Boken spoke

I have several thousand heavily loaded miles on my rear wheel (Alex
rim, Shimano hub, DT (I think) spokes), and even more on my front, the
componants of which escape me. Spokes break because the wheel isn't
tensioned properly, according to conventional wisdom. It's said that
machine-built wheels often have problems (mine were hand-built.)

So I'd suggest that you get the whole wheel trued and tensioned
properly. A typical LBS charge for this is between $15-$30 dollars,
perhaps less if the bike came from them.

Then again, if the bike came from an LBS with 'factory' wheels, you
might consider another, more service-oriented shop.

Jim said:

Why would a spoke break on a wheel with less than 300 miles. It broke

on

Quoted message said:

a smooth rode while riding about 24 or 25 MPH. The wheels are ALEX
at-400. Is this a good brand or should I expect trouble.

A boken has no spokes:

http://www.combatgear.co.uk/images/bok1.jpg

Spokes break on relatively new wheels either because the spokes are
defective, or (more commonly) because the wheels were improperly built.
This issue is addressed in the FAQ for this group.

Alex AT-400 is the kind of rim you have, not a kind of wheel. In my
experience, Alex rims are of consistently good quality.

Since your wheels are so new, I suggest you have the broken spoke
replaced and the wheels tensioned, trued, and stress-relieved by an
experienced wheel builder; it is likely that they will give you no more
trouble after that.

Chalo Colina

Brian Huntley said:

I have several thousand heavily loaded miles on my rear wheel (Alex
rim, Shimano hub, DT (I think) spokes), and even more on my front,
the componants of which escape me. Spokes break because the wheel
isn't tensioned properly, according to conventional wisdom. It's
said that machine-built wheels often have problems (mine were
hand-built.)

I see this stated often in this newsgroup with no explanation why
improper tension causes spoke failures. I believe that metal fatigue
has been identified as the cause of spoke failures yet no connection
between "properly tensioned" and fatigue has been presented. Would
you please offer some causal relationship between the two and define
what "properly tensioned" means.

Quoted message said:

So I'd suggest that you get the whole wheel trued and tensioned
properly. A typical LBS charge for this is between $15-$30 dollars,
perhaps less if the bike came from them.

How does one know whether the wheels are "properly tensioned" after
paying $15-$30 and why should one pay such a sum to a bicycle shop
that sold a bicycle with unreliable wheels?

Quoted message said:

Then again, if the bike came from an LBS with 'factory' wheels, you
might consider another, more service-oriented shop.

What is it with 'factory' wheels that makes them fail more readily?
We could use a definition of 'factory" wheels as well.

Jobst Brandt
[email hidden]

Jobst Brandt said:

Brian Huntley writes:
...

Quoted message said:

So I'd suggest that you get the whole wheel trued and tensioned
properly. A typical LBS charge for this is between $15-$30 dollars,
perhaps less if the bike came from them.

How does one know whether the wheels are "properly tensioned" after
paying $15-$30 and why should one pay such a sum to a bicycle shop
that sold a bicycle with unreliable wheels?...

If Jobst Brandt was less modest, he might recommend spending $24.95 at
Harris Cyclery: <http://www.sheldonbrown.com/harris/books.html>.

--
Tom Sherman - Earth

Quoted message said:

Quoted message said:

Then again, if the bike came from an LBS with 'factory' wheels, you
might consider another, more service-oriented shop.

What is it with 'factory' wheels that makes them fail more readily?
We could use a definition of 'factory" wheels as well.

OK, I'll help out if nobody else will. Somewhat ironic since the respondent
asking the rhetorical questions wrote the FAQ on the matter...

"Factory" wheels are often built up with the "little details" missing. For
example, it's common to see the spoke not pressed flat against the flange
where they exit the hub. Yikes. Over time, the spoke will gradually
straighten out, causing it to become loose. A wheel should always be built
with the spokes taking the shortest-possible distance between its ends; this
typically means physically flattening the spoke against the flange (a strong
thumb does the trick). This can easily be done to an already-built wheel;
just make sure you increase the tension afterward, since the spokes will now
be quite a bit looser.

