Re: I fixed a broken spoke! - Cycling Mob: Road Cycling, Mountain Biking and More

12-30-2006, 05:44 PM

Carl Fogel writes:

>>>> If you are breaking non-drive side spokes, this indicates without
>>>> a doubt that they are crap spokes. (based on info from your
>>>> previous posts, that you don't weigh 400lbs,etc)

>>> Even the best spokes fail if they are not formed to the hub and
>>> stress relieved. Don't push it off on the spoke manufacturer when
>>> it's the builder who needs to take measures to make the wheel
>>> durable.

>> Stress relief is just going around the wheel sort of pinching the
>> spokes?

> Forgive me, but your innocent response is too good not to cross-post
> to rec.bicycles.tech.

Don't be so condescending about finding an opening to present your
belief in the misplaced experiments you performed to support your
belief in stress relief. You are not forgiven.

> While pinching spoke pairs together probably helps to seat the
> spokes in the hub and the nipples in the rim, tests showed no
> further residual stresses being relieved after ordinary spoke
> tension, even when tension was much higher than the typical 60-lb
> tension increase that other testing shows can be achieved by
> pinching.

Consider that typically an outbound spoke is bent to yield when
tightened after a wheel is laced. This is apparent from its elbow
bend that was obtuse when new and acute after a wheel build. That the
elbow that is raised to tensile yield during tensioning should be
evident because all additional tension can only yield that portion of
the spoke in the elbow further. It will remain at yield, there being
no mechanism to make it less than that.

Because no over-tensioning followed by relaxation (manually stretching
spokes) is used, the elbow must be at yield in the finished wheel.
Therefore, the residual stress from elbow modification remains with
that spoke that is tensioned to less than yield stress in the absence
of stress relieving.

Your heating experiment was done on a relaxed spoke and does not
reveal what the tension was on the outside of an elbow bend, for
instance. If you raised your spoke tension to yield stress prior to
relaxing it and heating, then it is evidence of stress relieving by
momentary over-stress, nothing more.

> I pinched spokes together on various wheels with known forces and
> measured the tension changes. Despite the impressive bending, the
> spoke tension rose only about 55~65 for a 60 lb pinch. (The bending
> was not due to the spokes being stretched by tremendous tension
> increases, but to the slack gained when the rims bent into faint N
> or Z shapes.)

Any momentary overload will cause yielding in the portions of a spoke
that are at tensile yield stress and relaxing that overload
constitutes stress relief. I don't see what is not obvious about that
process.

Jobst Brandt

12-30-2006, 06:02 PM

On 31 Dec 2006 01:44:22 GMT, [Only registered and activated users can see links. ] wrote:

>Carl Fogel writes:
>
>>>>> If you are breaking non-drive side spokes, this indicates without
>>>>> a doubt that they are crap spokes. (based on info from your
>>>>> previous posts, that you don't weigh 400lbs,etc)
>
>>>> Even the best spokes fail if they are not formed to the hub and
>>>> stress relieved. Don't push it off on the spoke manufacturer when
>>>> it's the builder who needs to take measures to make the wheel
>>>> durable.
>
>>> Stress relief is just going around the wheel sort of pinching the
>>> spokes?
>
>> Forgive me, but your innocent response is too good not to cross-post
>> to rec.bicycles.tech.
>
>Don't be so condescending about finding an opening to present your
>belief in the misplaced experiments you performed to support your
>belief in stress relief. You are not forgiven.

[snip]

Dear Jobst,

Don't be such a pompous, paranoid ass, particularly 11 days after the
post first appeared.

Cheers,

Carl Fogel

12-30-2006, 07:18 PM

[Only registered and activated users can see links. ] wrote:
> Carl Fogel writes:
>
>>>>> If you are breaking non-drive side spokes, this indicates without
>>>>> a doubt that they are crap spokes. (based on info from your
>>>>> previous posts, that you don't weigh 400lbs,etc)
>
>>>> Even the best spokes fail if they are not formed to the hub and
>>>> stress relieved. Don't push it off on the spoke manufacturer when
>>>> it's the builder who needs to take measures to make the wheel
>>>> durable.
>
>>> Stress relief is just going around the wheel sort of pinching the
>>> spokes?
>
>> Forgive me, but your innocent response is too good not to cross-post
>> to rec.bicycles.tech.
>
> Don't be so condescending about finding an opening to present your
> belief in the misplaced experiments you performed to support your
> belief in stress relief. You are not forgiven.
>
>> While pinching spoke pairs together probably helps to seat the
>> spokes in the hub and the nipples in the rim, tests showed no
>> further residual stresses being relieved after ordinary spoke
>> tension, even when tension was much higher than the typical 60-lb
>> tension increase that other testing shows can be achieved by
>> pinching.
>
> Consider that typically an outbound spoke is bent to yield when
> tightened after a wheel is laced. This is apparent from its elbow
> bend that was obtuse when new and acute after a wheel build. That the
> elbow that is raised to tensile yield during tensioning should be
> evident because all additional tension can only yield that portion of
> the spoke in the elbow further. It will remain at yield, there being
> no mechanism to make it less than that.
>
> Because no over-tensioning followed by relaxation (manually stretching
> spokes) is used, the elbow must be at yield in the finished wheel.
> Therefore, the residual stress from elbow modification remains with
> that spoke that is tensioned to less than yield stress in the absence
> of stress relieving.
>
> Your heating experiment was done on a relaxed spoke and does not
> reveal what the tension was on the outside of an elbow bend, for
> instance. If you raised your spoke tension to yield stress prior to
> relaxing it and heating, then it is evidence of stress relieving by
> momentary over-stress, nothing more.
>
>> I pinched spokes together on various wheels with known forces and
>> measured the tension changes. Despite the impressive bending, the
>> spoke tension rose only about 55~65 for a 60 lb pinch. (The bending
>> was not due to the spokes being stretched by tremendous tension
>> increases, but to the slack gained when the rims bent into faint N
>> or Z shapes.)
>
> Any momentary overload will cause yielding in the portions of a spoke
> that are at tensile yield stress and relaxing that overload
> constitutes stress relief. I don't see what is not obvious about that
> process.

i'm an [ex] metallurgist, and i see nothing "obvious" about this
supposition at all. you repeatedly prove know nothing about materials
[particularly fatigue or deformation - metal yields to zero "brick
dragging" b.s!!!!], you've done no testing, you have no data. you even
have the temerity to claim "invention" of wheel building practice that
dates before your birth. and yet here you are, years after being
confronted with facts and data that would allow you to correct your
mistakes, still in denial. you've even been asked to perform simple
[cheap] industry standard testing that could /prove/ you correct if
you're so damned confident, but you won't. why not?

this is not a technology problem: this is an i.q. problem.