Weird Wheel Building Experience

Robert Perkins said:

I have a 700c wheel with a MA2 rim, 32 14-15-14 gauge butted DT spokes,
and a 7-speed Shimano XT hub.

I have had trouble with this rim since I built it up a few years ago.  I
use it on a travel bike I have with S&S couplers.

The wheel had two waves out of true.  One was 6 spokes long left side,
the other 6 spokes long on the right, each about 1cm out of true.  I
gradually backed off the tension on the spokes and the rim became
straighter.  At no tension, the rim had one short 3-spoke long bend of
about 8mm.

So, I thought, I will use my tensiometer and really slowly raise the
tension.  The wheel rim is pretty straight, and after getting even
tension on each sides' spokes, I can take out the imperfections.  I
tightened spokes by 1/2 turns at first, checking an correcting tension
after each revolution.  I then made 1/4 turns.  Though the spokes had
even tension, the rim started to deform again left and right!  After a
few rounds of tighten, then check tension to make sure it is even, and
tighten more, I gave up.  The wheel was wavy as could be.

So, I went back to my pre-tensiometer days.  Again, I first started
increasing tension by 1/2 turns.  At the end of each revolution, I trued
tbe wheel in my Park truing stand.  This went on for subsequent rounds.
  I did check tensions, which stayed pretty equal on the right (drive) side.

I then took out any high or low spots in the rim.

So, why is it that using a tensiometer to check even tension each round
led to a mambo rim?

Thanks, Rob

I'd reckon you over-tensioned it. the rim is toast.

Rob asks...

Quoted message said:

So, why is it that using a tensiometer to check
even tension each round led to a mambo rim?

...after writing

Quoted message said:

At no tension, the rim had one short 3-spoke long
bend of about 8mm.

If you think this one through just a bit more Rob, I believe you'll
know the answer to your question.

I like this post because it's another example of what the phrase "when
variables collide" means. Rob has should us that when you do little to
eliminate or reduced the effect of a variable, (bent rim) the _process_,
regardless of how precise it is (tensiometer each round) is all for
naught.

Good post Rob and thanks for sharing.

Best Regards - Mike Baldwin

...Rob has "should" us ? Should read _showed_ us....oh the irony! LOL

Best Regards - Mike Baldwin

PS - ...every now and then that pesky "only human" side of me is
exposed...

Michael Baldwin said:

I like this post because it's another example of what the phrase "when
variables collide" means. Rob has shown us that when you do little to
eliminate or reduced the effect of a variable, (bent rim) the _process_,
regardless of how precise it is (tensiometer each round) is all for
naught.

I think you are saying that the rim itself is the variable, since it
could have some sort of variance in the condition of the aluminum. I
don't build many wheels, and I could have damaged the rim in spots, I
guess, on the initial build, subsequent truings, plus of course road
damage.

Is it possible for a rim which, when untensioned, is straight, to react
differently to the same tension because of the underlying work hardening
of the different parts of the rim?

When I built the rim the second time, w/o the tensiometer, I used mostly
tone to make sure that the tension was uniform. That is a lot more fun,
I find, compared to using a tensiometer.

This rim has been on head-sized German cobbles and Arizona unpaved
mountain roads. Maybe that is why different parts of the rim reacted
differently to the same tension. Therein lies the extra variable, perhaps.

I went to work yesterday morning with the rim perfectly true, and when I
came home, it was once again out of true a bit in a couple of places.
Either spoke windup is unwinding, or the rim is yielding, or something
else is going on that I don't pretend to understand.

Yes, I stress relieved the spokes. Tension on the right side is
anywhere from 90-110 KgF according to the Park chart. I'm careful to
measure in the 1.8mm middle of the spoke.

R

In article <[email hidden]>,

Robert Perkins said:

I have a 700c wheel with a MA2 rim, 32 14-15-14 gauge butted DT
spokes, and a 7-speed Shimano XT hub.

I have had trouble with this rim since I built it up a few years ago.
I use it on a travel bike I have with S&S couplers.

The wheel had two waves out of true. One was 6 spokes long left
side, the other 6 spokes long on the right, each about 1cm out of
true. I gradually backed off the tension on the spokes and the rim
became straighter. At no tension, the rim had one short 3-spoke long
bend of about 8mm.

Those are the symptoms of an over-tensioned wheel. You didn't tell us
what the reading of the spoke tensiometer was. The rim has probably
taken a set and is now bent, with variations that large. I'd take the
wheel apart and see how the rim sits on a flat surface- my guess is that
it has a slight potato chip shape. You might be able to judiciously
bend it back into almost-plane and re-use it.

