's criteria. Your idea, harmony
>>> and equilibrium makes more sense.
>>>
>>> The taco test favors spoke design over rim design. Favoring either
>>> one separately fails to properly measure wheel design. After all,
>>> you wouldn't fault spokes, necessarily, should they explode while
>>> tightening them. Each material has limits. You wouldn't say that a
>>> curry is not well composed unless the roof of your mouth melted, a
>>> "design" which would favor one specific element of the composition
>>> over others.
>>>
>>> The taco test is just another macho-feather-spreading myth, not a
>>> reliable index. I have never heard that taking something _over_ the
>>> limit to achieve the limit is a sensible approach. When a
>>> manufacturer specifies a limit, and one regularly exceeds it, it's
>>> hard to understand how the design would have been at fault.
>>
>> Strange that the engineers who have to design things that work in real
>> life are on one side of this arguments, with the non-engineers on the
>> other. What can we learn from this?
>>
>
> we can learn that "engineers" that won't eat their own dog food are just
> so much hot air. and bored.
What is your purpose here, Bourbon Man?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
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Date: 04 Nov 2007 07:37:47
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> Sandy Leurre wrote:
>>>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>>>> Ben C <spamspam@spam.eggs> a r�fl�chi, et puis a d�clar� :
>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>
>>>>>> Do you have data showing that higher spoke tensions lead to more
>>>>>> flat-spotting of rims?
>>>>> No. But all I'm doing here is disputing the claim that a rim whose
>>>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>>>> sub-optimally engineered.
>>>>
>>>> It could be expressed differently. A rim meeting the taco test
>>>> satisfies the taco test, yet that is not necessarily an optimum
>>>> design, save for meeting that test's criteria. Your idea, harmony
>>>> and equilibrium makes more sense.
>>>>
>>>> The taco test favors spoke design over rim design. Favoring either
>>>> one separately fails to properly measure wheel design. After all,
>>>> you wouldn't fault spokes, necessarily, should they explode while
>>>> tightening them. Each material has limits. You wouldn't say that a
>>>> curry is not well composed unless the roof of your mouth melted, a
>>>> "design" which would favor one specific element of the composition
>>>> over others.
>>>>
>>>> The taco test is just another macho-feather-spreading myth, not a
>>>> reliable index. I have never heard that taking something _over_ the
>>>> limit to achieve the limit is a sensible approach. When a
>>>> manufacturer specifies a limit, and one regularly exceeds it, it's
>>>> hard to understand how the design would have been at fault.
>>>
>>> Strange that the engineers who have to design things that work in
>>> real life are on one side of this arguments, with the non-engineers
>>> on the other. What can we learn from this?
>>>
>>
>> we can learn that "engineers" that won't eat their own dog food are
>> just so much hot air. and bored.
>
> What is your purpose here, Bourbon Man?
>
backatcha - lightweight.
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Date: 04 Nov 2007 10:10:26
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> Sandy Leurre wrote:
>>>>> Dans le message de news:slrnfircjc.d6c.spamspam@bowser.marioworld,
>>>>> Ben C <spamspam@spam.eggs> a r�fl�chi, et puis a d�clar� :
>>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>
>>>>>>> Do you have data showing that higher spoke tensions lead to more
>>>>>>> flat-spotting of rims?
>>>>>> No. But all I'm doing here is disputing the claim that a rim whose
>>>>>> spoke bed cracks when built to just-sub-taco tension is necessarily
>>>>>> sub-optimally engineered.
>>>>>
>>>>> It could be expressed differently. A rim meeting the taco test
>>>>> satisfies the taco test, yet that is not necessarily an optimum
>>>>> design, save for meeting that test's criteria. Your idea, harmony
>>>>> and equilibrium makes more sense.
>>>>>
>>>>> The taco test favors spoke design over rim design. Favoring either
>>>>> one separately fails to properly measure wheel design. After all,
>>>>> you wouldn't fault spokes, necessarily, should they explode while
>>>>> tightening them. Each material has limits. You wouldn't say that
>>>>> a curry is not well composed unless the roof of your mouth melted,
>>>>> a "design" which would favor one specific element of the
>>>>> composition over others.
>>>>>
>>>>> The taco test is just another macho-feather-spreading myth, not a
>>>>> reliable index. I have never heard that taking something _over_
>>>>> the limit to achieve the limit is a sensible approach. When a
>>>>> manufacturer specifies a limit, and one regularly exceeds it, it's
>>>>> hard to understand how the design would have been at fault.
>>>>
>>>> Strange that the engineers who have to design things that work in
>>>> real life are on one side of this arguments, with the non-engineers
>>>> on the other. What can we learn from this?
>>>>
>>>
>>> we can learn that "engineers" that won't eat their own dog food are
>>> just so much hot air. and bored.
>>
>> What is your purpose here, Bourbon Man?
>>
>
> backatcha - lightweight.
I am bowled over by that response. [end sarcasm]
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
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Date: 04 Nov 2007 06:03:59
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
> [...]
>>>>> This would be an interesting experiment to do: build a wheel with high
>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>>> is a real issue.
>>>> But if the spoke tension were less, the rim would permanently deform
>>>> with the bottom spokes in a slack condition in this test?
>>> No, in this test, you stop before the spokes go slack.
>> But that is a different maximum load on the wheel, depending on original
>> spoke tension. How does that prove anything?
>
> If the rim yields before the spokes go slack it shows that you probably
> would have been better off with less spoke tension.
>
> [...]
>>> This is because the total stress on the rim is the load PLUS the
>>> precompression from all that spoke tension.
>> Yes, but does this make a practical difference?
>
> I don't know. That's why it would be a good experiment to do.
>
>> If the spokes go slack before the rim yields, then the wheel will fail
>> from other causes.
>
> You want to balance the two: as much spoke tension as you can get away
> with without bringing the rim too close to yield.
>
>> Do you have data showing that higher spoke tensions lead to more
>> flat-spotting of rims?
>
> No. But all I'm doing here is disputing the claim that a rim whose spoke
> bed cracks when built to just-sub-taco tension is necessarily
> sub-optimally engineered.
>
>>> So optimal spoke tension would seem to be whatever amount means that the
>>> rim is just about to deform plastically at the load at which the spokes
>>> are just going slack.
>>>
>>> There are (at least) three variables: load the rim the can support
>>> before it yields; load the wheel can support before the spokes go slack;
>>> amount of tension the spoke bed can support without cracking after a few
>>> thousand miles.
>>>
>>> All three (plus others not thought of) one would expect to be matched on
>>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>>> than it should be somewhere.
>> Remember that the buckling that occurs from excessive spoke tension
>> occurs along a different axis than the yielding that causes flat spots
>> on the rim.
>
> Indeed, I consider them to be different phenomena. How high tension
> relates to buckling I don't know. At very high tensions we know the rim
> tacos if you breathe on it. But at tensions people would actually use,
> it might be more likely to buckle due to the big displacements that
> happen when spokes go slack.
you need to be careful repeating that "big displacements" story. i have
mountain biked with a guy whose rear wheel was so slack spoked, the
spoke crossing made a grinding noise as they went slack under the hub as
it rolled. he rode that wheel for 6 months before i figured out that
that it wasn't just his poor maintenance. that's 6 months of all kinds
of hops, jumps and usual mtb abuse. and that wheel was as straight as
they come. if a 180# mountain biker with slack spokes doesn't
experience a problem, there's something wrong with the story.
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Date: 04 Nov 2007 08:48:09
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Ben C wrote:
>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> Ben C? wrote:
>> [...]
>>>>>> This would be an interesting experiment to do: build a wheel with
>>>>>> high
>>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>>> thing it gets in use). Measure spoke tension in the bottom spokes.
>>>>>> Keep
>>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>> deformed
>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>> tension
>>>>>> is a real issue.
>>>>> But if the spoke tension were less, the rim would permanently
>>>>> deform with the bottom spokes in a slack condition in this test?
>>>> No, in this test, you stop before the spokes go slack.
>>> But that is a different maximum load on the wheel, depending on
>>> original spoke tension. How does that prove anything?
>>
>> If the rim yields before the spokes go slack it shows that you probably
>> would have been better off with less spoke tension.
>>
>> [...]
>>>> This is because the total stress on the rim is the load PLUS the
>>>> precompression from all that spoke tension.
>>> Yes, but does this make a practical difference?
>>
>> I don't know. That's why it would be a good experiment to do.
>>
>>> If the spokes go slack before the rim yields, then the wheel will fail
>>> from other causes.
>>
>> You want to balance the two: as much spoke tension as you can get away
>> with without bringing the rim too close to yield.
>>
>>> Do you have data showing that higher spoke tensions lead to more
>>> flat-spotting of rims?
>>
>> No. But all I'm doing here is disputing the claim that a rim whose spoke
>> bed cracks when built to just-sub-taco tension is necessarily
>> sub-optimally engineered.
>>
>>>> So optimal spoke tension would seem to be whatever amount means that
>>>> the
>>>> rim is just about to deform plastically at the load at which the spokes
>>>> are just going slack.
>>>>
>>>> There are (at least) three variables: load the rim the can support
>>>> before it yields; load the wheel can support before the spokes go
>>>> slack;
>>>> amount of tension the spoke bed can support without cracking after a
>>>> few
>>>> thousand miles.
>>>>
>>>> All three (plus others not thought of) one would expect to be
>>>> matched on
>>>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>>>> than it should be somewhere.
>>> Remember that the buckling that occurs from excessive spoke tension
>>> occurs along a different axis than the yielding that causes flat
>>> spots on the rim.
>>
>> Indeed, I consider them to be different phenomena. How high tension
>> relates to buckling I don't know. At very high tensions we know the rim
>> tacos if you breathe on it. But at tensions people would actually use,
>> it might be more likely to buckle due to the big displacements that
>> happen when spokes go slack.
>
> you need to be careful repeating that "big displacements" story. i have
> mountain biked with a guy whose rear wheel was so slack spoked, the
> spoke crossing made a grinding noise as they went slack under the hub as
> it rolled. he rode that wheel for 6 months before i figured out that
> that it wasn't just his poor maintenance. that's 6 months of all kinds
> of hops, jumps and usual mtb abuse. and that wheel was as straight as
> they come. if a 180# mountain biker with slack spokes doesn't
> experience a problem, there's something wrong with the story.
Indeed (this can be interpreted several different ways other than what
Bourbon Man is suggesting).
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
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Date: 03 Nov 2007 17:27:24
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Ben C? wrote:
>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> Ben C? wrote:
>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> [...]
>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>> strength, or the same weight rim could be redesigned to allow for
>>>>>>> a stronger overall WHEEL.
>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>> tension it
>>>>>> can support?
>>>>>>
>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>> out of
>>>>>> the equation.
>>>>> There are several different ways a rim can yield. Which of these
>>>>> are you referring to?
>>>> Probably flat-spotting. We had a thread recently where we discussed how
>>>> tension might affect propensity to flat-spot. With high tensions the
>>>> rim
>>>> will flat spot more easily if it reaches yield stress before the spokes
>>>> go slack.
