Breaking Spokes

Old Crow or was it Wild Turkey said:

Quoted message said:

My reference to a kink is one induced by, for instance, a
wheel collapse in which a spoke is doubled back on itself
or one in which the wheel fell on an unoccupied pedal and
got snagged by a projecting part in a crash. These are
sharp bends in the middle of a spoke. Ones that cannot be
straightened by anything but a hammer and smooth surface
to fatten the kink, and even then it is doubtful to be
durable. In effect an unsupported "elbow".

Quoted message said:

Understood, but there are two types of "sharp" bend. The
bending that has a comparatively large radius like a
straightened paper clip, or the minor bend which has a
very small radius like a chain gouge. The smaller the
radius, the greater the stress concentration & the greater
fatigue propensity. The large radius bend induces similar
effects in the material to "correcting the line".

Quoted message said:

Quoted message said:

Quoted message said:

> Even smooth bends have practically no effect on spoke
> life. Replacement spokes must often be bent to insert
> them into the hub. The main thing is to stress relieve
> them after truing. That's what assures durability for
> high quality spokes.

Quoted message said:

Quoted message said:

Quoted message said:

Interesting qualification - that high quality spokes
assure durability. Can it therefore be inferred that you
don't feel confident that "stress relief" has the same
magical properties of infinite fatigue life on poor
quality spokes? If so, what would be the differentiator?

Quoted message said:

Quoted message said:

I see you didn't live in the days of Stella and Robergel
spokes from which I discovered the benefits of stress
relieving.

Quoted message said:

But I'm not too old to still find wheels with these spokes
at swap meets.

So? What is it that is unclear about why these spokes fail
so rapidly and why stress relieving reduces their failure
rate as you see it?

Quoted message said:

Quoted message said:

These spokes broke after such short duty that a large
statistical trend was discernable by stress relieving
although that did not stop spoke failures entirely. It
was with the advent of DT spokes that truly durable
spokes became available. Now there are several brands
that work well.

Quoted message said:

Yes, there are now several brands that work well. But
their long life is not the product of "stress relief";
it's the fact that in the 70's, it became economic to mass
produce vacuum degassed steels. Ultra-clean materials like
this are substantially more fatigue resistant because this
process virtually eliminates inclusions, thereby removing
a significant source of fatigue initiation.

Oh? So how do you explain the reports of repeated failures
in wheels with these spokes, ones built by people who, as
you, don't believe that stress relief is useful or don't
know about it.

How about an experiment? One that I have done. I take it
that you have access to materials testing equipment from
what you write. Take a spoke and manually give it some kinks
with as small a radius as you can. Tension that spoke to
customary service tension in a tensile tester using a
simulated 3mm flange hole and holder for a spoke nipple. I
think you'll notice that when relaxed again, the spoke will
still have kinks, kinks that in service would lead to
fatigue failure.

Now, tension the spoke to the yield stress and relax it
again. I think you'll see a perfectly straight spoke with no
residual stress. If that is not stress relieving, then you
may have abetter word for
it. Let me know what you find.

Quoted message said:

A traditional steel for example may have half the
fatigue limit in the transverse axis of a rolled sheet
compared to its longitudinal axis. The same alloy
composition, but vacuum degassed, may have very similar
fatigue limits in both orientations. When first seen,
the observation of this effect sparked a hunt for
explanation. Electron microscopy subsequently confirmed
fatigue initiation at tiny inclusions previously thought
to be insignificantly small.

So what does this have to do with stress relieving or not?

Quoted message said:

Quoted message said:

As I have described here often, spoke wire must be
ductile enough to withstand cold forming yet retain a
sufficiently high yield strength to resist fatigue
failures at normal spoke loadings. This had not been so
before DT spokes so there is where you should look for
the answer. Redaelli, Berg, and Prym spokes also did not
survive long even with stress relieving although it
extended their service life.

I see you have no comment on the high ductility and high
tensile strength of DT spoke wire.