"Factory" wheels also sometimes lack any lubrication between the spoke
nipple & the rim, which makes it difficult to tighten the nipples. If you're
truing such a wheel and don't have the time to remove the tire, tube &
rimstrip and apply lube, and you're having a difficult time tightening one
of the spokes, try doing it wheel still mounted in the bike and physically
deflect the wheel (by pulling it) in the direction that it needs to go. That
will lower the tension on the spokes that you need to tighten (until you let
go of the rim!), allowing you to get the tension where it needs to be
without destroying the spoke nipple.

"Factory" wheels are also likely not stress-relieved, which can cause
premature failure. Best to read from the FAQ
(http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html) on this point, but the
relevant section is quoted below-

"... spokes in a newly built wheel have locations where stress
is near yield, some more so than others. Because fatigue endurance of
a metal at or near the yield stress is short, cyclic loads in such
spokes will cause failures at high stress points.

"Stress relieving to relax these high stress points is accomplished by
over-stressing them in order to erase their memory. It is not done to
bed the spokes into the hub, as is often stated. Bedding-in occurs
sufficiently from tension. However, stretching spoke pairs with a
strong grasp at midspan, can momentarily increased tension by 50% to
100%. Because spokes are usually tensioned no higher than 1/3 their
yield stress, this operation has no effect on the spoke as a whole,
affecting only the small high stress zones where spokes are near
yield. By stretching them, these zones relax below yield by as much
as the overload."

Obviously, this can be performed on an already-built wheel without
difficulty.

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

Brian Huntley said:

Spokes break because the wheel isn't
tensioned properly, according to conventional wisdom. It's said that
machine-built wheels often have problems (mine were hand-built.)

Usually true, but, I've built wheel that broke spoke in a short
period of time. Sometimes, there is a bad spoke in a batch. They
don't break when stress relieving but do break after some use. I've
forgotten the details, but DT changed the bend in the head of their
spokes for a while a couple of years ago and there was spoke breaking
problems on new spokes.

Mike Jacoubowsky said:

Quoted message said:

Quoted message said:

Then again, if the bike came from an LBS with 'factory' wheels, you
might consider another, more service-oriented shop.

What is it with 'factory' wheels that makes them fail more readily?
We could use a definition of 'factory" wheels as well.

OK, I'll help out if nobody else will. Somewhat ironic since the respondent
asking the rhetorical questions wrote the FAQ on the matter...

"Factory" wheels are often built up with the "little details" missing. For
example, it's common to see the spoke not pressed flat against the flange
where they exit the hub. Yikes. Over time, the spoke will gradually
straighten out, causing it to become loose. A wheel should always be built
with the spokes taking the shortest-possible distance between its ends; this
typically means physically flattening the spoke against the flange (a strong
thumb does the trick). This can easily be done to an already-built wheel;
just make sure you increase the tension afterward, since the spokes will now
be quite a bit looser.

"Factory" wheels also sometimes lack any lubrication between the spoke
nipple & the rim, which makes it difficult to tighten the nipples. If you're
truing such a wheel and don't have the time to remove the tire, tube &
rimstrip and apply lube, and you're having a difficult time tightening one
of the spokes, try doing it wheel still mounted in the bike and physically
deflect the wheel (by pulling it) in the direction that it needs to go. That
will lower the tension on the spokes that you need to tighten (until you let
go of the rim!), allowing you to get the tension where it needs to be
without destroying the spoke nipple.

"Factory" wheels are also likely not stress-relieved, which can cause
premature failure. Best to read from the FAQ
(http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html) on this point, but the
relevant section is quoted below-

"... spokes in a newly built wheel have locations where stress
is near yield, some more so than others. Because fatigue endurance of
a metal at or near the yield stress is short, cyclic loads in such
spokes will cause failures at high stress points.