>>>>
>>>> This would be an interesting experiment to do: build a wheel with high
>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>> thing it gets in use). Measure spoke tension in the bottom spokes. Keep
>>>> adding weights until the tension goes to almost but not quite zero.
>>>> Remove weights. Check rim for permanent deformation. If it has deformed
>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>> is a real issue.
>>> But if the spoke tension were less, the rim would permanently deform
>>> with the bottom spokes in a slack condition in this test?
>>
>> No, in this test, you stop before the spokes go slack.
>
> But that is a different maximum load on the wheel, depending on original
> spoke tension.
think of the rim dude - that thing yielding is what determines wheel
failure.
> How does that prove anything?
>
>>> What would lower spoke tension gain in return for its known demerits?
>>
>> If it's true that the rim deforms before the spokes go slack, then
>> loosening them a bit would have allowed it to bear more load before it
>> deformed.
>>
>> When you crank up the spoke tension, you increase the load the wheel can
>> support before the spokes go slack (a good thing), but you reduce the
>> load the wheel can support before the rim yields plastically.
>>
>> This is because the total stress on the rim is the load PLUS the
>> precompression from all that spoke tension.
>
> Yes, but does this make a practical difference? If the spokes go slack
> before the rim yields, then the wheel will fail from other causes.
no it won't. that's jobstian presumption - and red herring swallowing.
i've got a wheel that goes slack easily on the non-drive side. no
failure. and i've seen an mtb wheel ridden for 6+ months, with spokes
so slack, the crossings used to audibly grind. no collapse there
either, and that thing was jumped.
> Do
> you have data showing that higher spoke tensions lead to more
> flat-spotting of rims?
think through the problem. if you compress two ends of a beam, then
3-point load it - it will yield sooner because of the compression.
>
>> So optimal spoke tension would seem to be whatever amount means that the
>> rim is just about to deform plastically at the load at which the spokes
>> are just going slack.
>>
>> There are (at least) three variables: load the rim the can support
>> before it yields; load the wheel can support before the spokes go slack;
>> amount of tension the spoke bed can support without cracking after a few
>> thousand miles.
>>
>> All three (plus others not thought of) one would expect to be matched on
>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>> than it should be somewhere.
>
> Remember that the buckling that occurs from excessive spoke tension
> occurs along a different axis than the yielding that causes flat spots
> on the rim.
but it's a further symptom of the same problem - excess hoop compression.
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Date: 03 Nov 2007 19:38:37
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> Ben C? wrote:
>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> Ben C? wrote:
>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>> Ben C? wrote:
>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> [...]
>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>>> strength, or the same weight rim could be redesigned to allow
>>>>>>>> for a stronger overall WHEEL.
>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>> tension it
>>>>>>> can support?
>>>>>>>
>>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>>> out of
>>>>>>> the equation.
>>>>>> There are several different ways a rim can yield. Which of these
>>>>>> are you referring to?
>>>>> Probably flat-spotting. We had a thread recently where we discussed
>>>>> how
>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>> the rim
>>>>> will flat spot more easily if it reaches yield stress before the
>>>>> spokes
>>>>> go slack.
>>>>>
>>>>> This would be an interesting experiment to do: build a wheel with high
>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>> thing it gets in use). Measure spoke tension in the bottom spokes.
>>>>> Keep
>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>> deformed
>>>>> permanently, then reduction in rim yield strength due to spoke tension
>>>>> is a real issue.
>>>> But if the spoke tension were less, the rim would permanently deform
>>>> with the bottom spokes in a slack condition in this test?
>>>
>>> No, in this test, you stop before the spokes go slack.
>>
>> But that is a different maximum load on the wheel, depending on
>> original spoke tension.
>
> think of the rim dude - that thing yielding is what determines wheel
> failure.
The test Ben C is proposing puts different maximum loads on the rim - if
neither rim yields before the bottom spokes become slack, the test
proves nothing.
>> How does that prove anything?
>>
>>>> What would lower spoke tension gain in return for its known demerits?
>>>
>>> If it's true that the rim deforms before the spokes go slack, then
>>> loosening them a bit would have allowed it to bear more load before it
>>> deformed.
>>>
>>> When you crank up the spoke tension, you increase the load the wheel can
>>> support before the spokes go slack (a good thing), but you reduce the
>>> load the wheel can support before the rim yields plastically.
>>>
>>> This is because the total stress on the rim is the load PLUS the
>>> precompression from all that spoke tension.
>>
>> Yes, but does this make a practical difference? If the spokes go slack
>> before the rim yields, then the wheel will fail from other causes.
>
> no it won't. that's jobstian presumption - and red herring swallowing.
> i've got a wheel that goes slack easily on the non-drive side. no
> failure. and i've seen an mtb wheel ridden for 6+ months, with spokes
> so slack, the crossings used to audibly grind. no collapse there
> either, and that thing was jumped.
Six (6) months is hardly a severe test of wheel durability. A rim braked
wheel should require no maintenance until the braking track wears to
thin (unless one is willing to put up with disposable wheels for a
slight performance increase).
>> Do you have data showing that higher spoke tensions lead to more
>> flat-spotting of rims?
>
> think through the problem. if you compress two ends of a beam, then
> 3-point load it - it will yield sooner because of the compression.
What happens in the real world?
>>> So optimal spoke tension would seem to be whatever amount means that the
>>> rim is just about to deform plastically at the load at which the spokes
>>> are just going slack.
>>>
>>> There are (at least) three variables: load the rim the can support
>>> before it yields; load the wheel can support before the spokes go slack;
>>> amount of tension the spoke bed can support without cracking after a few
>>> thousand miles.
>>>
>>> All three (plus others not thought of) one would expect to be matched on
>>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>>> than it should be somewhere.
>>
>> Remember that the buckling that occurs from excessive spoke tension
>> occurs along a different axis than the yielding that causes flat spots
>> on the rim.
>
> but it's a further symptom of the same problem - excess hoop compression.
>
Again, which is a greater problem in the real world? Rim yielding or
slack spokes?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | |
Date: 06 Nov 2007 00:46:01
From: Paul Kopit
Subject: Re: Spoke tension Question
|
On Sat, 03 Nov 2007 19:38:37 -0500, Tom Sherman
<sunsetss0003@REMOVETHISyahoo.com > wrote:
>A rim braked
>wheel should require no maintenance until the braking track wears to
>thin (unless one is willing to put up with disposable wheels for a
>slight performance increase).
I don't disagree but I've not had a wheel fail by wearing through the
brake track. I almost never ride in rain. I lose wheels, mainly
rims, when I hit stuff or crash.
The modern low spoke count wheels, with large space between spokes,
dent easier and become unrideable.
|
| | | | | | | | | | | |
Date: 04 Nov 2007 05:54:48
From: Ben C
Subject: Re: Spoke tension Question
|
On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com > wrote:
[...]
> The test Ben C is proposing puts different maximum loads on the rim - if
> neither rim yields before the bottom spokes become slack, the test
> proves nothing.
If the rim doesn't yield before the spokes go slack it means you could
have benefitted from higher tension (provided you didn't fatigue the
spoke bed too much).
If it does, it means tension was too high.
|
| | | | | | | | | | | | |
Date: 04 Nov 2007 05:53:33
From: jim beam
Subject: Re: Spoke tension Question
|
Ben C wrote:
> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
> [...]
>> The test Ben C is proposing puts different maximum loads on the rim - if
>> neither rim yields before the bottom spokes become slack, the test
>> proves nothing.
>
> If the rim doesn't yield before the spokes go slack it means you could
> have benefitted from higher tension (provided you didn't fatigue the
> spoke bed too much).
"provided you didn't fatigue the spoke bed too much" - and therein lies
the question. rims can easily withstand a few slack spokes - an
unspoked low profile ma2 bare hoop will take my full body weight without
folding. 3 or 4 spokes slack are /much/ less of a problem. seeking
tension at the borderline of yield is pointless and destructive for the
spoke bed.
>
> If it does, it means tension was too high.
|
| | | | | | | | | | | | | |
Date: 04 Nov 2007 08:44:45
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Ben C wrote:
>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>> [...]
>>> The test Ben C is proposing puts different maximum loads on the rim -
>>> if neither rim yields before the bottom spokes become slack, the test
>>> proves nothing.
>>
>> If the rim doesn't yield before the spokes go slack it means you could
>> have benefitted from higher tension (provided you didn't fatigue the
>> spoke bed too much).
>
> "provided you didn't fatigue the spoke bed too much" - and therein lies
> the question. rims can easily withstand a few slack spokes - an
> unspoked low profile ma2 bare hoop will take my full body weight without
> folding. 3 or 4 spokes slack are /much/ less of a problem. seeking
> tension at the borderline of yield is pointless and destructive for the
> spoke bed.
>
>
>>
>> If it does, it means tension was too high.
We are back to where we started. The rim is poorly designed if the spoke
bed fatigues well below the compressive hoop stress the rim can bear -
too much material in some places, too little in others.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | |
Date: 04 Nov 2007 07:25:05
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Ben C wrote:
>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>> [...]
>>>> The test Ben C is proposing puts different maximum loads on the rim
>>>> - if neither rim yields before the bottom spokes become slack, the
>>>> test proves nothing.
>>>
>>> If the rim doesn't yield before the spokes go slack it means you could
>>> have benefitted from higher tension (provided you didn't fatigue the
>>> spoke bed too much).
>>
>> "provided you didn't fatigue the spoke bed too much" - and therein
>> lies the question. rims can easily withstand a few slack spokes - an
>> unspoked low profile ma2 bare hoop will take my full body weight
>> without folding. 3 or 4 spokes slack are /much/ less of a problem.
>> seeking tension at the borderline of yield is pointless and
>> destructive for the spoke bed.
>>
>>
>>>
>>> If it does, it means tension was too high.
>
> We are back to where we started. The rim is poorly designed if the spoke
> bed fatigues well below the compressive hoop stress the rim can bear -
> too much material in some places, too little in others.
>
i can't decide whether you're stupid, or whether you've just here to
fuck about. given that you obstinately refuse to eat your own dog food,
i'd say the latter. but then again...
|
| | | | | | | | | | | | | | | |
Date: 04 Nov 2007 09:27:28
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Ben C wrote:
>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>> [...]
>>>>> The test Ben C is proposing puts different maximum loads on the rim
>>>>> - if neither rim yields before the bottom spokes become slack, the
>>>>> test proves nothing.
>>>>
>>>> If the rim doesn't yield before the spokes go slack it means you could
>>>> have benefitted from higher tension (provided you didn't fatigue the
>>>> spoke bed too much).
>>>
>>> "provided you didn't fatigue the spoke bed too much" - and therein
>>> lies the question. rims can easily withstand a few slack spokes - an
>>> unspoked low profile ma2 bare hoop will take my full body weight
>>> without folding. 3 or 4 spokes slack are /much/ less of a problem.
>>> seeking tension at the borderline of yield is pointless and
>>> destructive for the spoke bed.
>>>
>>>
>>>>
>>>> If it does, it means tension was too high.
