Do Spokes Stretch?

David White said:

I understand that spokes can (and should) "stretch" temporarily while a wheel
is in use. But my question is: can a normal human, using normal pressure on a
normal spoke wrench cause a spoke's measurable length to increase permanently
on the order of .2"?

I have a friend who rides American Classic 420 wheels on most of his bikes.
They employ a DT stainless spoke which is 1.5mm in the center (double butted).
He has had several cases where he could not get a spoke to tighten-up while
performing maintenance and he has had to replaced the spoke (with the proper
replacement).

He holds that the problem is that the spoke is stretching (I suppose like
taffy). I have only used heavier guage spokes. So it seems unlikely to me that
this could be the cause of his problems. Jobst or anyone else out there have
any position on this?

Thanks.

I'm convinced spokes can stretch. I had 15/16 double butted spokes on
a set of wheels once. Front and back. I kept having to tighten them.
Eventually replaced them with 14/15 and no more problems.

David White said:

I understand that spokes can (and should) "stretch" temporarily
while a wheel is in use. But my question is: can a normal human,
using normal pressure on a normal spoke wrench cause a spoke's
measurable length to increase permanently on the order of .2"?

No, you cannot stretch a spoke by tensioning it with a spoke nipple
and because tension does not increase significantly from there in a
wheel in use and because in its tensioned stress in a wheel the spoke
is at about 1/3 its yield stress, it will not stretch. If it were to
reach yield stress in use, it would break soon because it gets a
million stress cycles in about 2100km of riding (1300mi).

Quoted message said:

I have a friend who rides American Classic 420 wheels on most of his
bikes. They employ a DT stainless spoke which is 1.5mm in the
center (double butted). He has had several cases where he could not
get a spoke to tighten-up while performing maintenance and he has
had to replaced the spoke (with the proper replacement).

Could you expand on that. Why could he not tighten the spoke? You
should know that properly tightening DT Revolution spokes is a
difficult task anyway because they are torsionally so weak that they
rather twist than tighten, especially with a large diameter thread
that they have.

Quoted message said:

He holds that the problem is that the spoke is stretching (I suppose
like taffy). I have only used heavier gauge spokes. So it seems
unlikely to me that this could be the cause of his problems. Jobst
or anyone else out there have any position on this?

I don't understand the circumstances well enough to say more.

Jobst Brandt

Thanks for the responses so far. It seems I have not provided enough info so
here is what I know and have seen...

The problem seems to occur only on the radially laced, front AmerClassic 420
wheel. The ones in question have DT Revolution spokes that have very short, 2mm
butted ends and are 1.5mm in the center.

My buddy have purchased several sets of these used and occasionally, they
require some truing and tensioning upon arrival. He tests for even tension by
plucking the spokes like a harp string and listening to hear that spokes make
the same sound (which I think they should on a radially spoke front wheel).

Sometimes, one or two spoke require more tension and he uses a normal spoke
wrench to tighen them up. He works slowly but finds that sometimes the spokes
seem to never reach tension even with lots of turns. Since he has seen this
before, he first assumes the alloy nipple is hosed and replaces it with a brass
one. But this does not help. He gets the same result.

Sometimes he gets to a point where there is .2" of threaded spoke above the end
of the nipple and it seems that the threaded portion of the nipple is down the
spoke far enough to be off the threads. At this point, turning the spoke does
nothing and generally backing it off does nothing. At such a point, he has no
choice but to cut the spoke and replace it.

He has a stash of the proper spokes so he replaces them with new and generally
the problem does not reappear. He has no problems with spoke breakage nor does
he need to perform lots of on-going maintenance.

I find it near impossible to believe that normal spoke wrench work could
stretch a spoke (even of this thin diameter) by nearly 1/4". Maybe if one
placed the spoke into a special test rig built to try and stretch a spoke, but
not using anything like normal force via a spoke wrench. I'd think that the
spoke thread would strip or the nipple would round-over before the spoke wire
would stretch.

However, I assume that there is a point which, when overcome, the metal will
fatigue and once this starts on-going force will cause it to continue. I have
no idea how much force would be required to overcome this point but since the
spokes are stainless steel I would think it is a fairly high value.

