Wheel truer before I stress relieved



big Pete

New Member
Jun 17, 2004
122
0
0
Hi,

I just built my first wheel. I used Jobst Brandts book and Sheldon’s internet wheel building article. I built the wheel then trued it, it was strait and round I was very happy. Then I stress relieved (squeezed parallel spokes together with a firm/strong grip) the wheel was then trued again but I could not get it as true as my first truing before the stress reliving. What did I do wrong? Should I still be tweaking the wheel? The rim is a sunrim cr18, 36 spokes and 3 cross patern.

Thank you very much

Pete
 
big Pete said:
Hi,

I just built my first wheel. I used Jobst Brandts book and Sheldon’s internet wheel building article. I built the wheel then trued it, it was strait and round I was very happy. Then I stress relieved (squeezed parallel spokes together with a firm/strong grip) the wheel was then trued again but I could not get it as true as my first truing before the stress reliving. What did I do wrong? Should I still be tweaking the wheel? The rim is a sunrim cr18, 36 spokes and 3 cross patern.

Thank you very much

Pete
Keep working the process.
Are your spokes tension balanced?
Are your spokes aligned?
Some Sun rims don't come as true as you might like, but if the spokes are properly tensioned, tension balanced, aligned, and stress relieved; it is OK to have up to 0.5 mm variance in run-out.

David Ornee, Western Springs, IL

P.S.: Just built the MTB 26" CR18s and had similar results... not as good as most Mavic and Velocity rims... but accpetable.
 
On Thu, 14 Apr 2005 00:14:36 +1000, big Pete
<[email protected]> wrote:

>I just built my first wheel. I used Jobst Brandts book and Sheldon’s
>internet wheel building article. I built the wheel then trued it, it
>was strait and round I was very happy. Then I stress relieved (squeezed
>parallel spokes together with a firm/strong grip) the wheel was then
>trued again but I could not get it as true as my first truing before
>the stress reliving. What did I do wrong?


Nothing.

>Should I still be tweaking the wheel?


Yes.

Mastery of wheel truing comes with practice. Your experience thus far
is similar to what mine was at a similar point; perseverence, patience
and attention to details and fundamentals will yield the result you
seek, and each time it will get easier.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
On Wed, 13 Apr 2005 20:34:35 GMT, Werehatrack <[email protected]>
wrote:

>On Thu, 14 Apr 2005 00:14:36 +1000, big Pete
><[email protected]> wrote:
>
>>I just built my first wheel. I used Jobst Brandts book and Sheldon’s
>>internet wheel building article. I built the wheel then trued it, it
>>was strait and round I was very happy. Then I stress relieved (squeezed
>>parallel spokes together with a firm/strong grip) the wheel was then
>>trued again but I could not get it as true as my first truing before
>>the stress reliving. What did I do wrong?

>
>Nothing.
>
>>Should I still be tweaking the wheel?

>
>Yes.
>
>Mastery of wheel truing comes with practice. Your experience thus far
>is similar to what mine was at a similar point; perseverence, patience
>and attention to details and fundamentals will yield the result you
>seek, and each time it will get easier.


Am I correct in thinking this is akin to tuning a piano with 32 identical
strings at the same pitch?

Ron
 
big Pete wrote:
> Hi,
>
> I just built my first wheel. I used Jobst Brandts book and Sheldon’s
> internet wheel building article. I built the wheel then trued it, it
> was strait and round I was very happy. Then I stress relieved (squeezed
> parallel spokes together with a firm/strong grip) the wheel was then
> trued again but I could not get it as true as my first truing before
> the stress reliving. What did I do wrong? Should I still be tweaking
> the wheel? The rim is a sunrim cr18, 36 spokes and 3 cross patern.
>
> Thank you very much
>
> Pete
>
>

of course it goes out of true - you're over-stressing the hub/spoke &
spoke/rim contact points causing local yielding and therefore reducing
spoke tension. this is "bedding in". just repeat the process & true,
repeat process & true until it's done yielding. then you're set pretty
much for the life of the wheel. make sure you do not over tension.
this "tension as high as the rim will bear" nonsense will cause you
reliability problems & an increased propensity to taco. in fact, you
may be on the verge of it now, hence the difficulty truing.
 
[email protected] wrote:

> On Wed, 13 Apr 2005 20:34:35 GMT, Werehatrack wrote:
>>
>> Mastery of wheel truing comes with practice. Your experience thus far
>> is similar to what mine was at a similar point; perseverence, patience
>> and attention to details and fundamentals will yield the result you
>> seek, and each time it will get easier.

>
> Am I correct in thinking this is akin to tuning a piano with 32 identical
> strings at the same pitch?


I'm not a piano tuner, but I imagine there is little dependence of tension
in one string to the others, unlike spokes in a bicycle wheel.

--
Benjamin Lewis

Evelyn the dog, having undergone further modification, pondered the
significance of short-person behavior in pedal-depressed panchromatic
resonance and other highly ambient domains... "Arf", she said.
 