Quoted message said:

Quoted message said:

Quoted message said:

It's interesting how you're so very careful with your
claims; when challenged you fall back on your personal
use of just one brand of top quality spoke, as if it
were proof across the whole mechanical/materials
spectrum.

Quoted message said:

Quoted message said:

You create these characterizations of thin air to your
liking. Every so often someone with your attitude shows
up here on wreck.bike to attack what has been discovered
about bicycle parts apparently trying to defend myth and
lore from days gone by. I can't see any other goal but
then you never said what you believe is the cause of
failures. Instead of beating around the bush and
insinuating and alluding to some agenda, how about
stating what it is you believe is occurring.

Quoted message said:

What causes failures is well known. It's what alleviates
them that seems to be the issue here. All that "stress
relief" achieves is a wheel that is fully bedded in before
riding. Spokes do not therefore loosen and others do not
therefore carry disproportionate load. In that respect,
the practice referred to as "stress relief" is a good
thing, and thoroughly to be commended. But the business of
fatigue mitigation itself is achieved in the spoke
manufacturers factory, not the wheel builders bench.

"Well known"? From what you just said, it seems not to be.
Bedding in is already complete when spokes are tensioned and
even if it weren't, subsequent bedding in from use cannot
relax the tension of a spoke, the change in length being
insignificant compared to spoke elastic stretch from
tensioning. However, even if it did, your model of
overloaded spokes cannot explain the failure of left side
spokes in rear wheels that have as little as half the
tension of those on the right. Beyond these considerations,
high spoke tension is generally in the range of 1/3 the
yield stress of a spoke.

Would you explain your understanding of spoke failure in
this respect?

Quoted message said:

The explanation of "local yielding" you've presented as
theory on how to eliminate fatigue is unfortunately built
on some gross misconceptions. You assert that the steel in
spokes exhibits the same properties as mild steel, i.e.
the exhibition of yield and deformation without work
hardening as a method of reducing residual stress.

Where do you find that "unfortunate" scenario? I haven't
proposed anything of the sort. I see a straw man raising his
head. Where is Ray Bolger when we need him. He's probably
out there on a yellow brick road commiserating heart
warmingly with a tin man.

Quoted message said:

Reality is, stainless steel spoke wires /do/ work harden
immediately from yield, as the real-life spoke
stress/strain graphs in the back of your book show.
"Stress relief" therefore has the ability to not only
continue increasing the dislocation density of the
material [which /increases/ lattice stresses] at any point
where it does yield, [/if/ it yields, and that's
conjecture], but to also activate slip bands and initiate
cumulative damage effects.

I am reminded of Richard Feynman's appropriate words: "If
you can't explain it in plain English, you probably don't
understand it yourself."

Quoted message said:

The closest analogy to your explanation is something
called "coaxing" where a component is progressively loaded
and fatigue limits improved, but unfortunately, this
effect is only present in materials that exhibit strain
aging. Stainless steel is not one of them.

I see. Now it is specifically stainless steel that makes
spokes not fail. Are you proposing that other steel
components on bicycles, such as axles, cables, frames and
the like, would be more durable in such alloys?

Quoted message said:

So, you want to know my agenda? Update your book and get
rid of the glaring materials theory errors! And please
include the differential spoke tension formula for dished
wheels while you're at it.

What sort of "differential spoke tension formula" are you
suggesting and for what would this be useful, considering
that the difference is dependent on the hub offset,
something that cannot be changed. The graphic description in
the book makes that fairly clear as wheel as what the
results are.

Jobst Brandt [email hidden]

Quoted message said:

Most of the replies are either "build your own wheels, it
not rocket surgery", or "the person who built your wheels
didn't know what they were doing." If it isn't hard how
come I got three crappy wheels?

You got three people who don't know how to properly build
wheels. Isn't the answer obvious? It isn't rocket science,
but it does require you to do all the right things.
Unfortunately you can't look at a wheel and tell if it was
properly built. You can see if the wheel is true and if the
tension is even, but you can't tell if they stress relieved
the spokes.

