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Main
Date: 11 May 2007 18:00:10
From: RS
Subject: Mavic Open Pro, Open Pro CD, Ceramic
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What is the difference, except for price, in the 3 versions of the
venerable Mavic Open Pro rim? And are the higher priced version
money well spent? note: I rarely ride in the rain.
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Date: 15 May 2007 04:10:28
From: Ozark Bicycle
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 15, 1:07 am, jobst.bra...@stanfordalumni.org wrote:
> Michael Press writes:
> >>>>>>>> BTW, I have had a silver Open Pro rim crack around the
> >>>>>>>> eyelets (rear wheel). It was the tightest wheel I've ever
> >>>>>>>> owned. It would tend to indicate that spoke tension can
> >>>>>>>> cause the cracking.
> >>>>>>> But it should not. Rims should be built to sustain all the
> >>>>>>> spoke force it takes to potato chip the rim, as the Sun CR-18
> >>>>>>> can.
> >>>>>> Just because a rim can sustain potato-chip force in the truing
> >>>>>> stand doesn't mean that it won't fatigue prematurely if run at
> >>>>>> excessive tension (at just a bit less than the potato-chipping
> >>>>>> tension for example). I don't think the suggestion is that the
> >>>>>> nipples rip out while you're actually building the wheel. The
> >>>>>> wheel looks fine and rides fine, but fatigues prematurely
> >>>>>> because of the high mean stress in the stress cycle as the
> >>>>>> spokes load and unload.
> >>>>>> It appears from discussions that some rims have an acceptable
> >>>>>> fatigue life even when run at close to potato-chip tension
> >>>>>> (MA2), and that others don't (MA3). So the qualified statement
> >>>>>> is that "too much tension for the rim you've chosen" (or
> >>>>>> alternatively "choosing the wrong rim for the tension you've
> >>>>>> chosen") is what causes cracking.
> >>>>> My CR-18's have run for years fully tensioned without spoke
> >>>>> pull-out. Others have the same experience. There is no excuse
> >>>>> for spoke pull-out in a fully tensioned rim, just as there is no
> >>>>> excuse for cog wheels gouging free-hubs. These fabrications
> >>>>> have been made successfully forever in all mechanical domains,
> >>>>> including bicycles.
> >>>> what is your spoke tension?
> >>> I do not know. Just below the tension that buckles the rim. The
> >>> wheels have been true from day one.
> >> Don't you think it helps to know the tension? Why not use a
> >> tensiometer and follow the rim makers recommendation instead of
> >> increasing tension until the rim buckles?
> > 1. I do not think the rim makers can give me good information,
> > because they may not know it, and even knowing it, I may be
> > listening to the legal department.
> > 2. Were I to buy a tensiometer, I would buy that $300 jobbie; but I
> > do not build enough wheels. It would be an expensive toy, and there
> > are other toys ahead of it in the queue.
> > 3. So far my wheel building has not shown any problems. Knock on
> > wood.
> > 4. I only did the rim buckling exercise once, and was monitoring
> > all the way up the spoke pitch and feel of the tension both in the
> > act of plucking and in the force necessary to turn the nipple. I do
> > not need to buckle any more rims.
> > 5. I would like to know the tension, but currently do not need to.
> > I expect that many others need to; yourself most likely.
>
> I'll second that assessment. I haven't used my tensiometer in years.
>
All hail Baron Munchhausen! ;-)
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Date: 15 May 2007 04:09:48
From: Ozark Bicycle
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 15, 12:47 am, Michael Press <rub...@pacbell.net > wrote:
> In article
> <1179141333.711919.322...@p77g2000hsh.googlegroups.com>,
> Ozark Bicycle <bicycleatel...@ozarkbicycleservice.com> wrote:
>
>
>
>
>
> > On May 14, 12:40 am, Michael Press <rub...@pacbell.net> wrote:
> > > In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
> > > jim beam <spamvor...@bad.example.net> wrote:
>
> > > > Michael Press wrote:
> > > > > In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
> > > > > Ben C <spams...@spam.eggs> wrote:
>
> > > > >> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
> > > > >>> In article
> > > > >>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
> > > > >>> Orin <orin.e...@gmail.com> wrote:
> > > > >> [...]
> > > > >>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> > > > >>>> wheel). It was the tightest wheel I've ever owned. It would tend to
> > > > >>>> indicate that spoke tension can cause the cracking.
> > > > >>> But it should not. Rims should be built to sustain all the spoke
> > > > >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> > > > >> Just because a rim can sustain potato-chip force in the truing stand
> > > > >> doesn't mean that it won't fatigue prematurely if run at excessive
> > > > >> tension (at just a bit less than the potato-chipping tension for
> > > > >> example). I don't think the suggestion is that the nipples rip out while
> > > > >> you're actually building the wheel. The wheel looks fine and rides fine,
> > > > >> but fatigues prematurely because of the high mean stress in the stress
> > > > >> cycle as the spokes load and unload.
>
> > > > >> It appears from discussions that some rims have an acceptable fatigue
> > > > >> life even when run at close to potato-chip tension (MA2), and that
> > > > >> others don't (MA3). So the qualified statement is that "too much tension
> > > > >> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> > > > >> the tension you've chosen") is what causes cracking.
>
> > > > > My CR-18's have run for years fully tensioned without spoke
> > > > > pull-out. Others have the same experience. There is no excuse for
> > > > > spoke pull-out in a fully tensioned rim, just as there is no
> > > > > excuse for cog wheels gouging free-hubs. These fabrications have
> > > > > been made successfully forever in all mechanical domains,
> > > > > including bicycles.
>
> > > > what is your spoke tension?
>
> > > I do not know. Just below the tension that buckles the rim. The
> > > wheels have been true from day one.
>
> > Don't you think it helps to know the tension? Why not use a
> > tensiometer and follow the rim makers recommendation instead of
> > increasing tension until the rim buckles?
>
> 1. I do not think the rim makers can give me good information,
> because they may not know it,
If that's the case, find another rim maker.
> and even knowing it, I may be
> listening to the legal department.
The lawyers are telling them what, exactly? Don't let those rims
buckle, someone will be hurt and bring suit?
It's much more likely that a competent rim maker will supply a tension
figure that will obviate having spokes pulling through the rim; that
*is* in their interests.
<snip >
>
> 4. I only did the rim buckling exercise once, and was monitoring
> all the way up the spoke pitch and feel of the tension both in the
> act of plucking and in the force necessary to turn the nipple. I
> do not need to buckle any more rims.
The "rim buckling exercise" would be necessary each time you build on
new-to-your-experience rim, correct? And, after that, only time will
tell whether a given rim model is over-tensioned and doomed to early
failure.
>
> 5. I would like to know the tension, but currently do not need to.
> I expect that many others need to; yourself most likely.
>
As long as you keep using the same model rims, I suppose this may be
true.
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Date: 15 May 2007 18:51:06
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article
<1179227388.827824.225630@e65g2000hsc.googlegroups.com >,
Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com > wrote:
> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
> > In article
> > <1179141333.711919.322...@p77g2000hsh.googlegroups.com>,
> > Ozark Bicycle <bicycleatel...@ozarkbicycleservice.com> wrote:
> >
> >
> >
> >
> >
> > > On May 14, 12:40 am, Michael Press <rub...@pacbell.net> wrote:
> > > > In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
> > > > jim beam <spamvor...@bad.example.net> wrote:
> >
> > > > > Michael Press wrote:
> > > > > > In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
> > > > > > Ben C <spams...@spam.eggs> wrote:
> >
> > > > > >> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
> > > > > >>> In article
> > > > > >>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
> > > > > >>> Orin <orin.e...@gmail.com> wrote:
> > > > > >> [...]
> > > > > >>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> > > > > >>>> wheel). It was the tightest wheel I've ever owned. It would tend to
> > > > > >>>> indicate that spoke tension can cause the cracking.
> > > > > >>> But it should not. Rims should be built to sustain all the spoke
> > > > > >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> > > > > >> Just because a rim can sustain potato-chip force in the truing stand
> > > > > >> doesn't mean that it won't fatigue prematurely if run at excessive
> > > > > >> tension (at just a bit less than the potato-chipping tension for
> > > > > >> example). I don't think the suggestion is that the nipples rip out while
> > > > > >> you're actually building the wheel. The wheel looks fine and rides fine,
> > > > > >> but fatigues prematurely because of the high mean stress in the stress
> > > > > >> cycle as the spokes load and unload.
> >
> > > > > >> It appears from discussions that some rims have an acceptable fatigue
> > > > > >> life even when run at close to potato-chip tension (MA2), and that
> > > > > >> others don't (MA3). So the qualified statement is that "too much tension
> > > > > >> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> > > > > >> the tension you've chosen") is what causes cracking.
> >
> > > > > > My CR-18's have run for years fully tensioned without spoke
> > > > > > pull-out. Others have the same experience. There is no excuse for
> > > > > > spoke pull-out in a fully tensioned rim, just as there is no
> > > > > > excuse for cog wheels gouging free-hubs. These fabrications have
> > > > > > been made successfully forever in all mechanical domains,
> > > > > > including bicycles.
> >
> > > > > what is your spoke tension?
> >
> > > > I do not know. Just below the tension that buckles the rim. The
> > > > wheels have been true from day one.
> >
> > > Don't you think it helps to know the tension? Why not use a
> > > tensiometer and follow the rim makers recommendation instead of
> > > increasing tension until the rim buckles?
> >
> > 1. I do not think the rim makers can give me good information,
> > because they may not know it,
>
> If that's the case, find another rim maker.
If it is a good rim, I can live with their reticence.
> > and even knowing it, I may be
> > listening to the legal department.
>
> The lawyers are telling them what, exactly? Don't let those rims
> buckle, someone will be hurt and bring suit?
They may give a number that is lower than the spoke holes can support.
> It's much more likely that a competent rim maker will supply a tension
> figure that will obviate having spokes pulling through the rim; that
> *is* in their interests.
Yes.
> > 4. I only did the rim buckling exercise once, and was monitoring
> > all the way up the spoke pitch and feel of the tension both in the
> > act of plucking and in the force necessary to turn the nipple. I
> > do not need to buckle any more rims.
>
> The "rim buckling exercise" would be necessary each time you build on
> new-to-your-experience rim, correct?
Yes, and no. I have a good idea of how much tension any rim needs
for my purposes. I might try buckling a new rim and might not.
> And, after that, only time will
> tell whether a given rim model is over-tensioned and doomed to early
> failure.
Yes. So far, so good. In the case you draw, I would not buy that rim.
A proper rim is over-tensioned only if it buckles.
> > 5. I would like to know the tension, but currently do not need to.
> > I expect that many others need to; yourself most likely.
>
> As long as you keep using the same model rims, I suppose this may be
> true.
--
Michael Press
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Date: 15 May 2007 21:41:16
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Michael Press wrote:
> In article
> <1179227388.827824.225630@e65g2000hsc.googlegroups.com>,
> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
>
>> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
>>> In article
>>> <1179141333.711919.322...@p77g2000hsh.googlegroups.com>,
>>> Ozark Bicycle <bicycleatel...@ozarkbicycleservice.com> wrote:
>>>
>>>
>>>
>>>
>>>
>>>> On May 14, 12:40 am, Michael Press <rub...@pacbell.net> wrote:
>>>>> In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
>>>>> jim beam <spamvor...@bad.example.net> wrote:
>>>>>> Michael Press wrote:
>>>>>>> In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
>>>>>>> Ben C <spams...@spam.eggs> wrote:
>>>>>>>> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
>>>>>>>>> In article
>>>>>>>>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
>>>>>>>>> Orin <orin.e...@gmail.com> wrote:
>>>>>>>> [...]
>>>>>>>>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
>>>>>>>>>> wheel). It was the tightest wheel I've ever owned. It would tend to
>>>>>>>>>> indicate that spoke tension can cause the cracking.
>>>>>>>>> But it should not. Rims should be built to sustain all the spoke
>>>>>>>>> force it takes to potato chip the rim, as the Sun CR-18 can.
>>>>>>>> Just because a rim can sustain potato-chip force in the truing stand
>>>>>>>> doesn't mean that it won't fatigue prematurely if run at excessive
>>>>>>>> tension (at just a bit less than the potato-chipping tension for
>>>>>>>> example). I don't think the suggestion is that the nipples rip out while
>>>>>>>> you're actually building the wheel. The wheel looks fine and rides fine,
>>>>>>>> but fatigues prematurely because of the high mean stress in the stress
>>>>>>>> cycle as the spokes load and unload.
>>>>>>>> It appears from discussions that some rims have an acceptable fatigue
>>>>>>>> life even when run at close to potato-chip tension (MA2), and that
>>>>>>>> others don't (MA3). So the qualified statement is that "too much tension
>>>>>>>> for the rim you've chosen" (or alternatively "choosing the wrong rim for
>>>>>>>> the tension you've chosen") is what causes cracking.
>>>>>>> My CR-18's have run for years fully tensioned without spoke
>>>>>>> pull-out. Others have the same experience. There is no excuse for
>>>>>>> spoke pull-out in a fully tensioned rim, just as there is no
>>>>>>> excuse for cog wheels gouging free-hubs. These fabrications have
>>>>>>> been made successfully forever in all mechanical domains,
>>>>>>> including bicycles.
>>>>>> what is your spoke tension?
>>>>> I do not know. Just below the tension that buckles the rim. The
>>>>> wheels have been true from day one.
>>>> Don't you think it helps to know the tension? Why not use a
>>>> tensiometer and follow the rim makers recommendation instead of
>>>> increasing tension until the rim buckles?
>>> 1. I do not think the rim makers can give me good information,
>>> because they may not know it,
>> If that's the case, find another rim maker.
>
> If it is a good rim, I can live with their reticence.
>
>>> and even knowing it, I may be
>>> listening to the legal department.
>> The lawyers are telling them what, exactly? Don't let those rims
>> buckle, someone will be hurt and bring suit?
>
> They may give a number that is lower than the spoke holes can support.
>
>> It's much more likely that a competent rim maker will supply a tension
>> figure that will obviate having spokes pulling through the rim; that
>> *is* in their interests.
>
> Yes.
>
>>> 4. I only did the rim buckling exercise once, and was monitoring
>>> all the way up the spoke pitch and feel of the tension both in the
>>> act of plucking and in the force necessary to turn the nipple. I
>>> do not need to buckle any more rims.
>> The "rim buckling exercise" would be necessary each time you build on
>> new-to-your-experience rim, correct?
>
> Yes, and no. I have a good idea of how much tension any rim needs
> for my purposes. I might try buckling a new rim and might not.
>
>> And, after that, only time will
>> tell whether a given rim model is over-tensioned and doomed to early
>> failure.
>
> Yes. So far, so good. In the case you draw, I would not buy that rim.
> A proper rim is over-tensioned only if it buckles.
no true. buckling threshold is way over fatigue threshold. backing off
a little from buckling is still over fatigue.
>
>>> 5. I would like to know the tension, but currently do not need to.
>>> I expect that many others need to; yourself most likely.
>> As long as you keep using the same model rims, I suppose this may be
>> true.
>
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Date: 16 May 2007 13:39:31
From: Paul Kopit
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
I'm a relative novice in building wheels. Lately, I only use the
tensiometer when I think I'm done. Usually I am correct and the wheel
has the proper tension b4 I check. I judge by how difficult to turn
nips and the sound of the spokes. Squeezing the ones on the NDS helps
too.
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Date: 16 May 2007 01:25:10
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <KridnaKQcIPxFtfbnZ2dnUVZ_tDinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Michael Press wrote:
> > In article
> > <1179227388.827824.225630@e65g2000hsc.googlegroups.com>,
> > Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
> >> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
> >>> 4. I only did the rim buckling exercise once, and was monitoring
> >>> all the way up the spoke pitch and feel of the tension both in the
> >>> act of plucking and in the force necessary to turn the nipple. I
> >>> do not need to buckle any more rims.
> >> The "rim buckling exercise" would be necessary each time you build on
> >> new-to-your-experience rim, correct?
> >
> > Yes, and no. I have a good idea of how much tension any rim needs
> > for my purposes. I might try buckling a new rim and might not.
> >
> >> And, after that, only time will
> >> tell whether a given rim model is over-tensioned and doomed to early
> >> failure.
> >
> > Yes. So far, so good. In the case you draw, I would not buy that rim.
> > A proper rim is over-tensioned only if it buckles.
>
> no true. buckling threshold is way over fatigue threshold. backing off
> a little from buckling is still over fatigue.
I said something that may not be universally valid. Perhaps some
current rims are so strong transversally that they do not need be
tensioned near the buckling point. OK.
We have reports of certain rim models whose spoke holes cannot
sustain the spoke tension sufficient to keep the spokes tensioned
under cyclic load; leading to nipples unscrewing from the spokes.
Such a rim is not suitable for its intended purpose.
--
Michael Press
|
| | | | | |
Date: 16 May 2007 06:00:47
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Michael Press wrote:
> In article <KridnaKQcIPxFtfbnZ2dnUVZ_tDinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Michael Press wrote:
>>> In article
>>> <1179227388.827824.225630@e65g2000hsc.googlegroups.com>,
>>> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
>>>> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
>>>>> 4. I only did the rim buckling exercise once, and was monitoring
>>>>> all the way up the spoke pitch and feel of the tension both in the
>>>>> act of plucking and in the force necessary to turn the nipple. I
>>>>> do not need to buckle any more rims.
>>>> The "rim buckling exercise" would be necessary each time you build on
>>>> new-to-your-experience rim, correct?
>>> Yes, and no. I have a good idea of how much tension any rim needs
>>> for my purposes. I might try buckling a new rim and might not.
>>>
>>>> And, after that, only time will
>>>> tell whether a given rim model is over-tensioned and doomed to early
>>>> failure.
>>> Yes. So far, so good. In the case you draw, I would not buy that rim.
>>> A proper rim is over-tensioned only if it buckles.
>> no true. buckling threshold is way over fatigue threshold. backing off
>> a little from buckling is still over fatigue.
>
> I said something that may not be universally valid. Perhaps some
> current rims are so strong transversally that they do not need be
> tensioned near the buckling point. OK.
>
> We have reports of certain rim models whose spoke holes cannot
> sustain the spoke tension sufficient to keep the spokes tensioned
> under cyclic load; leading to nipples unscrewing from the spokes.
> Such a rim is not suitable for its intended purpose.
>
but that opinion is clouded by the jobstian misconception that wheels
get "stronger" as they are tensioned higher. once a wheel is tensioned
sufficiently for spokes not to loosen, the only result of increasing
tension is increasing propensity for fatigue and to buckle.
|
| | | | | | |
Date: 16 May 2007 23:24:20
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <G_GdnVEnff4dndbbnZ2dnUVZ_gGdnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Michael Press wrote:
> > In article <KridnaKQcIPxFtfbnZ2dnUVZ_tDinZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Michael Press wrote:
> >>> In article
> >>> <1179227388.827824.225630@e65g2000hsc.googlegroups.com>,
> >>> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
> >>>> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
> >>>>> 4. I only did the rim buckling exercise once, and was monitoring
> >>>>> all the way up the spoke pitch and feel of the tension both in the
> >>>>> act of plucking and in the force necessary to turn the nipple. I
> >>>>> do not need to buckle any more rims.
> >>>> The "rim buckling exercise" would be necessary each time you build on
> >>>> new-to-your-experience rim, correct?
> >>> Yes, and no. I have a good idea of how much tension any rim needs
> >>> for my purposes. I might try buckling a new rim and might not.
> >>>
> >>>> And, after that, only time will
> >>>> tell whether a given rim model is over-tensioned and doomed to early
> >>>> failure.
> >>> Yes. So far, so good. In the case you draw, I would not buy that rim.
> >>> A proper rim is over-tensioned only if it buckles.
> >> no true. buckling threshold is way over fatigue threshold. backing off
> >> a little from buckling is still over fatigue.
> >
> > I said something that may not be universally valid. Perhaps some
> > current rims are so strong transversally that they do not need be
> > tensioned near the buckling point. OK.
> >
> > We have reports of certain rim models whose spoke holes cannot
> > sustain the spoke tension sufficient to keep the spokes tensioned
> > under cyclic load; leading to nipples unscrewing from the spokes.
> > Such a rim is not suitable for its intended purpose.
> >
> but that opinion is clouded by the jobstian misconception that wheels
> get "stronger" as they are tensioned higher. once a wheel is tensioned
> sufficiently for spokes not to loosen, the only result of increasing
> tension is increasing propensity for fatigue and to buckle.
This is where I leave, since I have never figured out what a
stronger wheel is. Can a rim be built into a wheel so as to resist
permanent kinks in the rim from road bumps and holes?