My best guess is that somehow spokes that are too long have been installed
somewhere along the way and that this has simply been missed in production. My
buddy believes these are machine assembled since some many are made and given
that they are radially laced front wheels it is unlikely that someone would
drop some incorrect sized spokes into the machine hopper. We'll likely never
know. But it would seem that someone up on material science/mechanical
engineering should be able to help us determine if physical stretch is at work
here.

Hope this helps. Thanks for your input.

David White said:

I understand that spokes can (and should) "stretch" temporarily while a
wheel is in use. But my question is: can a normal human, using normal
pressure on a normal spoke wrench cause a spoke's measurable length to
increase permanently on the order of .2"?

I have a friend who rides American Classic 420 wheels on most of his
bikes. They employ a DT stainless spoke which is 1.5mm in the center
(double butted). He has had several cases where he could not get a spoke
to tighten-up while performing maintenance and he has had to replaced
the spoke (with the proper replacement).

He holds that the problem is that the spoke is stretching (I suppose
like taffy). I have only used heavier guage spokes. So it seems unlikely
to me that this could be the cause of his problems. Jobst or anyone else
out there have any position on this?

Thanks.

David White said:

My buddy have purchased several sets of these used and occasionally,
they require some truing and tensioning upon arrival. He tests for
even tension by plucking the spokes like a harp string and listening
to hear that spokes make the same sound (which I think they should
on a radially spoke front wheel).

Quoted message said:

Sometimes, one or two spoke require more tension and he uses a
normal spoke wrench to tighten them up. He works slowly but finds
that sometimes the spokes seem to never reach tension even with lots
of turns. Since he has seen this before, he first assumes the alloy
nipple is hosed and replaces it with a brass one. But this does not
help. He gets the same result.

Quoted message said:

Sometimes he gets to a point where there is .2" of threaded spoke
above the end of the nipple and it seems that the threaded portion
of the nipple is down the spoke far enough to be off the threads.
At this point, turning the spoke does nothing and generally backing
it off does nothing. At such a point, he has no choice but to cut
the spoke and replace it.

As I mentioned on this subject in the past, 1.5mm diameter spokes have
so little twist resistance that they do that rather than allow the
spoke nipple to be screwed on tighter. In spokes of the past, they
usually snapped at that point, because they were already reasonably
tight and taking them beyond yield in twist made them fracture.

As is evident from the stress-strain curves in "the Bicycle Wheel", DT
spokes can withstand going beyond yield for an amazing amount. I
believe the spokes in question cannot be readily tightened because
they need to be slacker to allow thread movement. The spokes are
probably only twisting when the nipple is turned and not advancing in
the thread.

To get around this problem, spokes must momentarily be slackened by
pulling the rim sideways toward the flange of that spoke. This is a
tedious process but it works. You must become sensitive to the
difference between thread motion and spoke twist, or the whole process
gets confused (as it has).

In the future, don't use spokes thinner than 1.6mm. I haven't used
any in many years for that reason.

Jobst Brandt

Here is a photo my buddy has taken of the spokes in question
<http://home.comcast.net/~whitedavidp/PC240001.JPG>. The ones with nipples
bottomed-out have been cut out of wheels. When I look at it, I am amazed to
believe that these all were supposed to have started out as the same length.

Jobst, if I understand your responses, you suggest that the spoke is twisting
in place when the nipple is tightened instead of the nipple proceeding down the
spoke as anticipated. But the nipple has move down the spoke to the point where
it has bottomed-out. If there is an application of torsional stress to the
spoke how could this account for the greatly increased length of the spokes in
the photo?

Thanks

David White said:

I understand that spokes can (and should) "stretch" temporarily while a
wheel is in use. But my question is: can a normal human, using normal
pressure on a normal spoke wrench cause a spoke's measurable length to
increase permanently on the order of .2"?

I have a friend who rides American Classic 420 wheels on most of his
bikes. They employ a DT stainless spoke which is 1.5mm in the center
(double butted). He has had several cases where he could not get a spoke
to tighten-up while performing maintenance and he has had to replaced
the spoke (with the proper replacement).

