Broken spokes...again

Werehatrack wrote:
On 12 Oct 2004 20:53:19 -0700, (AcctHitman)
wrote:


A couple of weeks ago, my LBS replaced a broken spoke on my rear
wheel. After three rides, the wheel was way out of true.


That should not have happened.


After I had
the wheel retrued, I broke two spokes on my next ride.

A friend suggested that the problem is the mix of new spokes and
seven-year-old spokes in the wheel.


The ages of the spokes should be no obstacle to their use together.


Does the wheel need to be
respoked or is the LBS just doing a bad job of trueing the wheel?


Truing is just one step. There's another that I suspect has been
neglected.


The wheel is on my MTB (used for pavement only). The spokes are
stainless steel, 14 gauge. The wheel has about 4700 miles of use over
seven years. I weight about 155 pounds.


My approach: Replace the currently failed spokes, retension and
stress-relieve all of the spokes (including the old ones),

for a material that has no endurance limit - the op specified that these
spokes are stainless steel - how does re-use of old spokes help provide
extended wheel life? particularly if they are made of inferior material
in the first place?

and retrue
the wheel. Do that, and I suspect that you'll have no further
problems. Chances are very good that the original spokes were not
stress-relieved to begin with, and that they are now showing the
effects. Be prepared for the possibility that a few more may fail
during the stress-relieving process, after which the wheel will likely
remain trouble-free for a long time.

If the lbs gives you a blank stare when you mention stress-relieving
the spokes, take that as a sign of the reason for the failures.

On Thu, 14 Oct 2004 06:38:10 -0700, jim beam
wrote:

My approach: Replace the currently failed spokes, retension and
stress-relieve all of the spokes (including the old ones),

for a material that has no endurance limit - the op specified that these
spokes are stainless steel - how does re-use of old spokes help provide
extended wheel life?

Non-argument; I could just as well ask "How does replacement extend
wheel life beyond that likely to be achieved with proper re-use of the
old ones?" Unless there is a demonstrable problem with the spokes
(not proven in this case, IMO), and unless the replacements are
demonstrably better, there's no reason to suspect that replacements
will offer any advantage in that area.

particularly if they are made of inferior material
in the first place?

While the OP stated that they were stainless, that alone is not
dispositive that they are "inferior material"; without knowing *what*
the alloy is, there's no way to determine if they're made from
material that's good, bad or indifferent. The same is true for
replacements unless the purchaser is conversant in the finer points of
spoke construction and brand reputation...if the brand is even evident
or admitted. The ones on the wheel have gone a good long while
without failing, and the evidence seems to suggest to me that the
problem lies in initial assembly and subsequent repair procedures. As
such, I see no reason to condemn the spokes out of hand. I've reused
lots of old spokes without problems (inspecting for obvious physical
faults, of course) including many that appeared to be made from
rust-resistant alloy materials. In point of fact, I almost never buy
a new spoke; the junk box almost always has a few in it of the correct
length if I find one with a frozen nipple or some such, and I haven't
had a spontaneous spoke failure in a very long time. Properly
selected and installed, if used spokes don't fail when tensioned and
stress-relieved, it's my experience that they don't fail any more
often than new ones. Improperly selected or installed, *any* spoke
can fail.


--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On Thu, 14 Oct 2004 06:38:10 -0700, jim beam
wrote:

My approach: Replace the currently failed spokes, retension and
stress-relieve all of the spokes (including the old ones),

for a material that has no endurance limit - the op specified that these
spokes are stainless steel - how does re-use of old spokes help provide
extended wheel life?

Non-argument; I could just as well ask "How does replacement extend
wheel life beyond that likely to be achieved with proper re-use of the
old ones?" Unless there is a demonstrable problem with the spokes
(not proven in this case, IMO), and unless the replacements are
demonstrably better, there's no reason to suspect that replacements
will offer any advantage in that area.

particularly if they are made of inferior material
in the first place?

While the OP stated that they were stainless, that alone is not
dispositive that they are "inferior material"; without knowing *what*
the alloy is, there's no way to determine if they're made from
material that's good, bad or indifferent. The same is true for
replacements unless the purchaser is conversant in the finer points of
spoke construction and brand reputation...if the brand is even evident
or admitted. The ones on the wheel have gone a good long while
without failing, and the evidence seems to suggest to me that the
problem lies in initial assembly and subsequent repair procedures. As
such, I see no reason to condemn the spokes out of hand. I've reused
lots of old spokes without problems (inspecting for obvious physical
faults, of course) including many that appeared to be made from
rust-resistant alloy materials. In point of fact, I almost never buy
a new spoke; the junk box almost always has a few in it of the correct
length if I find one with a frozen nipple or some such, and I haven't
had a spontaneous spoke failure in a very long time. Properly
selected and installed, if used spokes don't fail when tensioned and
stress-relieved, it's my experience that they don't fail any more
often than new ones. Improperly selected or installed, *any* spoke
can fail.