"Stress relieving to relax these high stress points is accomplished by
over-stressing them in order to erase their memory. It is not done to
bed the spokes into the hub, as is often stated. Bedding-in occurs
sufficiently from tension. However, stretching spoke pairs with a
strong grasp at midspan, can momentarily increased tension by 50% to
100%. Because spokes are usually tensioned no higher than 1/3 their
yield stress, this operation has no effect on the spoke as a whole,
affecting only the small high stress zones where spokes are near
yield. By stretching them, these zones relax below yield by as much
as the overload."

yet again, i gotta tell y'all that this "faq" needs to be revised. that
"theory" is at best a stretch, and at worst, simply the product of
imagination.

first, there's absolutely no proof tendered regarding residual stress,
just an assumption.

second, bedding in from simple tensioning is absolutely inadequate.
build a new wheel without "stress relief" and ride it around the block.
it'll be like a dogs leg when you get back home. that's because the
spokes are continuing to bed in.

and that ladies & gentlemen is all "stress relief" achieves! it simply
beds the spokes in properly so they don't go slack in use. sorry this
is not a sensational new theory that revolutionizes materials science,
but hey, i'm not trying to sell you anything either. the
preposterousness of claiming fatigue elimination with a simple spoke
squeeze while at the same time demonstrating fundamental ignorance of
deformation theory both boggles the mind and is frankly insulting to the
scientists & manufacturers that have spent decades on research to bring
you these materials.

Quoted message said:

Obviously, this can be performed on an already-built wheel without
difficulty.

and it will achieve nothing if the spokes are not made of quality
materials that have been processed correctly. many "machine built"
wheels are made to price not quality and that often means using inferior
spokes. since no one else here has bothered with this fundamental
question, may i ask the o.p. what brand of spokes are in this wheel?

Quoted message said:

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

jim beam said:

first, there's absolutely no proof tendered regarding residual stress,
just an assumption.

Jim, You're making it difficult to believe for people who want to. Last
time You and Peter Cole exchanged ideas on this you both agreed that
only neutron scans would show them.

Peter dug up the study (automotive industry) showing such scans and the
residual stresses. You refuted the study's applicability for bicycle
spokes. Fine, I'm still with you, but your last word on the matter of
why the study was not representative of residual stresses found in
bicycle spokes was the below:

"how many slip planes are available in a bcc lattice vs. fcc and what are
the relative dislocation activation energies?"

Jim, since You're an infinitely better material engineer than I'll ever
be, You should do better than that babble quoted above. There was no
explanation to it either.

Since you seem to be interested in clearing up the misunderstanding of
residual stresses in spokes and relieving them, it would greatly help
you if the masses you preach to could understand you. Otherwise it's
just preaching.

Jan Lindström

Jan Lindstrom said:

jim beam said:

first, there's absolutely no proof tendered regarding residual stress,
just an assumption.

Jim, You're making it difficult to believe for people who want to. Last
time You and Peter Cole exchanged ideas on this you both agreed that
only neutron scans would show them.

Peter dug up the study (automotive industry) showing such scans and the
residual stresses. You refuted the study's applicability for bicycle
spokes. Fine, I'm still with you, but your last word on the matter of
why the study was not representative of residual stresses found in
bicycle spokes was the below:

"how many slip planes are available in a bcc lattice vs. fcc and what are
the relative dislocation activation energies?"

Jim, since You're an infinitely better material engineer than I'll ever
be, You should do better than that babble quoted above. There was no
explanation to it either.

Since you seem to be interested in clearing up the misunderstanding of
residual stresses in spokes and relieving them, it would greatly help
you if the masses you preach to could understand you. Otherwise it's
just preaching.

Jan Lindström

Dear Jan,

It's not really babble, any more than our habit of using BB
when we mean bottom bracket.