He holds that the problem is that the spoke is stretching (I suppose
like taffy). I have only used heavier guage spokes. So it seems unlikely
to me that this could be the cause of his problems. Jobst or anyone else
out there have any position on this?

Thanks.

In article <[email hidden]>, David White

Quoted message said:

Thanks for the responses so far. It seems I have not provided enough info so
here is what I know and have seen...

The problem seems to occur only on the radially laced, front AmerClassic 420
wheel. The ones in question have DT Revolution spokes that have very short,
2mm
butted ends and are 1.5mm in the center.

My buddy have purchased several sets of these used and occasionally, they
require some truing and tensioning upon arrival. He tests for even tension by
plucking the spokes like a harp string and listening to hear that spokes make
the same sound (which I think they should on a radially spoke front wheel).

Sometimes, one or two spoke require more tension and he uses a normal spoke
wrench to tighen them up. He works slowly but finds that sometimes the spokes
seem to never reach tension even with lots of turns. Since he has seen this
before, he first assumes the alloy nipple is hosed and replaces it with a
brass
one. But this does not help. He gets the same result.

Sometimes he gets to a point where there is .2" of threaded spoke above the
end
of the nipple and it seems that the threaded portion of the nipple is down
the
spoke far enough to be off the threads. At this point, turning the spoke does
nothing and generally backing it off does nothing. At such a point, he has no
choice but to cut the spoke and replace it.

He has a stash of the proper spokes so he replaces them with new and
generally
the problem does not reappear. He has no problems with spoke breakage nor
does
he need to perform lots of on-going maintenance.

I find it near impossible to believe that normal spoke wrench work could
stretch a spoke (even of this thin diameter) by nearly 1/4". Maybe if one
placed the spoke into a special test rig built to try and stretch a spoke,
but
not using anything like normal force via a spoke wrench. I'd think that the
spoke thread would strip or the nipple would round-over before the spoke wire
would stretch.

However, I assume that there is a point which, when overcome, the metal will
fatigue and once this starts on-going force will cause it to continue. I have
no idea how much force would be required to overcome this point but since the
spokes are stainless steel I would think it is a fairly high value.

My best guess is that somehow spokes that are too long have been installed
somewhere along the way and that this has simply been missed in production.
My
buddy believes these are machine assembled since some many are made and given
that they are radially laced front wheels it is unlikely that someone would
drop some incorrect sized spokes into the machine hopper. We'll likely never
know. But it would seem that someone up on material science/mechanical
engineering should be able to help us determine if physical stretch is at work
here.

Hope this helps. Thanks for your input.

Metal under tension elongates, first they go through a phase where
elastic elongation dominates, when tension is removed, they spring back
to almost original length, but when tension is applied strong enough,
plastic elongation effect will become noticeable, and the extensions in
the metal stays, they will remain as strong though and sometimes even
stronger.

If (I am only making a suggestion here as I have no knowledge of the
actual application) the wheels in question have a faulty design, that
the spokes are not strong enough to carry the force of impact from the
bike and the rider together in motion, or that the previous owners of
those wheel had operated their bikes beyond their design limit, the
spokes may experience tension exceeding their elastic limit and will
suffer permanent elongation. If you really want to prove it, you can
remove some of the spokes and measure their actual length against each
other.

You've mentioned that your friend does not have to perform "ongoing
maintenance" on the corrected spokes, it could be that your friend is a
more gentle rider.

David White said:

My buddy have purchased several sets of these used and occasionally, they
require some truing and tensioning upon arrival. He tests for even tension by
plucking the spokes like a harp string and listening to hear that spokes make
the same sound (which I think they should on a radially spoke front wheel).

This isn't an accurate measure of tension, however. It's a useful
quick check, but not an accurate measure.

Quoted message said:

Sometimes, one or two spoke require more tension and he uses a normal spoke
wrench to tighen them up.

Two tools are needed. The other is a pair of vice-grips (with
something to provide "soft jaws" such as a piece of brass scrap in a
V-shape) clamped just below the nipple to keep the spoke from simply
winding up like a long torsion bar spring.

Quoted message said:

He works slowly but finds that sometimes the spokes
seem to never reach tension even with lots of turns. Since he has seen this
before, he first assumes the alloy nipple is hosed and replaces it with a brass
one. But this does not help. He gets the same result.

