Broken spokes...again

Quoted message said:

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

The general rule is that you might encounter two apparently-random spoke
failures, but by the time you get a third, you can pretty much assume the
rest are going to keep breaking.

Quoted message said:

A friend suggested that the problem is the mix of new spokes and
seven-year-old spokes in the wheel. Does the wheel need to be
respoked or is the LBS just doing a bad job of trueing the wheel?

Definitely respoke the wheel at this point. I doubt the shop did anything
wrong in truing the wheel, but the act of tightening and loosening spokes
may have been too much stress for them. They might not have turned freely,
which puts a lot more stress on the spokes as they twist during the truing
process.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

AcctHitman said:

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

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.

I weigh 140 lbs, I have built up a road wheel with 4 different kinds of used
spokes off customer's trashed wheels (bladed Alpina, straight 14g DT that's
10 years old, straight 14g Wheelsmith, straight 14g Union) and I have never
had problems with any of them detensioning.

The times that I have broken spokes were on large impacts that caused pinch
flats.

It's possible that the wheel tension is way off, and thus, it may help to
have it detensioned and retensioned, but if the tensions are already even,
it should be respoked as Mike said. To fix the "turning freely" problem,
make sure the wheel is stress-relieved.

--
Phil, Squid-in-Training

Did they replace the spokes with identicals?

I have a friend with a pair of troublesome Sestrieres. Well, they became troublesome after one spoke broke. The bike shop eventually replaced all with straight 14's and now the wheel goes out of true on every ride. Why?

The rims NEED the DT Revolutions to stay tensioned and true. When the first spoke broke, the LBS replaced it INCORRECTLY because they didn't unload the spoke nipple while it was being tensioned. This caused the spoke to wind up and this torsion caused it to fail (or the windup was relieved, causing the wheel to become untrue).

With straight 14's, windup is much less of a problem BUT the strain (elastic deformation) at correct tension is much less than the strain imposed by normal riding. This causes the spoke to unload during riding and the nipple twists off.

AcctHitman said:

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.

This is a clue.

Quoted message said:

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

Option b.

--

David L. Johnson

__o | A mathematician is a machine for turning coffee into theorems.
_`\(,_ | -- Paul Erdos
(_)/ (_) |

Weisse Luft said:

Did they replace the spokes with identicals?

I have a friend with a pair of troublesome Sestrieres. Well, they became
troublesome after one spoke broke. The bike shop eventually replaced all
with straight 14's and now the wheel goes out of true on every ride. Why?

Because the shop did a poor job of building the wheels. First clue is
using straight-gauge spokes.

Quoted message said:

The rims NEED the DT Revolutions to stay tensioned and true.

Excuse me, but that is horseshit. The rims are rims; they don't know
anything about spokes.

When the

Quoted message said:

first spoke broke, the LBS replaced it INCORRECTLY because they didn't
unload the spoke nipple while it was being tensioned. This caused the
spoke to wind up and this torsion caused it to fail

Windup is a sure sign of a poor wheel-builder.

(or the windup was

Quoted message said:

relieved, causing the wheel to become untrue).

Now, how much will the spoke length change when windup is released?

--

David L. Johnson

__o | Let's not escape into mathematics. Let's stay with reality. --
_`\(,_ | Michael Crichton
(_)/ (_) |

On Thu, 14 Oct 2004 07:40:32 +1000, Weisse Luft
<[email hidden]> wrote:

[snip]

Quoted message said:

With straight 14's, windup is much less of a problem BUT the strain
(elastic deformation) at correct tension is much less than the strain
imposed by normal riding. This causes the spoke to unload during
riding and the nipple twists off.

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

AcctHitman said:

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

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.

Thanks

chances are, if you have plain gauge spokes froma factory wheel, they're
something cheap & nasty & it's amazing they've lasted this long. have
the wheels respoked with quality components & you'll have no further
problems.

Weisse Luft said:

Did they replace the spokes with identicals?

I have a friend with a pair of troublesome Sestrieres. Well, they
became troublesome after one spoke broke. The bike shop eventually
replaced all with straight 14's and now the wheel goes out of true on
every ride. Why?