--
Michael Press
|
| | | | | | | |
Date: 16 May 2007 21:42:27
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Michael Press wrote:
> In article <G_GdnVEnff4dndbbnZ2dnUVZ_gGdnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Michael Press wrote:
>>> In article <KridnaKQcIPxFtfbnZ2dnUVZ_tDinZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Michael Press wrote:
>>>>> In article
>>>>> <1179227388.827824.225630@e65g2000hsc.googlegroups.com>,
>>>>> Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com> wrote:
>>>>>> On May 15, 12:47 am, Michael Press <rub...@pacbell.net> wrote:
>>>>>>> 4. I only did the rim buckling exercise once, and was monitoring
>>>>>>> all the way up the spoke pitch and feel of the tension both in the
>>>>>>> act of plucking and in the force necessary to turn the nipple. I
>>>>>>> do not need to buckle any more rims.
>>>>>> The "rim buckling exercise" would be necessary each time you build on
>>>>>> new-to-your-experience rim, correct?
>>>>> Yes, and no. I have a good idea of how much tension any rim needs
>>>>> for my purposes. I might try buckling a new rim and might not.
>>>>>
>>>>>> And, after that, only time will
>>>>>> tell whether a given rim model is over-tensioned and doomed to early
>>>>>> failure.
>>>>> Yes. So far, so good. In the case you draw, I would not buy that rim.
>>>>> A proper rim is over-tensioned only if it buckles.
>>>> no true. buckling threshold is way over fatigue threshold. backing off
>>>> a little from buckling is still over fatigue.
>>> I said something that may not be universally valid. Perhaps some
>>> current rims are so strong transversally that they do not need be
>>> tensioned near the buckling point. OK.
>>>
>>> We have reports of certain rim models whose spoke holes cannot
>>> sustain the spoke tension sufficient to keep the spokes tensioned
>>> under cyclic load; leading to nipples unscrewing from the spokes.
>>> Such a rim is not suitable for its intended purpose.
>>>
>> but that opinion is clouded by the jobstian misconception that wheels
>> get "stronger" as they are tensioned higher. once a wheel is tensioned
>> sufficiently for spokes not to loosen, the only result of increasing
>> tension is increasing propensity for fatigue and to buckle.
>
> This is where I leave, since I have never figured out what a
> stronger wheel is. Can a rim be built into a wheel so as to resist
> permanent kinks in the rim from road bumps and holes?
>
not with spoke tension, no. the argument that strength "increases" with
increasing pre-load fails to understand the principle that the tension
in spokes is "borrowed" from the rim. it's not being conjured up out of
thin air.
if you have a section of beam, compress it by squeezing on the ends, the
yield point of the beam material remains unaffected, regardless of loads
superimposed on it. let's say the yield of the material is 1,000N. if
the ends are squeezed by 500N, and a weight hung in the middle, the beam
could support a load that raised the compressive load on the upper part
of the beam by only 500N. the lower part of the beam could support
1,000N yield + 500N pre-load by superposition, but it'll still yield on
the upper part when total compressive load equals 1,000N, or 500N
pre-load + imposed load.
spoke tension compresses the rim. increasing compression from spoke
tension decreases the imposable load before compressive yield.
|
| | | | | | | | |
Date: 17 May 2007 03:03:26
From: Ben C
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On 2007-05-17, jim beam <spamvortex@bad.example.net > wrote:
> Michael Press wrote:
[...]
>> This is where I leave, since I have never figured out what a
>> stronger wheel is. Can a rim be built into a wheel so as to resist
>> permanent kinks in the rim from road bumps and holes?
>>
> not with spoke tension, no. the argument that strength "increases" with
> increasing pre-load fails to understand the principle that the tension
> in spokes is "borrowed" from the rim. it's not being conjured up out of
> thin air.
>
> if you have a section of beam, compress it by squeezing on the ends, the
> yield point of the beam material remains unaffected, regardless of loads
> superimposed on it. let's say the yield of the material is 1,000N. if
> the ends are squeezed by 500N, and a weight hung in the middle, the beam
> could support a load that raised the compressive load on the upper part
> of the beam by only 500N. the lower part of the beam could support
> 1,000N yield + 500N pre-load by superposition, but it'll still yield on
> the upper part when total compressive load equals 1,000N, or 500N
> pre-load + imposed load.
>
> spoke tension compresses the rim. increasing compression from spoke
> tension decreases the imposable load before compressive yield.
Good explanation. There is also the consideration that the contact patch
flattens and the bottom spokes experience reduced tension. So if the
spokes have borrowed strength from the rim, in a sense they give some of
it back to the flattened part on the ground.
If you hit a bump hard you might get a flat spot-- the rim flattens too
much and deforms permanently. Does high or low spoke tension have any
effect on how easy it is to get flat spots?
|
| | | | | | | | | |
Date: 17 May 2007 06:10:30
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Ben C wrote:
> On 2007-05-17, jim beam <spamvortex@bad.example.net> wrote:
>> Michael Press wrote:
> [...]
>>> This is where I leave, since I have never figured out what a
>>> stronger wheel is. Can a rim be built into a wheel so as to resist
>>> permanent kinks in the rim from road bumps and holes?
>>>
>> not with spoke tension, no. the argument that strength "increases" with
>> increasing pre-load fails to understand the principle that the tension
>> in spokes is "borrowed" from the rim. it's not being conjured up out of
>> thin air.
>>
>> if you have a section of beam, compress it by squeezing on the ends, the
>> yield point of the beam material remains unaffected, regardless of loads
>> superimposed on it. let's say the yield of the material is 1,000N. if
>> the ends are squeezed by 500N, and a weight hung in the middle, the beam
>> could support a load that raised the compressive load on the upper part
>> of the beam by only 500N. the lower part of the beam could support
>> 1,000N yield + 500N pre-load by superposition, but it'll still yield on
>> the upper part when total compressive load equals 1,000N, or 500N
>> pre-load + imposed load.
>>
>> spoke tension compresses the rim. increasing compression from spoke
>> tension decreases the imposable load before compressive yield.
>
> Good explanation. There is also the consideration that the contact patch
> flattens and the bottom spokes experience reduced tension. So if the
> spokes have borrowed strength from the rim, in a sense they give some of
> it back to the flattened part on the ground.
>
> If you hit a bump hard you might get a flat spot-- the rim flattens too
> much and deforms permanently. Does high or low spoke tension have any
> effect on how easy it is to get flat spots?
the spokes support the rim from a bracing perspective as long as they
have tension, but from a pre-load perspective, increasing tension
increases propensity to yield. as long as the rim has sufficient beam
strength to span between tensile spokes, it's not going to flat spot at
low tension. it's bending load before yield however will be affected by
high spoke tension.
|
| | | | | | | | | | |
Date: 17 May 2007 12:22:32
From: Ben C
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On 2007-05-17, jim beam <spamvortex@bad.example.net > wrote:
> Ben C wrote:
>> On 2007-05-17, jim beam <spamvortex@bad.example.net> wrote:
[...]
>>> spoke tension compresses the rim. increasing compression from spoke
>>> tension decreases the imposable load before compressive yield.
>>
>> Good explanation. There is also the consideration that the contact patch
>> flattens and the bottom spokes experience reduced tension. So if the
>> spokes have borrowed strength from the rim, in a sense they give some of
>> it back to the flattened part on the ground.
>>
>> If you hit a bump hard you might get a flat spot-- the rim flattens too
>> much and deforms permanently. Does high or low spoke tension have any
>> effect on how easy it is to get flat spots?
>
> the spokes support the rim from a bracing perspective as long as they
> have tension, but from a pre-load perspective, increasing tension
> increases propensity to yield. as long as the rim has sufficient beam
> strength to span between tensile spokes, it's not going to flat spot at
> low tension. it's bending load before yield however will be affected by
> high spoke tension.
I'm a bit confused by the last sentence. Say I have high spoke tension,
the rim is already in compression, let's say 500N away from yield. I
push the rim inwards. The tension in the spokes in that part of the rim
goes down as I push it in. The rim therefore remains roughly 500N from
yield until the spokes go completely slack. I increase my pushing force
another 500N, and now it yields. Is this correct?
If so it seems that high spoke tension would not make it any easier or
harder to flat-spot the rim.
|
| | | | | | | | | | | |
Date: 18 May 2007 16:37:49
From: Peter Cole
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Ben C wrote:
> On 2007-05-17, jim beam <spamvortex@bad.example.net> wrote:
>> Ben C wrote:
>>> On 2007-05-17, jim beam <spamvortex@bad.example.net> wrote:
> [...]
>>>> spoke tension compresses the rim. increasing compression from spoke
>>>> tension decreases the imposable load before compressive yield.
>>> Good explanation. There is also the consideration that the contact patch
>>> flattens and the bottom spokes experience reduced tension. So if the
>>> spokes have borrowed strength from the rim, in a sense they give some of
>>> it back to the flattened part on the ground.
>>>
>>> If you hit a bump hard you might get a flat spot-- the rim flattens too
>>> much and deforms permanently. Does high or low spoke tension have any
>>> effect on how easy it is to get flat spots?
>> the spokes support the rim from a bracing perspective as long as they
>> have tension, but from a pre-load perspective, increasing tension
>> increases propensity to yield. as long as the rim has sufficient beam
>> strength to span between tensile spokes, it's not going to flat spot at
>> low tension. it's bending load before yield however will be affected by
>> high spoke tension.
>
> I'm a bit confused by the last sentence. Say I have high spoke tension,
> the rim is already in compression, let's say 500N away from yield. I
> push the rim inwards. The tension in the spokes in that part of the rim
> goes down as I push it in. The rim therefore remains roughly 500N from
> yield until the spokes go completely slack. I increase my pushing force
> another 500N, and now it yields. Is this correct?
>
> If so it seems that high spoke tension would not make it any easier or
> harder to flat-spot the rim.
It doesn't, directly, it just makes the spokes less likely to loosen.
When a section of the rim tries to flatten, it must spread the rest of
the rim further apart. This spreading is resisted by the other (not in
flattening region) spokes. The degree of resistance to this spreading is
determined by the number of spokes, their thickness, and the modulus of
their material, pretension doesn't enter into it.
While it's strictly true that spoke tension puts the rim in compression,
and that pre-load would be added to the compressive load on the outside
of a flattening rim (from bending), the pre-load is rather modest in
comparison (~6kN) and spread over the rim cross section, while the
bending load is concentrated on the skin.
According to Gavin & his references, the rim & spokes may be accurately
modeled by a (circular) beam on (supported by) an elastic foundation.
The "support" is provided both by the spokes outside the flattening
zone, which must increase in length for the section of the rim to
flatten, as well as by the relative compression (reduction in tension)
of spokes in the flattening zone.
In simple terms, you can think of the spokes at the load point "helping"
to flatten the rim, while the others "hinder". As the rim deflects, the
helpers help less (tension lowers), the hinderers hinder more (tension
rises), both resist the deflection.
I think it's equally misleading to say either: "the wheel stands on its
spokes" or "hangs from its spokes". It is more accurate to say it
reaches equilibrium, with some spokes seeing (relative) compression,
while others see relative (and absolute) tension when loaded.
When a spoke goes totally slack, it ceases to contribute to the support
of the rim, which then becomes more prone to flattening from additional
load. In other words, the radial stiffness of the wheel goes down as
spokes go slack, reaching the stiffness of the rim alone in the limit.
|
| |
Date: 14 May 2007 04:15:33
From: Ozark Bicycle
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 14, 12:40 am, Michael Press <rub...@pacbell.net > wrote:
> In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
> jim beam <spamvor...@bad.example.net> wrote:
>
>
>
>
>
> > Michael Press wrote:
> > > In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
> > > Ben C <spams...@spam.eggs> wrote:
>
> > >> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
> > >>> In article
> > >>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
> > >>> Orin <orin.e...@gmail.com> wrote:
> > >> [...]
> > >>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> > >>>> wheel). It was the tightest wheel I've ever owned. It would tend to
> > >>>> indicate that spoke tension can cause the cracking.
> > >>> But it should not. Rims should be built to sustain all the spoke
> > >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> > >> Just because a rim can sustain potato-chip force in the truing stand
> > >> doesn't mean that it won't fatigue prematurely if run at excessive
> > >> tension (at just a bit less than the potato-chipping tension for
> > >> example). I don't think the suggestion is that the nipples rip out while
> > >> you're actually building the wheel. The wheel looks fine and rides fine,
> > >> but fatigues prematurely because of the high mean stress in the stress
> > >> cycle as the spokes load and unload.
>
> > >> It appears from discussions that some rims have an acceptable fatigue
> > >> life even when run at close to potato-chip tension (MA2), and that
> > >> others don't (MA3). So the qualified statement is that "too much tension
> > >> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> > >> the tension you've chosen") is what causes cracking.
>
> > > My CR-18's have run for years fully tensioned without spoke
> > > pull-out. Others have the same experience. There is no excuse for
> > > spoke pull-out in a fully tensioned rim, just as there is no
> > > excuse for cog wheels gouging free-hubs. These fabrications have
> > > been made successfully forever in all mechanical domains,
> > > including bicycles.
>
> > what is your spoke tension?
>
> I do not know. Just below the tension that buckles the rim. The
> wheels have been true from day one.
>
Don't you think it helps to know the tension? Why not use a
tensiometer and follow the rim makers recommendation instead of
increasing tension until the rim buckles?
|
| | |
Date: 15 May 2007 05:47:11
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article
<1179141333.711919.322720@p77g2000hsh.googlegroups.com >,
Ozark Bicycle <bicycleatelier@ozarkbicycleservice.com > wrote:
> On May 14, 12:40 am, Michael Press <rub...@pacbell.net> wrote:
> > In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
> > jim beam <spamvor...@bad.example.net> wrote:
> >
> >
> >
> >
> >
> > > Michael Press wrote:
> > > > In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
> > > > Ben C <spams...@spam.eggs> wrote:
> >
> > > >> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
> > > >>> In article
> > > >>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
> > > >>> Orin <orin.e...@gmail.com> wrote:
> > > >> [...]
> > > >>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> > > >>>> wheel). It was the tightest wheel I've ever owned. It would tend to
> > > >>>> indicate that spoke tension can cause the cracking.
> > > >>> But it should not. Rims should be built to sustain all the spoke
> > > >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> > > >> Just because a rim can sustain potato-chip force in the truing stand
> > > >> doesn't mean that it won't fatigue prematurely if run at excessive
> > > >> tension (at just a bit less than the potato-chipping tension for
> > > >> example). I don't think the suggestion is that the nipples rip out while
> > > >> you're actually building the wheel. The wheel looks fine and rides fine,
> > > >> but fatigues prematurely because of the high mean stress in the stress
> > > >> cycle as the spokes load and unload.
> >
> > > >> It appears from discussions that some rims have an acceptable fatigue
> > > >> life even when run at close to potato-chip tension (MA2), and that
> > > >> others don't (MA3). So the qualified statement is that "too much tension
> > > >> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> > > >> the tension you've chosen") is what causes cracking.
> >
> > > > My CR-18's have run for years fully tensioned without spoke
> > > > pull-out. Others have the same experience. There is no excuse for
> > > > spoke pull-out in a fully tensioned rim, just as there is no
> > > > excuse for cog wheels gouging free-hubs. These fabrications have
> > > > been made successfully forever in all mechanical domains,
> > > > including bicycles.
> >
> > > what is your spoke tension?
> >
> > I do not know. Just below the tension that buckles the rim. The
> > wheels have been true from day one.
>
> Don't you think it helps to know the tension? Why not use a
> tensiometer and follow the rim makers recommendation instead of
> increasing tension until the rim buckles?
1. I do not think the rim makers can give me good information,
because they may not know it, and even knowing it, I may be
listening to the legal department.
2. Were I to buy a tensiometer, I would buy that $300 jobbie; but
I do not build enough wheels. It would be an expensive toy, and
there are other toys ahead of it in the queue.
3. So far my wheel building has not shown any problems.
Knock on wood.
4. I only did the rim buckling exercise once, and was monitoring
all the way up the spoke pitch and feel of the tension both in the
act of plucking and in the force necessary to turn the nipple. I
do not need to buckle any more rims.
5. I would like to know the tension, but currently do not need to.
I expect that many others need to; yourself most likely.
--
Michael Press
|
| | | |
Date: 15 May 2007 06:07:39
From:
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Michael Press writes:
>>>>>>>> BTW, I have had a silver Open Pro rim crack around the
>>>>>>>> eyelets (rear wheel). It was the tightest wheel I've ever
>>>>>>>> owned. It would tend to indicate that spoke tension can
>>>>>>>> cause the cracking.
>>>>>>> But it should not. Rims should be built to sustain all the
>>>>>>> spoke force it takes to potato chip the rim, as the Sun CR-18
>>>>>>> can.
>>>>>> Just because a rim can sustain potato-chip force in the truing
>>>>>> stand doesn't mean that it won't fatigue prematurely if run at
>>>>>> excessive tension (at just a bit less than the potato-chipping
>>>>>> tension for example). I don't think the suggestion is that the
>>>>>> nipples rip out while you're actually building the wheel. The
>>>>>> wheel looks fine and rides fine, but fatigues prematurely
>>>>>> because of the high mean stress in the stress cycle as the
>>>>>> spokes load and unload.
>>>>>> It appears from discussions that some rims have an acceptable
>>>>>> fatigue life even when run at close to potato-chip tension
>>>>>> (MA2), and that others don't (MA3). So the qualified statement
>>>>>> is that "too much tension for the rim you've chosen" (or
>>>>>> alternatively "choosing the wrong rim for the tension you've
>>>>>> chosen") is what causes cracking.
>>>>> My CR-18's have run for years fully tensioned without spoke
>>>>> pull-out. Others have the same experience. There is no excuse
>>>>> for spoke pull-out in a fully tensioned rim, just as there is no
>>>>> excuse for cog wheels gouging free-hubs. These fabrications
>>>>> have been made successfully forever in all mechanical domains,
>>>>> including bicycles.
>>>> what is your spoke tension?
>>> I do not know. Just below the tension that buckles the rim. The
>>> wheels have been true from day one.
>> Don't you think it helps to know the tension? Why not use a
>> tensiometer and follow the rim makers recommendation instead of
>> increasing tension until the rim buckles?
> 1. I do not think the rim makers can give me good information,
> because they may not know it, and even knowing it, I may be
> listening to the legal department.
> 2. Were I to buy a tensiometer, I would buy that $300 jobbie; but I
> do not build enough wheels. It would be an expensive toy, and there
> are other toys ahead of it in the queue.
> 3. So far my wheel building has not shown any problems. Knock on
> wood.
> 4. I only did the rim buckling exercise once, and was monitoring
> all the way up the spoke pitch and feel of the tension both in the
> act of plucking and in the force necessary to turn the nipple. I do
> not need to buckle any more rims.
> 5. I would like to know the tension, but currently do not need to.
> I expect that many others need to; yourself most likely.
I'll second that assessment. I haven't used my tensiometer in years.
Jobst Brandt
|
| | | | |
Date: 16 May 2007 06:01:15
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
jobst.brandt@stanfordalumni.org wrote:
> Michael Press writes:
>
>>>>>>>>> BTW, I have had a silver Open Pro rim crack around the
>>>>>>>>> eyelets (rear wheel). It was the tightest wheel I've ever
>>>>>>>>> owned. It would tend to indicate that spoke tension can
>>>>>>>>> cause the cracking.
>
>>>>>>>> But it should not. Rims should be built to sustain all the
>>>>>>>> spoke force it takes to potato chip the rim, as the Sun CR-18
>>>>>>>> can.
>
>>>>>>> Just because a rim can sustain potato-chip force in the truing
>>>>>>> stand doesn't mean that it won't fatigue prematurely if run at
>>>>>>> excessive tension (at just a bit less than the potato-chipping
>>>>>>> tension for example). I don't think the suggestion is that the
>>>>>>> nipples rip out while you're actually building the wheel. The
>>>>>>> wheel looks fine and rides fine, but fatigues prematurely
>>>>>>> because of the high mean stress in the stress cycle as the
>>>>>>> spokes load and unload.
>
>>>>>>> It appears from discussions that some rims have an acceptable
>>>>>>> fatigue life even when run at close to potato-chip tension
>>>>>>> (MA2), and that others don't (MA3). So the qualified statement
>>>>>>> is that "too much tension for the rim you've chosen" (or
>>>>>>> alternatively "choosing the wrong rim for the tension you've
>>>>>>> chosen") is what causes cracking.
>
>>>>>> My CR-18's have run for years fully tensioned without spoke
>>>>>> pull-out. Others have the same experience. There is no excuse
>>>>>> for spoke pull-out in a fully tensioned rim, just as there is no
>>>>>> excuse for cog wheels gouging free-hubs. These fabrications
>>>>>> have been made successfully forever in all mechanical domains,
>>>>>> including bicycles.
>
>>>>> what is your spoke tension?
>
>>>> I do not know. Just below the tension that buckles the rim. The
>>>> wheels have been true from day one.
>
>>> Don't you think it helps to know the tension? Why not use a
>>> tensiometer and follow the rim makers recommendation instead of
>>> increasing tension until the rim buckles?