To materials engineers, spelling out body-centered versus
face-centered lattices instead of fcc and bcc on a newsgroup
would be about like typing rear-axle mounted spring-loaded
drive-chain de-railing mechanism instead of der.

http://www.okstate.edu/jgelder/solstate.html

To some degree, this sort of thing lies at the heart of the
debate and perhaps some of Jim's frustration. He's
handicapped by dealing with people like me. I have to
furtively look up fcc and bcc to make sure that I'm thinking
of the right thing, but I'd still have to re-read things to
get even a faint grip on the point.

On the one hand, we have "The Bicycle Wheel" illustrating
its point with plainly contradictory stress-strain graphs.
The graph in the text illustrating a handsome yield point
notch plainly does not match the appendix graphs in which
actual spokes were tested because stainless steel, like
aluminum, does not behave this way--no yield notch. If you
can find any acknowledgement of this by the author, I hope
that you'll provide a link.

On the other hand, we have someone who's a materials
engineer who rarely gets a response to the kind of points
that baffle laymen like you and me. Now and then someone who
can actually discuss materials at Jim's level does reply and
the rest of us can watch while they bat such stuff back and
forth.

I've asked about the spoke stress-relief theory on a
materials forum, but not gotten very far, partly because I
couldn't frame it very well and partly because it doesn't
seem to command any respect outside of rec.bicycles.tech.

The theory may, however, be perfectly true--it could be just
such an odd little niche that mainstream materials engineers
don't explore it. I waver back and forth, wondering whether
spoke-squeezing works and if so, how.

To close on a simpler note suggested in private email, look
at the thread profiles on modern spokes. As best I can
follow, many spoke makers use threads that are not like bolt
threads--the angles aren't quite as steep and the bottoms of
the grooves are subtly rounded. This kind of nuance (among
other things) may account for the improvement in spoke
quality that Jobst notes in his third edition.

But my private email took it for granted that a) I could
follow such details and that b) I was familiar with the
history of spoke threads.

The fact is, I have to take a) on faith because I don't
really know what angles and shapes are normal, and b) I have
no idea what threads looked like in 1980 or which
manufacturers have (or have not) changed their threads.

I expect that Jim and Jobst are debating the equivalent of
who-wrote-Shakespeare in my world. To anyone unfamiliar with
phrases like First Folio, Henslowe, foul papers, court hand,
bad quartos, vexed Bermoothes, tyger's hart, salted bacon,
and so forth, the argument is frustratingly hard to follow.

Carl Fogel

Quoted message said:

To materials engineers, spelling out body-centered versus
face-centered lattices instead of fcc and bcc on a newsgroup
would be about like typing rear-axle mounted spring-loaded
drive-chain de-railing mechanism instead of der.

http://www.okstate.edu/jgelder/solstate.html

To some degree, this sort of thing lies at the heart of the
debate and perhaps some of Jim's frustration. He's
handicapped by dealing with people like me. I have to
furtively look up fcc and bcc to make sure that I'm thinking
of the right thing, but I'd still have to re-read things to
get even a faint grip on the point.

This is where my point lies: Of course I'd want the material science
theory included in Jim's arguments, but I cannot make myself believe
that a competetent engineer could not communicate the theory in a format
that is understood by a person with technical training (like me).

It just seems to me a rational human being would rather explain his
theory in length (in layman's terms) once and for all than go through
endless handicapped debates.

Quoted message said:

I expect that Jim and Jobst are debating the equivalent of
who-wrote-Shakespeare in my world. To anyone unfamiliar with
phrases like First Folio, Henslowe, foul papers, court hand,
bad quartos, vexed Bermoothes, tyger's hart, salted bacon,
and so forth, the argument is frustratingly hard to follow.