Were it not for the next paragraph, I'd be expecting wind-up to be the
whole issue.

Quoted message said:

Sometimes he gets to a point where there is .2" of threaded spoke above the end
of the nipple and it seems that the threaded portion of the nipple is down the
spoke far enough to be off the threads. At this point, turning the spoke does
nothing and generally backing it off does nothing. At such a point, he has no
choice but to cut the spoke and replace it.

And at that point, I think it's probably the proper thing to do
anyway. Has he had this problem with any of the replacement spokes?

Quoted message said:

He has a stash of the proper spokes so he replaces them with new and generally
the problem does not reappear. He has no problems with spoke breakage nor does
he need to perform lots of on-going maintenance.

I find it near impossible to believe that normal spoke wrench work could
stretch a spoke (even of this thin diameter) by nearly 1/4". Maybe if one
placed the spoke into a special test rig built to try and stretch a spoke, but
not using anything like normal force via a spoke wrench. I'd think that the
spoke thread would strip or the nipple would round-over before the spoke wire
would stretch.

I tend to agree, but then again, the small experience that I've had
with the DT butted spokes left me with the impression that I'd rather
use anything else. Jobst Brandt's opinion is that the cited amount of
elongation is impossible. Absent a different explanation for the
observed behavior, however, I have no alternative view to offer
besides your surmise that elongation must be taking place. Has any
attempt been made to see if the spoke is still elongated after it's
been cut and removed?

Quoted message said:

However, I assume that there is a point which, when overcome, the metal will
fatigue and once this starts on-going force will cause it to continue. I have
no idea how much force would be required to overcome this point but since the
spokes are stainless steel I would think it is a fairly high value.

The specs say it should be beyond the limits of the threads.

Quoted message said:

My best guess is that somehow spokes that are too long have been installed
somewhere along the way and that this has simply been missed in production. My
buddy believes these are machine assembled since some many are made and given
that they are radially laced front wheels it is unlikely that someone would
drop some incorrect sized spokes into the machine hopper. We'll likely never
know. But it would seem that someone up on material science/mechanical
engineering should be able to help us determine if physical stretch is at work
here.

That the incorrect length spokes should not be present in a
machine-assembled wheel is a contention I would agree with,
particularly scattered across samples obtained from various sources.
It seems just as unlikely that the same error in replacement selection
would have been present across various wheels as well. It is,
however, not impossible that this is the case. Holmes' Maxim holds
that the wrong spokes must be present...but Holmes was only a
fictional detective. I believe that the next such wheel should be
carefully inspected for overlength spokes *before* tensioning is
attempted; this might save the trouble of having to cut them out if
they're discovered before the point of full thread overrun is reached.
If it can be observed that a spoke which had *some* tension became
stretched to the point you describe during the tensioning process,
that would prove that some other factor is operating to override the
theoretical prediction.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

David White said:

Here is a photo my buddy has taken of the spokes in question
<http://home.comcast.net/~whitedavidp/PC240001.JPG>. The ones with nipples
bottomed-out have been cut out of wheels. When I look at it, I am amazed to
believe that these all were supposed to have started out as the same length.

I does seem to be an improbable situation. Is it known that they
were, in fact, the same length to begin with? Was this checked?
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

David White said:

I understand that spokes can (and should) "stretch" temporarily while a
wheel is in use. But my question is: can a normal human, using normal
pressure on a normal spoke wrench cause a spoke's measurable length to
increase permanently on the order of .2"?

I have a friend who rides American Classic 420 wheels on most of his
bikes. They employ a DT stainless spoke which is 1.5mm in the center

I doubt seriously that your friends spokes are stretching that much.
That .2 inch stretch would be about 5mm on a spoke about (say) 230 mm,
or about 2% strain (stretch). There are not many high strength steels
that can do this without breaking. ISTM that your friend may have a
wheel with a flat spot, which is causing his problem. The symptons would
be about the same a you describe. YMMV.

HTH,
EJ in NJ

Quoted message said:

(double butted). He has had several cases where he could not get a spoke

Quoted message said:

to tighten-up while performing maintenance and he has had to replaced
the spoke (with the proper replacement).