>
>> 1. I do not think the rim makers can give me good information,
>> because they may not know it, and even knowing it, I may be
>> listening to the legal department.
>
>> 2. Were I to buy a tensiometer, I would buy that $300 jobbie; but I
>> do not build enough wheels. It would be an expensive toy, and there
>> are other toys ahead of it in the queue.
>
>> 3. So far my wheel building has not shown any problems. Knock on
>> wood.
>
>> 4. I only did the rim buckling exercise once, and was monitoring
>> all the way up the spoke pitch and feel of the tension both in the
>> act of plucking and in the force necessary to turn the nipple. I do
>> not need to buckle any more rims.
>
>> 5. I would like to know the tension, but currently do not need to.
>> I expect that many others need to; yourself most likely.
>
> I'll second that assessment. I haven't used my tensiometer in years.
>
and that's why you crack rims.
|
| | |
Date: 14 May 2007 11:54:38
From: * * Chas
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"Ozark Bicycle" <bicycleatelier@ozarkbicycleservice.com > wrote in message
news:1179141333.711919.322720@p77g2000hsh.googlegroups.com...
> On May 14, 12:40 am, Michael Press <rub...@pacbell.net> wrote:
> > In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbin...@speakeasy.net>,
> > jim beam <spamvor...@bad.example.net> wrote:
> >
> >
> >
> >
> >
> > > Michael Press wrote:
> > > > In article <slrnf4dpeo.3n7.spams...@bowser.marioworld>,
> > > > Ben C <spams...@spam.eggs> wrote:
> >
> > > >> On 2007-05-13, Michael Press <rub...@pacbell.net> wrote:
> > > >>> In article
> > > >>> <1179016903.162057.212...@q75g2000hsh.googlegroups.com>,
> > > >>> Orin <orin.e...@gmail.com> wrote:
> > > >> [...]
> > > >>>> BTW, I have had a silver Open Pro rim crack around the eyelets
(rear
> > > >>>> wheel). It was the tightest wheel I've ever owned. It would
tend to
> > > >>>> indicate that spoke tension can cause the cracking.
> > > >>> But it should not. Rims should be built to sustain all the spoke
> > > >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> > > >> Just because a rim can sustain potato-chip force in the truing
stand
> > > >> doesn't mean that it won't fatigue prematurely if run at
excessive
> > > >> tension (at just a bit less than the potato-chipping tension for
> > > >> example). I don't think the suggestion is that the nipples rip
out while
> > > >> you're actually building the wheel. The wheel looks fine and
rides fine,
> > > >> but fatigues prematurely because of the high mean stress in the
stress
> > > >> cycle as the spokes load and unload.
> >
> > > >> It appears from discussions that some rims have an acceptable
fatigue
> > > >> life even when run at close to potato-chip tension (MA2), and
that
> > > >> others don't (MA3). So the qualified statement is that "too much
tension
> > > >> for the rim you've chosen" (or alternatively "choosing the wrong
rim for
> > > >> the tension you've chosen") is what causes cracking.
> >
> > > > My CR-18's have run for years fully tensioned without spoke
> > > > pull-out. Others have the same experience. There is no excuse for
> > > > spoke pull-out in a fully tensioned rim, just as there is no
> > > > excuse for cog wheels gouging free-hubs. These fabrications have
> > > > been made successfully forever in all mechanical domains,
> > > > including bicycles.
> >
> > > what is your spoke tension?
> >
> > I do not know. Just below the tension that buckles the rim. The
> > wheels have been true from day one.
> >
>
> Don't you think it helps to know the tension? Why not use a
> tensiometer and follow the rim makers recommendation instead of
> increasing tension until the rim buckles?
>
I've never seen a rim buckle except from a side on impact like skidding
into a curb (and recently a 28 spoke rim from wheel suck during a hard
climb but that was a different cause).
The spokes I've seen pull out were on old tubular rims without eyelets and
maybe some old Fiame Yellow Label rims.
All of these were 36 spoke rims. I'm not real familiar with lower spoke
count wheels or exotic lacings so I don't know.
The only rim I've seen with cracking around the spoke holes is an old rear
wheel that I've had from the mid 1980s. It has a 36 hole Ambrosio 19 Extra
gray anodized rim with 3x 14 ga DT spokes on a Campy 126mm LF hub and
small cross section Specialized tire. The spokes were tensioned rock hard.
I only rode this wheel occasionally and mainly on smooth surface roads.
Last year I started riding on it in the evening after work. One of the
bike trails that I ride has a lot of places where the pavement has lifted
from tree roots.
After hitting those bumps a number of times in the dark I noticed that the
rear spokes where starting to loosen. I had to true the wheel after every
ride. That's when I noticed the stretching and cracking around the
eyelets.
The issue I've never seen mention in all of these discussions about rims
cracking around the eyelets is the spoke count and lacing patterns.
It seems to me that low spoke count wheels and/or some of the exotic
lacings are going to apply a lot more localized stress on the rims than
say a standard old 36H 3x pattern.
Chas.
|
| |
Date: 14 May 2007 00:39:02
From: Gary Young
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sun, 13 May 2007 22:11:25 -0700, jim beam wrote:
> Gary Young wrote:
> <snip>
>> You can only gain by explaining how anodizing can cause cracking -- unless
>> of course you're blowing smoke.
>
> so explaining it yet again is going to penetrate this time? i think not!
OK, fair enough. Just point me to the place where you explained it the
first time.
|
| | |
Date: 14 May 2007 11:45:03
From: _
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Mon, 14 May 2007 00:39:02 -0500, Gary Young wrote:
> On Sun, 13 May 2007 22:11:25 -0700, jim beam wrote:
>
>> Gary Young wrote:
>> <snip>
>>> You can only gain by explaining how anodizing can cause cracking -- unless
>>> of course you're blowing smoke.
>>
>> so explaining it yet again is going to penetrate this time? i think not!
>
> OK, fair enough. Just point me to the place where you explained it the
> first time.
Maybe it was where he explained thusly:
>
> fuck off. retard.
There ya go. Obvious, jim's right, reason and reference are not.
|
| | | |
Date: 14 May 2007 08:42:05
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <11480961dr5e7.rjutfmgvttdu$.dlg@40tude.net >,
_ <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com > wrote:
> On Mon, 14 May 2007 00:39:02 -0500, Gary Young wrote:
>
> > On Sun, 13 May 2007 22:11:25 -0700, jim beam wrote:
> >
> >> Gary Young wrote: <snip>
> >>> You can only gain by explaining how anodizing can cause cracking
> >>> -- unless of course you're blowing smoke.
> >>
> >> so explaining it yet again is going to penetrate this time? i
> >> think not!
> >
> > OK, fair enough. Just point me to the place where you explained it
> > the first time.
>
> Maybe it was where he explained thusly:
>
> >
> > fuck off. retard.
>
> There ya go. Obvious, jim's right, reason and reference are not.
And he gets a lot of attention and reinforcement for his behavior.
|
| | | | |
Date: 14 May 2007 13:58:02
From: _
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Mon, 14 May 2007 08:42:05 -0500, Tim McNamara wrote:
> In article <11480961dr5e7.rjutfmgvttdu$.dlg@40tude.net>,
> _ <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:
>
>> On Mon, 14 May 2007 00:39:02 -0500, Gary Young wrote:
>>
>>> On Sun, 13 May 2007 22:11:25 -0700, jim beam wrote:
>>>
>>>> Gary Young wrote: <snip>
>>>>> You can only gain by explaining how anodizing can cause cracking
>>>>> -- unless of course you're blowing smoke.
>>>>
>>>> so explaining it yet again is going to penetrate this time? i
>>>> think not!
>>>
>>> OK, fair enough. Just point me to the place where you explained it
>>> the first time.
>>
>> Maybe it was where he explained thusly:
>>
>>>
>>> fuck off. retard.
>>
>> There ya go. Obvious, jim's right, reason and reference are not.
>
> And he gets a lot of attention and reinforcement for his behavior.
When you go to the zoo, the crowds are *not* around the quiet animals - but
around the monkeys.
|
| | | | | |
Date: 14 May 2007 17:56:02
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <1n9m0uj5bm9n.1q3t153sn1q7v$.dlg@40tude.net >,
_ <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com > wrote:
> On Mon, 14 May 2007 08:42:05 -0500, Tim McNamara wrote:
>
> > In article <11480961dr5e7.rjutfmgvttdu$.dlg@40tude.net>,
> > _ <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:
> >
> >> On Mon, 14 May 2007 00:39:02 -0500, Gary Young wrote:
> >>
> >>> On Sun, 13 May 2007 22:11:25 -0700, jim beam wrote:
> >>>
> >>>> Gary Young wrote: <snip>
> >>>>> You can only gain by explaining how anodizing can cause
> >>>>> cracking -- unless of course you're blowing smoke.
> >>>>
> >>>> so explaining it yet again is going to penetrate this time? i
> >>>> think not!
> >>>
> >>> OK, fair enough. Just point me to the place where you explained
> >>> it the first time.
> >>
> >> Maybe it was where he explained thusly:
> >>
> >>>
> >>> fuck off. retard.
> >>
> >> There ya go. Obvious, jim's right, reason and reference are not.
> >
> > And he gets a lot of attention and reinforcement for his behavior.
>
> When you go to the zoo, the crowds are *not* around the quiet animals
> - but around the monkeys.
'struth!
|
| |
Date: 13 May 2007 23:59:44
From: Gary Young
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sun, 13 May 2007 20:51:43 -0700, jim beam wrote:
> Tim McNamara wrote:
>> In article <Xs6dnX6O4alkBNrbnZ2dnUVZ_vamnZ2d@speakeasy.net>,
>> jim beam <spamvortex@bad.example.net> wrote:
>>
>>> Gary Young wrote:
>>>> On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
>>>>
>>>>> i've taken the time to study the cracking that happens to anodizing
>>>>> at rim eyelets - it's essentially a "star" pattern of cracks
>>>>> radiating from the hole. we could therefore expect actual metal
>>>>> cracking, if anodizing to be the cause, to follow those cracks. what
>>>>> we find in practice however is that the metal frequently cracks at
>>>>> an angle to the anodizing crack, even on allegedly "unanodized"
>>>>> rims.
>>>> A google search turns up hundreds of references to "crazing" or
>>>> "spiderweb cracks" in connection with anodizing. This one, for
>>>> instance:
>>>>
>>>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>>>>
>>>> Furthermore, the initial anodizing cracks can be formed when the
>>>> extrusion is anodized before being rolled:
>>>>
>>>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>>>>
>>>> To my mind, that means that the cracks are not exclusively radial and
>>>> that they may exist even before tension is applied to the spokes.
>>> you need to buy a new rim and inspect it with a magnifier. you will
>>> find, for a mavic at any rate [which is anodized /after/ it is hooped]
>>> that the cracks /are/ exclusively radial and they most definitely /do/
>>> exist before a spoke has been anywhere near the rim.
>>
>> Another concession? My goodness. Jobst pointed this out years ago,
>> and at that time- disbelieving it and coincidentally needing a new rim-
>> I went down to Kenwood Cyclery with a magnifier and inspected a dozen
>> or so Mavic rims using oblique incident light to highlight the crazing.
>> Exactly as you say and as Jobst has said, crazing around the spoke
>> holes was present before the rims had ever been built up into wheels.
>
> <snip crap>
>
> anodizing /can/ cause cracking. stress corrosion agents crack metal
> also. but it's just plain stupid to attribute a failure to the wrong
> cause. in this case, there's no evidence supporting anodizing initiated
> cracking, so it doesn't matter /how/ cracked the anodizing is! but you
> don't understand that because you're too fucking retarded.
You could help educate us by explaining what sort of evidence would
indicate anodizing-initiated cracking. We could check your account against
the discussions that appear in the engineering references. If your
explanation agrees with what the references say, then you would go a long
way toward answering critics who say that anodizing-initiated cracking as
discussed by Jobst is referenced in engineering texts. In other words, you
would be able to demonstrate that those texts refer to a different process
than that pointed to by Jobst.
Finally, those of us in need of an education could take a fresh look at
rim cracking and perhaps see for ourselves that the relevant
indications aren't there.
You can only gain by explaining how anodizing can cause cracking -- unless
of course you're blowing smoke.
|
| | |
Date: 13 May 2007 22:11:25
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Gary Young wrote:
<snip >
> You can only gain by explaining how anodizing can cause cracking -- unless
> of course you're blowing smoke.
so explaining it yet again is going to penetrate this time? i think not!
|
| |
Date: 13 May 2007 15:13:17
From: Gary Young
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
> Harry Phinney wrote:
>> "jim beam" wrote
>>> yeah. jobst is the problem on this one. jobst thinks anodizing
>>> causes cracking because he did a dye penetrant test. there is no way
>>> a dye penetrant test determines whether anodizing has anything to do
>>> with it - all it does is identify presence, not cause. rim cracking
>>> is cause by spoke tension "as high as the rim can bear" - pure and
>>> simple.
>>
>> It is a mistake to claim that hard anodizing has no impact on the
>> fatigue resistance of aluminum products. The following are quotes from
>> "The Properties of Electordeposited Metals and Alloys a Handbook"
>> Second Edition, edited by William H. Safranek published by the AESFS,
>> 1986 ISBN 0-936569-00-X, all from chapter 3 - "Anodic Coatings on
>> Aluminum":
>>
>> " Typical thickness requirements for decorative applications not
>> subject to aggressive environment are about 7-10 micrometers. For
>> exterior architectural components, a thickness in the range of 18-25
>> micrometers is usually specified. Anodic coatings designed for wear
>> resistance may be produced in greater thickness, up to over 100
>> micrometers." (page 29)
>>
>> "In general, anodic coatings more than a few micons thick cause a
>> significant loss of fatigue strength in aluminum alloys. Most data on
>> this property have been for strong alloys of the 2000, 5000, and 7000
>> classes. Unsealed sulfuric acid and chromic acid coatings less than
>> about 5 micrometers thick had little or no effect on fatigue strength
>> at 100 million cycles." ... "Far greater losses were induced by sealing
>> the coatings in water; sealed sulfuric acid coatings 25 micrometers
>> thick induced fatigue strength losses approaching 35 percent at 100
>> million cycles. The effects of thick, hard anodic coatings on fatigue
>> are even greater. Coatings 25 micrometers up to 125 micrometers of one
>> proprietary hard anodic coating process reduced stress to failure at 10
>> million cycles by more than 50 percent." (page 32)
>>
>> Harry Phinney
>>
>>
> no, indeed it is no mistake. but it's a mistake to attribute cracking
> to anodizing without understanding the basics and bothering to be sure
> of the actual mechanism.
>
> i've taken the time to study the cracking that happens to anodizing at
> rim eyelets - it's essentially a "star" pattern of cracks radiating from
> the hole. we could therefore expect actual metal cracking, if anodizing
> to be the cause, to follow those cracks. what we find in practice
> however is that the metal frequently cracks at an angle to the anodizing
> crack, even on allegedly "unanodized" rims.
A google search turns up hundreds of references to "crazing" or "spiderweb
cracks" in connection with anodizing. This one, for instance:
http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
Furthermore, the initial anodizing cracks can be formed when the
extrusion is anodized before being rolled:
http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
To my mind, that means that the cracks are not exclusively radial and that
they may exist even before tension is applied to the spokes. Subsequently
the cracking occurs at the spoke holes because that is where tension is
highest. Because the rim is "anisotropic" -- i.e., weakest along the
direction of the extrusion -- it's not surprising that cracks in that
direction propagate the fastest. Furthermore, isn't it possible that a
crack propagating at a slight angle to the extrusion axis will change
direction because of the weakness in that direction?
> http://web.onetel.net.uk/~davidwgreen/rimpics/4.JPG
>
> both those cracks ["non-cracking" ma2 rim incidentally] are exactly
> aligned with the extrusion axis, but not anodizing crack axis.
>
> in ascii, [use monospaced font] - you would expect:
>
> --O--
>
> but you often get
>
> __O__
>
> or
> __
> __O
>
> so in the latter instances, you cannot attribute cracking simply to
> anodizing.
Of course not. Surface imperfections are not the sole cause (other forces
have to work together with it to propagate the crack), but as you've said
time and time again over the years, surface cracking is very important in
initiating dangerous cracks.
> bottom line, rims have a finite life because of braking abrasion.
> anodizing may indeed have a long term impact on a rim's fatigue life,
> but if that fatigue life still exceeds the projected wear life of the
> rim, who cares? the benefits of anodizing are substantial for anyone
> riding in weather conditions found outside palo alto.
>
>
What about the millions of people outside of Palo Alto who don't ride
regularly in bad weather? Or who use a beater bike when riding in bad
weather?
In any event, this is a pretty significant concession on your part.
> and let's not forget that the highly anisotropic nature of the rim
> material is going to give very different fatigue strengths in different
> orientations. excess spoke tension is going to raise the load to the
> material's fatigue threshold and expose those fatigue orientation
> differences, and /that/ is what's being observed, not the effects of
> anodizing.
That hardly rules out a role for anodizing cracks as initiators. It does
seem sensible that directional weakness would help explain which anodizing
cracks tend to propagate and the direction in which they propagate.
Again, this seems like a significant concession on your part -- in the
past you've chalked up such cracks to extrusion /flaws/, not the inherent
properties of an extrusion.
> spoke tension "as high as the rim can bear" is the real
> cause.
|
| | |
Date: 13 May 2007 16:06:33
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Gary Young wrote:
> On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
>
>> Harry Phinney wrote:
>>> "jim beam" wrote
>>>> yeah. jobst is the problem on this one. jobst thinks anodizing
>>>> causes cracking because he did a dye penetrant test. there is no way
>>>> a dye penetrant test determines whether anodizing has anything to do
>>>> with it - all it does is identify presence, not cause. rim cracking
>>>> is cause by spoke tension "as high as the rim can bear" - pure and
>>>> simple.
>>> It is a mistake to claim that hard anodizing has no impact on the
>>> fatigue resistance of aluminum products. The following are quotes from
>>> "The Properties of Electordeposited Metals and Alloys a Handbook"
>>> Second Edition, edited by William H. Safranek published by the AESFS,
>>> 1986 ISBN 0-936569-00-X, all from chapter 3 - "Anodic Coatings on
>>> Aluminum":
>>>
>>> " Typical thickness requirements for decorative applications not
>>> subject to aggressive environment are about 7-10 micrometers. For
>>> exterior architectural components, a thickness in the range of 18-25
>>> micrometers is usually specified. Anodic coatings designed for wear
>>> resistance may be produced in greater thickness, up to over 100
>>> micrometers." (page 29)
>>>
>>> "In general, anodic coatings more than a few micons thick cause a
>>> significant loss of fatigue strength in aluminum alloys. Most data on
>>> this property have been for strong alloys of the 2000, 5000, and 7000
>>> classes. Unsealed sulfuric acid and chromic acid coatings less than
>>> about 5 micrometers thick had little or no effect on fatigue strength
>>> at 100 million cycles." ... "Far greater losses were induced by sealing
>>> the coatings in water; sealed sulfuric acid coatings 25 micrometers
>>> thick induced fatigue strength losses approaching 35 percent at 100
>>> million cycles. The effects of thick, hard anodic coatings on fatigue
>>> are even greater. Coatings 25 micrometers up to 125 micrometers of one
>>> proprietary hard anodic coating process reduced stress to failure at 10
>>> million cycles by more than 50 percent." (page 32)
>>>
>>> Harry Phinney
>>>
>>>
>> no, indeed it is no mistake. but it's a mistake to attribute cracking
>> to anodizing without understanding the basics and bothering to be sure
>> of the actual mechanism.
>>
>> i've taken the time to study the cracking that happens to anodizing at
>> rim eyelets - it's essentially a "star" pattern of cracks radiating from
>> the hole. we could therefore expect actual metal cracking, if anodizing
>> to be the cause, to follow those cracks. what we find in practice
>> however is that the metal frequently cracks at an angle to the anodizing
>> crack, even on allegedly "unanodized" rims.
>
> A google search turns up hundreds of references to "crazing" or "spiderweb
> cracks" in connection with anodizing. This one, for instance:
>
> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>
> Furthermore, the initial anodizing cracks can be formed when the
> extrusion is anodized before being rolled:
>
> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>
> To my mind, that means that the cracks are not exclusively radial and that
> they may exist even before tension is applied to the spokes.
you need to buy a new rim and inspect it with a magnifier. you will
find, for a mavic at any rate [which is anodized /after/ it is hooped]
that the cracks /are/ exclusively radial and they most definitely /do/
exist before a spoke has been anywhere near the rim.
> Subsequently
> the cracking occurs at the spoke holes because that is where tension is
> highest.
yes, but not necessarily because of anodizing.
> Because the rim is "anisotropic" -- i.e., weakest along the
> direction of the extrusion -- it's not surprising that cracks in that
> direction propagate the fastest.
not only is it not surprising, it's pretty much inevitable.