Quoted message said:

I am also frustrated that there is an elitist attitude that
hand built wheels are the only way to go and that only
fools buy ready made wheelsets.

Not elitest at all. It is just that if you can get a good
wheel builder, custom hand made wheels are a better value
for your money.

Quoted message said:

I have had much more fun on my rides since I switched to
the Ksyrium Elite rear wheel.

Unfortunately this is what happens because a lot of shops
don't have a competent wheel builder. A customer has no
choice but to buy over priced pre-built wheels. This is one
reason to build your own wheels. The investment is small and
the rewards are great.
------------
Alex

Quoted message said:

Of course I could learn to build a great wheel, but I
would rather spend my free time riding and I think that
you missed my major point. I tried really hard, many
times, to purchase a reliable hand built 36 spoke rear
wheel. The longest any of them lasted was under 500 miles!
I purchased a "wheel in a box" and have had wonderful
results for over 1500 miles. The advice that is constantly
voiced in this group is that hand built wheels are better,
but there are at least two heavy riders who have had great
results with the Mavic Ksyrium Elite rear wheels.

If they lasted only 500 miles there is a problem, either in
materials or technique. I built a set of 36 spoke wheels
this winter. Took me an evening. Have almost 1000 miles,
mostly 'loaded' (e.g., carrying panniers filled with stuff).
Still true as the night I built them, not a complaint from
the spokes. I expect the same will be true at 10K miles. If
past experience is a guide, I can expect to wear the braking
surface down before anything else goes. Simple task for a
rainy night, since I do not ride on rainy nights unless I
have to :-)

Wait until you pop a spoke on the Ksyrium's. If you are not
near a major city, expect to wait a while if you want one of
those fancy spokes as a replacement.

- rick

Alex Rodriguez said:

says...

Quoted message said:

Most of the replies are either "build your own wheels, it
not rocket surgery", or "the person who built your wheels
didn't know what they were doing." If it isn't hard how
come I got three crappy wheels?

You got three people who don't know how to properly build
wheels. Isn't the answer obvious? It isn't rocket science,
but it does require you to do all the right things.
Unfortunately you can't look at a wheel and tell if it was
properly built. You can see if the wheel is true and if
the tension is even, but you can't tell if they stress
relieved the spokes.

Fortunately, stress relieving a second time doesn't hurt,
and is easy to do, so you can just do it yourself when you
get home even if you don't want to build your own wheels.

--
Benjamin Lewis

Don't take life so serious, son, it ain't nohow permanent.
-- Walt Kelly

On 30 May 2004 13:53:32 GMT, [email hidden] (Qui si parla

Campagnolo ) said:

Stress relieving does not necessarily take windup out of
spokes. They are two different issues, with two different
'techniques'.

I've deluded myself into thining I've found an easy way to
alleviate windup. When the wheel is near finished, I put a
tire w/o air on it and ride it around the street. I take the
wheel back and check the true again and rarely need to do
anything. No pinging noises on the first ride.

"Rick Warner" <[email hidden]> wrote in message
"]news:[email hidden]...

news:<[email hidden]>...

Quoted message said:

Quoted message said:

Of course I could learn to build a great wheel, but I
would rather spend

my

Quoted message said:

Quoted message said:

free time riding and I think that you missed my major
point. I tried

really

Quoted message said:

Quoted message said:

hard, many times, to purchase a reliable hand built 36
spoke rear wheel. The longest any of them lasted was
under 500 miles! I purchased a

"wheel in

Quoted message said:

Quoted message said:

a box" and have had wonderful results for over 1500
miles. The advice

that

Quoted message said:

Quoted message said:

is constantly voiced in this group is that hand built
wheels are better,

but

Quoted message said:

Quoted message said:

there are at least two heavy riders who have had great
results with the Mavic Ksyrium Elite rear wheels.