--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On Thu, 14 Oct 2004 05:14:59 GMT, Werehatrack
wrote:

On 12 Oct 2004 20:53:19 -0700, (AcctHitman)
wrote:

A couple of weeks ago, my LBS replaced a broken spoke on my rear
wheel. After three rides, the wheel was way out of true.

That should not have happened.

After I had
the wheel retrued, I broke two spokes on my next ride.

A friend suggested that the problem is the mix of new spokes and
seven-year-old spokes in the wheel.

The ages of the spokes should be no obstacle to their use together.

Does the wheel need to be
respoked or is the LBS just doing a bad job of trueing the wheel?

Truing is just one step. There's another that I suspect has been
neglected.

The wheel is on my MTB (used for pavement only). The spokes are
stainless steel, 14 gauge. The wheel has about 4700 miles of use over
seven years. I weight about 155 pounds.

My approach: Replace the currently failed spokes, retension and
stress-relieve all of the spokes (including the old ones), and retrue
the wheel. Do that, and I suspect that you'll have no further
problems. Chances are very good that the original spokes were not
stress-relieved to begin with, and that they are now showing the
effects. Be prepared for the possibility that a few more may fail
during the stress-relieving process, after which the wheel will likely
remain trouble-free for a long time.

If the lbs gives you a blank stare when you mention stress-relieving
the spokes, take that as a sign of the reason for the failures.

Dear Werehatrack,

As you may be aware, I find the stress-relief business
fascinating, so bear with me. I'm not arguing, just making
sure that I follow you.

Are you suggesting that stress-relief (presumably the
spoke-squeezing kind) would improve spokes on a wheel where
a number of spokes have already broken?

And have you had spokes break on old wheels like this when
you squeezed or twist them? I have a vague notion that I've
read something like this, but I couldn't find anything when
I looked.

Thanks,

Carl Fogel

On Thu, 14 Oct 2004 05:14:59 GMT, Werehatrack
wrote:

On 12 Oct 2004 20:53:19 -0700, (AcctHitman)
wrote:

A couple of weeks ago, my LBS replaced a broken spoke on my rear
wheel. After three rides, the wheel was way out of true.

That should not have happened.

After I had
the wheel retrued, I broke two spokes on my next ride.

A friend suggested that the problem is the mix of new spokes and
seven-year-old spokes in the wheel.

The ages of the spokes should be no obstacle to their use together.

Does the wheel need to be
respoked or is the LBS just doing a bad job of trueing the wheel?

Truing is just one step. There's another that I suspect has been
neglected.

The wheel is on my MTB (used for pavement only). The spokes are
stainless steel, 14 gauge. The wheel has about 4700 miles of use over
seven years. I weight about 155 pounds.

My approach: Replace the currently failed spokes, retension and
stress-relieve all of the spokes (including the old ones), and retrue
the wheel. Do that, and I suspect that you'll have no further
problems. Chances are very good that the original spokes were not
stress-relieved to begin with, and that they are now showing the
effects. Be prepared for the possibility that a few more may fail
during the stress-relieving process, after which the wheel will likely
remain trouble-free for a long time.

If the lbs gives you a blank stare when you mention stress-relieving
the spokes, take that as a sign of the reason for the failures.

Dear Werehatrack,

As you may be aware, I find the stress-relief business
fascinating, so bear with me. I'm not arguing, just making
sure that I follow you.

Are you suggesting that stress-relief (presumably the
spoke-squeezing kind) would improve spokes on a wheel where
a number of spokes have already broken?

And have you had spokes break on old wheels like this when
you squeezed or twist them? I have a vague notion that I've
read something like this, but I couldn't find anything when
I looked.

Thanks,

Carl Fogel

Wrote:
On Thu, 14 Oct 2004 07:40:32 +1000,
Dear Weisse,

Perhaps I'm not following you, but you seem to be saying
that spokes stretch much more (increased strain and tension)
during riding, which is the opposite of what I thought
happens.

That is, don't the pre-tensioned spokes lose tension (not
gain) as they roll under the hub? There's a very slight
increase in tension on the other spokes, but it's nowhere
near the huge, routine loss of tension under the axle.

Jobst has made the point that in a crash the spokes don't
rip out of the rim under increased tension--tension is lost
as the wheel deforms.

Could you have meant that repeatedly losing and regaining
the normal tension is what "causes the spoke to unload
during riding and the nipple twists off"?