Carl Fogel

But Carl, you could explain the topic of who-wrote-Shakespeare to
someone out of your world, if needed, couldn't you? Rather than spend
endless hours spewing out the "First Folio, Henslowe, foul papers, court
hand, bad quartos, vexed Bermoothes, tyger's hart, salted bacon" mantra.

Jan Lindström

"jim beam" <[email hidden]> wrote in message
news:1108652111.1ffeee802b89f62d4b7cdc1a5e13d4df@teranews...

Quoted message said:

Mike Jacoubowsky said:

Quoted message said:

>Then again, if the bike came from an LBS with 'factory' wheels, you
>might consider another, more service-oriented shop.

What is it with 'factory' wheels that makes them fail more readily?
We could use a definition of 'factory" wheels as well.

OK, I'll help out if nobody else will. Somewhat ironic since the
respondent asking the rhetorical questions wrote the FAQ on the matter...

"Factory" wheels are often built up with the "little details" missing.
For example, it's common to see the spoke not pressed flat against the
flange where they exit the hub. Yikes. Over time, the spoke will
gradually straighten out, causing it to become loose. A wheel should
always be built with the spokes taking the shortest-possible distance
between its ends; this typically means physically flattening the spoke
against the flange (a strong thumb does the trick). This can easily be
done to an already-built wheel; just make sure you increase the tension
afterward, since the spokes will now be quite a bit looser.

"Factory" wheels also sometimes lack any lubrication between the spoke
nipple & the rim, which makes it difficult to tighten the nipples. If
you're truing such a wheel and don't have the time to remove the tire,
tube & rimstrip and apply lube, and you're having a difficult time
tightening one of the spokes, try doing it wheel still mounted in the
bike and physically deflect the wheel (by pulling it) in the direction
that it needs to go. That will lower the tension on the spokes that you
need to tighten (until you let go of the rim!), allowing you to get the
tension where it needs to be without destroying the spoke nipple.

"Factory" wheels are also likely not stress-relieved, which can cause
premature failure. Best to read from the FAQ
(http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html) on this point, but the
relevant section is quoted below-

"... spokes in a newly built wheel have locations where stress
is near yield, some more so than others. Because fatigue endurance of
a metal at or near the yield stress is short, cyclic loads in such
spokes will cause failures at high stress points.

"Stress relieving to relax these high stress points is accomplished by
over-stressing them in order to erase their memory. It is not done to
bed the spokes into the hub, as is often stated. Bedding-in occurs
sufficiently from tension. However, stretching spoke pairs with a
strong grasp at midspan, can momentarily increased tension by 50% to
100%. Because spokes are usually tensioned no higher than 1/3 their
yield stress, this operation has no effect on the spoke as a whole,
affecting only the small high stress zones where spokes are near
yield. By stretching them, these zones relax below yield by as much
as the overload."

yet again, i gotta tell y'all that this "faq" needs to be revised. that
"theory" is at best a stretch, and at worst, simply the product of
imagination.

In all honesty, people would probably take you more seriously if you
capitalized your prose where appropriate.

Would stress-relieving in Brandt's fashion, oven mitts and everything,
*cause a problem* after a wheelbuild?

--
Phil, Squid-in-Training

On Fri, 18 Feb 2005 02:28:39 GMT,
[email hidden] wrote:

[snip]

Quoted message said:

I think you'll find that reports of broken spokes are fairly uniformly
divided among left and right spokes, except that right hand spokes are
more trouble to replace being behind the sprocket cluster.

[snip]

Dear Jobst,

In my experience, drive side spokes break far more often. I
thought that this was commonly noted on rec.bicycles.tech
and attributed to the higher tension on the drive side.

I just looked through a few years of embarrassing
spreadsheets and found that at least 25 (and possibly 30)
out of my last 31 broken spokes have been drive-side:

rear DS 25
rear NDS 1
rear ??? 5 (sloppy record keeping)

My rear spoke failures favor the drive-side from 81% to 97%
of the time.