If they lasted only 500 miles there is a problem, either
in materials or technique. I built a set of 36 spoke
wheels this winter. Took me an evening. Have almost 1000
miles, mostly 'loaded' (e.g., carrying panniers filled
with stuff). Still true as the night I built them, not a
complaint from the spokes. I expect the same will be true
at 10K miles. If past experience is a guide, I can expect
to wear the braking surface down before anything else
goes. Simple task for a rainy night, since I do not ride
on rainy nights unless I have to :-)

Wait until you pop a spoke on the Ksyrium's. If you are
not near a major city, expect to wait a while if you want
one of those fancy spokes as a replacement.

- rick

I purchased 4 drive side and 4 non drive side spokes when I
got the wheel.

Quoted message said:

"Tim McNamara" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

You edited the message wrong. It went like this:

> But how do you "ruin" the rim? Did it become
> impossible to true after?
>
Yes.

<snip>

Quoted message said:

Quoted message said:

When you say the rim was "not truable," by whom was it
not truable?

The rims were declared not truable by the service
department of LBS. I was shocked and asked that more
senior techs give a second opinion and all the techs
agreed. With the Open Pro rim one spoke actually pulled
through the rim and it was instant trash.

I'd have been shocked and skeptical to say the least. Now,
I don't like the Open Pro or any anodized rims, having had
a string of failures in which the rims cracked around the
spoke holes. I've cracked an Open Pro, but the spoke didn't
pull through the rim- it couldn't because there's a big
metal socket around the nipple. If it had, there's have
been a hole bigger than 1 cm across left in the rim and it
would have probably been a very dramatic catastrophic
failure. Such a failure isn't from the wheel build but from
a flaw in the rim.

Quoted message said:

I weigh 245 lbs so I think that I am seeing problems that
lighter riders never see.

Touring cyclists put these loads on wheels all the time.
It's nothing new. And they get thousands of miles of trouble-
free performance. Unless you're doing lots of sideways
skids, slamming into curbs and potholes, etc, this shouldn't
be a problem. A properly built 36 spoke wheel ought to be
able to support close to an 800 pound load before
collapsing.

Quoted message said:

The thing that is frustrating to me is that I took
appropriate steps to getting wheels built. I went to good
shops, explained my situation with breaking rear spokes,
always took the shops recommendations as to the best parts
for me, asked that the wheels be built by their best wheel
builder, and brought the wheels back to the shop for
maintenance if there was any sign loose spokes or being
out of true but I still did not get a wheel to last 500
miles. Most of the replies are either "build your own
wheels, it not rocket surgery", or "the person who built
your wheels didn't know what they were doing." If it isn't
hard how come I got three crappy wheels?

You may have gotten three bike shops that think they know
how to build wheels, but really don't. If I was to recommend
a wheel to you, it would be a 36 spoke Ultegra hub, with DT
14-15 gauge double butted spokes, and a Mavic MA2 rim (which
you're not going to find, in all likelihood, it being out of
production). Properly built, I'd be nothing but astonished
if that didn't work well for you for many many more than 500
miles. You'd need to go with a different rim, perhaps a
Torelli Master which is similar to an MA2.

Quoted message said:

I am also frustrated that there is an elitist attitude
that hand built wheels are the only way to go and that
only fools buy ready made wheelsets.

You're reading more into people's comments than there is.

Quoted message said:

I have had much more fun on my rides since I switched to
the Ksyrium Elite rear wheel.

And good luck to you- and carry a cell phone. If you break a
spoke, those wheels will be instantly unrideable.

Comments in the body of the message.

"Tim McNamara" <[email hidden]> wrote in message news:m2smdf3r9a.fsf@Stella-
Blue.local...

Quoted message said:

Quoted message said:

"Tim McNamara" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

> You edited the message wrong. It went like this:
>
>> But how do you "ruin" the rim? Did it become
>> impossible to true after?
>>
> Yes.

<snip>

Quoted message said:

Quoted message said:

When you say the rim was "not truable," by whom was it
not truable?