The rims NEED the DT Revolutions to stay tensioned and true. When the
first spoke broke, the LBS replaced it INCORRECTLY because they didn't
unload the spoke nipple while it was being tensioned. This caused the
spoke to wind up and this torsion caused it to fail (or the windup was
relieved, causing the wheel to become untrue).

i'll bet the shop used spokes that are too long. once the thread's
reached its limit, all that happens is that the spoke winds up. moment
it gets ridden, guess what, it relaxes & the wheels out again. i
recommend building with 1 or 2 mm shorter spokes & trying again.
they'll stay true after that.

Quoted message said:

With straight 14's, windup is much less of a problem BUT the strain
(elastic deformation) at correct tension is much less than the strain
imposed by normal riding. This causes the spoke to unload during
riding and the nipple twists off.

the nipple doesn't unscrew if correct tension was applied in the first
place.

On 12 Oct 2004 20:53:19 -0700, [email hidden] (AcctHitman)

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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

Werehatrack said:

On 12 Oct 2004 20:53:19 -0700, [email hidden] (AcctHitman)

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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?

Quoted message said:

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 <[email hidden]>

Quoted message said:

Quoted message said:

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.

Quoted message said:

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.

Werehatrack said:

On 12 Oct 2004 20:53:19 -0700, [email hidden] (AcctHitman)

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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

[email hidden said:

"]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 tension as straight 14's. This is in the build process and it explains why truing with DB's is more difficult.

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

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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.

Werehatrack said:

On Thu, 14 Oct 2004 15:57:36 -0600, [email hidden] wrote:

[snip]

Quoted message said:

Quoted message said:

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

Werehatrack said:

On Thu, 14 Oct 2004 06:38:10 -0700, jim beam <[email hidden]>

Quoted message said:

Quoted message said:

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.

Quoted message said:

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.

spoke quality is really important. surface finish, bend execution for
the spoke elbow & quality of material from which the spoke is make are
all vital. no amount of "stress relief" can compensate for
defficiencies in these areas. sure, you can reuse old spokes, but
statistically, a spoke with many stress cycles on it is closer to its
end of life. period.

the biggest factor in spoke life, based on my collection of failed
spokes from friends, bike shops & strangers limping home on wobbly
wheels, is that spoke quality is really really important.

On Thu, 14 Oct 2004 20:54:09 -0700, jim beam <[email hidden]>

Quoted message said:

the biggest factor in spoke life, based on my collection of failed
spokes from friends, bike shops & strangers limping home on wobbly
wheels, is that spoke quality is really really important.

I'd put quality equal to proper installation; a good spoke with a
botched build has no better outlook than a poor spoke in my
experience. The big kicker with spokes when it comes to quality is
the uncertainty factor; someone with little knowledge of the subject
has little or no chance of spotting a bad one, and too many bike shops
sell whatever comes in from their lowest-price supplier. Prhaps just
as bad, I've had a few "name brand" spokes come through with nicked
elbows and malformed threads, which is why I'm not bashful about doing
a build with spokes from the recycle bin. *Those* have proven
themselves reliable...and I am far from convinced that the probable
service life of a properly-installed spoke is shorter than the
owner's.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Quoted message said:

Dear Werehatrack,

Jobst has a site?

Hopefully,

Carl Fogel

It's not his site per se, but a bunch of his articles can be found
(interspersed with those of others) here:

http://draco.acs.uci.edu/rbfaq/FAQ/index.html
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Carl Fogel said:

Quoted message said:

Quoted message said:

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

Quoted message said:

Quoted message said:

Jobst's site, IIRC, has further information.

Quoted message said:

Dear Werehatrack,

Quoted message said:

Jobst has a site?

Quoted message said:

Hopefully,

Not really, and I assume you meant "I hope" rather than the dangling
"hopefully" that avoids authorship of the sentiment. You can't be
quoted as having expressed hope that way. That would be an opinion
and we never want to be called opinionated.

Jobst Brandt
[email hidden]