Of course, this might reflect some quirk in the way that the
factory built the wheels or that I later abused them with a
spoke wrench.

Carl Fogel

On Fri, 18 Feb 2005 02:49:56 GMT, "Phil, Squid-in-Training"
<[email hidden]> wrote:

[snip]

Quoted message said:

In all honesty, people would probably take you more seriously if you
capitalized your prose where appropriate.

[snip]

dear phil,

in all honestie we must tell you that people who judge
physicks according to grammar spelling punctuation--are
missing the point

e.e. cummings
W. Shaxpere
Emily D.
I. Newton

Jan Lindstrom said:

Quoted message said:

To materials engineers, spelling out body-centered versus
face-centered lattices instead of fcc and bcc on a newsgroup
would be about like typing rear-axle mounted spring-loaded
drive-chain de-railing mechanism instead of der.

http://www.okstate.edu/jgelder/solstate.html

To some degree, this sort of thing lies at the heart of the
debate and perhaps some of Jim's frustration. He's
handicapped by dealing with people like me. I have to
furtively look up fcc and bcc to make sure that I'm thinking
of the right thing, but I'd still have to re-read things to
get even a faint grip on the point.

This is where my point lies: Of course I'd want the material science
theory included in Jim's arguments, but I cannot make myself believe
that a competetent engineer could not communicate the theory in a format
that is understood by a person with technical training (like me).

thanks for pointing that out. it's hard because if i lapse into
"techno-babble", people complain, jobst particularly. you on the other
hand want more. damned if i do, damned if i don't. [why exactly jobst
is afraid of getting into the gritty details with me if he thinks he can
prove the point, i don't know, but hey.] i've tried doing ascii graphs
here, but they get munged by google so aren't much use in archive.
i have also quoted text references in the past and strongly encourage
anyone interested in this subject to have their library loan them a copy
of "mechanical metallurgy" by dieter. it's a superb text & conceptually
very accessible. it very clearly walks the reader through the
principles of deformation theory, fatigue, even residual stress.

Quoted message said:

It just seems to me a rational human being would rather explain his
theory in length (in layman's terms) once and for all than go through
endless handicapped debates.

in as plain english as i can command, there's not that much to explain.
if a manufacturer can go into the research necessary to determine the
cost/benefit of an expensive fabrication route like vacuum degassed wire
and the microscopy necessary to determine the extent of crack nucleation
at micro-inclusions in the steel matrix so they can specify exactly
/how/ clean that steel needs to be, can't we also be fairly confident
that residual stress resulting from fabrication route is also on their
radar screen? i say yes. it's not like there aren't easy ways to
mitigate residual stress in the factory. in the case of wire drawing,
this is done by an additional cold work operation immediately subsequent
to the initial forming operation - a pair of drawing dies are used, one
reducing by a larger amount, say 20%, the second by 1% - 2%. there's
absolutely no reason why this isn't being done on spoke elbow bending
operations too. i can't however say for sure this is because i don't
have access to the the tools necessary to determine each manufacturer's
exact methodology, but it's /not/ reasonable to assume, in the light of
the evidence we see in the material & the quality of the product, to
just assume that all spoke manufacturers are just coat hanger mongers.
then again, i'm not claiming i can eliminate fatigue in a material
without an endurance limit either.

Quoted message said:

Quoted message said:

I expect that Jim and Jobst are debating the equivalent of
who-wrote-Shakespeare in my world. To anyone unfamiliar with
phrases like First Folio, Henslowe, foul papers, court hand,
bad quartos, vexed Bermoothes, tyger's hart, salted bacon,
and so forth, the argument is frustratingly hard to follow.