>>
>> We are back to where we started. The rim is poorly designed if the
>> spoke bed fatigues well below the compressive hoop stress the rim can
>> bear - too much material in some places, too little in others.
>>
>
> i can't decide whether you're stupid, or whether you've just here to
> fuck about. given that you obstinately refuse to eat your own dog food,
> i'd say the latter. but then again...
Yeah, they do not teach optimization of design in materials science courses.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 07:37:16
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Ben C wrote:
>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> [...]
>>>>>> The test Ben C is proposing puts different maximum loads on the
>>>>>> rim - if neither rim yields before the bottom spokes become slack,
>>>>>> the test proves nothing.
>>>>>
>>>>> If the rim doesn't yield before the spokes go slack it means you could
>>>>> have benefitted from higher tension (provided you didn't fatigue the
>>>>> spoke bed too much).
>>>>
>>>> "provided you didn't fatigue the spoke bed too much" - and therein
>>>> lies the question. rims can easily withstand a few slack spokes -
>>>> an unspoked low profile ma2 bare hoop will take my full body weight
>>>> without folding. 3 or 4 spokes slack are /much/ less of a problem.
>>>> seeking tension at the borderline of yield is pointless and
>>>> destructive for the spoke bed.
>>>>
>>>>
>>>>>
>>>>> If it does, it means tension was too high.
>>>
>>> We are back to where we started. The rim is poorly designed if the
>>> spoke bed fatigues well below the compressive hoop stress the rim can
>>> bear - too much material in some places, too little in others.
>>>
>>
>> i can't decide whether you're stupid, or whether you've just here to
>> fuck about. given that you obstinately refuse to eat your own dog
>> food, i'd say the latter. but then again...
>
> Yeah, they do not teach optimization of design in materials science
> courses.
>
actually, they teach us how to fix the problems engineers create when
they don't know what they're doing and won't eat their own dog food.
"optimization of design" doesn't include materials??? geeze - i wonder
how the heck you guys ever graduate.
|
| | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 10:08:41
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Ben C wrote:
>>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>> [...]
>>>>>>> The test Ben C is proposing puts different maximum loads on the
>>>>>>> rim - if neither rim yields before the bottom spokes become
>>>>>>> slack, the test proves nothing.
>>>>>>
>>>>>> If the rim doesn't yield before the spokes go slack it means you
>>>>>> could
>>>>>> have benefitted from higher tension (provided you didn't fatigue the
>>>>>> spoke bed too much).
>>>>>
>>>>> "provided you didn't fatigue the spoke bed too much" - and therein
>>>>> lies the question. rims can easily withstand a few slack spokes -
>>>>> an unspoked low profile ma2 bare hoop will take my full body weight
>>>>> without folding. 3 or 4 spokes slack are /much/ less of a
>>>>> problem. seeking tension at the borderline of yield is pointless
>>>>> and destructive for the spoke bed.
>>>>>
>>>>>
>>>>>>
>>>>>> If it does, it means tension was too high.
>>>>
>>>> We are back to where we started. The rim is poorly designed if the
>>>> spoke bed fatigues well below the compressive hoop stress the rim
>>>> can bear - too much material in some places, too little in others.
>>>>
>>>
>>> i can't decide whether you're stupid, or whether you've just here to
>>> fuck about. given that you obstinately refuse to eat your own dog
>>> food, i'd say the latter. but then again...
>>
>> Yeah, they do not teach optimization of design in materials science
>> courses.
>>
>
> actually, they teach us how to fix the problems engineers create when
> they don't know what they're doing and won't eat their own dog food.
What curriculum is this?
> "optimization of design" doesn't include materials??? geeze - i wonder
> how the heck you guys ever graduate.
Whoever said "optimization of design" doesn't include materials"? "jim
beam" is off on a flight of fancy here.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 08:14:46
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> "jim beam" wrote:
>>>> Tom Sherman wrote:
>>>>> "jim beam" wrote:
>>>>>> Ben C wrote:
>>>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>> [...]
>>>>>>>> The test Ben C is proposing puts different maximum loads on the
>>>>>>>> rim - if neither rim yields before the bottom spokes become
>>>>>>>> slack, the test proves nothing.
>>>>>>>
>>>>>>> If the rim doesn't yield before the spokes go slack it means you
>>>>>>> could
>>>>>>> have benefitted from higher tension (provided you didn't fatigue the
>>>>>>> spoke bed too much).
>>>>>>
>>>>>> "provided you didn't fatigue the spoke bed too much" - and therein
>>>>>> lies the question. rims can easily withstand a few slack spokes -
>>>>>> an unspoked low profile ma2 bare hoop will take my full body
>>>>>> weight without folding. 3 or 4 spokes slack are /much/ less of a
>>>>>> problem. seeking tension at the borderline of yield is pointless
>>>>>> and destructive for the spoke bed.
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> If it does, it means tension was too high.
>>>>>
>>>>> We are back to where we started. The rim is poorly designed if the
>>>>> spoke bed fatigues well below the compressive hoop stress the rim
>>>>> can bear - too much material in some places, too little in others.
>>>>>
>>>>
>>>> i can't decide whether you're stupid, or whether you've just here to
>>>> fuck about. given that you obstinately refuse to eat your own dog
>>>> food, i'd say the latter. but then again...
>>>
>>> Yeah, they do not teach optimization of design in materials science
>>> courses.
>>>
>>
>> actually, they teach us how to fix the problems engineers create when
>> they don't know what they're doing and won't eat their own dog food.
>
> What curriculum is this?
>
>> "optimization of design" doesn't include materials??? geeze - i
>> wonder how the heck you guys ever graduate.
>
> Whoever said "optimization of design" doesn't include materials"? "jim
> beam" is off on a flight of fancy here.
>
lightweight. eat your own dog food. build your test wheel and publish
your results.
|
| | | | | | | | | | | | | | | | | | | |
Date: 04 Nov 2007 10:26:50
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> Tom Sherman wrote:
>>>> "jim beam" wrote:
>>>>> Tom Sherman wrote:
>>>>>> "jim beam" wrote:
>>>>>>> Ben C wrote:
>>>>>>>> On 2007-11-04, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>> wrote:
>>>>>>>> [...]
>>>>>>>>> The test Ben C is proposing puts different maximum loads on the
>>>>>>>>> rim - if neither rim yields before the bottom spokes become
>>>>>>>>> slack, the test proves nothing.
>>>>>>>>
>>>>>>>> If the rim doesn't yield before the spokes go slack it means you
>>>>>>>> could
>>>>>>>> have benefitted from higher tension (provided you didn't fatigue
>>>>>>>> the
>>>>>>>> spoke bed too much).
>>>>>>>
>>>>>>> "provided you didn't fatigue the spoke bed too much" - and
>>>>>>> therein lies the question. rims can easily withstand a few slack
>>>>>>> spokes - an unspoked low profile ma2 bare hoop will take my full
>>>>>>> body weight without folding. 3 or 4 spokes slack are /much/ less
>>>>>>> of a problem. seeking tension at the borderline of yield is
>>>>>>> pointless and destructive for the spoke bed.
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> If it does, it means tension was too high.
>>>>>>
>>>>>> We are back to where we started. The rim is poorly designed if the
>>>>>> spoke bed fatigues well below the compressive hoop stress the rim
>>>>>> can bear - too much material in some places, too little in others.
>>>>>>
>>>>>
>>>>> i can't decide whether you're stupid, or whether you've just here
>>>>> to fuck about. given that you obstinately refuse to eat your own
>>>>> dog food, i'd say the latter. but then again...
>>>>
>>>> Yeah, they do not teach optimization of design in materials science
>>>> courses.
>>>>
>>>
>>> actually, they teach us how to fix the problems engineers create when
>>> they don't know what they're doing and won't eat their own dog food.
>>
>> What curriculum is this?
>>
>>> "optimization of design" doesn't include materials??? geeze - i
>>> wonder how the heck you guys ever graduate.
>>
>> Whoever said "optimization of design" doesn't include materials"? "jim
>> beam" is off on a flight of fancy here.
>>
>
> lightweight. eat your own dog food. build your test wheel and publish
> your results.
What is with all the dog food references? New diet in the "beam" household?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | |
Date: 03 Nov 2007 18:22:26
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>> Tom Sherman wrote:
>>> Ben C? wrote:
>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>> Ben C? wrote:
>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:
>>>>>>> Ben C? wrote:
>>>>>>>> On 2007-11-03, Tom Sherman <sunsetss0003@REMOVETHISyahoo.com>
>>>>>>>> wrote:
>>>> [...]
>>>>>>>>> Then these rims are poorly designed, since there is excess
>>>>>>>>> material that creates stiffness in bending that is greater than
>>>>>>>>> the wheel needs to remain true at maximum allowable spoke
>>>>>>>>> tension. The rim could be made lighter for a given WHEEL
>>>>>>>>> strength, or the same weight rim could be redesigned to allow
>>>>>>>>> for a stronger overall WHEEL.
>>>>>>>> I hear this a lot but isn't this based on the premise that the
>>>>>>>> performance of a wheel is solely a function of how much spoke
>>>>>>>> tension it
>>>>>>>> can support?
>>>>>>>>
>>>>>>>> That seems to leave yield strength of the rim itself completely
>>>>>>>> out of
>>>>>>>> the equation.
>>>>>>> There are several different ways a rim can yield. Which of these
>>>>>>> are you referring to?
>>>>>> Probably flat-spotting. We had a thread recently where we
>>>>>> discussed how
>>>>>> tension might affect propensity to flat-spot. With high tensions
>>>>>> the rim
>>>>>> will flat spot more easily if it reaches yield stress before the
>>>>>> spokes
>>>>>> go slack.
>>>>>>
>>>>>> This would be an interesting experiment to do: build a wheel with
>>>>>> high
>>>>>> tension, and keep loading it (weight downwards on the hub, the same
>>>>>> thing it gets in use). Measure spoke tension in the bottom spokes.
>>>>>> Keep
>>>>>> adding weights until the tension goes to almost but not quite zero.
>>>>>> Remove weights. Check rim for permanent deformation. If it has
>>>>>> deformed
>>>>>> permanently, then reduction in rim yield strength due to spoke
>>>>>> tension
>>>>>> is a real issue.
>>>>> But if the spoke tension were less, the rim would permanently
>>>>> deform with the bottom spokes in a slack condition in this test?
>>>>
>>>> No, in this test, you stop before the spokes go slack.
>>>
>>> But that is a different maximum load on the wheel, depending on
>>> original spoke tension.
>>
>> think of the rim dude - that thing yielding is what determines wheel
>> failure.
>
> The test Ben C is proposing puts different maximum loads on the rim - if
> neither rim yields before the bottom spokes become slack, the test
> proves nothing.
>
>>> How does that prove anything?
>>>
>>>>> What would lower spoke tension gain in return for its known demerits?
>>>>
>>>> If it's true that the rim deforms before the spokes go slack, then
>>>> loosening them a bit would have allowed it to bear more load before it
>>>> deformed.