He holds that the problem is that the spoke is stretching (I suppose
like taffy). I have only used heavier guage spokes. So it seems unlikely
to me that this could be the cause of his problems. Jobst or anyone else
out there have any position on this?

Thanks.

David White said:

Here is a photo my buddy has taken of the spokes in question
<http://home.comcast.net/~whitedavidp/PC240001.JPG>. The ones with
nipples bottomed-out have been cut out of wheels. When I look at it, I
am amazed to believe that these all were supposed to have started out as
the same length.

Yes.
I have experienced a few times a very tight new wheel in
which, to get out a high spot at the seam, I tightened one
new lubricated spoke/nipple until several millimeters stuck
out the back. Without moving the rim at all. Clearly a case
of spoke stretch.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

In article <[email hidden]>, David White

Quoted message said:

Here is a photo my buddy has taken of the spokes in question
<http://home.comcast.net/~whitedavidp/PC240001.JPG>. The ones with nipples
bottomed-out have been cut out of wheels. When I look at it, I am amazed to
believe that these all were supposed to have started out as the same length.

It is really surprising to see such big difference in length, but you
can easily check if the spokes were different in length to start with,
or it was really tension stretching by sliding a caliper (a micrometer
is better if you have one) along the whole length of the "stretched"
spokes, what you will be looking for is change in diameter.

Typically spokes are roll formed therefore should have very uniform
cross sectional diameter, if you notice any change in diameter (unless
they are not stainless steel and have rusted), the spoke has suffered
elongation or begin stretched.

David White said:

I understand that spokes can (and should) "stretch" temporarily while a wheel
is in use. But my question is: can a normal human, using normal pressure on a
normal spoke wrench cause a spoke's measurable length to increase permanently
on the order of .2"?

I have a friend who rides American Classic 420 wheels on most of his bikes.
They employ a DT stainless spoke which is 1.5mm in the center (double butted).
He has had several cases where he could not get a spoke to tighten-up while
performing maintenance and he has had to replaced the spoke (with the proper
replacement).

He holds that the problem is that the spoke is stretching (I suppose like
taffy). I have only used heavier guage spokes. So it seems unlikely to me that
this could be the cause of his problems. Jobst or anyone else out there have
any position on this?

Thanks.

I have seen samples of American Classic wheels with DT Revolution spokes with overly long spokes. Many of the samples I saw and measured had spokes that were 4 - 5 mm too long.
DT Revolution spokes have a little more elasticity than DT Competition spokes, but nothing in the range that would cause the problems described. From the picture, it sure looks like the spokes were just too long to start with.

Quoted message said:

David White said:

My buddy have purchased several sets of these used and occasionally,
they require some truing and tensioning upon arrival. He tests for
even tension by plucking the spokes like a harp string and listening
to hear that spokes make the same sound (which I think they should
on a radially spoke front wheel).

Quoted message said:

Sometimes, one or two spoke require more tension and he uses a
normal spoke wrench to tighten them up. He works slowly but finds
that sometimes the spokes seem to never reach tension even with lots
of turns. Since he has seen this before, he first assumes the alloy
nipple is hosed and replaces it with a brass one. But this does not
help. He gets the same result.

Quoted message said:

Sometimes he gets to a point where there is .2" of threaded spoke
above the end of the nipple and it seems that the threaded portion
of the nipple is down the spoke far enough to be off the threads.
At this point, turning the spoke does nothing and generally backing
it off does nothing. At such a point, he has no choice but to cut
the spoke and replace it.

At first, creep came into my mind, but after reviewing the concept, it
appears that it manifests in SS at temperatures above 1000F.

Quoted message said:

As I mentioned on this subject in the past, 1.5mm diameter spokes have
so little twist resistance that they do that rather than allow the
spoke nipple to be screwed on tighter. In spokes of the past, they
usually snapped at that point, because they were already reasonably
tight and taking them beyond yield in twist made them fracture.

As is evident from the stress-strain curves in "the Bicycle Wheel", DT
spokes can withstand going beyond yield for an amazing amount. I
believe the spokes in question cannot be readily tightened because
they need to be slacker to allow thread movement. The spokes are
probably only twisting when the nipple is turned and not advancing in
the thread.