> Furthermore, isn't it possible that a
> crack propagating at a slight angle to the extrusion axis will change
> direction because of the weakness in that direction?
arguably for shallow angles, but that will drop quickly as angle
increases, and not for angles above 45 degrees.
>
>
>> http://web.onetel.net.uk/~davidwgreen/rimpics/4.JPG
>>
>> both those cracks ["non-cracking" ma2 rim incidentally] are exactly
>> aligned with the extrusion axis, but not anodizing crack axis.
>>
>> in ascii, [use monospaced font] - you would expect:
>>
>> --O--
>>
>> but you often get
>>
>> __O__
>>
>> or
>> __
>> __O
>>
>> so in the latter instances, you cannot attribute cracking simply to
>> anodizing.
>
> Of course not. Surface imperfections are not the sole cause (other forces
> have to work together with it to propagate the crack), but as you've said
> time and time again over the years, surface cracking is very important in
> initiating dangerous cracks.
/any/ cracks, yes. and rim cracks start at the surface - of the eyelet
hole. don't forget, the eyelet holes are punched through and the holes
themselves have stress risers - in additional to the material's own
directional crack propagation preferences.
>
>
>> bottom line, rims have a finite life because of braking abrasion.
>> anodizing may indeed have a long term impact on a rim's fatigue life,
>> but if that fatigue life still exceeds the projected wear life of the
>> rim, who cares? the benefits of anodizing are substantial for anyone
>> riding in weather conditions found outside palo alto.
>>
>>
> What about the millions of people outside of Palo Alto who don't ride
> regularly in bad weather? Or who use a beater bike when riding in bad
> weather?
>
> In any event, this is a pretty significant concession on your part.
it's not a question of concession - it's a matter of stating facts. the
biggest fact is that while anodizing /can/ be a crack initiator, the
facts in this situation don't support that mechanism. just because
something exists doesn't mean it's always the case. just like false
brinelling.
>
>> and let's not forget that the highly anisotropic nature of the rim
>> material is going to give very different fatigue strengths in different
>> orientations. excess spoke tension is going to raise the load to the
>> material's fatigue threshold and expose those fatigue orientation
>> differences, and /that/ is what's being observed, not the effects of
>> anodizing.
>
> That hardly rules out a role for anodizing cracks as initiators. It does
> seem sensible that directional weakness would help explain which anodizing
> cracks tend to propagate and the direction in which they propagate.
if all rim cracks /always/ followed anodizing cracks, then it would be a
possible candidate. but they don't. so it's not. real simple.
>
> Again, this seems like a significant concession on your part -- in the
> past you've chalked up such cracks to extrusion /flaws/, not the inherent
> properties of an extrusion.
there is some overlap in that flaws will inevitably be oriented the same
as the extrusion axis, but they're not the same thing. the obvious
differentiator is stress magnitude for failure, but analysis is more
subtle than that. over-simplification can cause confusion, but that's
why it's good to seek clarification.
>
>> spoke tension "as high as the rim can bear" is the real
>> cause.
|
| | | |
Date: 13 May 2007 22:30:47
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <Xs6dnX6O4alkBNrbnZ2dnUVZ_vamnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Gary Young wrote:
> > On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
> >
> >> i've taken the time to study the cracking that happens to
> >> anodizing at rim eyelets - it's essentially a "star" pattern of
> >> cracks radiating from the hole. we could therefore expect actual
> >> metal cracking, if anodizing to be the cause, to follow those
> >> cracks. what we find in practice however is that the metal
> >> frequently cracks at an angle to the anodizing crack, even on
> >> allegedly "unanodized" rims.
> >
> > A google search turns up hundreds of references to "crazing" or
> > "spiderweb cracks" in connection with anodizing. This one, for
> > instance:
> >
> > http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> >
> > Furthermore, the initial anodizing cracks can be formed when the
> > extrusion is anodized before being rolled:
> >
> > http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> >
> > To my mind, that means that the cracks are not exclusively radial
> > and that they may exist even before tension is applied to the
> > spokes.
>
> you need to buy a new rim and inspect it with a magnifier. you will
> find, for a mavic at any rate [which is anodized /after/ it is
> hooped] that the cracks /are/ exclusively radial and they most
> definitely /do/ exist before a spoke has been anywhere near the rim.
Another concession? My goodness. Jobst pointed this out years ago, and
at that time- disbelieving it and coincidentally needing a new rim- I
went down to Kenwood Cyclery with a magnifier and inspected a dozen or
so Mavic rims using oblique incident light to highlight the crazing.
Exactly as you say and as Jobst has said, crazing around the spoke holes
was present before the rims had ever been built up into wheels.
However, contrary to your claim, the crazing in the anodizing was not
exclusively radial around the spoke hole, even before the wheel was
built. There were both mostly radial and mostly concentric cracks.
Once the wheel is laced and tensioned, flexing the rim walls
oh-so-slightly, there are even more cracks that appear visible with a
magnifier and oblique incident lighting. These also are not exclusively
radial to simple observation.
As has been pointed out by Mr. Phinney and Mr. Young, the metallurgy
industry has identified this phenomenon already and there is no reason
to think that the laws of physics for rims are different than other
anodized aluminum structures. We have the test case of the MA-2 and the
MA-40, which differed only in the latter being anodized, showing a very
much higher failure rate in the anodized specimens (acknowledging, of
course, that this is based on collections of anecdotes; real data would
be nice but is unlikely to come along anytime soon, so we are stuck with
the rough equivalent of an epidemiological model for gathering
information).
Is anodizing the sole cause of rim failures by cracking? Of course not,
or we'd have unbuilt rims spontaneously cracking up all over the place.
The spokes have to be tensioned, the rims have to be loaded and ridden
so that the tiny microflexing movements occur as each point on the rim
rolls through the load-affected zone. All those load cycles propagate
cracks originating in the anodized layer through the aluminum substrate.
Might there be other contributors? Sure. Thickness of the anodized
layer and whether the anodizing was sealed were both referenced as
affecting service life in Mr. Phinney's citation, IIRC. Thinner or
thicker spokes might affect how quickly cracks propagate, as this
affects the length of the load affected zone and therefore the magnitude
of rim flex under load. Initial spoke tension might play a role. And
the magnitude of the load (e.g., the weight of the rider) might also
reasonably play a role. I am sure there are other variables that might
be considered.
However, with the exception of anodizing, all those other variables are
present in wheels built with non-anodized rims. We have had a spate of
reports of cracked anodized rims, and not a similar spate of reports
about non-anodized rims (with the exception of ultralight rims like the
GEL 280, which were also known to crack). That suggests that anodizing
is the culprit.
|
| | | | |
Date: 13 May 2007 20:51:43
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Tim McNamara wrote:
> In article <Xs6dnX6O4alkBNrbnZ2dnUVZ_vamnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Gary Young wrote:
>>> On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
>>>
>>>> i've taken the time to study the cracking that happens to
>>>> anodizing at rim eyelets - it's essentially a "star" pattern of
>>>> cracks radiating from the hole. we could therefore expect actual
>>>> metal cracking, if anodizing to be the cause, to follow those
>>>> cracks. what we find in practice however is that the metal
>>>> frequently cracks at an angle to the anodizing crack, even on
>>>> allegedly "unanodized" rims.
>>> A google search turns up hundreds of references to "crazing" or
>>> "spiderweb cracks" in connection with anodizing. This one, for
>>> instance:
>>>
>>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>>>
>>> Furthermore, the initial anodizing cracks can be formed when the
>>> extrusion is anodized before being rolled:
>>>
>>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
>>>
>>> To my mind, that means that the cracks are not exclusively radial
>>> and that they may exist even before tension is applied to the
>>> spokes.
>> you need to buy a new rim and inspect it with a magnifier. you will
>> find, for a mavic at any rate [which is anodized /after/ it is
>> hooped] that the cracks /are/ exclusively radial and they most
>> definitely /do/ exist before a spoke has been anywhere near the rim.
>
> Another concession? My goodness. Jobst pointed this out years ago, and
> at that time- disbelieving it and coincidentally needing a new rim- I
> went down to Kenwood Cyclery with a magnifier and inspected a dozen or
> so Mavic rims using oblique incident light to highlight the crazing.
> Exactly as you say and as Jobst has said, crazing around the spoke holes
> was present before the rims had ever been built up into wheels.
<snip crap >
anodizing /can/ cause cracking. stress corrosion agents crack metal
also. but it's just plain stupid to attribute a failure to the wrong
cause. in this case, there's no evidence supporting anodizing initiated
cracking, so it doesn't matter /how/ cracked the anodizing is! but you
don't understand that because you're too fucking retarded.
|
| | | | | |
Date: 14 May 2007 08:40:24
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <kYudnUGFbbFMQdrbnZ2dnUVZ_gWdnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <Xs6dnX6O4alkBNrbnZ2dnUVZ_vamnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Gary Young wrote:
> >>> On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
> >>>
> >>>> i've taken the time to study the cracking that happens to
> >>>> anodizing at rim eyelets - it's essentially a "star" pattern of
> >>>> cracks radiating from the hole. we could therefore expect
> >>>> actual metal cracking, if anodizing to be the cause, to follow
> >>>> those cracks. what we find in practice however is that the
> >>>> metal frequently cracks at an angle to the anodizing crack, even
> >>>> on allegedly "unanodized" rims.
> >>> A google search turns up hundreds of references to "crazing" or
> >>> "spiderweb cracks" in connection with anodizing. This one, for
> >>> instance:
> >>>
> >>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> >>>
> >>> Furthermore, the initial anodizing cracks can be formed when the
> >>> extrusion is anodized before being rolled:
> >>>
> >>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> >>>
> >>> To my mind, that means that the cracks are not exclusively radial
> >>> and that they may exist even before tension is applied to the
> >>> spokes.
> >> you need to buy a new rim and inspect it with a magnifier. you
> >> will find, for a mavic at any rate [which is anodized /after/ it
> >> is hooped] that the cracks /are/ exclusively radial and they most
> >> definitely /do/ exist before a spoke has been anywhere near the
> >> rim.
> >
> > Another concession? My goodness. Jobst pointed this out years
> > ago, and at that time- disbelieving it and coincidentally needing a
> > new rim- I went down to Kenwood Cyclery with a magnifier and
> > inspected a dozen or so Mavic rims using oblique incident light to
> > highlight the crazing. Exactly as you say and as Jobst has said,
> > crazing around the spoke holes was present before the rims had ever
> > been built up into wheels.
>
> <snip crap>
>
> anodizing /can/ cause cracking.
We agree.
> stress corrosion agents crack metal also.
I'll take your word for it.
> but it's just plain stupid to attribute a failure to the wrong cause.
Indeed. And yet you persist in doing so.
> in this case, there's no evidence supporting anodizing initiated
> cracking, so it doesn't matter /how/ cracked the anodizing is!
You have not shown that to be the case, and the evidence from real
metallurgists contradicts your claim.
> but you don't understand that because you're too fucking retarded.
LOL.
|
| | | | | | |
Date: 14 May 2007 12:00:53
From: * * Chas
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-D92A2A.08402414052007@news.iphouse.com...
> In article <kYudnUGFbbFMQdrbnZ2dnUVZ_gWdnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
> > Tim McNamara wrote:
> > > In article <Xs6dnX6O4alkBNrbnZ2dnUVZ_vamnZ2d@speakeasy.net>,
> > > jim beam <spamvortex@bad.example.net> wrote:
> > >
> > >> Gary Young wrote:
> > >>> On Sun, 13 May 2007 09:39:55 -0700, jim beam wrote:
> > >>>
> > >>>> i've taken the time to study the cracking that happens to
> > >>>> anodizing at rim eyelets - it's essentially a "star" pattern of
> > >>>> cracks radiating from the hole. we could therefore expect
> > >>>> actual metal cracking, if anodizing to be the cause, to follow
> > >>>> those cracks. what we find in practice however is that the
> > >>>> metal frequently cracks at an angle to the anodizing crack, even
> > >>>> on allegedly "unanodized" rims.
> > >>> A google search turns up hundreds of references to "crazing" or
> > >>> "spiderweb cracks" in connection with anodizing. This one, for
> > >>> instance:
> > >>>
> > >>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> > >>>
> > >>> Furthermore, the initial anodizing cracks can be formed when the
> > >>> extrusion is anodized before being rolled:
> > >>>
> > >>> http://www.eng-tips.com/viewthread.cfm?qid=178879&page=1
> > >>>
> > >>> To my mind, that means that the cracks are not exclusively radial
> > >>> and that they may exist even before tension is applied to the
> > >>> spokes.
> > >> you need to buy a new rim and inspect it with a magnifier. you
> > >> will find, for a mavic at any rate [which is anodized /after/ it
> > >> is hooped] that the cracks /are/ exclusively radial and they most
> > >> definitely /do/ exist before a spoke has been anywhere near the
> > >> rim.
> > >
> > > Another concession? My goodness. Jobst pointed this out years
> > > ago, and at that time- disbelieving it and coincidentally needing a
> > > new rim- I went down to Kenwood Cyclery with a magnifier and
> > > inspected a dozen or so Mavic rims using oblique incident light to
> > > highlight the crazing. Exactly as you say and as Jobst has said,
> > > crazing around the spoke holes was present before the rims had ever
> > > been built up into wheels.
> >
> > <snip crap>
> >
> > anodizing /can/ cause cracking.
>
> We agree.
>
> > stress corrosion agents crack metal also.
>
> I'll take your word for it.
>
> > but it's just plain stupid to attribute a failure to the wrong cause.
>
> Indeed. And yet you persist in doing so.
>
> > in this case, there's no evidence supporting anodizing initiated
> > cracking, so it doesn't matter /how/ cracked the anodizing is!
>
> You have not shown that to be the case, and the evidence from real
> metallurgists contradicts your claim.
>
> > but you don't understand that because you're too fucking retarded.
>
> LOL.
Cmon.... it's all very simple: up is down, black is white, yes is no!
Chas.
|
| |
Date: 12 May 2007 17:41:43
From: Orin
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 12, 6:39 am, jim beam <spamvor...@bad.example.net > wrote:
> RS wrote:
> > In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
> > spamvor...@bad.example.net says...
>
> >> RS wrote:
> >>> What is the difference, except for price, in the 3 versions of the
> >>> venerable Mavic Open Pro rim? And are the higher priced version
> >>> money well spent? note: I rarely ride in the rain.
>
> >> what's your objective if you don't ride in the rain? ceramic rims are
> >> impervious to the rain-road grit. cd rims are similar, but not as hard
> >> or long lasting. ordinary open pros are not very resistant to grit at all.
> > I was asking as to any other differences in construction, finish, longevity
> > and intended use. Its why I'm asking, I don't know.
>
> if you're not riding in the rain, a standard rim is fine. there's no
> other differences in construction other than the finishes and their
> function.
But if you are riding in the rain...
Wednesday, I took the tire off my (silver) SON/Open Pro in order to
loan the wheel out and found the braking surface utterly concave. So
much so that I wouldn't ride it, never mind loan it to someone.
Fortunately, the LBS had lots of 36 hole silver Open Pros, so I got to
try the tape the new rim to the old and transfer the spokes technique.
BTW, I have had a silver Open Pro rim crack around the eyelets (rear
wheel). It was the tightest wheel I've ever owned. It would tend to
indicate that spoke tension can cause the cracking.
Orin.
|
| | |
Date: 12 May 2007 22:26:05
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article
<1179016903.162057.212560@q75g2000hsh.googlegroups.com >,
Orin <orin.eman@gmail.com > wrote:
> On May 12, 6:39 am, jim beam <spamvor...@bad.example.net> wrote:
> > RS wrote:
> > > In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
> > > spamvor...@bad.example.net says...
> >
> > >> RS wrote:
> > >>> What is the difference, except for price, in the 3 versions of the
> > >>> venerable Mavic Open Pro rim? And are the higher priced version
> > >>> money well spent? note: I rarely ride in the rain.
> >
> > >> what's your objective if you don't ride in the rain? ceramic rims are
> > >> impervious to the rain-road grit. cd rims are similar, but not as hard
> > >> or long lasting. ordinary open pros are not very resistant to grit at all.
> > > I was asking as to any other differences in construction, finish, longevity
> > > and intended use. Its why I'm asking, I don't know.
> >
> > if you're not riding in the rain, a standard rim is fine. there's no
> > other differences in construction other than the finishes and their
> > function.
>
> But if you are riding in the rain...
>
> Wednesday, I took the tire off my (silver) SON/Open Pro in order to
> loan the wheel out and found the braking surface utterly concave. So
> much so that I wouldn't ride it, never mind loan it to someone.
> Fortunately, the LBS had lots of 36 hole silver Open Pros, so I got to
> try the tape the new rim to the old and transfer the spokes technique.
>
> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> wheel). It was the tightest wheel I've ever owned. It would tend to
> indicate that spoke tension can cause the cracking.
But it should not. Rims should be built to sustain all the spoke
force it takes to potato chip the rim, as the Sun CR-18 can.
--
Michael Press
|
| | | |
Date: 13 May 2007 05:20:12
From: Ben C
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On 2007-05-13, Michael Press <rubrum@pacbell.net > wrote:
> In article
><1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
> Orin <orin.eman@gmail.com> wrote:
[...]
>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
>> wheel). It was the tightest wheel I've ever owned. It would tend to
>> indicate that spoke tension can cause the cracking.
>
> But it should not. Rims should be built to sustain all the spoke
> force it takes to potato chip the rim, as the Sun CR-18 can.
Just because a rim can sustain potato-chip force in the truing stand
doesn't mean that it won't fatigue prematurely if run at excessive
tension (at just a bit less than the potato-chipping tension for
example). I don't think the suggestion is that the nipples rip out while
you're actually building the wheel. The wheel looks fine and rides fine,
but fatigues prematurely because of the high mean stress in the stress
cycle as the spokes load and unload.
It appears from discussions that some rims have an acceptable fatigue
life even when run at close to potato-chip tension (MA2), and that
others don't (MA3). So the qualified statement is that "too much tension
for the rim you've chosen" (or alternatively "choosing the wrong rim for
the tension you've chosen") is what causes cracking.
|
| | | | |
Date: 13 May 2007 15:02:53
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <slrnf4dpeo.3n7.spamspam@bowser.marioworld >,
Ben C <spamspam@spam.eggs > wrote:
> On 2007-05-13, Michael Press <rubrum@pacbell.net> wrote:
> > In article
> ><1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
> > Orin <orin.eman@gmail.com> wrote:
> [...]
> >> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> >> wheel). It was the tightest wheel I've ever owned. It would tend to
> >> indicate that spoke tension can cause the cracking.
> >
> > But it should not. Rims should be built to sustain all the spoke
> > force it takes to potato chip the rim, as the Sun CR-18 can.
>
> Just because a rim can sustain potato-chip force in the truing stand
> doesn't mean that it won't fatigue prematurely if run at excessive
> tension (at just a bit less than the potato-chipping tension for
> example). I don't think the suggestion is that the nipples rip out while
> you're actually building the wheel. The wheel looks fine and rides fine,
> but fatigues prematurely because of the high mean stress in the stress
> cycle as the spokes load and unload.
>
> It appears from discussions that some rims have an acceptable fatigue
> life even when run at close to potato-chip tension (MA2), and that
> others don't (MA3). So the qualified statement is that "too much tension
> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> the tension you've chosen") is what causes cracking.
My CR-18's have run for years fully tensioned without spoke
pull-out. Others have the same experience. There is no excuse for
spoke pull-out in a fully tensioned rim, just as there is no
excuse for cog wheels gouging free-hubs. These fabrications have
been made successfully forever in all mechanical domains,
including bicycles.
--
Michael Press
|
| | | | | |
Date: 13 May 2007 22:37:04
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <rubrum-9AC37E.15025313052007@newsclstr03.news.prodigy.net >,
Michael Press <rubrum@pacbell.net > wrote:
> In article <slrnf4dpeo.3n7.spamspam@bowser.marioworld>,
> Ben C <spamspam@spam.eggs> wrote:
>
> > On 2007-05-13, Michael Press <rubrum@pacbell.net> wrote:
> > > In article
> > ><1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
> > > Orin <orin.eman@gmail.com> wrote:
> > [...]
> > >> BTW, I have had a silver Open Pro rim crack around the eyelets
> > >> (rear wheel). It was the tightest wheel I've ever owned. It
> > >> would tend to indicate that spoke tension can cause the
> > >> cracking.
> > >
> > > But it should not. Rims should be built to sustain all the spoke
> > > force it takes to potato chip the rim, as the Sun CR-18 can.
> >
> > Just because a rim can sustain potato-chip force in the truing
> > stand doesn't mean that it won't fatigue prematurely if run at
> > excessive tension (at just a bit less than the potato-chipping
> > tension for example). I don't think the suggestion is that the
> > nipples rip out while you're actually building the wheel. The wheel
> > looks fine and rides fine, but fatigues prematurely because of the
> > high mean stress in the stress cycle as the spokes load and unload.