>>>>
>>>> When you crank up the spoke tension, you increase the load the wheel
>>>> can
>>>> support before the spokes go slack (a good thing), but you reduce the
>>>> load the wheel can support before the rim yields plastically.
>>>>
>>>> This is because the total stress on the rim is the load PLUS the
>>>> precompression from all that spoke tension.
>>>
>>> Yes, but does this make a practical difference? If the spokes go
>>> slack before the rim yields, then the wheel will fail from other causes.
>>
>> no it won't. that's jobstian presumption - and red herring
>> swallowing. i've got a wheel that goes slack easily on the non-drive
>> side. no failure. and i've seen an mtb wheel ridden for 6+ months,
>> with spokes so slack, the crossings used to audibly grind. no
>> collapse there either, and that thing was jumped.
>
> Six (6) months is hardly a severe test of wheel durability.
it is when it's alleged that wheels "collapse" as soon as spokes go
slack [because they don't].
> A rim braked
> wheel should require no maintenance until the braking track wears to
> thin (unless one is willing to put up with disposable wheels for a
> slight performance increase).
>
>>> Do you have data showing that higher spoke tensions lead to more
>>> flat-spotting of rims?
>>
>> think through the problem. if you compress two ends of a beam, then
>> 3-point load it - it will yield sooner because of the compression.
>
> What happens in the real world?
compression /is/ real world.
>
>>>> So optimal spoke tension would seem to be whatever amount means that
>>>> the
>>>> rim is just about to deform plastically at the load at which the spokes
>>>> are just going slack.
>>>>
>>>> There are (at least) three variables: load the rim the can support
>>>> before it yields; load the wheel can support before the spokes go
>>>> slack;
>>>> amount of tension the spoke bed can support without cracking after a
>>>> few
>>>> thousand miles.
>>>>
>>>> All three (plus others not thought of) one would expect to be
>>>> matched on
>>>> an optimized rim; otherwise it's stronger than it needs to be or weaker
>>>> than it should be somewhere.
>>>
>>> Remember that the buckling that occurs from excessive spoke tension
>>> occurs along a different axis than the yielding that causes flat
>>> spots on the rim.
>>
>> but it's a further symptom of the same problem - excess hoop compression.
>>
> Again, which is a greater problem in the real world? Rim yielding or
> slack spokes?
real world is rim yielding due to spoke tension "as high as the rim can
bear". it's the #1 cause of rim failure - it exacerbates buckling,
flat spotting and causes rim cracking. slack spokes are a problem for
the spokes, not so much the rim.
|
| | | | | | | | | | | | |
Date: 03 Nov 2007 20:26:16
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
>
> real world is rim yielding due to spoke tension "as high as the rim can
> bear". it's the #1 cause of rim failure - it exacerbates buckling,
> flat spotting and causes rim cracking. slack spokes are a problem for
> the spokes, not so much the rim.
I do not seem to have these problems? Could it be that I use relatively
heavy rims, small diameter wheels, and relatively wide tires?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | | | | | | | | | | |
Date: 03 Nov 2007 18:49:55
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> "jim beam" wrote:
>>
>> real world is rim yielding due to spoke tension "as high as the rim
>> can bear". it's the #1 cause of rim failure - it exacerbates
>> buckling, flat spotting and causes rim cracking. slack spokes are a
>> problem for the spokes, not so much the rim.
>
> I do not seem to have these problems? Could it be that I use relatively
> heavy rims, small diameter wheels, and relatively wide tires?
>
hmmm, let's see, which will buckle first, the 2m pole or the 1m pole?
|
| | | | | | | | | | | | | | |
Date: 04 Nov 2007 08:41:48
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>>
>>> real world is rim yielding due to spoke tension "as high as the rim
>>> can bear". it's the #1 cause of rim failure - it exacerbates
>>> buckling, flat spotting and causes rim cracking. slack spokes are a
>>> problem for the spokes, not so much the rim.
>>
>> I do not seem to have these problems? Could it be that I use
>> relatively heavy rims, small diameter wheels, and relatively wide tires?
>>
>
> hmmm, let's see, which will buckle first, the 2m pole or the 1m pole?
Insufficient information provided in the question for this to be
answered. Are other variable similar, and if not, how do they differ?
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | |
Date: 02 Nov 2007 18:04:21
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Ozark Bicycle wrote:
>> On Oct 31, 12:45 pm, phs...@gmail.com wrote:
>>> Ozark Bicycle skrev:
>>>
>>>> "The Jobst taco method" is way outta date and not applicable to modern
>>>> rims (which are more resistant to 'doing the taco' than are box shape
>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>>> If people bothered to look up in Jobst Brandt's book (3. ed.) page
>>> 105, he specifically says that the "taco" method only applies to
>>> conventional road rims under 430 grams with 36 spokes (perhaps 32
>>> spokes too).
>>> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
>>> "Taco" method.
>>>
>>> I see the "Taco" method as an easy, practical way to get the safe
>>> maximum tension on a standard wheel set. The method is in no way
>>> "outdated", on the contrary,
>>
>> IME, many modern profile rims will have their recommended spoke
>> tension maximum before fhey 'deform' per the method recommended by
>> Jobst Brandt....
>
> Then these rims are poorly designed,
eh? so by that rationale, rims are also poorly designed because they
dent when you ride up 6" curbs? because that's well within the range of
daily experience.
> since there is excess material that
> creates stiffness in bending that is greater than the wheel needs to
> remain true at maximum allowable spoke tension. The rim could be made
> lighter for a given WHEEL strength, or the same weight rim could be
> redesigned to allow for a stronger overall WHEEL.
er....
|
| | |
Date: 31 Oct 2007 16:43:15
From: Michael Press
Subject: Re: Spoke tension Question
|
In article
<1193862515.970812.83510@o80g2000hse.googlegroups.com >,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com > wrote:
> And, when the DS tension is too high, the spoke bed cracks around the
> DS spokeholes. The solution to keeping the NDS spokes from going slack
> is a mild threadlock.
The solution is to buy only rims whose spoke beds can
sustain 110 kgf. Then the manufacturers would make
more of them. There are rims now that can sustain
the whole nine yards.
--
Michael Press
|
| | | |
Date: 02 Nov 2007 19:23:39
From: Tom Sherman
Subject: Re: Spoke tension Question
|
Michael Press wrote:
> In article
> <1193862515.970812.83510@o80g2000hse.googlegroups.com>,
> Ozark Bicycle
> <bicycleatelier@ozarkbicycleservice.com> wrote:
>
>> And, when the DS tension is too high, the spoke bed cracks around the
>> DS spokeholes. The solution to keeping the NDS spokes from going slack
>> is a mild threadlock.
>
> The solution is to buy only rims whose spoke beds can
> sustain 110 kgf. Then the manufacturers would make
> more of them. There are rims now that can sustain
> the whole nine yards.
>
butbutbut, these sensible wheels do not impress when the bicycle is
parked at the coffee shop!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| | | | |
Date: 02 Nov 2007 18:16:17
From: jim beam
Subject: Re: Spoke tension Question
|
Tom Sherman wrote:
> Michael Press wrote:
>> In article <1193862515.970812.83510@o80g2000hse.googlegroups.com>,
>> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
>>
>>> And, when the DS tension is too high, the spoke bed cracks around the
>>> DS spokeholes. The solution to keeping the NDS spokes from going slack
>>> is a mild threadlock.
>>
>> The solution is to buy only rims whose spoke beds can sustain 110 kgf.
>> Then the manufacturers would make more of them. There are rims now
>> that can sustain
>> the whole nine yards.
>>
> butbutbut, these sensible wheels do not impress when the bicycle is
> parked at the coffee shop!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>
but but but they impress more than the toy-sized wheels seen on some 'bents.
|
| | | | | |
Date: 03 Nov 2007 06:11:10
From: Tom Sherman
Subject: Re: Spoke tension Question
|
"jim beam" wrote:
> Tom Sherman wrote:
>> Michael Press wrote:
>>> In article <1193862515.970812.83510@o80g2000hse.googlegroups.com>,
>>> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
>>>
>>>> And, when the DS tension is too high, the spoke bed cracks around the
>>>> DS spokeholes. The solution to keeping the NDS spokes from going slack
>>>> is a mild threadlock.
>>>
>>> The solution is to buy only rims whose spoke beds can sustain 110
>>> kgf. Then the manufacturers would make more of them. There are rims
>>> now that can sustain
>>> the whole nine yards.
>>>
>> butbutbut, these sensible wheels do not impress when the bicycle is
>> parked at the coffee shop!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>>
>
> but but but they impress more than the toy-sized wheels seen on some
> 'bents.
butbutbut [1], a lot of girls find a bike with an ISO 305-mm/406-mm
front/rear wheel set cute.
N.B. "jim beam" introduced the subject of recumbent bicycles to this thread.
[1] Gratuitous gdanielsism.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| |
Date: 31 Oct 2007 13:23:03
From: Hank Wirtz
Subject: Re: Spoke tension Question
|
On Oct 30, 9:32 pm, Michael Press <rub...@pacbell.net > wrote:
> In article
> <1193795805.725768.313...@50g2000hsm.googlegroups.com>,
> Ozark Bicycle
>
>
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> > > On Oct 30, 11:29 am, Ozark Bicycle
>
> > > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > > On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>
> > > > > Ozark Bicycle wrote:
> > > > > > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > > > > > Jas51 wrote:
> > > > > > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > > > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > > > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > > > > > proper technique?
>
> > > > > > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > > > > > in 1988, as you can't find your Park model, tension each spoke till
> > > > > > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > > > > > when plucked. Make sure to have your ears calibrated beforehand.
>
> > > > > > Next step: Use Google to find the best price on a new rim. Rinse and
> > > > > > repeat. ;-)
>
> > > > > All kidding aside, I do have a general pitch which I true around,
> > > > > dished wheels getting an average of that tone. It doesn't distinguish
> > > > > between specific brands of rims, some which can take more tension--but
> > > > > the wheels stay true, and that's all that matters in the end. ;-) I've
> > > > > only had one rim ever go bad on me, and that was a cracked MA3 a
> > > > > couple years ago--which I doubt had to do with spoke tension. As long
> > > > > as the tension is good enough, the spokes seated in the flanges, and
> > > > > the overall tension even--you're still miles ahead of factory tuned
> > > > > junk.
>
> > > > > The Jobst taco method strikes me as a bit more dangerous than my
> > > > > rather plebian ways, seeing as he's a proponent of socketed rims,
> > > > > which I assume are going to be a bit more resistant to cracking
> > > > > compared to eyeletted or plain hole stoff.
>
> > > > "The Jobst taco method" is way outta date and not applicable to modern
> > > > rims (which are more resistant to 'doing the taco' than are box shape
> > > > rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
>
> > >http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> > > think $54 is a reasonable investment -- less than a Open Pro rim full
> > > price. -- Jay Beattie
>
> > Considering the investment in a pair of hubs, pair of rims, 60+
> > spokes, etc., it seems foolish to "cheap out" and not buy a Park
> > Tensiometer.