Carl Fogel

But Carl, you could explain the topic of who-wrote-Shakespeare to
someone out of your world, if needed, couldn't you? Rather than spend
endless hours spewing out the "First Folio, Henslowe, foul papers, court
hand, bad quartos, vexed Bermoothes, tyger's hart, salted bacon" mantra.

from my viewpoint, the self-appointed "expert" who, confuses strain
aging & non-strain aging materials, who doesn't understand the nature of
cold work or work hardening & who doesn't understand the nature of
fatigue is never going to be mistaken for a technical shakespeare.

Quoted message said:

Jan Lindström

Phil said:

"jim beam" <[email hidden]> wrote in message
news:1108652111.1ffeee802b89f62d4b7cdc1a5e13d4df@teranews...

Quoted message said:

Mike Jacoubowsky said:

>>Then again, if the bike came from an LBS with 'factory' wheels, you
>>might consider another, more service-oriented shop.
>
>What is it with 'factory' wheels that makes them fail more readily?
>We could use a definition of 'factory" wheels as well.

OK, I'll help out if nobody else will. Somewhat ironic since the
respondent asking the rhetorical questions wrote the FAQ on the matter...

"Factory" wheels are often built up with the "little details" missing.
For example, it's common to see the spoke not pressed flat against the
flange where they exit the hub. Yikes. Over time, the spoke will
gradually straighten out, causing it to become loose. A wheel should
always be built with the spokes taking the shortest-possible distance
between its ends; this typically means physically flattening the spoke
against the flange (a strong thumb does the trick). This can easily be
done to an already-built wheel; just make sure you increase the tension
afterward, since the spokes will now be quite a bit looser.

"Factory" wheels also sometimes lack any lubrication between the spoke
nipple & the rim, which makes it difficult to tighten the nipples. If
you're truing such a wheel and don't have the time to remove the tire,
tube & rimstrip and apply lube, and you're having a difficult time
tightening one of the spokes, try doing it wheel still mounted in the
bike and physically deflect the wheel (by pulling it) in the direction
that it needs to go. That will lower the tension on the spokes that you
need to tighten (until you let go of the rim!), allowing you to get the
tension where it needs to be without destroying the spoke nipple.

"Factory" wheels are also likely not stress-relieved, which can cause
premature failure. Best to read from the FAQ
(http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html) on this point, but the
relevant section is quoted below-

"... spokes in a newly built wheel have locations where stress
is near yield, some more so than others. Because fatigue endurance of
a metal at or near the yield stress is short, cyclic loads in such
spokes will cause failures at high stress points.

"Stress relieving to relax these high stress points is accomplished by
over-stressing them in order to erase their memory. It is not done to
bed the spokes into the hub, as is often stated. Bedding-in occurs
sufficiently from tension. However, stretching spoke pairs with a
strong grasp at midspan, can momentarily increased tension by 50% to
100%. Because spokes are usually tensioned no higher than 1/3 their
yield stress, this operation has no effect on the spoke as a whole,
affecting only the small high stress zones where spokes are near
yield. By stretching them, these zones relax below yield by as much
as the overload."

yet again, i gotta tell y'all that this "faq" needs to be revised. that
"theory" is at best a stretch, and at worst, simply the product of
imagination.

In all honesty, people would probably take you more seriously if you
capitalized your prose where appropriate.

Would stress-relieving in Brandt's fashion, oven mitts and everything,
*cause a problem* after a wheelbuild?

absolutely not. as a wheelbuilding practice, it works just great and is
to be strongly recommended, but all it's doing is bedding the spokes in.

Carl Fogel said:

Quoted message said:

I think you'll find that reports of broken spokes are fairly
uniformly divided among left and right spokes, except that right
hand spokes are more trouble to replace being behind the sprocket
cluster.

Quoted message said:

In my experience, drive side spokes break far more often. I thought
that this was commonly noted on rec.bicycles.tech and attributed to
the higher tension on the drive side.

Quoted message said:

I just looked through a few years of embarrassing spreadsheets and
found that at least 25 (and possibly 30) out of my last 31 broken
spokes have been drive-side:

Quoted message said:

rear DS 25
rear NDS 1
rear ??? 5 (sloppy record keeping)

Quoted message said:

My rear spoke failures favor the drive-side from 81% to 97% of the
time.