Robert Perkins said:

I have a 700c wheel with a MA2 rim, 32 14-15-14 gauge butted DT spokes,
and a 7-speed Shimano XT hub.

I have had trouble with this rim since I built it up a few years ago. I
use it on a travel bike I have with S&S couplers.

The wheel had two waves out of true. One was 6 spokes long left side,
the other 6 spokes long on the right, each about 1cm out of true. I
gradually backed off the tension on the spokes and the rim became
straighter. At no tension, the rim had one short 3-spoke long bend of
about 8mm.

So, I thought, I will use my tensiometer and really slowly raise the
tension. The wheel rim is pretty straight, and after getting even
tension on each sides' spokes, I can take out the imperfections. I
tightened spokes by 1/2 turns at first, checking an correcting tension
after each revolution. I then made 1/4 turns. Though the spokes had
even tension, the rim started to deform again left and right! After a
few rounds of tighten, then check tension to make sure it is even, and
tighten more, I gave up. The wheel was wavy as could be.

So, I went back to my pre-tensiometer days. Again, I first started
increasing tension by 1/2 turns. At the end of each revolution, I trued
tbe wheel in my Park truing stand. This went on for subsequent rounds.
I did check tensions, which stayed pretty equal on the right (drive) side.
I then took out any high or low spots in the rim.
So, why is it that using a tensiometer to check even tension each round
led to a mambo rim?

Without seeing the wheel, here are some thoughts:
If you fully detension the rim, does it lie straight? Is it round?
Probably not.
A bent rim will require uneven tension to run in a single plane. Making
every spoke the same tension will not help and is more likely to
exacerbate the problem than to correct it, especially if it is not round.

A tensiometer is quite useful to check the average tension of a uniform
new wheel. Try making the rim both straight and round and then check
each and every spoke. The tension variance will quantify just how
wrecked this rim is.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Andrew Muzi said:

Quoted message said:

I have a 700c wheel with a MA2 rim, 32 14-15-14 gauge butted DT
spokes, and a 7-speed Shimano XT hub.

Quoted message said:

Quoted message said:

I have had trouble with this rim since I built it up a few years
ago. I use it on a travel bike I have with S&S couplers.

Quoted message said:

Quoted message said:

The wheel had two waves out of true. One was 6 spokes long left
side, the other 6 spokes long on the right, each about 1cm out of
true. I gradually backed off the tension on the spokes and the rim
became straighter. At no tension, the rim had one short 3-spoke
long bend of about 8mm.

Quoted message said:

Quoted message said:

So, I thought, I will use my tensiometer and really slowly raise
the tension. The wheel rim is pretty straight, and after getting
even tension on each sides' spokes, I can take out the
imperfections. I tightened spokes by 1/2 turns at first, checking
an correcting tension after each revolution. I then made 1/4
turns. Though the spokes had even tension, the rim started to
deform again left and right! After a few rounds of tighten, then
check tension to make sure it is even, and tighten more, I gave up.
The wheel was wavy as could be.

Quoted message said:

Quoted message said:

So, I went back to my pre-tensiometer days. Again, I first started
increasing tension by 1/2 turns. At the end of each revolution, I
trued the wheel in my Park truing stand. This went on for
subsequent rounds. I did check tensions, which stayed pretty equal
on the right (drive) side. I then took out any high or low spots
in the rim. So, why is it that using a tensiometer to check even
tension each round led to a mambo rim?

Quoted message said:

Without seeing the wheel, here are some thoughts:

Quoted message said:

If you fully de-tension the rim, does it lie straight? Is it round?
Probably not. A bent rim will require uneven tension to run in a
single plane. Making every spoke the same tension will not help and
is more likely to exacerbate the problem than to correct it,
especially if it is not round.

Quoted message said:

A tensiometer is quite useful to check the average tension of a
uniform new wheel. Try making the rim both straight and round and
then check each and every spoke. The tension variance will quantify
just how wrecked this rim is.

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Jobst Brandt

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Are you suggesting that the particular mountain range is one of the
variables in wheel building? Of is it the elevation that distorts
rims? 😉

R

RicodJour ? said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Are you suggesting that the particular mountain range is one of the
variables in wheel building? Of is it the elevation that distorts
rims? 😉

It all depends on how the variables collide! 😉

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Quoted message said:

Andrew Muzi said:

Quoted message said:

I have a 700c wheel with a MA2 rim, 32 14-15-14 gauge butted DT
spokes, and a 7-speed Shimano XT hub.

Quoted message said:

Quoted message said:

I have had trouble with this rim since I built it up a few years
ago. I use it on a travel bike I have with S&S couplers.