>
> If I were to buy a tensiometer I would be foolish to cheap out on
> the Park tensiometer rather than the DT Swiss Tensio Spoke Tensiometer
>
> <http://www.bikemannetwork.com/biking/p/TL1925>
>
> --
> Michael Press- Hide quoted text -
>
> - Show quoted text -
I don't get what you mean here. The DT costs five and a half times as
much ($336 vs ~$60) For most wheelbuilders, is that justifiable?
|
| | |
Date: 31 Oct 2007 15:54:12
From: Michael Press
Subject: Re: Spoke tension Question
|
In article
<1193862183.115333.165430@y27g2000pre.googlegroups.com >
,
Hank Wirtz <hank@wirtznet.net > wrote:
> On Oct 30, 9:32 pm, Michael Press <rub...@pacbell.net> wrote:
> > In article
> > <1193795805.725768.313...@50g2000hsm.googlegroups.com>,
> > Ozark Bicycle
> >
> >
> >
> >
> >
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> > > > On Oct 30, 11:29 am, Ozark Bicycle
> >
> > > > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > > > On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> >
> > > > > > Ozark Bicycle wrote:
> > > > > > > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > > > > > > Jas51 wrote:
> > > > > > > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > > > > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > > > > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > > > > > > proper technique?
> >
> > > > > > > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > > > > > > in 1988, as you can't find your Park model, tension each spoke till
> > > > > > > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > > > > > > when plucked. Make sure to have your ears calibrated beforehand.
> >
> > > > > > > Next step: Use Google to find the best price on a new rim. Rinse and
> > > > > > > repeat. ;-)
> >
> > > > > > All kidding aside, I do have a general pitch which I true around,
> > > > > > dished wheels getting an average of that tone. It doesn't distinguish
> > > > > > between specific brands of rims, some which can take more tension--but
> > > > > > the wheels stay true, and that's all that matters in the end. ;-) I've
> > > > > > only had one rim ever go bad on me, and that was a cracked MA3 a
> > > > > > couple years ago--which I doubt had to do with spoke tension. As long
> > > > > > as the tension is good enough, the spokes seated in the flanges, and
> > > > > > the overall tension even--you're still miles ahead of factory tuned
> > > > > > junk.
> >
> > > > > > The Jobst taco method strikes me as a bit more dangerous than my
> > > > > > rather plebian ways, seeing as he's a proponent of socketed rims,
> > > > > > which I assume are going to be a bit more resistant to cracking
> > > > > > compared to eyeletted or plain hole stoff.
> >
> > > > > "The Jobst taco method" is way outta date and not applicable to modern
> > > > > rims (which are more resistant to 'doing the taco' than are box shape
> > > > > rims) and modern, more highly dished 130mm 8-10sp rear wheels.
> >
> > > >http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> > > > think $54 is a reasonable investment -- less than a Open Pro rim full
> > > > price.
> >
> > > Considering the investment in a pair of hubs, pair of rims, 60+
> > > spokes, etc., it seems foolish to "cheap out" and not buy a Park
> > > Tensiometer.
> >
> > If I were to buy a tensiometer I would be foolish to cheap out on
> > the Park tensiometer rather than the DT Swiss Tensio Spoke Tensiometer
>
> I don't get what you mean here. The DT costs five and a half times as
> much ($336 vs ~$60) For most wheelbuilders, is that justifiable?
I do not attempt and have not attempted to justify
purchase of a tension meter. In fact I do not have one
and may never purchase one.
Jay Beattie implies that I would be penny wise and
pound foolish not to purchase a Park tension meter with
the purchase of hubs, spokes, and rims to build into
wheels at home. I simply extend his reasoning to the
choice of the tension meter.
--
Michael Press
|
| |
Date: 31 Oct 2007 13:08:22
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 31, 11:45 am, phs...@gmail.com wrote:
> Ozark Bicycle skrev:
>
> > "The Jobst taco method" is way outta date and not applicable to modern
> > rims (which are more resistant to 'doing the taco' than are box shape
> > rims) and modern, more highly dished 130mm 8-10sp rear wheels.
>
> If people bothered to look up in Jobst Brandt's book (3. ed.) page
> 105, he specifically says that the "taco" method only applies to
> conventional road rims under 430 grams with 36 spokes (perhaps 32
> spokes too).
> MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
> "Taco" method.
>
> I see the "Taco" method as an easy, practical way to get the safe
> maximum tension on a standard wheel set. The method is in no way
> "outdated", on the contrary, since highly dished wheels often require
> very high DS tension so that the NDS tension becomes sufficiently
> high.
>
> So not only are you wrong about what Jobst Brandt's "Taco" method is,
> you are also wrong about it being outdated.
It is outdated in the sense that it results in tensions that will
cause cracking in sub-430 gram rims, e.g., Aerohead and OpenPro. If I
had to guess, soft-taco time comes at about 140+kgf for an Aerohead.
The manufacturer recommends tensions in the 110 kgf range (IIRC),
which presumably will keep the wheel true without causing spoke hole
cracking. -- Jay Beattie.
|
| |
Date: 31 Oct 2007 18:49:54
From: datakoll
Subject: Re: Spoke tension Question
|
we here at elysianfields.org call 'the taco method', the sine wave
problem.
our problem with the sine wave problem is
the sine waved rim does not red dilly retrue.
now I ahven't gone an blown the trueing process into sine wave
surreality for many a moon caws of the configuration's irredamable
nature.
basically doing that from group 2 is not inorder due to mental health
concerns and a need to eat dinner.
my question, relevant to TACOING paired with TENSION-o-meter
was based on: if all my (it actually) trued spokes are uneven, does
using the -meter to ID values and move values into balance
true the wheel?
is that given or variable?
maybe I'l go out and ask the lizards?
|
| |
Date: 31 Oct 2007 11:45:10
From:
Subject: Re: Spoke tension Question
|
Ozark Bicycle skrev:
> "The Jobst taco method" is way outta date and not applicable to modern
> rims (which are more resistant to 'doing the taco' than are box shape
> rims) and modern, more highly dished 130mm 8-10sp rear wheels.
If people bothered to look up in Jobst Brandt's book (3. ed.) page
105, he specifically says that the "taco" method only applies to
conventional road rims under 430 grams with 36 spokes (perhaps 32
spokes too).
MTB rims, carbon rims, heavy v-rims, 24 spoke rims etc. can't use the
"Taco" method.
I see the "Taco" method as an easy, practical way to get the safe
maximum tension on a standard wheel set. The method is in no way
"outdated", on the contrary, since highly dished wheels often require
very high DS tension so that the NDS tension becomes sufficiently
high.
So not only are you wrong about what Jobst Brandt's "Taco" method is,
you are also wrong about it being outdated.
--
Regards
|
| |
Date: 31 Oct 2007 11:30:50
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 31, 10:52 am, carlfo...@comcast.net wrote:
> On Wed, 31 Oct 2007 11:05:39 -0600, A Muzi <a...@yellowjersey.org>
> wrote:
>
> >I can reasonably see a guy who does the same wheel with many iterations
> >every day not needing one as much as a guy who does occasional wheels
> >with various rims, sizes, spokes, spoke count.
>
> >The phrase "Jobst taco method" is not a fair synopsis of the author's point.
>
> Dear Andrew,
>
> What's unfair about it?
>
> Jobst suggested a practical method for raising spoke tension in the
> era of 36-spoke MA2 rims. Back then, tension gauges and recommended
> tensions were as scarce as hen's teeth, so a practical method was
> needed.
>
> Keep raising the spoke tension until the wheel goes out of true when
> spoke pairs are squeezed. Then back all the spokes off half a turn,
> true the wheel, and put the spoke wrench away.
>
> In other words, raise the tension until the rim tacos when the spokes
> are squeezed, then back off half a turn.
>
> Can anyone think of a better three-word phrase to describe this
> process than calling it the "Jobst taco method"?
As I recall, the Book talks about a wave in the rim -- not a real
"taco." The rim is not toasted and returns to its proper shape when
tension is reduced. It's a "soft taco" -- maybe a flour taco.
Certainly not a fried corn taco or chimichanga.
I never used the soft taco technique since I could get a Mod 58 or a
ModE/E2/MA2 rock hard (almost no movement at the right crosses) before
the rim deformed. This was plenty of tension to keep the wheel true
forever. I have never tried this technique with modern rims (Open Pro
or Aeroheads) because I had a good sense of where tension should be
from years of building wheels -- but I have gotten cracking in both
those rims at tensions below the soft-taco point and at or near my old
"works for MA2s" tensions. Thus, the tensiometer. Now that I have
built four or five of the Aerohead OC rims and a bunch of OpenPros, I
could probably skip the tensiometer -- but why? I want to get my
money out of it. Plus, it gets borrowed by the neighborhood wheel
builders, one of whom lends me his impact hammer and floor jack when
it is time to throw on my snow tires. Reason enough to own it. -- Jay
Beattie.
|
| | |
Date: 31 Oct 2007 13:52:32
From: A Muzi
Subject: Re: Spoke tension Question
|
>> A Muzi <a...@yellowjersey.org> wrote:
>>> I can reasonably see a guy who does the same wheel with many iterations
>>> every day not needing one as much as a guy who does occasional wheels
>>> with various rims, sizes, spokes, spoke count.
>>> The phrase "Jobst taco method" is not a fair synopsis of the author's point.
> carlfo...@comcast.net wrote:
>> What's unfair about it?
>>
>> Jobst suggested a practical method for raising spoke tension in the
>> era of 36-spoke MA2 rims. Back then, tension gauges and recommended
>> tensions were as scarce as hen's teeth, so a practical method was
>> needed.
>>
>> Keep raising the spoke tension until the wheel goes out of true when
>> spoke pairs are squeezed. Then back all the spokes off half a turn,
>> true the wheel, and put the spoke wrench away.
>>
>> In other words, raise the tension until the rim tacos when the spokes
>> are squeezed, then back off half a turn.
>>
>> Can anyone think of a better three-word phrase to describe this
>> process than calling it the "Jobst taco method"?
Jay Beattie wrote:
> As I recall, the Book talks about a wave in the rim -- not a real
> "taco." The rim is not toasted and returns to its proper shape when
> tension is reduced. It's a "soft taco" -- maybe a flour taco.
> Certainly not a fried corn taco or chimichanga.
>
> I never used the soft taco technique since I could get a Mod 58 or a
> ModE/E2/MA2 rock hard (almost no movement at the right crosses) before
> the rim deformed. This was plenty of tension to keep the wheel true
> forever. I have never tried this technique with modern rims (Open Pro
> or Aeroheads) because I had a good sense of where tension should be
> from years of building wheels -- but I have gotten cracking in both
> those rims at tensions below the soft-taco point and at or near my old
> "works for MA2s" tensions. Thus, the tensiometer. Now that I have
> built four or five of the Aerohead OC rims and a bunch of OpenPros, I
> could probably skip the tensiometer -- but why? I want to get my
> money out of it. Plus, it gets borrowed by the neighborhood wheel
> builders, one of whom lends me his impact hammer and floor jack when
> it is time to throw on my snow tires. Reason enough to own it.