Sorry if this is just a quibble about a phrase that I'm
misunderstanding or just a hasty bit of typing, but "the
strain . . . at correct tension is much less than the strain
imposed by normal riding" sounds as if the spoke tension is
rising immensely after the wheel is built.

Carl Fogel

Let me see if I can explain it better.

14/17 DB's require almost TWICE the strain to produce the same tensio
as straight 14's. This is in the build process and it explains wh
truing with DB's is more difficult.

When Sestriere's are rebuilt with straight 14's, the decreased buil
strain is easily offset at the bottom section of the wheel when loade
to normal levels. Once the strain is offset, no tension in the spo
allows the nipple to untwist (and makes the wheel dependent on th
other spokes for stability, thanks to paired spoking, temporary tru
isn't horribly affected)

--
Weisse Luft

Wrote:
On Thu, 14 Oct 2004 07:40:32 +1000,
Dear Weisse,

Perhaps I'm not following you, but you seem to be saying
that spokes stretch much more (increased strain and tension)
during riding, which is the opposite of what I thought
happens.

That is, don't the pre-tensioned spokes lose tension (not
gain) as they roll under the hub? There's a very slight
increase in tension on the other spokes, but it's nowhere
near the huge, routine loss of tension under the axle.

Jobst has made the point that in a crash the spokes don't
rip out of the rim under increased tension--tension is lost
as the wheel deforms.

Could you have meant that repeatedly losing and regaining
the normal tension is what "causes the spoke to unload
during riding and the nipple twists off"?

Sorry if this is just a quibble about a phrase that I'm
misunderstanding or just a hasty bit of typing, but "the
strain . . . at correct tension is much less than the strain
imposed by normal riding" sounds as if the spoke tension is
rising immensely after the wheel is built.

Carl Fogel

Let me see if I can explain it better.

14/17 DB's require almost TWICE the strain to produce the same tensio
as straight 14's. This is in the build process and it explains wh
truing with DB's is more difficult.

When Sestriere's are rebuilt with straight 14's, the decreased buil
strain is easily offset at the bottom section of the wheel when loade
to normal levels. Once the strain is offset, no tension in the spo
allows the nipple to untwist (and makes the wheel dependent on th
other spokes for stability, thanks to paired spoking, temporary tru
isn't horribly affected)

--
Weisse Luft

On Thu, 14 Oct 2004 15:57:36 -0600, wrote:

Dear Werehatrack,

As you may be aware, I find the stress-relief business
fascinating, so bear with me. I'm not arguing, just making
sure that I follow you.

Are you suggesting that stress-relief (presumably the
spoke-squeezing kind) would improve spokes on a wheel where
a number of spokes have already broken?

Spokes which remain sound but which still have not been so treated (I
prefer the lever method, using an old crank) should respond favorably
to this, yes. The key is that when a used spoke is installed in a new
location *for that spoke*, it should get the same preparation as a new
one.

And have you had spokes break on old wheels like this when
you squeezed or twist them?

Yes, but nipple failures outnumber them. Spoke failures during stress
relief are rare but not unknown, and on inspection it usually becomes
obvious that the failed spokes had other problems. If I recall
correctly, all of such failures were either at the elbow or at the
start of the threads; not surprising.

I have a vague notion that I've
read something like this, but I couldn't find anything when
I looked.

Jobst's site, IIRC, has further information.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On Thu, 14 Oct 2004 15:57:36 -0600, wrote:

Dear Werehatrack,

As you may be aware, I find the stress-relief business
fascinating, so bear with me. I'm not arguing, just making
sure that I follow you.

Are you suggesting that stress-relief (presumably the
spoke-squeezing kind) would improve spokes on a wheel where
a number of spokes have already broken?

Spokes which remain sound but which still have not been so treated (I
prefer the lever method, using an old crank) should respond favorably
to this, yes. The key is that when a used spoke is installed in a new
location *for that spoke*, it should get the same preparation as a new
one.

And have you had spokes break on old wheels like this when
you squeezed or twist them?

Yes, but nipple failures outnumber them. Spoke failures during stress
relief are rare but not unknown, and on inspection it usually becomes
obvious that the failed spokes had other problems. If I recall
correctly, all of such failures were either at the elbow or at the
start of the threads; not surprising.

I have a vague notion that I've
read something like this, but I couldn't find anything when
I looked.

Jobst's site, IIRC, has further information.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On Thu, 14 Oct 2004 22:41:22 GMT, Werehatrack
wrote:

On Thu, 14 Oct 2004 15:57:36 -0600, wrote:

[snip]

I have a vague notion that I've
read something like this, but I couldn't find anything when
I looked.

Jobst's site, IIRC, has further information.

Dear Werehatrack,

Jobst has a site?

Hopefully,

Carl Fogel