Quoted message said:

Quoted message said:

The wheel had two waves out of true. One was 6 spokes long left
side, the other 6 spokes long on the right, each about 1cm out of
true. I gradually backed off the tension on the spokes and the rim
became straighter. At no tension, the rim had one short 3-spoke
long bend of about 8mm.

Quoted message said:

Quoted message said:

So, I thought, I will use my tensiometer and really slowly raise
the tension. The wheel rim is pretty straight, and after getting
even tension on each sides' spokes, I can take out the
imperfections. I tightened spokes by 1/2 turns at first, checking
an correcting tension after each revolution. I then made 1/4
turns. Though the spokes had even tension, the rim started to
deform again left and right! After a few rounds of tighten, then
check tension to make sure it is even, and tighten more, I gave up.
The wheel was wavy as could be.

Quoted message said:

Quoted message said:

So, I went back to my pre-tensiometer days. Again, I first started
increasing tension by 1/2 turns. At the end of each revolution, I
trued the wheel in my Park truing stand. This went on for
subsequent rounds. I did check tensions, which stayed pretty equal
on the right (drive) side. I then took out any high or low spots
in the rim. So, why is it that using a tensiometer to check even
tension each round led to a mambo rim?

Quoted message said:

Without seeing the wheel, here are some thoughts:

Quoted message said:

If you fully de-tension the rim, does it lie straight? Is it round?
Probably not. A bent rim will require uneven tension to run in a
single plane. Making every spoke the same tension will not help and
is more likely to exacerbate the problem than to correct it,
especially if it is not round.

Quoted message said:

A tensiometer is quite useful to check the average tension of a
uniform new wheel. Try making the rim both straight and round and
then check each and every spoke. The tension variance will quantify
just how wrecked this rim is.

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

but you first reported using that rim back in november 2005.

http://groups.google.com/group/rec.bicycles.tech/msg/59d553503863411c

if you've done 5000 miles in two years, or 2500 miles per year, to have
ridden that "same" wheel [or at least, hub and spokes] 300000 miles, it
would have taken...

Ricod Jour said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Quoted message said:

Are you suggesting that the particular mountain range is one of the
variables in wheel building? Of is it the elevation that distorts
rims? 😉

Not funny! The Alps have little flatland and many fast descent with
heavy braking, in contrast to riding the local parade route to display
fancy equipment (locally that would be Foothill Expy).

http://www.paloaltobicycles.com/alps_photos.html

Jobst Brandt

RicodJour said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Are you suggesting that the particular mountain range is one of the
variables in wheel building? Of is it the elevation that distorts
rims? 😉

Corilois effect on fast North/South descents. Well known for causing
rims to warp.

Rob asks

Quoted message said:

Is it possible for a rim which, when untensioned, is
straight, to react differently to the same tension because of
the underlying work hardening of the different parts of the
rim?

Rob, I'm not sure "work hardening" is an applicable term in this case.
The average alloy rim begins life as an extruded hoop. I'm unaware of
any "work hardening" relative to the extrusion process.
But your rim Rob, _untensioned_, had what you described as a 8mm (I
think?) deflection (bend, dent, etc) That was the _variable_ that I
felt needed addressing. Jobst Brandt's book, the Bicycle Wheel has a
section devoted to fixing dented rims.
In the past, I like yourself, have struggled along trying to get a
wheel to stay true. Only _after_ I decided to relieve all of the
tension did I realize I was trying to true a "wowed" rim.
Also, Andrew Muzi's reply to your post is spot on in my opinion.

Best Regards - Mike Baldwin

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Jobst Brandt

That is what I thought. With just a small defect, I should have been
able to keep the rim true through building through the whole process.
I started off with no tension, and then increased it by 1/2 turns, then
checking spoke tension after each round of tightening and equalizing the
tension. I didn't try to make the rim "true" after every round, just
equal tension according to the tensiometer. I figured I would do that
after the rim was up to about 80KgF. After 4 rounds I was building a
pretzel.

When I initially untensioned the wheel, I was expecting to have to bend
the potato chip untensioned rim back into shape. I was mystified that
it was actually pretty true, having just the 10mm wobble. I use a Park
TS-2 truing stand.

I probably trashed the rim somehow earlier with an amateurish build.
But, hey, it is fun.

Rob "most of the wheels I've built actually work" Perkins

jim beam said:

but you first reported using that rim back in november 2005.

http://groups.google.com/group/rec.bicycles.tech/msg/59d553503863411c

if you've done 5000 miles in two years, or 2500 miles per year, to have
ridden that "same" wheel [or at least, hub and spokes] 300000 miles, it
would have taken...