Yes, I agree. Semantically, I considered 'taco' synonymous with 'dead'.
YMMV if you are able to distinguish, as Jay does, among tacos.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 31 Oct 2007 07:03:36
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Oct 30, 11:24 pm, Jay Beattie <jbeat...@lindsayhart.com > wrote:
> On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net> wrote:
>
>
>
> > Ozark Bicycle wrote:
> > > On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> > >> On Oct 30, 11:29 am, Ozark Bicycle
>
> > >> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > >>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> > >>>> Ozark Bicycle wrote:
> > >>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > >>>>>> Jas51 wrote:
> > >>>>>>> Using the rim taco-method of setting spoke tension, should a tire be
> > >>>>>>> mounted and inflated beforehand? Ive always brung the spokes up to tension
> > >>>>>>> with no tire mounted, but the 160 psi thread got me wondering. What's the
> > >>>>>>> proper technique?
> > >>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > >>>>>> in 1988, as you can't find your Park model, tension each spoke till
> > >>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > >>>>>> when plucked. Make sure to have your ears calibrated beforehand.
> > >>>>> Next step: Use Google to find the best price on a new rim. Rinse and
> > >>>>> repeat. ;-)
> > >>>> All kidding aside, I do have a general pitch which I true around,
> > >>>> dished wheels getting an average of that tone. It doesn't distinguish
> > >>>> between specific brands of rims, some which can take more tension--but
> > >>>> the wheels stay true, and that's all that matters in the end. ;-) I've
> > >>>> only had one rim ever go bad on me, and that was a cracked MA3 a
> > >>>> couple years ago--which I doubt had to do with spoke tension. As long
> > >>>> as the tension is good enough, the spokes seated in the flanges, and
> > >>>> the overall tension even--you're still miles ahead of factory tuned
> > >>>> junk.
> > >>>> The Jobst taco method strikes me as a bit more dangerous than my
> > >>>> rather plebian ways, seeing as he's a proponent of socketed rims,
> > >>>> which I assume are going to be a bit more resistant to cracking
> > >>>> compared to eyeletted or plain hole stoff.
> > >>> "The Jobst taco method" is way outta date and not applicable to modern
> > >>> rims (which are more resistant to 'doing the taco' than are box shape
> > >>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
> > >>http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> > >> think $54 is a reasonable investment -- less than a Open Pro rim full
> > >> price. -- Jay Beattie
>
> > > Considering the investment in a pair of hubs, pair of rims, 60+
> > > spokes, etc., it seems foolish to "cheap out" and not buy a Park
> > > Tensiometer.
>
> > yeahbut some individuals think their psychic powers make them exempt
> > from the physics of earthly matter. they "don't need no steenkin'
> > tensiometer", remember?- Hide quoted text -
>
> I think the Book has to abandon the MA2/6 speed paradigm. It is no
> longer the real world. -- Jay Beattie
BINGO!!!
|
| |
Date: 31 Oct 2007 13:20:34
From: datakoll
Subject: Re: Spoke tension Question
|
geee, all I asked was HOW Jay Beattie used his tension-o-meter
or HOW the meter use avoids tacoing
or WHEN the meter is used.
to evaluate using the meter.
|
| | |
Date: 31 Oct 2007 22:14:46
From: jim beam
Subject: Re: Spoke tension Question
|
datakoll wrote:
>
> geee, all I asked was HOW Jay Beattie used his tension-o-meter
> or HOW the meter use avoids tacoing
by preventing excess spoke tension.
> or WHEN the meter is used.
during final tensioning.
> to evaluate using the meter.
it's not perfect, but for the money, the park meter is a rockin' good
deal. and its designers recognize that spoke gauge affects spoke stiffness.
|
| |
Date: 30 Oct 2007 22:24:01
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net > wrote:
> Ozark Bicycle wrote:
> > On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> >> On Oct 30, 11:29 am, Ozark Bicycle
>
> >> <bicycleatel...@ozarkbicycleservice.com> wrote:
> >>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> >>>> Ozark Bicycle wrote:
> >>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> >>>>>> Jas51 wrote:
> >>>>>>> Using the rim taco-method of setting spoke tension, should a tire be
> >>>>>>> mounted and inflated beforehand? Ive always brung the spokes up to tension
> >>>>>>> with no tire mounted, but the 160 psi thread got me wondering. What's the
> >>>>>>> proper technique?
> >>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> >>>>>> in 1988, as you can't find your Park model, tension each spoke till
> >>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
> >>>>>> when plucked. Make sure to have your ears calibrated beforehand.
> >>>>> Next step: Use Google to find the best price on a new rim. Rinse and
> >>>>> repeat. ;-)
> >>>> All kidding aside, I do have a general pitch which I true around,
> >>>> dished wheels getting an average of that tone. It doesn't distinguish
> >>>> between specific brands of rims, some which can take more tension--but
> >>>> the wheels stay true, and that's all that matters in the end. ;-) I've
> >>>> only had one rim ever go bad on me, and that was a cracked MA3 a
> >>>> couple years ago--which I doubt had to do with spoke tension. As long
> >>>> as the tension is good enough, the spokes seated in the flanges, and
> >>>> the overall tension even--you're still miles ahead of factory tuned
> >>>> junk.
> >>>> The Jobst taco method strikes me as a bit more dangerous than my
> >>>> rather plebian ways, seeing as he's a proponent of socketed rims,
> >>>> which I assume are going to be a bit more resistant to cracking
> >>>> compared to eyeletted or plain hole stoff.
> >>> "The Jobst taco method" is way outta date and not applicable to modern
> >>> rims (which are more resistant to 'doing the taco' than are box shape
> >>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
> >>http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> >> think $54 is a reasonable investment -- less than a Open Pro rim full
> >> price. -- Jay Beattie
>
> > Considering the investment in a pair of hubs, pair of rims, 60+
> > spokes, etc., it seems foolish to "cheap out" and not buy a Park
> > Tensiometer.
>
> yeahbut some individuals think their psychic powers make them exempt
> from the physics of earthly matter. they "don't need no steenkin'
> tensiometer", remember?- Hide quoted text -
I think the Book has to abandon the MA2/6 speed paradigm. It is no
longer the real world. -- Jay Beattie
|
| | |
Date: 31 Oct 2007 22:10:54
From: jim beam
Subject: Re: Spoke tension Question
|
Jay Beattie wrote:
> On Oct 30, 8:16 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Ozark Bicycle wrote:
>>> On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
>>>> On Oct 30, 11:29 am, Ozark Bicycle
>>>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>>>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>>>>>> Ozark Bicycle wrote:
>>>>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
>>>>>>>> Jas51 wrote:
>>>>>>>>> Using the rim taco-method of setting spoke tension, should a tire be
>>>>>>>>> mounted and inflated beforehand? Ive always brung the spokes up to tension
>>>>>>>>> with no tire mounted, but the 160 psi thread got me wondering. What's the
>>>>>>>>> proper technique?
>>>>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
>>>>>>>> in 1988, as you can't find your Park model, tension each spoke till
>>>>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
>>>>>>>> when plucked. Make sure to have your ears calibrated beforehand.
>>>>>>> Next step: Use Google to find the best price on a new rim. Rinse and
>>>>>>> repeat. ;-)
>>>>>> All kidding aside, I do have a general pitch which I true around,
>>>>>> dished wheels getting an average of that tone. It doesn't distinguish
>>>>>> between specific brands of rims, some which can take more tension--but
>>>>>> the wheels stay true, and that's all that matters in the end. ;-) I've
>>>>>> only had one rim ever go bad on me, and that was a cracked MA3 a
>>>>>> couple years ago--which I doubt had to do with spoke tension. As long
>>>>>> as the tension is good enough, the spokes seated in the flanges, and
>>>>>> the overall tension even--you're still miles ahead of factory tuned
>>>>>> junk.
>>>>>> The Jobst taco method strikes me as a bit more dangerous than my
>>>>>> rather plebian ways, seeing as he's a proponent of socketed rims,
>>>>>> which I assume are going to be a bit more resistant to cracking
>>>>>> compared to eyeletted or plain hole stoff.
>>>>> "The Jobst taco method" is way outta date and not applicable to modern
>>>>> rims (which are more resistant to 'doing the taco' than are box shape
>>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
>>>> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
>>>> think $54 is a reasonable investment -- less than a Open Pro rim full
>>>> price. -- Jay Beattie
>>> Considering the investment in a pair of hubs, pair of rims, 60+
>>> spokes, etc., it seems foolish to "cheap out" and not buy a Park
>>> Tensiometer.
>> yeahbut some individuals think their psychic powers make them exempt
>> from the physics of earthly matter. they "don't need no steenkin'
>> tensiometer", remember?- Hide quoted text -
>
> I think the Book has to abandon the MA2/6 speed paradigm. It is no
> longer the real world. -- Jay Beattie
>
good luck with that thought. jobst doesn't correct mistakes still
selling to an audience that overwhelmingly doesn't know any better, or
worse, even care.
|
| |
Date: 31 Oct 2007 02:47:04
From: datakoll
Subject: Re: Spoke tension Question
|
- buy quoted text -
I agree but if we can't fijnd an expert to step forward then explain
what the tension-o-meter is used for
, why not go hole hawg with: http://www.dtswiss.com/Products/Proline/DT-tensio-digital.aspx
|
| |
Date: 30 Oct 2007 18:56:45
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com > wrote:
> On Oct 30, 11:29 am, Ozark Bicycle
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>
> > > Ozark Bicycle wrote:
> > > > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > > > Jas51 wrote:
> > > > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > > > proper technique?
>
> > > > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > > > in 1988, as you can't find your Park model, tension each spoke till
> > > > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > > > when plucked. Make sure to have your ears calibrated beforehand.
>
> > > > Next step: Use Google to find the best price on a new rim. Rinse and
> > > > repeat. ;-)
>
> > > All kidding aside, I do have a general pitch which I true around,
> > > dished wheels getting an average of that tone. It doesn't distinguish
> > > between specific brands of rims, some which can take more tension--but
> > > the wheels stay true, and that's all that matters in the end. ;-) I've
> > > only had one rim ever go bad on me, and that was a cracked MA3 a
> > > couple years ago--which I doubt had to do with spoke tension. As long
> > > as the tension is good enough, the spokes seated in the flanges, and
> > > the overall tension even--you're still miles ahead of factory tuned
> > > junk.
>
> > > The Jobst taco method strikes me as a bit more dangerous than my
> > > rather plebian ways, seeing as he's a proponent of socketed rims,
> > > which I assume are going to be a bit more resistant to cracking
> > > compared to eyeletted or plain hole stoff.