Quoted message said:

Of course, this might reflect some quirk in the way that the factory
built the wheels or that I later abused them with a spoke wrench.

I'm going from reports we read in this newsgroup. Certainly tension
should have an influence on failures, but residual stress is what
breaks the spoke (it isn't the tension alone) and the left side spokes
take a more severe bend to bend around their flange.

Jobst Brandt
[email hidden]

Carl Fogel said:

Quoted message said:

In all honesty, people would probably take you more seriously if
you capitalized your prose where appropriate.

Quoted message said:

[snip]

Quoted message said:

in all honestie we must tell you that people who judge physicks
according to grammar spelling punctuation--are missing the point

An attempt at wearing your pants so low we can see cleavage is another
way of showing individuality. Poor spelling, punctuation and all
lower case is a similar attempt at individuality as I see it. I
formerly assumed that people will outgrow that, but as I see 50+
adults playing childish games in their SUV's with megapipes, low
section tires and spinning wheel caps, I have my doubts. These
$50,000 cars are no longer child's play although they ruin our
roadsides where there are no barriers to keep them from making mud
holes.

It's much like the writers who respond to my critique of their MAS
ploys with four letter words and insinuations. Their commentary
mainly underscores the attitude I sensed in the original posting that
was just a smart-ass "question" in which the (wrong) answer was
offered. You also could take into account that I have been seeing
these ploys for a long time. I think that in the religious exchange,
several of the secular writers have shown greater credibility than
those who are rude and illiterate in their responses.

If you are not affected that way by the tone of the response, I think
you are not taking advantage of message content to assess whether the
information offered is credible.

Jobst Brandt
[email hidden]

Quoted message said:

Quoted message said:

As has been mentioned here often, typically outbound
spokes from a flange take on an acute angle from insertion and
tensioning. That means they are at yield (take a bend) and tensioning
them guarantees they remain there. This can cause fatigue failures in
less than 300 miles. 300 miles being roughly 230000 stress reversals.

but you advocate "correcting the spoke line" which actually introduces
residual stress. and it doesn't do much for the resultant elbow angle
either being as they come from factory optimised for common hub usage at
around 95 degrees.

OK, dumb question time for the metallurgists. Does it make a difference (in
terms of spoke durability) if the spoke is bent, once, over the flange (to
straighten its path) while building, as opposed to a spoke that has an
outward curve that gradually straightens over time, through normal use?

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

Mike Jacoubowsky said:

Quoted message said:

Quoted message said:

As has been mentioned here often, typically outbound
spokes from a flange take on an acute angle from insertion and
tensioning. That means they are at yield (take a bend) and tensioning
them guarantees they remain there. This can cause fatigue failures in
less than 300 miles. 300 miles being roughly 230000 stress reversals.

but you advocate "correcting the spoke line" which actually introduces
residual stress. and it doesn't do much for the resultant elbow angle
either being as they come from factory optimised for common hub usage at
around 95 degrees.

OK, dumb question time for the metallurgists. Does it make a difference (in
terms of spoke durability) if the spoke is bent, once, over the flange (to
straighten its path) while building, as opposed to a spoke that has an
outward curve that gradually straightens over time, through normal use?

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

they don't really sraighten over time - that implies creep. and they
don't need to be bent during build. once the hub hole is deformed where
the spoke elbow seats, the spoke elbow needs to be at a slightly obtuse
angle in order to align properly, assuming the flanges are canted
towards the rim, as most hubs are.

if they /are/ bent, then theoretically, it could have a negative impact
on fatigue life, but to be honest, i don't see a lot of evidence for
significant impact. [negative impacts could be tensile residual stress
or much more likely, exaggerated "orange peel" effects on the surface
acting as nucleators.]