> >
> > It appears from discussions that some rims have an acceptable
> > fatigue life even when run at close to potato-chip tension (MA2),
> > and that others don't (MA3). So the qualified statement is that
> > "too much tension for the rim you've chosen" (or alternatively
> > "choosing the wrong rim for the tension you've chosen") is what
> > causes cracking.
>
> My CR-18's have run for years fully tensioned without spoke pull-out.
> Others have the same experience. There is no excuse for spoke
> pull-out in a fully tensioned rim
My CR-16s have lasted over 10 years and I'd guess about 30,000 miles on
one of my bikes. They don't even have single ferrules, the CR-18 being
an improved version of these rims. By comparison, I had a spate of
anodized Mavic rims that didn't last 2,000 miles on the rear wheel
before cracking. My MA-2s have never cracked yet, although none of hte
current ones have gotten as many miles on the. Potholes have claimed
the lives of too many rims...
|
| | | | | |
Date: 13 May 2007 16:07:27
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Michael Press wrote:
> In article <slrnf4dpeo.3n7.spamspam@bowser.marioworld>,
> Ben C <spamspam@spam.eggs> wrote:
>
>> On 2007-05-13, Michael Press <rubrum@pacbell.net> wrote:
>>> In article
>>> <1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
>>> Orin <orin.eman@gmail.com> wrote:
>> [...]
>>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
>>>> wheel). It was the tightest wheel I've ever owned. It would tend to
>>>> indicate that spoke tension can cause the cracking.
>>> But it should not. Rims should be built to sustain all the spoke
>>> force it takes to potato chip the rim, as the Sun CR-18 can.
>> Just because a rim can sustain potato-chip force in the truing stand
>> doesn't mean that it won't fatigue prematurely if run at excessive
>> tension (at just a bit less than the potato-chipping tension for
>> example). I don't think the suggestion is that the nipples rip out while
>> you're actually building the wheel. The wheel looks fine and rides fine,
>> but fatigues prematurely because of the high mean stress in the stress
>> cycle as the spokes load and unload.
>>
>> It appears from discussions that some rims have an acceptable fatigue
>> life even when run at close to potato-chip tension (MA2), and that
>> others don't (MA3). So the qualified statement is that "too much tension
>> for the rim you've chosen" (or alternatively "choosing the wrong rim for
>> the tension you've chosen") is what causes cracking.
>
> My CR-18's have run for years fully tensioned without spoke
> pull-out. Others have the same experience. There is no excuse for
> spoke pull-out in a fully tensioned rim, just as there is no
> excuse for cog wheels gouging free-hubs. These fabrications have
> been made successfully forever in all mechanical domains,
> including bicycles.
>
what is your spoke tension?
|
| | | | | | |
Date: 13 May 2007 22:40:10
From: Michael Press
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <Xs6dnXmO4amyB9rbnZ2dnUVZ_vbinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Michael Press wrote:
> > In article <slrnf4dpeo.3n7.spamspam@bowser.marioworld>,
> > Ben C <spamspam@spam.eggs> wrote:
> >
> >> On 2007-05-13, Michael Press <rubrum@pacbell.net> wrote:
> >>> In article
> >>> <1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
> >>> Orin <orin.eman@gmail.com> wrote:
> >> [...]
> >>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
> >>>> wheel). It was the tightest wheel I've ever owned. It would tend to
> >>>> indicate that spoke tension can cause the cracking.
> >>> But it should not. Rims should be built to sustain all the spoke
> >>> force it takes to potato chip the rim, as the Sun CR-18 can.
> >> Just because a rim can sustain potato-chip force in the truing stand
> >> doesn't mean that it won't fatigue prematurely if run at excessive
> >> tension (at just a bit less than the potato-chipping tension for
> >> example). I don't think the suggestion is that the nipples rip out while
> >> you're actually building the wheel. The wheel looks fine and rides fine,
> >> but fatigues prematurely because of the high mean stress in the stress
> >> cycle as the spokes load and unload.
> >>
> >> It appears from discussions that some rims have an acceptable fatigue
> >> life even when run at close to potato-chip tension (MA2), and that
> >> others don't (MA3). So the qualified statement is that "too much tension
> >> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> >> the tension you've chosen") is what causes cracking.
> >
> > My CR-18's have run for years fully tensioned without spoke
> > pull-out. Others have the same experience. There is no excuse for
> > spoke pull-out in a fully tensioned rim, just as there is no
> > excuse for cog wheels gouging free-hubs. These fabrications have
> > been made successfully forever in all mechanical domains,
> > including bicycles.
> >
> what is your spoke tension?
I do not know. Just below the tension that buckles the rim. The
wheels have been true from day one.
--
Michael Press
|
| | | | |
Date: 13 May 2007 09:50:37
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Ben C wrote:
> On 2007-05-13, Michael Press <rubrum@pacbell.net> wrote:
>> In article
>> <1179016903.162057.212560@q75g2000hsh.googlegroups.com>,
>> Orin <orin.eman@gmail.com> wrote:
> [...]
>>> BTW, I have had a silver Open Pro rim crack around the eyelets (rear
>>> wheel). It was the tightest wheel I've ever owned. It would tend to
>>> indicate that spoke tension can cause the cracking.
>> But it should not. Rims should be built to sustain all the spoke
>> force it takes to potato chip the rim, as the Sun CR-18 can.
>
> Just because a rim can sustain potato-chip force in the truing stand
> doesn't mean that it won't fatigue prematurely if run at excessive
> tension (at just a bit less than the potato-chipping tension for
> example). I don't think the suggestion is that the nipples rip out while
> you're actually building the wheel. The wheel looks fine and rides fine,
> but fatigues prematurely because of the high mean stress in the stress
> cycle as the spokes load and unload.
>
> It appears from discussions that some rims have an acceptable fatigue
> life even when run at close to potato-chip tension (MA2), and that
> others don't (MA3). So the qualified statement is that "too much tension
> for the rim you've chosen" (or alternatively "choosing the wrong rim for
> the tension you've chosen") is what causes cracking.
indeed.
|
| | | | |
Date: 13 May 2007 16:38:32
From:
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Ben C? writes:
>>> BTW, I have had a silver Open Pro rim crack around the eyelets
>>> (rear wheel). It was the tightest wheel I've ever owned. It
>>> would tend to indicate that spoke tension can cause the cracking.
>> But it should not. Rims should be built to sustain all the spoke
>> force it takes to potato chip the rim, as the Sun CR-18 can.
> Just because a rim can sustain potato-chip force in the truing stand
> doesn't mean that it won't fatigue prematurely if run at excessive
> tension (at just a bit less than the potato-chipping tension for
> example). I don't think the suggestion is that the nipples rip out
> while you're actually building the wheel. The wheel looks fine and
> rides fine, but fatigues prematurely because of the high mean stress
> in the stress cycle as the spokes load and unload.
The term excessive tension is new to wheels in the decline of durable
rims. Excessive tension was formerly the force to buckle the rim in
compression, rims being designed with sockets to enable them to be
limited by the buckling. I and my colleagues still use rims that can
run until the sidewalls are worn out without spokes pulling out while
being tensioned high enough so the spokes to not rattle in use and
require glue to keep spoke nipples from unscrewing. That tension is
close to the buckling load.
We have not advanced in this respect.
> It appears from discussions that some rims have an acceptable
> fatigue life even when run at close to potato-chip tension (MA2),
> and that others don't (MA3). So the qualified statement is that
> "too much tension for the rim you've chosen" (or alternatively
> "choosing the wrong rim for the tension you've chosen") is what
> causes cracking.
I'm not sure but I think this paragraph says the same thing in words
less obvious to me, but I can't say for sure.
Jobst Brandt
|
| | | | | |
Date: 13 May 2007 09:54:08
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
jobst.brandt@stanfordalumni.org wrote:
> Ben C? writes:
>
>>>> BTW, I have had a silver Open Pro rim crack around the eyelets
>>>> (rear wheel). It was the tightest wheel I've ever owned. It
>>>> would tend to indicate that spoke tension can cause the cracking.
>
>>> But it should not. Rims should be built to sustain all the spoke
>>> force it takes to potato chip the rim, as the Sun CR-18 can.
>
>> Just because a rim can sustain potato-chip force in the truing stand
>> doesn't mean that it won't fatigue prematurely if run at excessive
>> tension (at just a bit less than the potato-chipping tension for
>> example). I don't think the suggestion is that the nipples rip out
>> while you're actually building the wheel. The wheel looks fine and
>> rides fine, but fatigues prematurely because of the high mean stress
>> in the stress cycle as the spokes load and unload.
>
> The term excessive tension is new to wheels in the decline of durable
> rims. Excessive tension was formerly the force to buckle the rim in
> compression, rims being designed with sockets to enable them to be
> limited by the buckling. I and my colleagues still use rims that can
> run until the sidewalls are worn out without spokes pulling out while
> being tensioned high enough so the spokes to not rattle in use and
> require glue to keep spoke nipples from unscrewing. That tension is
> close to the buckling load.
>
> We have not advanced in this respect.
>
>> It appears from discussions that some rims have an acceptable
>> fatigue life even when run at close to potato-chip tension (MA2),
>> and that others don't (MA3). So the qualified statement is that
>> "too much tension for the rim you've chosen" (or alternatively
>> "choosing the wrong rim for the tension you've chosen") is what
>> causes cracking.
>
> I'm not sure but I think this paragraph says the same thing in words
> less obvious to me, but I can't say for sure.
>
you could just say "i got it wrong".
|
| | |
Date: 12 May 2007 21:37:12
From: Donald Gillies
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
I can easily believe that heat-treated rims crack more easily than
plain vanilla non-anodized rims, but it's not for the metallurgical
reasons that you might think.
I had heat-treated rims on a TREK 500 in 1985. After going down an
Illinois pothole, i couldn't get it true. Turns out bikeshop couldn't
get it true. Ok, i got a new rim.
A few months later, and the same pothole at my second rim. It turns
out that heat-treated rims are so stiff that they are very difficult
to bring true once bent. Thus, if you _CAN_ re-true a bent heat
treated rim, you are probably using excessive spoke tension to get the
job done.
So, heat treating might lead to more cracks, but so would any
treatment that stiffens a rim.
And, by the way, in my experience all heat-treated rims are anodized.
A naive person might then say that anodized rims have more cracks
around the spoke holes, and they'd be right ... *sigh* ...
- Don Gillies
San Diego, CA
|
| |
Date: 12 May 2007 18:53:43
From: Gary Young
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sat, 12 May 2007 15:01:21 -0700, jim beam wrote:
> landotter wrote:
>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>
>>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
>>> better than that by now. there is 100% correlation between those that
>>> say they have cracking and those that don't use manufacturer spoke
>>> tension, regardless of rim finish.
>>
>> Erm, with the previous generation's MA3, the correlation between
>> cracking and anodizing is well documented.
>
> no it's not because there is _no_ unanodized ma3 available for
> comparison! an ma3 may crack, but that cannot simply be attributed to
> anodizing.
>
> if "mr. condemn a whole industry with underinformed supposition" had
> bothered to do /any/ homework on this subject at all, he'd have looked
> into anisotropy and extrusion flaws.
In the past, you've often attributed cracks along the circumference to
extrusion flaws. I think it's a significant change in your position that
you now mention anisotropy. After all, anisotropy is a property of even
the best-made rims, isn't it? Wouldn't one expect many anodizing cracks to
take the path of least resistance as they propagate?
I suppose you might argue that anodizing cranks don't propagate into the
aluminum substrate. That seems an unusual position for you take since the
importance of surface finish is one of your constant refrains.
Or is it that you deny that anodizing cracks?
>> That's not an Open Pro of
>> course. Got one hanging in the garage that I should get around to
>> throwing away...
>>
>> Velocity and Alex rims are the way to go. Cheaper and stronger. Unless
>> you're rerimming and need the same ERD of course.
>>
>>
>>
>>
|
| | |
Date: 12 May 2007 18:11:29
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Gary Young wrote:
> On Sat, 12 May 2007 15:01:21 -0700, jim beam wrote:
>
>> landotter wrote:
>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>
>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
>>>> better than that by now. there is 100% correlation between those that
>>>> say they have cracking and those that don't use manufacturer spoke
>>>> tension, regardless of rim finish.
>>> Erm, with the previous generation's MA3, the correlation between
>>> cracking and anodizing is well documented.
>> no it's not because there is _no_ unanodized ma3 available for
>> comparison! an ma3 may crack, but that cannot simply be attributed to
>> anodizing.
>>
>> if "mr. condemn a whole industry with underinformed supposition" had
>> bothered to do /any/ homework on this subject at all, he'd have looked
>> into anisotropy and extrusion flaws.
>
> In the past, you've often attributed cracks along the circumference to
> extrusion flaws. I think it's a significant change in your position that
> you now mention anisotropy.
eh? anisotropy is the result of extrusion...
> After all, anisotropy is a property of even
> the best-made rims, isn't it?
not "best-made", simply "extruded". /all/ aluminum rims are extruded afaik.
> Wouldn't one expect many anodizing cracks to
> take the path of least resistance as they propagate?
"least resistance" with regard to what???
>
> I suppose you might argue that anodizing cranks don't propagate into the
> aluminum substrate. That seems an unusual position for you take since the
> importance of surface finish is one of your constant refrains.
eh?
>
> Or is it that you deny that anodizing cracks?
no gary, it cracks. but there's no observable connection between
anodizing crack angle and rim crack angle. if the two are not
coincident, the anodizing's not the cause. particularly when you're
trying to cite a dye penetrant test as evidence.
>
>
>
>>> That's not an Open Pro of
>>> course. Got one hanging in the garage that I should get around to
>>> throwing away...
>>>
>>> Velocity and Alex rims are the way to go. Cheaper and stronger. Unless
>>> you're rerimming and need the same ERD of course.
>>>
>>>
>>>
>>>
|
| |
Date: 12 May 2007 15:54:14
From: landotter
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net > wrote:
> landotter wrote:
> > On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> landotter wrote:
> >>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
> >>>> better than that by now. there is 100% correlation between those that
> >>>> say they have cracking and those that don't use manufacturer spoke
> >>>> tension, regardless of rim finish.
> >>> Erm, with the previous generation's MA3, the correlation between
> >>> cracking and anodizing is well documented.
> >> no it's not because there is _no_ unanodized ma3 available for
> >> comparison! an ma3 may crack, but that cannot simply be attributed to
> >> anodizing.
>
> > Yes it most likely can. It was the dark ano ones that had a really
> > nasty habit of cracking. The lightly anodized silvery ones didn't tend
> > to crack AFAIK. Maybe a bunch of light ano ones did and I didn't hear
> > about it. Testimony welcome.
>
> i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
> up. they were on sale at nashbar a while back. i put about 6k on a
> road pair before relegating them to "backup" position. the other pair
> are on a track bike. no evidence of any cracking in either application
> yet. i used a tensiometer during build.
That's certainly testimony, but not evidence. I'd never cracked a rim
in my life till I cracked a non-drive side nipple on an MA3. No
tensionmeter here, but my spoke wrenches are so shitty that if I tried
to bring a rim up to spectacular tension, I'd round off the nipple.
So no high tension here, just a 185# rider. Didn't hit anything, just
heard it pop on a descent. This assumption that it's a poor build is a
bit presumptuous if not a wee bit arrogant. It's pretty widely known
that hard-ano Mavics are notorious for this. I don't know why you feel
the need to be contrary.
|
| | |
Date: 12 May 2007 18:00:49
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
landotter wrote:
> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>> landotter wrote:
>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> landotter wrote:
>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
>>>>>> better than that by now. there is 100% correlation between those that
>>>>>> say they have cracking and those that don't use manufacturer spoke
>>>>>> tension, regardless of rim finish.
>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>> cracking and anodizing is well documented.
>>>> no it's not because there is _no_ unanodized ma3 available for
>>>> comparison! an ma3 may crack, but that cannot simply be attributed to
>>>> anodizing.
>>> Yes it most likely can. It was the dark ano ones that had a really
>>> nasty habit of cracking. The lightly anodized silvery ones didn't tend
>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't hear
>>> about it. Testimony welcome.
>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
>> up. they were on sale at nashbar a while back. i put about 6k on a
>> road pair before relegating them to "backup" position. the other pair
>> are on a track bike. no evidence of any cracking in either application
>> yet. i used a tensiometer during build.
>
> That's certainly testimony, but not evidence. I'd never cracked a rim
> in my life till I cracked a non-drive side nipple on an MA3. No
> tensionmeter here, but my spoke wrenches are so shitty that if I tried
> to bring a rim up to spectacular tension, I'd round off the nipple.
>
> So no high tension here, just a 185# rider. Didn't hit anything, just
> heard it pop on a descent. This assumption that it's a poor build is a
> bit presumptuous if not a wee bit arrogant. It's pretty widely known
> that hard-ano Mavics are notorious for this. I don't know why you feel
> the need to be contrary.
>
why do i keep interjecting reality and not accept the propagation of
myth you mean? "widely known" on r.b.t. is not "widely known" in the
real world. after all, "widely known" "facts" on r.b.t. include the
elimination of metal fatigue in materials with no fatigue endurance
limit and that all spokes are "swaged".
i've got [and have ridden hard] cd open pro's, x618's and ma3's. for
years. never a crack. the only rims i have that evidence any form of
cracking at the eyelets are silver anodized x517's. and their spoke
tension is /way/ [3x] over spec. if cracking of cd rims is "well known"
in the real world, why don't i have cracked rims??? i weigh #205.
|
| | | |
Date: 12 May 2007 23:05:30
From: * * Chas
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
> landotter wrote:
> > On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> landotter wrote:
> >>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> landotter wrote:
> >>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should
know
> >>>>>> better than that by now. there is 100% correlation between those
that
> >>>>>> say they have cracking and those that don't use manufacturer
spoke
> >>>>>> tension, regardless of rim finish.
> >>>>> Erm, with the previous generation's MA3, the correlation between
> >>>>> cracking and anodizing is well documented.
> >>>> no it's not because there is _no_ unanodized ma3 available for
> >>>> comparison! an ma3 may crack, but that cannot simply be attributed
to
> >>>> anodizing.
> >>> Yes it most likely can. It was the dark ano ones that had a really
> >>> nasty habit of cracking. The lightly anodized silvery ones didn't
tend
> >>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
hear
> >>> about it. Testimony welcome.
> >> i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
> >> up. they were on sale at nashbar a while back. i put about 6k on a
> >> road pair before relegating them to "backup" position. the other
pair
> >> are on a track bike. no evidence of any cracking in either
application
> >> yet. i used a tensiometer during build.
> >
> > That's certainly testimony, but not evidence. I'd never cracked a rim
> > in my life till I cracked a non-drive side nipple on an MA3. No
> > tensionmeter here, but my spoke wrenches are so shitty that if I tried
> > to bring a rim up to spectacular tension, I'd round off the nipple.
> >
> > So no high tension here, just a 185# rider. Didn't hit anything, just
> > heard it pop on a descent. This assumption that it's a poor build is a
> > bit presumptuous if not a wee bit arrogant. It's pretty widely known
> > that hard-ano Mavics are notorious for this. I don't know why you feel
> > the need to be contrary.
> >
> why do i keep interjecting reality and not accept the propagation of
> myth you mean? "widely known" on r.b.t. is not "widely known" in the
> real world. after all, "widely known" "facts" on r.b.t. include the
> elimination of metal fatigue in materials with no fatigue endurance
> limit and that all spokes are "swaged".
All spokes are swaged! Spokes are made of wire that has been drawn or
extruded through a metal die. This amounts to swaging.
http://en.wikipedia.org/wiki/Swagelok
Spoke heads are upset which is another form of swaging.
http://www.thefreedictionary.com/swage
Chas.
|
| | | | |
Date: 13 May 2007 09:46:30
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
* * Chas wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
>> landotter wrote:
>>> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> landotter wrote:
>>>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> landotter wrote:
>>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should
> know
>>>>>>>> better than that by now. there is 100% correlation between those
> that
>>>>>>>> say they have cracking and those that don't use manufacturer
> spoke
>>>>>>>> tension, regardless of rim finish.
>>>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>>>> cracking and anodizing is well documented.
>>>>>> no it's not because there is _no_ unanodized ma3 available for
>>>>>> comparison! an ma3 may crack, but that cannot simply be attributed
> to
>>>>>> anodizing.
>>>>> Yes it most likely can. It was the dark ano ones that had a really
>>>>> nasty habit of cracking. The lightly anodized silvery ones didn't
> tend
>>>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
> hear
>>>>> about it. Testimony welcome.
>>>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
>>>> up. they were on sale at nashbar a while back. i put about 6k on a
>>>> road pair before relegating them to "backup" position. the other
> pair
>>>> are on a track bike. no evidence of any cracking in either
> application
>>>> yet. i used a tensiometer during build.
>>> That's certainly testimony, but not evidence. I'd never cracked a rim
>>> in my life till I cracked a non-drive side nipple on an MA3. No
>>> tensionmeter here, but my spoke wrenches are so shitty that if I tried
>>> to bring a rim up to spectacular tension, I'd round off the nipple.