Hey, Jim, thanks for helping provide great info for this thread. I now
much better understand what is going on with my rim.

Rob "Yap Yap Yap" Perkins

Robert Perkins said:

jim beam said:

but you first reported using that rim back in november 2005.

http://groups.google.com/group/rec.bicycles.tech/msg/59d553503863411c

if you've done 5000 miles in two years, or 2500 miles per year, to
have ridden that "same" wheel [or at least, hub and spokes] 300000
miles, it would have taken...

Hey, Jim, thanks for helping provide great info for this thread. I now
much better understand what is going on with my rim.

Rob "Yap Yap Yap" Perkins

i'd have thought that by reading the andrew muzi sub-thread, you'd have
the answer by now. because he's right on the money. if not, go back to it.

Frank Leake said:

Quoted message said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued
with hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like
that straight as can be for about 5000 miles, including a tour
over the Alps last summer.

Quoted message said:

Quoted message said:

Are you suggesting that the particular mountain range is one of the
variables in wheel building? Of is it the elevation that distorts
rims?

Quoted message said:

Corilois effect on fast North/South descents. Well known for
causing rims to warp.

Who discovered this new effect? I've never hear of it. Please expand.

Jobst Brandt

Robert Perkins said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim. That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer. I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

I guess I forgot a summer on that. Its been over the Alps a couple of
summers. In any case, there is no problem with a small wow like that.

The best way to straighten a wobbly wheel, that would otherwise
require largely uneven spoke tension, is with relaxed tension but
without slack spokes. Laying the wheel on the floor and springing the
wheel downward by pressing down with hands to either side of the wow
usually straightens it. This is an easily reversible process if you
overshoot. Don't do this on a fully tensioned wheel or you will get
permanent distortion.

Quoted message said:

That is what I thought. With just a small defect, I should have
been able to keep the rim true through building through the whole
process. I started off with no tension, and then increased it by
1/2 turns, then checking spoke tension after each round of
tightening and equalizing the tension. I didn't try to make the rim
"true" after every round, just equal tension according to the
tensiometer. I figured I would do that after the rim was up to
about 80KgF. After 4 rounds I was building a pretzel.

For final tensioning, a half turn may be a bit large unless you are
sure of your target tension with that move. I don't know what your
rim can hold or what is specified by the manufacturer, but from what
you say, it seems you exceeded its maximum tension. Had you stress
relieved after each round of tightening, you would have known for
sure at what tension that was.

Quoted message said:

When I initially untensioned the wheel, I was expecting to have to
bend the potato chip untensioned rim back into shape. I was
mystified that it was actually pretty true, having just the 10mm
wobble. I use a Park TS-2 truing stand.

Quoted message said:

I probably trashed the rim somehow earlier with an amateurish build.
But, hey, it is fun.

As I said, 10mm isn't a big wow if it spans a quarter wheel. That
type of wow is usually a sign of excess tension. Try a lower tension
and get hat wheel round and true.

Jobst Brandt

Robert Perkins said:

Quoted message said:

With a wow of 10mm, this is not a wrecked rim.  That can be trued with
hardly and audible pitch difference in plucked spokes, barely
detectable on a tensiometer.  I am currently riding an MA-40 that
someone discarded for such a "flaw" and it has been running like that
straight as can be for about 5000 miles, including a tour over the
Alps last summer.

Quoted message said:

Jobst Brandt

That is what I thought.  With just a small defect, I should have been
able to keep the rim true through building through the whole process.
I started off with no tension, and then increased it by 1/2 turns, then
checking spoke tension after each round of tightening and equalizing the
tension.  I didn't try to make the rim "true" after every round, just
equal tension according to the tensiometer.  I figured I would do that
after the rim was up to about 80KgF.  After 4 rounds I was building a
pretzel.

When I initially untensioned the wheel, I was expecting to have to bend
the potato chip untensioned rim back into shape.  I was mystified that
it was actually pretty true, having just the 10mm wobble. I use a Park
TS-2 truing stand.

I probably trashed the rim somehow earlier with an amateurish build.
But, hey, it is fun.

Rob "most of the wheels I've built actually work" Perkins

I don't see how you could deform an MA-2 with 90-110 kgf. I've run
those suckers much higher with no problems, except spoke hole cracking
years later. Did you side load the wheel while building? The MA-2 is
about the most forgiving road rim in the world for a new builder, next
to maybe a SuperChamp Mod 58. It's like the instant pudding of wheel
building.-- Jay Beattie.