To get around this problem, spokes must momentarily be slackened by
pulling the rim sideways toward the flange of that spoke. This is a
tedious process but it works. You must become sensitive to the
difference between thread motion and spoke twist, or the whole process
gets confused (as it has).

Usually at the correct tensions, even lubed spokes and nipples will undergo
a static/kinetic friction cycling as the spoke is tensioned. One can feel
it as the nipple and spoke turn together, then they slip and the spoke
attains higher tension. With a wheelbuilder paying even cursory attention,
excessive spoke windup can be avoided. Not only that, but black DT spokes
have a textured, characteristically brown surface that is rough enough for
anyone to see if the spoke is turning.

I built my race wheels with AC hubs and DT Revolutions in these same butted
diameters. There was only a little spoke windup, and using JB's slackening
method above, very even tension was achieved. They keep oh-so-true and the
wheels are about the same weight as AC's Sprint 350 wheelset but at 1/4 of
the price and 1/4 more spokes! AC's superlight rear left flange is so far
inward that an offset rim puts slightly *more* tension on the left side than
the right side.

--
Phil, Squid-in-Training

David White said:

Quoted message said:

I understand that spokes can (and should) "stretch" temporarily
while a wheel is in use. But my question is: can a normal human,
using normal pressure on a normal spoke wrench cause a spoke's
measurable length to increase permanently on the order of .2"?

Quoted message said:

Quoted message said:

I have a friend who rides American Classic 420 wheels on most of
his bikes. They employ a DT stainless spoke which is 1.5mm in the
center (double butted). He has had several cases where he could
not get a spoke to tighten-up while performing maintenance and he
has had to replaced the spoke (with the proper replacement).

Quoted message said:

Quoted message said:

He holds that the problem is that the spoke is stretching (I
suppose like taffy). I have only used heavier gauge spokes. So it
seems unlikely to me that this could be the cause of his problems.
Jobst or anyone else out there have any position on this?

Quoted message said:

Here is a photo my buddy has taken of the spokes in question:

http://home.comcast.net/~whitedavidp/PC240001.JPG

Quoted message said:

The ones with nipples bottomed-out have been cut out of wheels. When
I look at it, I am amazed to believe that these all were supposed to
have started out as the same length.

From the picture it seems the broken spokes are twisted and show a
helical pattern on them. That follows the scenario I mentioned. The
nipple does not turn on the spoke but takes it along as it turns and
goes beyond yield. When a material yields, it does so in the
direction of force, which in this case is both tensile and torsional
(what normally causes fracture) but because the DT spoke material has
both a high yield strength AND ductility, it permanently twists and
elongates simultaneously.

Quoted message said:

Jobst, if I understand your responses, you suggest that the spoke is
twisting in place when the nipple is tightened instead of the nipple
proceeding down the spoke as anticipated. But the nipple has move
down the spoke to the point where it has bottomed-out. If there is
an application of torsional stress to the spoke how could this
account for the greatly increased length of the spokes in the photo?

The spoke is twisting and stretching at the same time but the nipple
must also be advancing a little bit at a time as the spoke work
hardens allowing for some thread movement. I have not seen such a
spoke failure but I think if you look carefully, you'll see that the
spoke is twisted... permanently. As I said, you need to look for
spoke twist as you do this. That can be done with a swipe with a
Sharpie down one side of the spoke, or more dramatically by a small
tape flag stuck on the spoke.

Jobst Brandt

Taman Zonta said:

Metal under tension elongates, first they go through a phase where
elastic elongation dominates, when tension is removed, they spring
back to almost original length, but when tension is applied strong
enough, plastic elongation effect will become noticeable, and the
extensions in the metal stays, they will remain as strong though and
sometimes even stronger.

Quoted message said:

If (I am only making a suggestion here as I have no knowledge of the
actual application) the wheels in question have a faulty design,
that the spokes are not strong enough to carry the force of impact
from the bike and the rider together in motion, or that the previous
owners of those wheel had operated their bikes beyond their design
limit, the spokes may experience tension exceeding their elastic
limit and will suffer permanent elongation. If you really want to
prove it, you can remove some of the spokes and measure their actual
length against each other.