>>>
>>> So no high tension here, just a 185# rider. Didn't hit anything, just
>>> heard it pop on a descent. This assumption that it's a poor build is a
>>> bit presumptuous if not a wee bit arrogant. It's pretty widely known
>>> that hard-ano Mavics are notorious for this. I don't know why you feel
>>> the need to be contrary.
>>>
>> why do i keep interjecting reality and not accept the propagation of
>> myth you mean? "widely known" on r.b.t. is not "widely known" in the
>> real world. after all, "widely known" "facts" on r.b.t. include the
>> elimination of metal fatigue in materials with no fatigue endurance
>> limit and that all spokes are "swaged".
>
> All spokes are swaged! Spokes are made of wire that has been drawn or
> extruded through a metal die. This amounts to swaging.
>
> http://en.wikipedia.org/wiki/Swagelok
that's incorrect! swaging is a hammering process. a process using a
die is called drawing - the deformation mechanics, while both involving
plastic deformation, are different.
>
> Spoke heads are upset which is another form of swaging.
>
> http://www.thefreedictionary.com/swage
>
> Chas.
yes, the heads are swaged. but the butting of spokes, the subject in
question, is by one of 3 processes - swaging, drawing or grinding. the
latter involves no plastic deformation of the wire core, the former two
do. to call /all/ butted spokes "swaged" is simply incorrect and a
mistake based on insufficient understanding of metal forming techniques.
|
| | | | | |
Date: 13 May 2007 17:20:17
From: * * Chas
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:1ZWdnYsIvJp63drbnZ2dnUVZ_oupnZ2d@speakeasy.net...
> * * Chas wrote:
> > "jim beam" <spamvortex@bad.example.net> wrote in message
> > news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
> >> landotter wrote:
> >>> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>> landotter wrote:
> >>>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>> landotter wrote:
> >>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
should
> > know
> >>>>>>>> better than that by now. there is 100% correlation between
those
> > that
> >>>>>>>> say they have cracking and those that don't use manufacturer
> > spoke
> >>>>>>>> tension, regardless of rim finish.
> >>>>>>> Erm, with the previous generation's MA3, the correlation between
> >>>>>>> cracking and anodizing is well documented.
> >>>>>> no it's not because there is _no_ unanodized ma3 available for
> >>>>>> comparison! an ma3 may crack, but that cannot simply be
attributed
> > to
> >>>>>> anodizing.
> >>>>> Yes it most likely can. It was the dark ano ones that had a really
> >>>>> nasty habit of cracking. The lightly anodized silvery ones didn't
> > tend
> >>>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
> > hear
> >>>>> about it. Testimony welcome.
> >>>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims
built
> >>>> up. they were on sale at nashbar a while back. i put about 6k on
a
> >>>> road pair before relegating them to "backup" position. the other
> > pair
> >>>> are on a track bike. no evidence of any cracking in either
> > application
> >>>> yet. i used a tensiometer during build.
> >>> That's certainly testimony, but not evidence. I'd never cracked a
rim
> >>> in my life till I cracked a non-drive side nipple on an MA3. No
> >>> tensionmeter here, but my spoke wrenches are so shitty that if I
tried
> >>> to bring a rim up to spectacular tension, I'd round off the nipple.
> >>>
> >>> So no high tension here, just a 185# rider. Didn't hit anything,
just
> >>> heard it pop on a descent. This assumption that it's a poor build is
a
> >>> bit presumptuous if not a wee bit arrogant. It's pretty widely known
> >>> that hard-ano Mavics are notorious for this. I don't know why you
feel
> >>> the need to be contrary.
> >>>
> >> why do i keep interjecting reality and not accept the propagation of
> >> myth you mean? "widely known" on r.b.t. is not "widely known" in the
> >> real world. after all, "widely known" "facts" on r.b.t. include the
> >> elimination of metal fatigue in materials with no fatigue endurance
> >> limit and that all spokes are "swaged".
> >
> > All spokes are swaged! Spokes are made of wire that has been drawn or
> > extruded through a metal die. This amounts to swaging.
> >
> > http://en.wikipedia.org/wiki/Swagelok
>
> that's incorrect! swaging is a hammering process. a process using a
> die is called drawing - the deformation mechanics, while both involving
> plastic deformation, are different.
>
> >
> > Spoke heads are upset which is another form of swaging.
> >
> > http://www.thefreedictionary.com/swage
> >
> > Chas.
>
> yes, the heads are swaged. but the butting of spokes, the subject in
> question, is by one of 3 processes - swaging, drawing or grinding. the
> latter involves no plastic deformation of the wire core, the former two
> do. to call /all/ butted spokes "swaged" is simply incorrect and a
> mistake based on insufficient understanding of metal forming techniques.
NO! read the links.... In the English language ALL forms of drawing or
extruding metal through a die can be technically considered SWAGING!
Hot or cold "upsetting" - putting a larger end on a part such as a spoke
head or a bolt head is also considered swaging.
The terminology and most of the technology is as old as the metal working
arts!
Chas.
|
| | | | | | |
Date: 13 May 2007 17:39:21
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
* * Chas wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:1ZWdnYsIvJp63drbnZ2dnUVZ_oupnZ2d@speakeasy.net...
>> * * Chas wrote:
>>> "jim beam" <spamvortex@bad.example.net> wrote in message
>>> news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
>>>> landotter wrote:
>>>>> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> landotter wrote:
>>>>>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>> landotter wrote:
>>>>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
> should
>>> know
>>>>>>>>>> better than that by now. there is 100% correlation between
> those
>>> that
>>>>>>>>>> say they have cracking and those that don't use manufacturer
>>> spoke
>>>>>>>>>> tension, regardless of rim finish.
>>>>>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>>>>>> cracking and anodizing is well documented.
>>>>>>>> no it's not because there is _no_ unanodized ma3 available for
>>>>>>>> comparison! an ma3 may crack, but that cannot simply be
> attributed
>>> to
>>>>>>>> anodizing.
>>>>>>> Yes it most likely can. It was the dark ano ones that had a really
>>>>>>> nasty habit of cracking. The lightly anodized silvery ones didn't
>>> tend
>>>>>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
>>> hear
>>>>>>> about it. Testimony welcome.
>>>>>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims
> built
>>>>>> up. they were on sale at nashbar a while back. i put about 6k on
> a
>>>>>> road pair before relegating them to "backup" position. the other
>>> pair
>>>>>> are on a track bike. no evidence of any cracking in either
>>> application
>>>>>> yet. i used a tensiometer during build.
>>>>> That's certainly testimony, but not evidence. I'd never cracked a
> rim
>>>>> in my life till I cracked a non-drive side nipple on an MA3. No
>>>>> tensionmeter here, but my spoke wrenches are so shitty that if I
> tried
>>>>> to bring a rim up to spectacular tension, I'd round off the nipple.
>>>>>
>>>>> So no high tension here, just a 185# rider. Didn't hit anything,
> just
>>>>> heard it pop on a descent. This assumption that it's a poor build is
> a
>>>>> bit presumptuous if not a wee bit arrogant. It's pretty widely known
>>>>> that hard-ano Mavics are notorious for this. I don't know why you
> feel
>>>>> the need to be contrary.
>>>>>
>>>> why do i keep interjecting reality and not accept the propagation of
>>>> myth you mean? "widely known" on r.b.t. is not "widely known" in the
>>>> real world. after all, "widely known" "facts" on r.b.t. include the
>>>> elimination of metal fatigue in materials with no fatigue endurance
>>>> limit and that all spokes are "swaged".
>>> All spokes are swaged! Spokes are made of wire that has been drawn or
>>> extruded through a metal die. This amounts to swaging.
>>>
>>> http://en.wikipedia.org/wiki/Swagelok
>> that's incorrect! swaging is a hammering process. a process using a
>> die is called drawing - the deformation mechanics, while both involving
>> plastic deformation, are different.
>>
>>> Spoke heads are upset which is another form of swaging.
>>>
>>> http://www.thefreedictionary.com/swage
>>>
>>> Chas.
>> yes, the heads are swaged. but the butting of spokes, the subject in
>> question, is by one of 3 processes - swaging, drawing or grinding. the
>> latter involves no plastic deformation of the wire core, the former two
>> do. to call /all/ butted spokes "swaged" is simply incorrect and a
>> mistake based on insufficient understanding of metal forming techniques.
>
> NO! read the links.... In the English language ALL forms of drawing or
> extruding metal through a die can be technically considered SWAGING!
not when i was a boy. i think you'd notice the difference if your
finger was drawn or hammered.
>
> Hot or cold "upsetting" - putting a larger end on a part such as a spoke
> head or a bolt head is also considered swaging.
upsetting is a subset of swaging, yes. and it's not drawing!
>
> The terminology and most of the technology is as old as the metal working
> arts!
yeah, and mistaken terminology is older than that.
if you don't know any better and are looking for some way to describe
something, maybe. but if there's a distinction, with better terminology
more appropriate and descriptive, why wouldn't you use it?
|
| | | | | | | |
Date: 13 May 2007 17:42:53
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
jim beam wrote:
> * * Chas wrote:
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news:1ZWdnYsIvJp63drbnZ2dnUVZ_oupnZ2d@speakeasy.net...
>>> * * Chas wrote:
>>>> "jim beam" <spamvortex@bad.example.net> wrote in message
>>>> news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
>>>>> landotter wrote:
>>>>>> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>> landotter wrote:
>>>>>>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>>> landotter wrote:
>>>>>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
>> should
>>>> know
>>>>>>>>>>> better than that by now. there is 100% correlation between
>> those
>>>> that
>>>>>>>>>>> say they have cracking and those that don't use manufacturer
>>>> spoke
>>>>>>>>>>> tension, regardless of rim finish.
>>>>>>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>>>>>>> cracking and anodizing is well documented.
>>>>>>>>> no it's not because there is _no_ unanodized ma3 available for
>>>>>>>>> comparison! an ma3 may crack, but that cannot simply be
>> attributed
>>>> to
>>>>>>>>> anodizing.
>>>>>>>> Yes it most likely can. It was the dark ano ones that had a really
>>>>>>>> nasty habit of cracking. The lightly anodized silvery ones didn't
>>>> tend
>>>>>>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
>>>> hear
>>>>>>>> about it. Testimony welcome.
>>>>>>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims
>> built
>>>>>>> up. they were on sale at nashbar a while back. i put about 6k on
>> a
>>>>>>> road pair before relegating them to "backup" position. the other
>>>> pair
>>>>>>> are on a track bike. no evidence of any cracking in either
>>>> application
>>>>>>> yet. i used a tensiometer during build.
>>>>>> That's certainly testimony, but not evidence. I'd never cracked a
>> rim
>>>>>> in my life till I cracked a non-drive side nipple on an MA3. No
>>>>>> tensionmeter here, but my spoke wrenches are so shitty that if I
>> tried
>>>>>> to bring a rim up to spectacular tension, I'd round off the nipple.
>>>>>>
>>>>>> So no high tension here, just a 185# rider. Didn't hit anything,
>> just
>>>>>> heard it pop on a descent. This assumption that it's a poor build is
>> a
>>>>>> bit presumptuous if not a wee bit arrogant. It's pretty widely known
>>>>>> that hard-ano Mavics are notorious for this. I don't know why you
>> feel
>>>>>> the need to be contrary.
>>>>>>
>>>>> why do i keep interjecting reality and not accept the propagation of
>>>>> myth you mean? "widely known" on r.b.t. is not "widely known" in the
>>>>> real world. after all, "widely known" "facts" on r.b.t. include the
>>>>> elimination of metal fatigue in materials with no fatigue endurance
>>>>> limit and that all spokes are "swaged".
>>>> All spokes are swaged! Spokes are made of wire that has been drawn or
>>>> extruded through a metal die. This amounts to swaging.
>>>>
>>>> http://en.wikipedia.org/wiki/Swagelok
>>> that's incorrect! swaging is a hammering process. a process using a
>>> die is called drawing - the deformation mechanics, while both involving
>>> plastic deformation, are different.
>>>
>>>> Spoke heads are upset which is another form of swaging.
>>>>
>>>> http://www.thefreedictionary.com/swage
>>>>
>>>> Chas.
>>> yes, the heads are swaged. but the butting of spokes, the subject in
>>> question, is by one of 3 processes - swaging, drawing or grinding. the
>>> latter involves no plastic deformation of the wire core, the former two
>>> do. to call /all/ butted spokes "swaged" is simply incorrect and a
>>> mistake based on insufficient understanding of metal forming techniques.
>>
>> NO! read the links.... In the English language ALL forms of drawing or
>> extruding metal through a die can be technically considered SWAGING!
>
> not when i was a boy. i think you'd notice the difference if your
> finger was drawn or hammered.
>
>>
>> Hot or cold "upsetting" - putting a larger end on a part such as a spoke
>> head or a bolt head is also considered swaging.
>
> upsetting is a subset of swaging, yes. and it's not drawing!
>
>>
>> The terminology and most of the technology is as old as the metal working
>> arts!
>
> yeah, and mistaken terminology is older than that.
and i should add - i'm not into metal arts - i'm into metal science.
>
> if you don't know any better and are looking for some way to describe
> something, maybe. but if there's a distinction, with better terminology
> more appropriate and descriptive, why wouldn't you use it?
|
| | | | | | |
Date: 13 May 2007 17:33:15
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
* * Chas wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:1ZWdnYsIvJp63drbnZ2dnUVZ_oupnZ2d@speakeasy.net...
>> * * Chas wrote:
>>> "jim beam" <spamvortex@bad.example.net> wrote in message
>>> news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
>>>> landotter wrote:
>>>>> On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> landotter wrote:
>>>>>>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>> landotter wrote:
>>>>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
> should
>>> know
>>>>>>>>>> better than that by now. there is 100% correlation between
> those
>>> that
>>>>>>>>>> say they have cracking and those that don't use manufacturer
>>> spoke
>>>>>>>>>> tension, regardless of rim finish.
>>>>>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>>>>>> cracking and anodizing is well documented.
>>>>>>>> no it's not because there is _no_ unanodized ma3 available for
>>>>>>>> comparison! an ma3 may crack, but that cannot simply be
> attributed
>>> to
>>>>>>>> anodizing.
>>>>>>> Yes it most likely can. It was the dark ano ones that had a really
>>>>>>> nasty habit of cracking. The lightly anodized silvery ones didn't
>>> tend
>>>>>>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
>>> hear
>>>>>>> about it. Testimony welcome.
>>>>>> i've got testimony - i've got 2 pairs of ma3 hard anodized rims
> built
>>>>>> up. they were on sale at nashbar a while back. i put about 6k on
> a
>>>>>> road pair before relegating them to "backup" position. the other
>>> pair
>>>>>> are on a track bike. no evidence of any cracking in either
>>> application
>>>>>> yet. i used a tensiometer during build.
>>>>> That's certainly testimony, but not evidence. I'd never cracked a
> rim
>>>>> in my life till I cracked a non-drive side nipple on an MA3. No
>>>>> tensionmeter here, but my spoke wrenches are so shitty that if I
> tried
>>>>> to bring a rim up to spectacular tension, I'd round off the nipple.
>>>>>
>>>>> So no high tension here, just a 185# rider. Didn't hit anything,
> just
>>>>> heard it pop on a descent. This assumption that it's a poor build is
> a
>>>>> bit presumptuous if not a wee bit arrogant. It's pretty widely known
>>>>> that hard-ano Mavics are notorious for this. I don't know why you
> feel
>>>>> the need to be contrary.
>>>>>
>>>> why do i keep interjecting reality and not accept the propagation of
>>>> myth you mean? "widely known" on r.b.t. is not "widely known" in the
>>>> real world. after all, "widely known" "facts" on r.b.t. include the
>>>> elimination of metal fatigue in materials with no fatigue endurance
>>>> limit and that all spokes are "swaged".
>>> All spokes are swaged! Spokes are made of wire that has been drawn or
>>> extruded through a metal die. This amounts to swaging.
>>>
>>> http://en.wikipedia.org/wiki/Swagelok
>> that's incorrect! swaging is a hammering process. a process using a
>> die is called drawing - the deformation mechanics, while both involving
>> plastic deformation, are different.
>>
>>> Spoke heads are upset which is another form of swaging.
>>>
>>> http://www.thefreedictionary.com/swage
>>>
>>> Chas.
>> yes, the heads are swaged. but the butting of spokes, the subject in
>> question, is by one of 3 processes - swaging, drawing or grinding. the
>> latter involves no plastic deformation of the wire core, the former two
>> do. to call /all/ butted spokes "swaged" is simply incorrect and a
>> mistake based on insufficient understanding of metal forming techniques.
>
> NO! read the links.... In the English language ALL forms of drawing or
> extruding metal through a die can be technically considered SWAGING!
>
> Hot or cold "upsetting" - putting a larger end on a part such as a spoke
> head or a bolt head is also considered swaging.
>
> The terminology and most of the technology is as old as the metal working
> arts!
>
> Chas.
>
>
|
| | | | |
Date: 13 May 2007 00:31:39
From:
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sat, 12 May 2007 23:05:30 -0700, "* * Chas"
<verktygjunk@aol.spamski.com > wrote:
>
>"jim beam" <spamvortex@bad.example.net> wrote in message
>news:UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net...
>> landotter wrote:
>> > On May 12, 5:42 pm, jim beam <spamvor...@bad.example.net> wrote:
>> >> landotter wrote:
>> >>> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>> >>>> landotter wrote:
>> >>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>> >>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should
>know
>> >>>>>> better than that by now. there is 100% correlation between those
>that
>> >>>>>> say they have cracking and those that don't use manufacturer
>spoke
>> >>>>>> tension, regardless of rim finish.
>> >>>>> Erm, with the previous generation's MA3, the correlation between
>> >>>>> cracking and anodizing is well documented.
>> >>>> no it's not because there is _no_ unanodized ma3 available for
>> >>>> comparison! an ma3 may crack, but that cannot simply be attributed
>to
>> >>>> anodizing.
>> >>> Yes it most likely can. It was the dark ano ones that had a really
>> >>> nasty habit of cracking. The lightly anodized silvery ones didn't
>tend
>> >>> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't
>hear
>> >>> about it. Testimony welcome.
>> >> i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
>> >> up. they were on sale at nashbar a while back. i put about 6k on a
>> >> road pair before relegating them to "backup" position. the other
>pair
>> >> are on a track bike. no evidence of any cracking in either
>application
>> >> yet. i used a tensiometer during build.
>> >
>> > That's certainly testimony, but not evidence. I'd never cracked a rim
>> > in my life till I cracked a non-drive side nipple on an MA3. No
>> > tensionmeter here, but my spoke wrenches are so shitty that if I tried
>> > to bring a rim up to spectacular tension, I'd round off the nipple.
>> >
>> > So no high tension here, just a 185# rider. Didn't hit anything, just
>> > heard it pop on a descent. This assumption that it's a poor build is a
>> > bit presumptuous if not a wee bit arrogant. It's pretty widely known
>> > that hard-ano Mavics are notorious for this. I don't know why you feel
>> > the need to be contrary.
>> >
>> why do i keep interjecting reality and not accept the propagation of
>> myth you mean? "widely known" on r.b.t. is not "widely known" in the
>> real world. after all, "widely known" "facts" on r.b.t. include the
>> elimination of metal fatigue in materials with no fatigue endurance
>> limit and that all spokes are "swaged".
>
>All spokes are swaged! Spokes are made of wire that has been drawn or
>extruded through a metal die. This amounts to swaging.
>
>http://en.wikipedia.org/wiki/Swagelok
>
>Spoke heads are upset which is another form of swaging.
>
>http://www.thefreedictionary.com/swage
>
>Chas.
Dear Chas,
Must . . . fight . . . urge . . . to . . . pun . . .
Aaargh!
There seems to be a SWAG somewhere in this thread.
Cheers,
Carl Fogel
|
| | | |
Date: 13 May 2007 00:30:39
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <UMSdneWqQ5bf_tvbnZ2dnUVZ_jmdnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> why do i keep interjecting reality and not accept the propagation of
> myth you mean? "widely known" on r.b.t. is not "widely known" in the
> real world.
Umm, except the published measurements by metallurgists on the effect
anodizing has on reducing the fatigue life of aluminum structures. Mr.
Phinney gave you one quoted citation. I gave you a number of them a
couple of years ago. But that part of the real world doesn't count as
far as you're concerned.
|
| |
Date: 12 May 2007 15:26:47
From: landotter
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net > wrote:
> landotter wrote:
> > On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>
> >> yeah, and it's all unsubstantiated jobstian bullshit. you should know
> >> better than that by now. there is 100% correlation between those that
> >> say they have cracking and those that don't use manufacturer spoke
> >> tension, regardless of rim finish.
>
> > Erm, with the previous generation's MA3, the correlation between
> > cracking and anodizing is well documented.