On Thu, 14 Apr 2005 13:51:58 -0700, Benjamin Lewis
<[email protected]> wrote:

>[email protected] wrote:
>
>> On Wed, 13 Apr 2005 20:34:35 GMT, Werehatrack wrote:
>>>
>>> Mastery of wheel truing comes with practice. Your experience thus far
>>> is similar to what mine was at a similar point; perseverence, patience
>>> and attention to details and fundamentals will yield the result you
>>> seek, and each time it will get easier.

>>
>> Am I correct in thinking this is akin to tuning a piano with 32 identical
>> strings at the same pitch?

>
>I'm not a piano tuner, but I imagine there is little dependence of tension
>in one string to the others, unlike spokes in a bicycle wheel.


Dear Benjamin,

Actually, there's notable (sorry, couldn't resist it)
dependence between the strings. Ya gotta tension 'em up to
roughly the correct levels and then adjust 'em. There's 15
to 20 tons of tension involved with 150-200 lbs per string:

http://pianoeducation.org/pnotunng.html

http://www.bluebookofpianos.com/tuning.htm

Even with a violin, the four comparatively tiny strings must
first be raised to roughly correct tension, then tuned one
by one more precisely, and then fiddled around (sorry again)
a little more again.

A quick demonstration of the interdependence is to tune a
fiddle carefully, admire the charming fifth of its two upper
A & E strings, and then slack off the lowest string, G. The
A-E chord immediately goes sour.

When tuned, the four violin strings press down sideways on
the bridge near the middle with about thirty pounds of
force:

http://www.rivertonmusic.com/newsletters.asp

This tension and pressure bows the ends of the fiddle up and
its middle down. If you lose a quarter of that tension and
pressure, the long wooden frame straightens a little, like
a 4-strand archer's bow if one strand is cut. (There's also
a sideways imbalance--the neck would curve a bit toward the
A-E side.)

Carl Fogel
 
[email protected] wrote:
> Actually, there's notable (sorry, couldn't resist it)
> dependence between the strings. Ya gotta tension 'em up to
> roughly the correct levels and then adjust 'em. There's 15
> to 20 tons of tension involved with 150-200 lbs per string:
>
> Even with a violin, the four comparatively tiny strings must
> first be raised to roughly correct tension, then tuned one
> by one more precisely, and then fiddled around (sorry again)
> a little more again.


You're right about this, but there is a fundamental difference: raising
tension on a string on a violin or piano will tend to reduce tension on
other strings; raising tension on a spoke will also raise the tension
on opposing spokes. If a wheelbuilder starts working around a wheel
bringing each spoke up to a certain pitch, they will wind up with a big
mess, even if done incrementally.

It seems to me that progressively tensioning spokes by giving each one
the same amount of turn from the spoke wrench works better than relying
on pitch. Theoretically, with perfect components and perfect
measurement, this should result in equilized tension and round wheels.
Practically, it seems like I am able to get wheels true and round this
way, using tension differences (plucking) as an aid to final truing of
the wheels- to help determine which spokes to adjust.
 
<[email protected]> wrote in message
news:[email protected]...
>
> Even with a violin, the four comparatively tiny strings must
> first be raised to roughly correct tension, then tuned one
> by one more precisely, and then fiddled around (sorry again)
> a little more again.
>


Interesting, but hardly relevant to a bicycle wheel.

The aim of tuning a musical instrument is to bring the pitch(es) to match to
within a few - or less - cents. A similar difference in tone of a bicycle
spoke will produce essentially no difference to the truth of the rim. If
your wheel is true (and tight, and stress-relieved, etcetera) and all the
spokes are within a fifth, ride it.
 
[email protected] wrote:

> <[email protected]> wrote:
>>
>> I'm not a piano tuner, but I imagine there is little dependence of
>> tension in one string to the others, unlike spokes in a bicycle wheel.

>
> Dear Benjamin,
>
> Actually, there's notable (sorry, couldn't resist it) dependence between
> the strings. Ya gotta tension 'em up to roughly the correct levels and
> then adjust 'em. There's 15 to 20 tons of tension involved with 150-200
> lbs per string:
>
> http://pianoeducation.org/pnotunng.html
>
> http://www.bluebookofpianos.com/tuning.htm
>
> Even with a violin, the four comparatively tiny strings must first be
> raised to roughly correct tension, then tuned one by one more precisely,
> and then fiddled around (sorry again) a little more again.


I agree, but this effect is small compared to a bicycle wheel. Think about
the change in tension in one spoke if you remove all the others...

On a violin or guitar, if you remove all but one string, the change in that
string will be less than a quarter-tone, in my recollection.

On the other hand, much more precision in string tension is needed in a
musical instrument. Still, in my experience, more iterations are required
in wheel building than in violin/guitar tuning, and I expect the same is
true for a piano.

I would be interested to know what the change in pitch of a single piano
string would be if all the others were removed.

--
Benjamin Lewis

Evelyn the dog, having undergone further modification, pondered the
significance of short-person behavior in pedal-depressed panchromatic
resonance and other highly ambient domains... "Arf", she said.
 