>
> > "The Jobst taco method" is way outta date and not applicable to modern
> > rims (which are more resistant to 'doing the taco' than are box shape
> > rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
>
> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> think $54 is a reasonable investment -- less than a Open Pro rim full
> price. -- Jay Beattie
Considering the investment in a pair of hubs, pair of rims, 60+
spokes, etc., it seems foolish to "cheap out" and not buy a Park
Tensiometer.
|
| | |
Date: 30 Oct 2007 21:32:18
From: Michael Press
Subject: Re: Spoke tension Question
|
In article
<1193795805.725768.313520@50g2000hsm.googlegroups.com >,
Ozark Bicycle
<bicycleatelier@ozarkbicycleservice.com > wrote:
> On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
> > On Oct 30, 11:29 am, Ozark Bicycle
> >
> >
> >
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
> >
> > > > Ozark Bicycle wrote:
> > > > > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > > > > Jas51 wrote:
> > > > > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > > > > proper technique?
> >
> > > > > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > > > > in 1988, as you can't find your Park model, tension each spoke till
> > > > > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > > > > when plucked. Make sure to have your ears calibrated beforehand.
> >
> > > > > Next step: Use Google to find the best price on a new rim. Rinse and
> > > > > repeat. ;-)
> >
> > > > All kidding aside, I do have a general pitch which I true around,
> > > > dished wheels getting an average of that tone. It doesn't distinguish
> > > > between specific brands of rims, some which can take more tension--but
> > > > the wheels stay true, and that's all that matters in the end. ;-) I've
> > > > only had one rim ever go bad on me, and that was a cracked MA3 a
> > > > couple years ago--which I doubt had to do with spoke tension. As long
> > > > as the tension is good enough, the spokes seated in the flanges, and
> > > > the overall tension even--you're still miles ahead of factory tuned
> > > > junk.
> >
> > > > The Jobst taco method strikes me as a bit more dangerous than my
> > > > rather plebian ways, seeing as he's a proponent of socketed rims,
> > > > which I assume are going to be a bit more resistant to cracking
> > > > compared to eyeletted or plain hole stoff.
> >
> > > "The Jobst taco method" is way outta date and not applicable to modern
> > > rims (which are more resistant to 'doing the taco' than are box shape
> > > rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
> >
> > http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
> > think $54 is a reasonable investment -- less than a Open Pro rim full
> > price. -- Jay Beattie
>
>
> Considering the investment in a pair of hubs, pair of rims, 60+
> spokes, etc., it seems foolish to "cheap out" and not buy a Park
> Tensiometer.
If I were to buy a tensiometer I would be foolish to cheap out on
the Park tensiometer rather than the DT Swiss Tensio Spoke Tensiometer
<http://www.bikemannetwork.com/biking/p/TL1925 >
--
Michael Press
|
| | |
Date: 30 Oct 2007 21:16:22
From: jim beam
Subject: Re: Spoke tension Question
|
Ozark Bicycle wrote:
> On Oct 30, 5:49 pm, Jay Beattie <jbeat...@lindsayhart.com> wrote:
>> On Oct 30, 11:29 am, Ozark Bicycle
>>
>>
>>
>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>>>> Ozark Bicycle wrote:
>>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
>>>>>> Jas51 wrote:
>>>>>>> Using the rim taco-method of setting spoke tension, should a tire be
>>>>>>> mounted and inflated beforehand? Ive always brung the spokes up to tension
>>>>>>> with no tire mounted, but the 160 psi thread got me wondering. What's the
>>>>>>> proper technique?
>>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
>>>>>> in 1988, as you can't find your Park model, tension each spoke till
>>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
>>>>>> when plucked. Make sure to have your ears calibrated beforehand.
>>>>> Next step: Use Google to find the best price on a new rim. Rinse and
>>>>> repeat. ;-)
>>>> All kidding aside, I do have a general pitch which I true around,
>>>> dished wheels getting an average of that tone. It doesn't distinguish
>>>> between specific brands of rims, some which can take more tension--but
>>>> the wheels stay true, and that's all that matters in the end. ;-) I've
>>>> only had one rim ever go bad on me, and that was a cracked MA3 a
>>>> couple years ago--which I doubt had to do with spoke tension. As long
>>>> as the tension is good enough, the spokes seated in the flanges, and
>>>> the overall tension even--you're still miles ahead of factory tuned
>>>> junk.
>>>> The Jobst taco method strikes me as a bit more dangerous than my
>>>> rather plebian ways, seeing as he's a proponent of socketed rims,
>>>> which I assume are going to be a bit more resistant to cracking
>>>> compared to eyeletted or plain hole stoff.
>>> "The Jobst taco method" is way outta date and not applicable to modern
>>> rims (which are more resistant to 'doing the taco' than are box shape
>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
>> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
>> think $54 is a reasonable investment -- less than a Open Pro rim full
>> price. -- Jay Beattie
>
>
> Considering the investment in a pair of hubs, pair of rims, 60+
> spokes, etc., it seems foolish to "cheap out" and not buy a Park
> Tensiometer.
>
yeahbut some individuals think their psychic powers make them exempt
from the physics of earthly matter. they "don't need no steenkin'
tensiometer", remember?
|
| | | |
Date: 31 Oct 2007 11:05:39
From: A Muzi
Subject: Re: Spoke tension Question
|
>>>> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>>>>> Ozark Bicycle wrote:
>>>>>> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
>>>>>>> Jas51 wrote:
>>>>>>>> Using the rim taco-method of setting spoke tension, should a
>>>>>>>> tire be
>>>>>>>> mounted and inflated beforehand? Ive always brung the spokes up
>>>>>>>> to tension
>>>>>>>> with no tire mounted, but the 160 psi thread got me wondering.
>>>>>>>> What's the
>>>>>>>> proper technique?
>>>>>>> Bare rim. Using a really shitty spoke wrench you got carded at a
>>>>>>> Kmart
>>>>>>> in 1988, as you can't find your Park model, tension each spoke till
>>>>>>> your index finger hurts and it goes "twinnng!" instead of "twooong!"
>>>>>>> when plucked. Make sure to have your ears calibrated beforehand.
>>>>>> Next step: Use Google to find the best price on a new rim. Rinse and
>>>>>> repeat. ;-)
>>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>>>> All kidding aside, I do have a general pitch which I true around,
>>>>> dished wheels getting an average of that tone. It doesn't distinguish
>>>>> between specific brands of rims, some which can take more tension--but
>>>>> the wheels stay true, and that's all that matters in the end. ;-) I've
>>>>> only had one rim ever go bad on me, and that was a cracked MA3 a
>>>>> couple years ago--which I doubt had to do with spoke tension. As long
>>>>> as the tension is good enough, the spokes seated in the flanges, and
>>>>> the overall tension even--you're still miles ahead of factory tuned
>>>>> junk.
>>>>> The Jobst taco method strikes me as a bit more dangerous than my
>>>>> rather plebian ways, seeing as he's a proponent of socketed rims,
>>>>> which I assume are going to be a bit more resistant to cracking
>>>>> compared to eyeletted or plain hole stoff.
>>> On Oct 30, 11:29 am, Ozark Bicycle
>>>> "The Jobst taco method" is way outta date and not applicable to modern
>>>> rims (which are more resistant to 'doing the taco' than are box shape
>>>> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide
>>>> quoted text -
>> Jay Beattie <jbeat...@lindsayhart.com> wrote:
>>> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
>>> think $54 is a reasonable investment -- less than a Open Pro rim full
>>> price. -- Jay Beattie
> Ozark Bicycle wrote:
>> Considering the investment in a pair of hubs, pair of rims, 60+
>> spokes, etc., it seems foolish to "cheap out" and not buy a Park
>> Tensiometer.
jim beam wrote:
> yeahbut some individuals think their psychic powers make them exempt
> from the physics of earthly matter. they "don't need no steenkin'
> tensiometer", remember?
I can reasonably see a guy who does the same wheel with many iterations
every day not needing one as much as a guy who does occasional wheels
with various rims, sizes, spokes, spoke count.
The phrase "Jobst taco method" is not a fair synopsis of the author's point.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | |
Date: 31 Oct 2007 11:52:45
From:
Subject: Re: Spoke tension Question
|
On Wed, 31 Oct 2007 11:05:39 -0600, A Muzi <am@yellowjersey.org >
wrote:
>I can reasonably see a guy who does the same wheel with many iterations
>every day not needing one as much as a guy who does occasional wheels
>with various rims, sizes, spokes, spoke count.
>
>The phrase "Jobst taco method" is not a fair synopsis of the author's point.
Dear Andrew,
What's unfair about it?
Jobst suggested a practical method for raising spoke tension in the
era of 36-spoke MA2 rims. Back then, tension gauges and recommended
tensions were as scarce as hen's teeth, so a practical method was
needed.
Keep raising the spoke tension until the wheel goes out of true when
spoke pairs are squeezed. Then back all the spokes off half a turn,
true the wheel, and put the spoke wrench away.
In other words, raise the tension until the rim tacos when the spokes
are squeezed, then back off half a turn.
Can anyone think of a better three-word phrase to describe this
process than calling it the "Jobst taco method"?
Cheers,
Carl Fogel
|
| | | | | |
Date: 31 Oct 2007 16:39:02
From: Michael Press
Subject: Re: Spoke tension Question
|
In article
<2ofhi3lj8qmg6u82boq8srcu2j4999vbem@4ax.com >,
carlfogel@comcast.net wrote:
> Keep raising the spoke tension until the wheel goes out of true when
> spoke pairs are squeezed. Then back all the spokes off half a turn,
> true the wheel, and put the spoke wrench away.
Not yet. The spokes need to be tension balanced.
(And before that the spokes could be stress relieved.)
--
Michael Press
|
| |
Date: 31 Oct 2007 01:55:08
From: datakoll
Subject: Re: Spoke tension Question
|
On Oct 30, 9:32 pm, datakoll <datak...@yahoo.com > wrote:
> OK JAY a bargain
> and from Oak Park!
> but what good is it? relative to the trueing process?
I know! There's a chip in the tension-o-meter. When spoke tension
records as unevenly nearing the universal taco level, a signal goes
forth and this guy shows up on your lawn.
http://www.synergise.com/travel/Homepage/ecards/switzerland_horn.jpg
|
| | |
Date: 02 Nov 2007 19:03:46
From: Tom Sherman
Subject: Re: Spoke tension Question
|
datakoll aka gene daniels wrote:
> On Oct 30, 9:32 pm, datakoll <datak...@yahoo.com> wrote:
>> OK JAY a bargain
>> and from Oak Park!
>> but what good is it? relative to the trueing process?
>
> I know! There's a chip in the tension-o-meter. When spoke tension
> records as unevenly nearing the universal taco level, a signal goes
> forth and this guy shows up on your lawn.
>
> http://www.synergise.com/travel/Homepage/ecards/switzerland_horn.jpg
>
So that is the secret Jobst picked up while riding in the Alps.
--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?
|
| |
Date: 31 Oct 2007 01:32:06
From: datakoll
Subject: Re: Spoke tension Question
|
OK JAY a bargain
and from Oak Park!
but what good is it? relative to the trueing process?
|
| |
Date: 30 Oct 2007 16:49:35
From: Jay Beattie
Subject: Re: Spoke tension Question
|
On Oct 30, 11:29 am, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Oct 30, 10:49 am, landotter <landot...@gmail.com> wrote:
>
>
>
>
>
> > Ozark Bicycle wrote:
> > > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > > Jas51 wrote:
> > > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > > proper technique?