>
> no it's not because there is _no_ unanodized ma3 available for
> comparison! an ma3 may crack, but that cannot simply be attributed to
> anodizing.
Yes it most likely can. It was the dark ano ones that had a really
nasty habit of cracking. The lightly anodized silvery ones didn't tend
to crack AFAIK. Maybe a bunch of light ano ones did and I didn't hear
about it. Testimony welcome.
|
| | |
Date: 12 May 2007 15:42:47
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
landotter wrote:
> On May 12, 5:01 pm, jim beam <spamvor...@bad.example.net> wrote:
>> landotter wrote:
>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
>>>> better than that by now. there is 100% correlation between those that
>>>> say they have cracking and those that don't use manufacturer spoke
>>>> tension, regardless of rim finish.
>>> Erm, with the previous generation's MA3, the correlation between
>>> cracking and anodizing is well documented.
>> no it's not because there is _no_ unanodized ma3 available for
>> comparison! an ma3 may crack, but that cannot simply be attributed to
>> anodizing.
>
> Yes it most likely can. It was the dark ano ones that had a really
> nasty habit of cracking. The lightly anodized silvery ones didn't tend
> to crack AFAIK. Maybe a bunch of light ano ones did and I didn't hear
> about it. Testimony welcome.
>
i've got testimony - i've got 2 pairs of ma3 hard anodized rims built
up. they were on sale at nashbar a while back. i put about 6k on a
road pair before relegating them to "backup" position. the other pair
are on a track bike. no evidence of any cracking in either application
yet. i used a tensiometer during build.
|
| |
Date: 12 May 2007 14:20:46
From: landotter
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net > wrote:
> yeah, and it's all unsubstantiated jobstian bullshit. you should know
> better than that by now. there is 100% correlation between those that
> say they have cracking and those that don't use manufacturer spoke
> tension, regardless of rim finish.
Erm, with the previous generation's MA3, the correlation between
cracking and anodizing is well documented. That's not an Open Pro of
course. Got one hanging in the garage that I should get around to
throwing away...
Velocity and Alex rims are the way to go. Cheaper and stronger.
Unless you're rerimming and need the same ERD of course.
|
| | |
Date: 12 May 2007 15:01:21
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
landotter wrote:
> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>
>> yeah, and it's all unsubstantiated jobstian bullshit. you should know
>> better than that by now. there is 100% correlation between those that
>> say they have cracking and those that don't use manufacturer spoke
>> tension, regardless of rim finish.
>
> Erm, with the previous generation's MA3, the correlation between
> cracking and anodizing is well documented.
no it's not because there is _no_ unanodized ma3 available for
comparison! an ma3 may crack, but that cannot simply be attributed to
anodizing.
if "mr. condemn a whole industry with underinformed supposition" had
bothered to do /any/ homework on this subject at all, he'd have looked
into anisotropy and extrusion flaws.
> That's not an Open Pro of
> course. Got one hanging in the garage that I should get around to
> throwing away...
>
> Velocity and Alex rims are the way to go. Cheaper and stronger.
> Unless you're rerimming and need the same ERD of course.
>
>
>
|
| | | |
Date: 13 May 2007 00:26:51
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> landotter wrote:
> > On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
> >
> >> yeah, and it's all unsubstantiated jobstian bullshit. you should
> >> know better than that by now. there is 100% correlation between
> >> those that say they have cracking and those that don't use
> >> manufacturer spoke tension, regardless of rim finish.
> >
> > Erm, with the previous generation's MA3, the correlation between
> > cracking and anodizing is well documented.
>
> no it's not because there is _no_ unanodized ma3 available for
> comparison! an ma3 may crack, but that cannot simply be attributed
> to anodizing.
Correct. It was the MA-2 and the MA-40, the latter being an anodized
version of the former and much more prone to cracking. And contrary to
your assertion, unless you can show that the laws of physics are
different for MA-3 rims that other rims and other anodized aluminum
structures, the attribution can reasonably be made.
> if "mr. condemn a whole industry with underinformed supposition" had
> bothered to do /any/ homework on this subject at all, he'd have
> looked into anisotropy and extrusion flaws.
The MA-2 and the MA-40 used the same construction, the same alloy and
the same extrusion. The MA-40 was prone to cracking, the MA-2 was not.
And while you're at it, jim, perhaps you should do *your* homework since
metallurgists have published measurements showing that anodizing reduces
the fatigue life of aluminum alloys by 30-50%. Hell, I pointed that
stuff out to you a couple of years ago, it's readily available on the
Internets via the Google. Funny that your colleagues appear to be in
agreement with Mr. Brandt.
Not that you'll believe a word of it, though. Metallurgists are
obviously in on the conspiracy between Jobst and the rest of the
engineering world.
|
| | | | |
Date: 13 May 2007 09:48:24
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Tim McNamara wrote:
> In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> landotter wrote:
>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>
>>>> yeah, and it's all unsubstantiated jobstian bullshit. you should
>>>> know better than that by now. there is 100% correlation between
>>>> those that say they have cracking and those that don't use
>>>> manufacturer spoke tension, regardless of rim finish.
>>> Erm, with the previous generation's MA3, the correlation between
>>> cracking and anodizing is well documented.
>> no it's not because there is _no_ unanodized ma3 available for
>> comparison! an ma3 may crack, but that cannot simply be attributed
>> to anodizing.
>
> Correct. It was the MA-2 and the MA-40, the latter being an anodized
> version of the former and much more prone to cracking. And contrary to
> your assertion, unless you can show that the laws of physics are
> different for MA-3 rims that other rims and other anodized aluminum
> structures, the attribution can reasonably be made.
>
>> if "mr. condemn a whole industry with underinformed supposition" had
>> bothered to do /any/ homework on this subject at all, he'd have
>> looked into anisotropy and extrusion flaws.
>
> The MA-2 and the MA-40 used the same construction, the same alloy and
> the same extrusion. The MA-40 was prone to cracking, the MA-2 was not.
>
> And while you're at it, jim, perhaps you should do *your* homework since
> metallurgists have published measurements showing that anodizing reduces
> the fatigue life of aluminum alloys by 30-50%. Hell, I pointed that
> stuff out to you a couple of years ago, it's readily available on the
> Internets via the Google. Funny that your colleagues appear to be in
> agreement with Mr. Brandt.
>
> Not that you'll believe a word of it, though. Metallurgists are
> obviously in on the conspiracy between Jobst and the rest of the
> engineering world.
timmy boy is back from vacation, and seemingly still as impervious to
learning as he ever was! stupidity has no shelf life i guess.
|
| | | | | |
Date: 13 May 2007 12:47:22
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <1ZWdnYoIvJrF3NrbnZ2dnUVZ_ovinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> landotter wrote:
> >>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
> >>>
> >>>> yeah, and it's all unsubstantiated jobstian bullshit. you
> >>>> should know better than that by now. there is 100% correlation
> >>>> between those that say they have cracking and those that don't
> >>>> use manufacturer spoke tension, regardless of rim finish.
> >>> Erm, with the previous generation's MA3, the correlation between
> >>> cracking and anodizing is well documented.
> >> no it's not because there is _no_ unanodized ma3 available for
> >> comparison! an ma3 may crack, but that cannot simply be
> >> attributed to anodizing.
> >
> > Correct. It was the MA-2 and the MA-40, the latter being an
> > anodized version of the former and much more prone to cracking.
> > And contrary to your assertion, unless you can show that the laws
> > of physics are different for MA-3 rims that other rims and other
> > anodized aluminum structures, the attribution can reasonably be
> > made.
> >
> >> if "mr. condemn a whole industry with underinformed supposition"
> >> had bothered to do /any/ homework on this subject at all, he'd
> >> have looked into anisotropy and extrusion flaws.
> >
> > The MA-2 and the MA-40 used the same construction, the same alloy
> > and the same extrusion. The MA-40 was prone to cracking, the MA-2
> > was not.
> >
> > And while you're at it, jim, perhaps you should do *your* homework
> > since metallurgists have published measurements showing that
> > anodizing reduces the fatigue life of aluminum alloys by 30-50%.
> > Hell, I pointed that stuff out to you a couple of years ago, it's
> > readily available on the Internets via the Google. Funny that your
> > colleagues appear to be in agreement with Mr. Brandt.
> >
> > Not that you'll believe a word of it, though. Metallurgists are
> > obviously in on the conspiracy between Jobst and the rest of the
> > engineering world.
>
> timmy boy is back from vacation, and seemingly still as impervious to
> learning as he ever was! stupidity has no shelf life i guess.
It's always interesting that when others contradict you with facts that
disprove your waffle, you just resort to personal attacks. That nobody
buys it seems to escape your attention. In this case, the facts are
that metallurgists say you're wrong. Not Jobst, not Krygowski, not me-
the people who make their living in the field you claim to be trained in
are the ones who contradict your claims. Why is that?
And "back from vacation?" What vacation was this? I haven't gone
anywhere and have been posting every day.
|
| | | | | | |
Date: 13 May 2007 10:54:57
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Tim McNamara wrote:
> In article <1ZWdnYoIvJrF3NrbnZ2dnUVZ_ovinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> landotter wrote:
>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net> wrote:
>>>>>
>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
>>>>>> should know better than that by now. there is 100% correlation
>>>>>> between those that say they have cracking and those that don't
>>>>>> use manufacturer spoke tension, regardless of rim finish.
>>>>> Erm, with the previous generation's MA3, the correlation between
>>>>> cracking and anodizing is well documented.
>>>> no it's not because there is _no_ unanodized ma3 available for
>>>> comparison! an ma3 may crack, but that cannot simply be
>>>> attributed to anodizing.
>>> Correct. It was the MA-2 and the MA-40, the latter being an
>>> anodized version of the former and much more prone to cracking.
>>> And contrary to your assertion, unless you can show that the laws
>>> of physics are different for MA-3 rims that other rims and other
>>> anodized aluminum structures, the attribution can reasonably be
>>> made.
>>>
>>>> if "mr. condemn a whole industry with underinformed supposition"
>>>> had bothered to do /any/ homework on this subject at all, he'd
>>>> have looked into anisotropy and extrusion flaws.
>>> The MA-2 and the MA-40 used the same construction, the same alloy
>>> and the same extrusion. The MA-40 was prone to cracking, the MA-2
>>> was not.
>>>
>>> And while you're at it, jim, perhaps you should do *your* homework
>>> since metallurgists have published measurements showing that
>>> anodizing reduces the fatigue life of aluminum alloys by 30-50%.
>>> Hell, I pointed that stuff out to you a couple of years ago, it's
>>> readily available on the Internets via the Google. Funny that your
>>> colleagues appear to be in agreement with Mr. Brandt.
>>>
>>> Not that you'll believe a word of it, though. Metallurgists are
>>> obviously in on the conspiracy between Jobst and the rest of the
>>> engineering world.
>> timmy boy is back from vacation, and seemingly still as impervious to
>> learning as he ever was! stupidity has no shelf life i guess.
>
> It's always interesting that when others contradict you with facts that
> disprove your waffle, you just resort to personal attacks. That nobody
> buys it seems to escape your attention. In this case, the facts are
> that metallurgists say you're wrong. Not Jobst, not Krygowski, not me-
> the people who make their living in the field you claim to be trained in
> are the ones who contradict your claims. Why is that?
you're retard timmy boy. you're not reading and even if you did, you've
demonstrated no capacity to comprehend. today is yet another example.
>
> And "back from vacation?" What vacation was this? I haven't gone
> anywhere and have been posting every day.
as have i, but you've been notably absent from any of my postings.
evidently you're feeling bored and want to get back into it. short
retention span for retards i guess.
|
| | | | | | | |
Date: 13 May 2007 13:25:29
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <TIqdndDY88lvzdrbnZ2dnUVZ_tmknZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <1ZWdnYoIvJrF3NrbnZ2dnUVZ_ovinZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> landotter wrote:
> >>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net>
> >>>>> wrote:
> >>>>>
> >>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
> >>>>>> should know better than that by now. there is 100%
> >>>>>> correlation between those that say they have cracking and
> >>>>>> those that don't use manufacturer spoke tension, regardless of
> >>>>>> rim finish.
> >>>>> Erm, with the previous generation's MA3, the correlation
> >>>>> between cracking and anodizing is well documented.
> >>>> no it's not because there is _no_ unanodized ma3 available for
> >>>> comparison! an ma3 may crack, but that cannot simply be
> >>>> attributed to anodizing.
> >>> Correct. It was the MA-2 and the MA-40, the latter being an
> >>> anodized version of the former and much more prone to cracking.
> >>> And contrary to your assertion, unless you can show that the laws
> >>> of physics are different for MA-3 rims that other rims and other
> >>> anodized aluminum structures, the attribution can reasonably be
> >>> made.
> >>>
> >>>> if "mr. condemn a whole industry with underinformed supposition"
> >>>> had bothered to do /any/ homework on this subject at all, he'd
> >>>> have looked into anisotropy and extrusion flaws.
> >>> The MA-2 and the MA-40 used the same construction, the same alloy
> >>> and the same extrusion. The MA-40 was prone to cracking, the
> >>> MA-2 was not.
> >>>
> >>> And while you're at it, jim, perhaps you should do *your*
> >>> homework since metallurgists have published measurements showing
> >>> that anodizing reduces the fatigue life of aluminum alloys by
> >>> 30-50%. Hell, I pointed that stuff out to you a couple of years
> >>> ago, it's readily available on the Internets via the Google.
> >>> Funny that your colleagues appear to be in agreement with Mr.
> >>> Brandt.
> >>>
> >>> Not that you'll believe a word of it, though. Metallurgists are
> >>> obviously in on the conspiracy between Jobst and the rest of the
> >>> engineering world.
> >> timmy boy is back from vacation, and seemingly still as impervious
> >> to learning as he ever was! stupidity has no shelf life i guess.
> >
> > It's always interesting that when others contradict you with facts
> > that disprove your waffle, you just resort to personal attacks.
> > That nobody buys it seems to escape your attention. In this case,
> > the facts are that metallurgists say you're wrong. Not Jobst, not
> > Krygowski, not me- the people who make their living in the field
> > you claim to be trained in are the ones who contradict your claims.
> > Why is that?
>
> you're retard timmy boy. you're not reading and even if you did,
> you've demonstrated no capacity to comprehend. today is yet another
> example.
LOL! There you go again.
> > And "back from vacation?" What vacation was this? I haven't gone
> > anywhere and have been posting every day.
>
> as have i, but you've been notably absent from any of my postings.
You haven't been paying attention, then, as I have responded to several
posts of yours in the past week.
> evidently you're feeling bored and want to get back into it. short
> retention span for retards i guess.
Ah, well, at least I can write with correct capitalization and
punctuation, as well as writing out complete and coherent thoughts. I
can even write full sentences without puerile name calling. Your
writing, on the other hand, wouldn't pass a standardized 8th grade
English test. Generally the quality of verbal expression is directly
correlated to intelligence. You can possibly draw your own conclusions;
the rest of us have.
|
| | | | | | | | |
Date: 13 May 2007 15:41:29
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Tim McNamara wrote:
> In article <TIqdndDY88lvzdrbnZ2dnUVZ_tmknZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <1ZWdnYoIvJrF3NrbnZ2dnUVZ_ovinZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> landotter wrote:
>>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
>>>>>>>> should know better than that by now. there is 100%
>>>>>>>> correlation between those that say they have cracking and
>>>>>>>> those that don't use manufacturer spoke tension, regardless of
>>>>>>>> rim finish.
>>>>>>> Erm, with the previous generation's MA3, the correlation
>>>>>>> between cracking and anodizing is well documented.
>>>>>> no it's not because there is _no_ unanodized ma3 available for
>>>>>> comparison! an ma3 may crack, but that cannot simply be
>>>>>> attributed to anodizing.
>>>>> Correct. It was the MA-2 and the MA-40, the latter being an
>>>>> anodized version of the former and much more prone to cracking.
>>>>> And contrary to your assertion, unless you can show that the laws
>>>>> of physics are different for MA-3 rims that other rims and other
>>>>> anodized aluminum structures, the attribution can reasonably be
>>>>> made.
>>>>>
>>>>>> if "mr. condemn a whole industry with underinformed supposition"
>>>>>> had bothered to do /any/ homework on this subject at all, he'd
>>>>>> have looked into anisotropy and extrusion flaws.
>>>>> The MA-2 and the MA-40 used the same construction, the same alloy
>>>>> and the same extrusion. The MA-40 was prone to cracking, the
>>>>> MA-2 was not.
>>>>>
>>>>> And while you're at it, jim, perhaps you should do *your*
>>>>> homework since metallurgists have published measurements showing
>>>>> that anodizing reduces the fatigue life of aluminum alloys by
>>>>> 30-50%. Hell, I pointed that stuff out to you a couple of years
>>>>> ago, it's readily available on the Internets via the Google.
>>>>> Funny that your colleagues appear to be in agreement with Mr.
>>>>> Brandt.
>>>>>
>>>>> Not that you'll believe a word of it, though. Metallurgists are
>>>>> obviously in on the conspiracy between Jobst and the rest of the
>>>>> engineering world.
>>>> timmy boy is back from vacation, and seemingly still as impervious
>>>> to learning as he ever was! stupidity has no shelf life i guess.
>>> It's always interesting that when others contradict you with facts
>>> that disprove your waffle, you just resort to personal attacks.
>>> That nobody buys it seems to escape your attention. In this case,
>>> the facts are that metallurgists say you're wrong. Not Jobst, not
>>> Krygowski, not me- the people who make their living in the field
>>> you claim to be trained in are the ones who contradict your claims.
>>> Why is that?
>> you're retard timmy boy. you're not reading and even if you did,
>> you've demonstrated no capacity to comprehend. today is yet another
>> example.
>
> LOL! There you go again.
>
>>> And "back from vacation?" What vacation was this? I haven't gone
>>> anywhere and have been posting every day.
>> as have i, but you've been notably absent from any of my postings.
>
> You haven't been paying attention, then, as I have responded to several
> posts of yours in the past week.
you weren't paying attention - you asked /me/ questions that others had
answered. retard.
>
>> evidently you're feeling bored and want to get back into it. short
>> retention span for retards i guess.
>
> Ah, well, at least I can write with correct capitalization and
> punctuation,
gosh! call the cops!
> as well as writing out complete and coherent thoughts. I
> can even write full sentences without puerile name calling. Your
> writing, on the other hand, wouldn't pass a standardized 8th grade
> English test. Generally the quality of verbal expression is directly
> correlated to intelligence. You can possibly draw your own conclusions;
> the rest of us have.
fuck off. retard.
|
| | | | | | | | | |
Date: 13 May 2007 22:32:26
From: Tim McNamara
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <iKadnVLUFamECdrbnZ2dnUVZ_qHinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <TIqdndDY88lvzdrbnZ2dnUVZ_tmknZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <1ZWdnYoIvJrF3NrbnZ2dnUVZ_ovinZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <eMednXfmfcWupNvbnZ2dnUVZ_rCsnZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> landotter wrote:
> >>>>>>> On May 12, 1:24 pm, jim beam <spamvor...@bad.example.net>
> >>>>>>> wrote:
> >>>>>>>
> >>>>>>>> yeah, and it's all unsubstantiated jobstian bullshit. you
> >>>>>>>> should know better than that by now. there is 100%
> >>>>>>>> correlation between those that say they have cracking and
> >>>>>>>> those that don't use manufacturer spoke tension, regardless
> >>>>>>>> of rim finish.
> >>>>>>> Erm, with the previous generation's MA3, the correlation
> >>>>>>> between cracking and anodizing is well documented.
> >>>>>> no it's not because there is _no_ unanodized ma3 available for
> >>>>>> comparison! an ma3 may crack, but that cannot simply be
> >>>>>> attributed to anodizing.
> >>>>> Correct. It was the MA-2 and the MA-40, the latter being an
> >>>>> anodized version of the former and much more prone to cracking.
> >>>>> And contrary to your assertion, unless you can show that the
> >>>>> laws of physics are different for MA-3 rims that other rims and
> >>>>> other anodized aluminum structures, the attribution can
> >>>>> reasonably be made.
> >>>>>
> >>>>>> if "mr. condemn a whole industry with underinformed
> >>>>>> supposition" had bothered to do /any/ homework on this subject
> >>>>>> at all, he'd have looked into anisotropy and extrusion flaws.
> >>>>> The MA-2 and the MA-40 used the same construction, the same
> >>>>> alloy and the same extrusion. The MA-40 was prone to cracking,
> >>>>> the MA-2 was not.
> >>>>>
> >>>>> And while you're at it, jim, perhaps you should do *your*
> >>>>> homework since metallurgists have published measurements
> >>>>> showing that anodizing reduces the fatigue life of aluminum
> >>>>> alloys by 30-50%. Hell, I pointed that stuff out to you a
> >>>>> couple of years ago, it's readily available on the Internets
> >>>>> via the Google. Funny that your colleagues appear to be in
> >>>>> agreement with Mr. Brandt.