On 15 Apr 2005 10:24:23 -0700,
[email protected] wrote:

>[email protected] wrote:
>> Actually, there's notable (sorry, couldn't resist it)
>> dependence between the strings. Ya gotta tension 'em up to
>> roughly the correct levels and then adjust 'em. There's 15
>> to 20 tons of tension involved with 150-200 lbs per string:
>>
>> Even with a violin, the four comparatively tiny strings must
>> first be raised to roughly correct tension, then tuned one
>> by one more precisely, and then fiddled around (sorry again)
>> a little more again.

>
>You're right about this, but there is a fundamental difference: raising
>tension on a string on a violin or piano will tend to reduce tension on
>other strings; raising tension on a spoke will also raise the tension
>on opposing spokes. If a wheelbuilder starts working around a wheel
>bringing each spoke up to a certain pitch, they will wind up with a big
>mess, even if done incrementally.
>
>It seems to me that progressively tensioning spokes by giving each one
>the same amount of turn from the spoke wrench works better than relying
>on pitch. Theoretically, with perfect components and perfect
>measurement, this should result in equilized tension and round wheels.
>Practically, it seems like I am able to get wheels true and round this
>way, using tension differences (plucking) as an aid to final truing of
>the wheels- to help determine which spokes to adjust.


Dear STW,

Nice point about the inverted effect of tension change.

When I'm damaging helpless wheels in a truing stand, I now
use a tensiometer. It shows both the relative tension
(whoops, that's awfully loose) and the absolute tension
(oops, let's try what the manufacturer suggested).

Carl Fogel
 
Hey Big Pete -

One comment that was made by an earlier poster has practical
ramifications - that is that the tension of all spokes is in part
dependent on the tension of others. At least in my wheel building
practice.

Chief among these ramifications is that during the final truing
process, in order to maintain the current tension in the wheel, when
spokes are tensioned on one side, the other adjacent spokes (that run
to the other side of the hub) should be slackened. The key to good
wheels is high (per Jobst) and UNIFORM tension. This process does
that.

The ratio of the lateral vectors of the spoke tension determine the
relative slacking/tensioning on rear wheels (1 to 1 for front, although
with some complications to be discussed later). For a 3x rear, the
ratio of the vectors is 2:1 (nondrive:drive) which means that if you
adjust a DS spoke by a 1/2 turn, an opposite 1/4 turn (that 2:1 ratio
in lateral tension) is performed to maintain the uniformity of the
tension of the wheel.

Trial and error will lead to the proper amount of adjustment to provide
the appropriate shift in the trueness of the wheel - your first
attempts will result in slight overshoot because you will turn the one
spoke on one side of the wheel to correct the wheel but when the
opposing spokes are adjusted, it will move slightly more.

The complications I alluded to are as follows: generally, when
performing final truing, your target spoke (the one in the center of
the area out of true) should be adjusted first. Then, BOTH of the
spokes from the opposite side of the hub should be adjusted, but the
opposite and equal (in terms of lateral tension vector)adjustment that
would have been applied to one spoke is divided between those two
spokes.

You will be able to get that final true you are looking for.

App, who was feeling especially long-winded tonight.
 
Ed wrote:
> In article <[email protected]>,
> [email protected] says...
>
>> You're right about this, but there is a fundamental difference:
>> raising tension on a string on a violin or piano will tend to reduce
>> tension on other strings; raising tension on a spoke will also raise
>> the tension on opposing spokes. If a wheelbuilder starts working
>> around a wheel bringing each spoke up to a certain pitch, they will
>> wind up with a big mess, even if done incrementally.
>>
>> It seems to me that progressively tensioning spokes by giving each
>> one the same amount of turn from the spoke wrench works better than
>> relying on pitch. Theoretically, with perfect components and perfect
>> measurement, this should result in equilized tension and round
>> wheels. Practically, it seems like I am able to get wheels true and
>> round this way, using tension differences (plucking) as an aid to
>> final truing of the wheels- to help determine which spokes to adjust.
>>

> Does anyone build wheels by alternating the tightening across the
> wheel like tightening lug nuts on a car?


No, but I do that for disc brake rotors.
--
Phil, Squid-in-Training
 
> In article <[email protected]>,
> [email protected] says...
>>You're right about this, but there is a fundamental difference: raising
>>tension on a string on a violin or piano will tend to reduce tension on
>>other strings; raising tension on a spoke will also raise the tension
>>on opposing spokes. If a wheelbuilder starts working around a wheel
>>bringing each spoke up to a certain pitch, they will wind up with a big
>>mess, even if done incrementally.
>>
>>It seems to me that progressively tensioning spokes by giving each one
>>the same amount of turn from the spoke wrench works better than relying
>>on pitch. Theoretically, with perfect components and perfect
>>measurement, this should result in equilized tension and round wheels.
>>Practically, it seems like I am able to get wheels true and round this
>>way, using tension differences (plucking) as an aid to final truing of
>>the wheels- to help determine which spokes to adjust.


Ed wrote:
> Does anyone build wheels by alternating the tightening across the wheel like
> tightening lug nuts on a car?


Only if you want to add a half-hour to a twenty minuite job.

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

Similar threads