I think you'll find that riding the bicycle primarily slackens spokes
when loads are carried by a wheel. The greatest stresses the spokes
receive are during truing. Therefore, the above assessment should be
revised.

Quoted message said:

You've mentioned that your friend does not have to perform "ongoing
maintenance" on the corrected spokes, it could be that your friend
is a more gentle rider.

You might explain what that does for spokes. I doubt that that is the
case.

Jobst Brandt

Were is the hatrack said:

Quoted message said:

My buddy have purchased several sets of these used and
occasionally, they require some truing and tensioning upon
arrival. He tests for even tension by plucking the spokes like a
harp string and listening to hear that spokes make the same sound
(which I think they should on a radially spoke front wheel).

Quoted message said:

This isn't an accurate measure of tension, however. It's a useful
quick check, but not an accurate measure.

Quoted message said:

Quoted message said:

Sometimes, one or two spoke require more tension and he uses a
normal spoke wrench to tighten them up.

Quoted message said:

Two tools are needed. The other is a pair of vice-grips (with
something to provide "soft jaws" such as a piece of brass scrap in a
V-shape) clamped just below the nipple to keep the spoke from simply
winding up like a long torsion bar spring.

I doubt that you can actually do that because if you try, you'll see
that you cannot hold a spoke without biting into it with saw-tooth
plier faces. This is often suggested and each time I wonder whether
the advice comes from experience or is merely hypothetical. Long ago,
I tried it and found the only way to overcome thread friction was to
unload the spoke by pulling the rim toward the home flange of the
spoke to be adjusted.

Jobst Brandt

Ernie Willson said:

Quoted message said:

I understand that spokes can (and should) "stretch" temporarily
while a wheel is in use. But my question is: can a normal human,
using normal pressure on a normal spoke wrench cause a spoke's
measurable length to increase permanently on the order of .2"?

Quoted message said:

Quoted message said:

I have a friend who rides American Classic 420 wheels on most of
his bikes. They employ a DT stainless spoke which is 1.5mm in the
center

Quoted message said:

I doubt seriously that your friends spokes are stretching that much.
That .2 inch stretch would be about 5mm on a spoke about (say) 230
mm, or about 2% strain (stretch). There are not many high strength
steels that can do this without breaking. ISTM that your friend may
have a wheel with a flat spot, which is causing his problem. The
symptoms would be about the same a you describe. YMMV.

As I mentioned, the stress/strain curves in "the Bicycle Wheel" show
that DT spokes have such a long ductile strain that the spokes tested
did not break but elongated like so much rubber within the stroke of
the testing machine. It is an unusual alloy, ideal for the purpose.
Look at the charts!

Jobst Brandt

Taman Zonta said:

It is really surprising to see such big difference in length, but
you can easily check if the spokes were different in length to start
with, or it was really tension stretching by sliding a caliper (a
micrometer is better if you have one) along the whole length of the
"stretched" spokes, what you will be looking for is change in
diameter.

Quoted message said:

Typically spokes are roll formed therefore should have very uniform
cross sectional diameter, if you notice any change in diameter
(unless they are not stainless steel and have rusted), the spoke has
suffered elongation or begin stretched.

DT swaged spokes are hammer swaged in a machine of great precision
that can reliably make a desired spoke diameter of previously work
hardened wire. Their spokes are made of the same stock whether 2.0mm
straight gauge or 1.5 diameter swaged spokes with a 2.0mm threaded
end. The material ductility apparently does not change much over that
working range or it would fail in manufacture.

Jobst Brandt

In article <[email hidden]>,

Quoted message said:

I doubt that you can actually do that because if you try, you'll see
that you cannot hold a spoke without biting into it with saw-tooth
plier faces. This is often suggested and each time I wonder whether
the advice comes from experience or is merely hypothetical. Long ago,

I've done this with ovalized spokes. I padded the jaws with paper folded over
many times. Using two vice grips, I was able to un-twist a spoke that had
taken a permanent 90 degree twist (loosening the nipple didn't further
un-twist the spoke).