> >>>>>
> >>>>> Not that you'll believe a word of it, though. Metallurgists
> >>>>> are obviously in on the conspiracy between Jobst and the rest
> >>>>> of the engineering world.
> >>>> timmy boy is back from vacation, and seemingly still as
> >>>> impervious to learning as he ever was! stupidity has no shelf
> >>>> life i guess.
> >>> It's always interesting that when others contradict you with
> >>> facts that disprove your waffle, you just resort to personal
> >>> attacks. That nobody buys it seems to escape your attention. In
> >>> this case, the facts are that metallurgists say you're wrong.
> >>> Not Jobst, not Krygowski, not me- the people who make their
> >>> living in the field you claim to be trained in are the ones who
> >>> contradict your claims.
> >>> Why is that?
> >> you're retard timmy boy. you're not reading and even if you did,
> >> you've demonstrated no capacity to comprehend. today is yet
> >> another example.
> >
> > LOL! There you go again.
> >
> >>> And "back from vacation?" What vacation was this? I haven't
> >>> gone anywhere and have been posting every day.
> >> as have i, but you've been notably absent from any of my postings.
> >
> > You haven't been paying attention, then, as I have responded to
> > several posts of yours in the past week.
>
> you weren't paying attention - you asked /me/ questions that others
> had answered. retard.
>
> >
> >> evidently you're feeling bored and want to get back into it.
> >> short retention span for retards i guess.
> >
> > Ah, well, at least I can write with correct capitalization and
> > punctuation,
>
> gosh! call the cops!
>
> > as well as writing out complete and coherent thoughts. I can even
> > write full sentences without puerile name calling. Your writing,
> > on the other hand, wouldn't pass a standardized 8th grade English
> > test. Generally the quality of verbal expression is directly
> > correlated to intelligence. You can possibly draw your own
> > conclusions; the rest of us have.
>
> fuck off. retard.
You kiss your mama with that mouth?
|
| | | | | | | | | |
Date: 13 May 2007 23:46:41
From: _
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On Sun, 13 May 2007 15:41:29 -0700, jim beam wrote:
>> as well as writing out complete and coherent thoughts. I
>> can even write full sentences without puerile name calling. Your
>> writing, on the other hand, wouldn't pass a standardized 8th grade
>> English test. Generally the quality of verbal expression is directly
>> correlated to intelligence. You can possibly draw your own conclusions;
>> the rest of us have.
>
> fuck off. retard.
You are Bill Sornson and I claim my five pounds.
|
| |
Date: 12 May 2007 08:46:58
From: Qui si parla Campagnolo
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
On May 12, 6:35 am, jim beam <spamvor...@bad.example.net > wrote:
> Qui si parla Campagnolo wrote:
>
>
>
> > On May 11, 11:36 pm, RS <r_schil...@comcast.net> wrote:
> >> In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
> >> spamvor...@bad.example.net says...
>
> >>> RS wrote:
> >>>> What is the difference, except for price, in the 3 versions of the
> >>>> venerable Mavic Open Pro rim? And are the higher priced version
> >>>> money well spent? note: I rarely ride in the rain.
> >>> what's your objective if you don't ride in the rain? ceramic rims are
> >>> impervious to the rain-road grit. cd rims are similar, but not as hard
> >>> or long lasting. ordinary open pros are not very resistant to grit at all.
> >> I was asking as to any other differences in construction, finish, longevity
> >> and intended use. Its why I'm asking, I don't know.
>
> > They all start as a basic OpenPro rim, then dipped for hard
> > anodizing(tend to crack around eyelets,
>
> all open pros are anodized - even the silver. if you mean the cd's
> crack, i've never seen it on mine - and i have good mileage on them.
> they're built to manufacturer spec spoke tension. the only people here
> who report eyelet problems with eyelet cracking do not have it exclusive
> to cd's and do not build with tensiometers.
Google MA-40, CD, vs MA-40 silver. 'Anodizing' for color is not the
same thing as 'hard anodizing'. 2 completely different
processes.Having eyelets installed after hard anodizing, causing small
cracks that often lead to eyelets pulling out is common knowledge
among wheelbuilders..Jobst??
>
> > since the eyelets are
> > installed after the 'dipping', or have a ceramic strip glued
>
> glued??? plasma arc spray!!! high tech. expensive.
whatever-glued, plasma arc sprayed...not welded.
>
> > onto the
> > side wall..but construction of all the same. use the basic silver or
> > black..not the CD, IMO.
>
> basic, sure. no point spending more if not riding in the rain.
|
| | |
Date: 12 May 2007 11:24:47
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Qui si parla Campagnolo wrote:
> On May 12, 6:35 am, jim beam <spamvor...@bad.example.net> wrote:
>> Qui si parla Campagnolo wrote:
>>
>>
>>
>>> On May 11, 11:36 pm, RS <r_schil...@comcast.net> wrote:
>>>> In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
>>>> spamvor...@bad.example.net says...
>>>>> RS wrote:
>>>>>> What is the difference, except for price, in the 3 versions of the
>>>>>> venerable Mavic Open Pro rim? And are the higher priced version
>>>>>> money well spent? note: I rarely ride in the rain.
>>>>> what's your objective if you don't ride in the rain? ceramic rims are
>>>>> impervious to the rain-road grit. cd rims are similar, but not as hard
>>>>> or long lasting. ordinary open pros are not very resistant to grit at all.
>>>> I was asking as to any other differences in construction, finish, longevity
>>>> and intended use. Its why I'm asking, I don't know.
>>> They all start as a basic OpenPro rim, then dipped for hard
>>> anodizing(tend to crack around eyelets,
>> all open pros are anodized - even the silver. if you mean the cd's
>> crack, i've never seen it on mine - and i have good mileage on them.
>> they're built to manufacturer spec spoke tension. the only people here
>> who report eyelet problems with eyelet cracking do not have it exclusive
>> to cd's and do not build with tensiometers.
>
> Google MA-40, CD, vs MA-40 silver.
yeah, and it's all unsubstantiated jobstian bullshit. you should know
better than that by now. there is 100% correlation between those that
say they have cracking and those that don't use manufacturer spoke
tension, regardless of rim finish.
> 'Anodizing' for color is not the
> same thing as 'hard anodizing'. 2 completely different
> processes.Having eyelets installed after hard anodizing, causing small
> cracks that often lead to eyelets pulling out is common knowledge
> among wheelbuilders..Jobst??
yeah. jobst is the problem on this one. jobst thinks anodizing causes
cracking because he did a dye penetrant test. there is no way a dye
penetrant test determines whether anodizing has anything to do with it -
all it does is identify presence, not cause. rim cracking is cause by
spoke tension "as high as the rim can bear" - pure and simple.
>>> since the eyelets are
>>> installed after the 'dipping', or have a ceramic strip glued
>> glued??? plasma arc spray!!! high tech. expensive.
> whatever-glued, plasma arc sprayed...not welded.
whatever??? dude, there's a /world/ of freakin' difference between
plasma arc deposition and glue!!! that's like saying "whatever" to the
difference in properties between rubber and glass!!!
>>> onto the
>>> side wall..but construction of all the same. use the basic silver or
>>> black..not the CD, IMO.
>> basic, sure. no point spending more if not riding in the rain.
>
>
|
| | | |
Date: 12 May 2007 19:22:45
From: Harry Phinney
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"jim beam" wrote
> yeah. jobst is the problem on this one. jobst thinks anodizing causes
> cracking because he did a dye penetrant test. there is no way a dye
> penetrant test determines whether anodizing has anything to do with it -
> all it does is identify presence, not cause. rim cracking is cause by
> spoke tension "as high as the rim can bear" - pure and simple.
It is a mistake to claim that hard anodizing has no impact on the fatigue
resistance of aluminum products. The following are quotes from "The
Properties of Electordeposited Metals and Alloys a Handbook" Second Edition,
edited by William H. Safranek published by the AESFS, 1986 ISBN
0-936569-00-X, all from chapter 3 - "Anodic Coatings on Aluminum":
" Typical thickness requirements for decorative applications not subject to
aggressive environment are about 7-10 micrometers. For exterior
architectural components, a thickness in the range of 18-25 micrometers is
usually specified. Anodic coatings designed for wear resistance may be
produced in greater thickness, up to over 100 micrometers." (page 29)
"In general, anodic coatings more than a few micons thick cause a
significant loss of fatigue strength in aluminum alloys. Most data on this
property have been for strong alloys of the 2000, 5000, and 7000 classes.
Unsealed sulfuric acid and chromic acid coatings less than about 5
micrometers thick had little or no effect on fatigue strength at 100 million
cycles." ... "Far greater losses were induced by sealing the coatings in
water; sealed sulfuric acid coatings 25 micrometers thick induced fatigue
strength losses approaching 35 percent at 100 million cycles. The effects
of thick, hard anodic coatings on fatigue are even greater. Coatings 25
micrometers up to 125 micrometers of one proprietary hard anodic coating
process reduced stress to failure at 10 million cycles by more than 50
percent." (page 32)
Harry Phinney
|
| | | | |
Date: 13 May 2007 09:39:55
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
Harry Phinney wrote:
> "jim beam" wrote
>> yeah. jobst is the problem on this one. jobst thinks anodizing causes
>> cracking because he did a dye penetrant test. there is no way a dye
>> penetrant test determines whether anodizing has anything to do with it -
>> all it does is identify presence, not cause. rim cracking is cause by
>> spoke tension "as high as the rim can bear" - pure and simple.
>
> It is a mistake to claim that hard anodizing has no impact on the fatigue
> resistance of aluminum products. The following are quotes from "The
> Properties of Electordeposited Metals and Alloys a Handbook" Second Edition,
> edited by William H. Safranek published by the AESFS, 1986 ISBN
> 0-936569-00-X, all from chapter 3 - "Anodic Coatings on Aluminum":
>
> " Typical thickness requirements for decorative applications not subject to
> aggressive environment are about 7-10 micrometers. For exterior
> architectural components, a thickness in the range of 18-25 micrometers is
> usually specified. Anodic coatings designed for wear resistance may be
> produced in greater thickness, up to over 100 micrometers." (page 29)
>
> "In general, anodic coatings more than a few micons thick cause a
> significant loss of fatigue strength in aluminum alloys. Most data on this
> property have been for strong alloys of the 2000, 5000, and 7000 classes.
> Unsealed sulfuric acid and chromic acid coatings less than about 5
> micrometers thick had little or no effect on fatigue strength at 100 million
> cycles." ... "Far greater losses were induced by sealing the coatings in
> water; sealed sulfuric acid coatings 25 micrometers thick induced fatigue
> strength losses approaching 35 percent at 100 million cycles. The effects
> of thick, hard anodic coatings on fatigue are even greater. Coatings 25
> micrometers up to 125 micrometers of one proprietary hard anodic coating
> process reduced stress to failure at 10 million cycles by more than 50
> percent." (page 32)
>
> Harry Phinney
>
>
no, indeed it is no mistake. but it's a mistake to attribute cracking
to anodizing without understanding the basics and bothering to be sure
of the actual mechanism.
i've taken the time to study the cracking that happens to anodizing at
rim eyelets - it's essentially a "star" pattern of cracks radiating from
the hole. we could therefore expect actual metal cracking, if anodizing
to be the cause, to follow those cracks. what we find in practice
however is that the metal frequently cracks at an angle to the anodizing
crack, even on allegedly "unanodized" rims.
http://web.onetel.net.uk/~davidwgreen/rimpics/4.JPG
both those cracks ["non-cracking" ma2 rim incidentally] are exactly
aligned with the extrusion axis, but not anodizing crack axis.
in ascii, [use monospaced font] - you would expect:
--O--
but you often get
__O__
or
__
__O
so in the latter instances, you cannot attribute cracking simply to
anodizing.
bottom line, rims have a finite life because of braking abrasion.
anodizing may indeed have a long term impact on a rim's fatigue life,
but if that fatigue life still exceeds the projected wear life of the
rim, who cares? the benefits of anodizing are substantial for anyone
riding in weather conditions found outside palo alto.
and let's not forget that the highly anisotropic nature of the rim
material is going to give very different fatigue strengths in different
orientations. excess spoke tension is going to raise the load to the
material's fatigue threshold and expose those fatigue orientation
differences, and /that/ is what's being observed, not the effects of
anodizing. spoke tension "as high as the rim can bear" is the real cause.
|
| | | | |
Date: 13 May 2007 01:36:03
From: * * Chas
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
"Harry Phinney" <harryDASHphinney@comcast.net > wrote in message
news:D-ednemJ7KLG69vbnZ2dnUVZ_gKdnZ2d@comcast.com...
> "jim beam" wrote
> > yeah. jobst is the problem on this one. jobst thinks anodizing
causes
> > cracking because he did a dye penetrant test. there is no way a dye
> > penetrant test determines whether anodizing has anything to do with
it -
> > all it does is identify presence, not cause. rim cracking is cause by
> > spoke tension "as high as the rim can bear" - pure and simple.
>
> It is a mistake to claim that hard anodizing has no impact on the
fatigue
> resistance of aluminum products. The following are quotes from "The
> Properties of Electordeposited Metals and Alloys a Handbook" Second
Edition,
> edited by William H. Safranek published by the AESFS, 1986 ISBN
> 0-936569-00-X, all from chapter 3 - "Anodic Coatings on Aluminum":
>
> " Typical thickness requirements for decorative applications not subject
to
> aggressive environment are about 7-10 micrometers. For exterior
> architectural components, a thickness in the range of 18-25 micrometers
is
> usually specified. Anodic coatings designed for wear resistance may be
> produced in greater thickness, up to over 100 micrometers." (page 29)
>
> "In general, anodic coatings more than a few micons thick cause a
> significant loss of fatigue strength in aluminum alloys. Most data on
this
> property have been for strong alloys of the 2000, 5000, and 7000
classes.
> Unsealed sulfuric acid and chromic acid coatings less than about 5
> micrometers thick had little or no effect on fatigue strength at 100
million
> cycles." ... "Far greater losses were induced by sealing the coatings in
> water; sealed sulfuric acid coatings 25 micrometers thick induced
fatigue
> strength losses approaching 35 percent at 100 million cycles. The
effects
> of thick, hard anodic coatings on fatigue are even greater. Coatings 25
> micrometers up to 125 micrometers of one proprietary hard anodic coating
> process reduced stress to failure at 10 million cycles by more than 50
> percent." (page 32)
>
> Harry Phinney
>
Good references.
Aluminum Oxide is a ceramic like substance that's fairly inert. It's at
least twice as hard as the hardest tool steels and about half the hardness
of diamond.
Rubies, sapphires and much of the abrasives used in sand paper and
grinding wheels are forms of aluminum oxide.
Pure aluminum will immediately start to corrode when exposed to air
forming a thin layer of aluminum oxide which will inhibit further
oxidation and corrosion.
Aluminum alloys especially those the 6000 series containing magnesium are
more susceptible to exposure to the elements and will continue to corrode
even after the initial aluminum oxide layer forms. Anodization is used to
protect these alloys from corrosion.
Anodized aluminum consists of a layer of aluminum oxide (Al2O3) in the
form of amorphous alumina crystals that are integral to the surface of the
part.
Decorative Type I and Type II anodization is accomplished in a chromic or
sulfuric acid bath and creates an aluminum oxide layer from 5 to 25
microns thick (.0002" to .0009"). Dye can be added to the surface to
create a wide array of colors.
Hard anodization is a separate process that yields a thicker layer of
aluminum oxide for increased chemical, corrosion or wear resistance. These
coatings can be up to 200 microns thick (.008"). The color ranges from
gray to dark brown.
Since the aluminum oxide layer is so hard it will crack when the metal
substrate flexes. With Type I or Type II anodizing this doesn't create
much of a problem because the coatings are so thin and they're an integral
part of the surface.
With thick hard anodizing, cracks that form in the surface will eventually
work their way into the aluminum substrate especially in highly stressed
areas like the spoke eyelets.
Another factor contributing to rims cracking at the eyelets is the thin
wall thickness of the aluminum extrusions used in modern rims. The steel
grommets or eyelets should distribute the forces of spoke tension to both
inner and outer surfaces but may not do a very good job at that.
Uniform spoke tension should put less stress on the eyelets than either
over tightened or loose spokes.
One other form of anodization is plasma electrolytic oxidation which
results in a more crystalline type of coating and is probably what rim
makers call "ceramic" coatings.
Chas.
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Date: 12 May 2007 05:27:13
From: Qui si parla Campagnolo
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
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On May 11, 11:36 pm, RS <r_schil...@comcast.net > wrote:
> In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
> spamvor...@bad.example.net says...
>
> >RS wrote:
> >> What is the difference, except for price, in the 3 versions of the
> >> venerable Mavic Open Pro rim? And are the higher priced version
> >> money well spent? note: I rarely ride in the rain.
>
> >what's your objective if you don't ride in the rain? ceramic rims are
> >impervious to the rain-road grit. cd rims are similar, but not as hard
> >or long lasting. ordinary open pros are not very resistant to grit at all.
>
> I was asking as to any other differences in construction, finish, longevity
> and intended use. Its why I'm asking, I don't know.
They all start as a basic OpenPro rim, then dipped for hard
anodizing(tend to crack around eyelets, since the eyelets are
installed after the 'dipping', or have a ceramic strip glued onto the
side wall..but construction of all the same. use the basic silver or
black..not the CD, IMO.
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Date: 12 May 2007 06:35:13
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
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Qui si parla Campagnolo wrote:
> On May 11, 11:36 pm, RS <r_schil...@comcast.net> wrote:
>> In article <UOOdnQpazoY5qtjbnZ2dneKdnZydn...@speakeasy.net>,
>> spamvor...@bad.example.net says...
>>
>>> RS wrote:
>>>> What is the difference, except for price, in the 3 versions of the
>>>> venerable Mavic Open Pro rim? And are the higher priced version
>>>> money well spent? note: I rarely ride in the rain.
>>> what's your objective if you don't ride in the rain? ceramic rims are
>>> impervious to the rain-road grit. cd rims are similar, but not as hard
>>> or long lasting. ordinary open pros are not very resistant to grit at all.
>> I was asking as to any other differences in construction, finish, longevity
>> and intended use. Its why I'm asking, I don't know.
>
> They all start as a basic OpenPro rim, then dipped for hard
> anodizing(tend to crack around eyelets,
all open pros are anodized - even the silver. if you mean the cd's
crack, i've never seen it on mine - and i have good mileage on them.
they're built to manufacturer spec spoke tension. the only people here
who report eyelet problems with eyelet cracking do not have it exclusive
to cd's and do not build with tensiometers.
> since the eyelets are
> installed after the 'dipping', or have a ceramic strip glued
glued??? plasma arc spray!!! high tech. expensive.
> onto the
> side wall..but construction of all the same. use the basic silver or
> black..not the CD, IMO.
basic, sure. no point spending more if not riding in the rain.
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Date: 11 May 2007 20:42:27
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
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RS wrote:
> What is the difference, except for price, in the 3 versions of the
> venerable Mavic Open Pro rim? And are the higher priced version
> money well spent? note: I rarely ride in the rain.
>
what's your objective if you don't ride in the rain? ceramic rims are
impervious to the rain-road grit. cd rims are similar, but not as hard
or long lasting. ordinary open pros are not very resistant to grit at all.
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Date: 11 May 2007 22:36:18
From: RS
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
In article <UOOdnQpazoY5qtjbnZ2dneKdnZydnZ2d@speakeasy.net >,
spamvortex@bad.example.net says...
>
>
>RS wrote:
>> What is the difference, except for price, in the 3 versions of the
>> venerable Mavic Open Pro rim? And are the higher priced version
>> money well spent? note: I rarely ride in the rain.
>>
>what's your objective if you don't ride in the rain? ceramic rims are
>impervious to the rain-road grit. cd rims are similar, but not as hard
>or long lasting. ordinary open pros are not very resistant to grit at all.
I was asking as to any other differences in construction, finish, longevity
and intended use. Its why I'm asking, I don't know.
|
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Date: 12 May 2007 06:39:07
From: jim beam
Subject: Re: Mavic Open Pro, Open Pro CD, Ceramic
|
RS wrote:
> In article <UOOdnQpazoY5qtjbnZ2dneKdnZydnZ2d@speakeasy.net>,
> spamvortex@bad.example.net says...
>>
>> RS wrote:
>>> What is the difference, except for price, in the 3 versions of the
>>> venerable Mavic Open Pro rim? And are the higher priced version
>>> money well spent? note: I rarely ride in the rain.
>>>
>> what's your objective if you don't ride in the rain? ceramic rims are
>> impervious to the rain-road grit. cd rims are similar, but not as hard
>> or long lasting. ordinary open pros are not very resistant to grit at all.
> I was asking as to any other differences in construction, finish, longevity
> and intended use. Its why I'm asking, I don't know.
>
if you're not riding in the rain, a standard rim is fine. there's no
other differences in construction other than the finishes and their
function.
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