>
> > > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > > in 1988, as you can't find your Park model, tension each spoke till
> > > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > > when plucked. Make sure to have your ears calibrated beforehand.
>
> > > Next step: Use Google to find the best price on a new rim. Rinse and
> > > repeat. ;-)
>
> > All kidding aside, I do have a general pitch which I true around,
> > dished wheels getting an average of that tone. It doesn't distinguish
> > between specific brands of rims, some which can take more tension--but
> > the wheels stay true, and that's all that matters in the end. ;-) I've
> > only had one rim ever go bad on me, and that was a cracked MA3 a
> > couple years ago--which I doubt had to do with spoke tension. As long
> > as the tension is good enough, the spokes seated in the flanges, and
> > the overall tension even--you're still miles ahead of factory tuned
> > junk.
>
> > The Jobst taco method strikes me as a bit more dangerous than my
> > rather plebian ways, seeing as he's a proponent of socketed rims,
> > which I assume are going to be a bit more resistant to cracking
> > compared to eyeletted or plain hole stoff.
>
> "The Jobst taco method" is way outta date and not applicable to modern
> rims (which are more resistant to 'doing the taco' than are box shape
> rims) and modern, more highly dished 130mm 8-10sp rear wheels.- Hide quoted text -
http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2539-00' I
think $54 is a reasonable investment -- less than a Open Pro rim full
price. -- Jay Beattie
|
| |
Date: 30 Oct 2007 23:21:17
From: datakoll
Subject: Re: Spoke tension Question
|
"If you follow Jobst's procedure, you raise spoke tension on a bare
rim
until the rim goes out of true when you squeeze spoke pairs. Then you
back off half a turn on all the spoke nipples. You have a margin of
safety. "
I agree with Ozark! but Ima Group 2 wheelflogger not an expert Group
1.
Why why why spend the time building a wheel then screw it up with
overtension?
Divinity deleted.
Why the taco method could maybe possibly produce an eternal Group 1
wheel.
Then again it might not and then you good buddy just blew all that
time and energy coming up to JB's Group 1 acceptance thrashold.
I share your pain.
DO NOT DEFORM THE RIM BEFORE HITTING A POTHOLE
(this does not state JB is wrong-it sez I am not going to redo)
so? well, if you knew what then reretrueing would be no problem
in Group 1.
clean ears with H2O2/Qtip so yawl will hear the the boat trailer towed
by drunks piloting a Surburban.
clean when no roaring goes on.
|
| |
Date: 30 Oct 2007 11:29:46
From: Ozark Bicycle
Subject: Re: Spoke tension Question
|
On Oct 30, 10:49 am, landotter <landot...@gmail.com > wrote:
> Ozark Bicycle wrote:
> > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > Jas51 wrote:
> > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > proper technique?
>
> > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > in 1988, as you can't find your Park model, tension each spoke till
> > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > when plucked. Make sure to have your ears calibrated beforehand.
>
> > Next step: Use Google to find the best price on a new rim. Rinse and
> > repeat. ;-)
>
> All kidding aside, I do have a general pitch which I true around,
> dished wheels getting an average of that tone. It doesn't distinguish
> between specific brands of rims, some which can take more tension--but
> the wheels stay true, and that's all that matters in the end. ;-) I've
> only had one rim ever go bad on me, and that was a cracked MA3 a
> couple years ago--which I doubt had to do with spoke tension. As long
> as the tension is good enough, the spokes seated in the flanges, and
> the overall tension even--you're still miles ahead of factory tuned
> junk.
>
> The Jobst taco method strikes me as a bit more dangerous than my
> rather plebian ways, seeing as he's a proponent of socketed rims,
> which I assume are going to be a bit more resistant to cracking
> compared to eyeletted or plain hole stoff.
"The Jobst taco method" is way outta date and not applicable to modern
rims (which are more resistant to 'doing the taco' than are box shape
rims) and modern, more highly dished 130mm 8-10sp rear wheels.
|
| |
Date: 30 Oct 2007 09:49:55
From: landotter
Subject: Re: Spoke tension Question
|
Ozark Bicycle wrote:
> On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > Jas51 wrote:
> > > Using the rim taco-method of setting spoke tension, should a tire be
> > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > proper technique?
> >
> > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > in 1988, as you can't find your Park model, tension each spoke till
> > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > when plucked. Make sure to have your ears calibrated beforehand.
>
> Next step: Use Google to find the best price on a new rim. Rinse and
> repeat. ;-)
All kidding aside, I do have a general pitch which I true around,
dished wheels getting an average of that tone. It doesn't distinguish
between specific brands of rims, some which can take more tension--but
the wheels stay true, and that's all that matters in the end. ;-) I've
only had one rim ever go bad on me, and that was a cracked MA3 a
couple years ago--which I doubt had to do with spoke tension. As long
as the tension is good enough, the spokes seated in the flanges, and
the overall tension even--you're still miles ahead of factory tuned
junk.
The Jobst taco method strikes me as a bit more dangerous than my
rather plebian ways, seeing as he's a proponent of socketed rims,
which I assume are going to be a bit more resistant to cracking
compared to eyeletted or plain hole stoff.
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Date: 30 Oct 2007 21:27:26
From: Michael Press
Subject: Re: Spoke tension Question
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In article
<1193762995.308449.104000@57g2000hsv.googlegroups.com >,
landotter <landotter@gmail.com > wrote:
> Ozark Bicycle wrote:
> > On Oct 30, 8:17 am, landotter <landot...@gmail.com> wrote:
> > > Jas51 wrote:
> > > > Using the rim taco-method of setting spoke tension, should a tire be
> > > > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > > > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > > > proper technique?
> > >
> > > Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> > > in 1988, as you can't find your Park model, tension each spoke till
> > > your index finger hurts and it goes "twinnng!" instead of "twooong!"
> > > when plucked. Make sure to have your ears calibrated beforehand.
> >
> > Next step: Use Google to find the best price on a new rim. Rinse and
> > repeat. ;-)
>
> All kidding aside, I do have a general pitch which I true around,
> dished wheels getting an average of that tone. It doesn't distinguish
> between specific brands of rims, some which can take more tension--but
> the wheels stay true, and that's all that matters in the end. ;-) I've
> only had one rim ever go bad on me, and that was a cracked MA3 a
> couple years ago--which I doubt had to do with spoke tension. As long
> as the tension is good enough, the spokes seated in the flanges, and
> the overall tension even--you're still miles ahead of factory tuned
> junk.
>
> The Jobst taco method strikes me as a bit more dangerous than my
> rather plebian ways, seeing as he's a proponent of socketed rims,
> which I assume are going to be a bit more resistant to cracking
> compared to eyeletted or plain hole stoff.
I did it once, and will not have to do it again.
I now know what a fully tensioned wheel is like.
--
Michael Press
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Date: 30 Oct 2007 09:11:41
From: Ozark Bicycle
Subject: Re: Spoke tension Question
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On Oct 30, 8:17 am, landotter <landot...@gmail.com > wrote:
> Jas51 wrote:
> > Using the rim taco-method of setting spoke tension, should a tire be
> > mounted and inflated beforehand? Ive always brung the spokes up to tension
> > with no tire mounted, but the 160 psi thread got me wondering. What's the
> > proper technique?
>
> Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
> in 1988, as you can't find your Park model, tension each spoke till
> your index finger hurts and it goes "twinnng!" instead of "twooong!"
> when plucked. Make sure to have your ears calibrated beforehand.
Next step: Use Google to find the best price on a new rim. Rinse and
repeat. ;-)
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Date: 30 Oct 2007 07:17:35
From: landotter
Subject: Re: Spoke tension Question
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Jas51 wrote:
> Using the rim taco-method of setting spoke tension, should a tire be
> mounted and inflated beforehand? Ive always brung the spokes up to tension
> with no tire mounted, but the 160 psi thread got me wondering. What's the
> proper technique?
Bare rim. Using a really shitty spoke wrench you got carded at a Kmart
in 1988, as you can't find your Park model, tension each spoke till
your index finger hurts and it goes "twinnng!" instead of "twooong!"
when plucked. Make sure to have your ears calibrated beforehand.
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Date: 30 Oct 2007 16:11:29
From: Leo Lichtman
Subject: Re: Spoke tension Question
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"landotter" wrote: (clip) it goes "twinnng!" instead of "twooong!" when
plucked. Make sure to have your ears calibrated beforehand.
^^^^^^^^^^^^^^^^^^^^^
I have tinnitis, which makes it hard for me to distinguish between "twing"
and "twooong." Are there spokes made that resonate at a lower pitch?
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Date: 30 Oct 2007 03:55:07
From: Ozark Bicycle
Subject: Re: Spoke tension Question
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On Oct 29, 11:55 pm, Jas51 <ja...@emord.net > wrote:
> Using the rim taco-method of setting spoke tension, should a tire be
> mounted and inflated beforehand? Ive always brung the spokes up to tension
> with no tire mounted, but the 160 psi thread got me wondering. What's the
> proper technique?
It's a 9.995 on the RBT Troll-o-Meter!
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Date: 30 Oct 2007 00:22:07
From:
Subject: Re: Spoke tension Question
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On Mon, 29 Oct 2007 21:55:39 -0800, Jas51 <jas51@emord.net > wrote:
>Using the rim taco-method of setting spoke tension, should a tire be
>mounted and inflated beforehand? Ive always brung the spokes up to tension
>with no tire mounted, but the 160 psi thread got me wondering. What's the
>proper technique?
Dear Jas,
Bringing spokes up to tension on a bare rim is the sensible approach.
Think about what happens when you get a flat tire.
If you follow Jobst's procedure, you raise spoke tension on a bare rim
until the rim goes out of true when you squeeze spoke pairs. Then you
back off half a turn on all the spoke nipples. You have a margin of
safety.
When you inflate the tire, it constricts around the rim, lowers the
spoke tension even more, and gives you an even bigger margin of
safety.
A flat tire on this wheel just lets the spoke tension rise back up to
half a turn below where the rim might go out of true.
In contrast, bad things could happen if you followed Jobst's procedure
with an inflated tire on the rim that you're bringing up to tension.
You'd still bring the spoke tension up to the same level, squeeze a
spoke pair, watch the rim go out of true, and back off half a turn on
all the spoke nipples.
So the spoke tension would be the same--but only as long as the tire
was inflated.
When you get a flat tire, the tire relaxes its grip on the rim, so the
spoke tension would rise. You had only a half-turn margin of safety
when the tire was inflated, so the spoke tension might rise past that.
Your weight raises the spoke tension slightly on the spokes that
aren't under the axle. You also probably put some side loads into the
wheel as you ride. And you're bumping along the road, slowing down
with a flat tire.
Your over-tensioned wheel can be forgiven if it thinks someone is
squeezing its spoke pairs and decides to go out of true.
Now you have a flat to fix, plus a rim to re-true by the side of the
road. It's probably cold or raining.
Jobst's bare-rim tensioning procedure avoids this potential problem.
Cheers,
Carl Fogel
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