The rims were declared not truable by the service
department of LBS. I was shocked and asked that more
senior techs give a second opinion and all the techs
agreed. With the Open Pro rim one spoke actually pulled
through the rim and it was instant trash.

I'd have been shocked and skeptical to say the least. Now,
I don't like the Open Pro or any anodized rims, having had
a string of failures in which the rims cracked around the
spoke holes. I've cracked an Open Pro, but the spoke
didn't pull through the rim- it couldn't because there's a
big metal socket around the nipple. If it had, there's
have been a hole bigger than 1 cm across left in the rim
and it would have probably been a very dramatic
catastrophic failure. Such a failure isn't from the wheel
build but from a flaw in the rim.

Yep, you have it right. The metal socket, and spoke, pulled
right through the rim. You were also right that it was
catastropic to me. I was going up a steep hill and suddenly
there was a bang. I tried riding home but there was no way.
I called a friend to get me.

Quoted message said:

Quoted message said:

I weigh 245 lbs so I think that I am seeing problems
that lighter riders never see.

Touring cyclists put these loads on wheels all the time.
It's nothing new. And they get thousands of miles of trouble-
free performance. Unless you're doing lots of sideways
skids, slamming into curbs and potholes, etc, this
shouldn't be a problem. A properly built 36 spoke wheel
ought to be able to support close to an 800 pound load
before collapsing.

Quoted message said:

The thing that is frustrating to me is that I took
appropriate steps to getting wheels built. I went to
good shops, explained my situation with breaking rear
spokes, always took the shops recommendations as to the
best parts for me, asked that the wheels be built by
their best wheel builder, and brought the wheels back to
the shop for maintenance if there was any sign loose
spokes or being out of true but I still did not get a
wheel to last 500 miles. Most of the replies are either
"build your own wheels, it not rocket surgery", or "the
person who built your wheels didn't know what they were
doing." If it isn't hard how come I got three crappy
wheels?

You may have gotten three bike shops that think they know
how to build wheels, but really don't. If I was to
recommend a wheel to you, it would be a 36 spoke Ultegra
hub, with DT 14-15 gauge double butted spokes, and a Mavic
MA2 rim (which you're not going to find, in all
likelihood, it being out of production). Properly built,
I'd be nothing but astonished if that didn't work well for
you for many many more than 500 miles. You'd need to go
with a different rim, perhaps a Torelli Master which is
similar to an MA2.

This is interesting. You described the exact wheel that one
of the shops built, but to be accurate I am not sure that
spokes were DT. I think that they were DT but not 100% sure.
The rest of the wheel is accuate..with a 3X pattern.

Quoted message said:

Quoted message said:

I am also frustrated that there is an elitist attitude
that hand built wheels are the only way to go and that
only fools buy ready made wheelsets.

You're reading more into people's comments than there is.

Quoted message said:

I have had much more fun on my rides since I switched to
the Ksyrium Elite rear wheel.

And good luck to you- and carry a cell phone. If you break
a spoke, those wheels will be instantly unrideable.

I think that I will leave the cell phone comment alone.
There is a cell phone thread that is running already.

Paul Kopit said:

Quoted message said:

Stress relieving does not necessarily take windup out of
spokes. They are two different issues, with two different
'techniques'.

Quoted message said:

I've deluded myself into thinking I've found an easy way
to alleviate windup. When the wheel is near finished, I
put a tire w/o air on it and ride it around the street. I
take the wheel back and check the true again and rarely
need to do anything. No pinging noises on the first ride.

It's much easier and reliable to develop an overshoot and
back of motion in your truing hand as is described in "the
Bicycle Wheel" with diagram of torque. Besides, after spokes
untwist, trueness generally changes and requires rework...
that will re-introduce twist... in infinite regression.

Jobst Brandt [email hidden]

RWM wrote:
:: Comments in the body of the message.
::
:: "Tim McNamara" <[email hidden]> wrote in message
:: "]news:[email hidden]...

:::
:::: "Tim McNamara" <[email hidden]> wrote in message
:::: "]news:[email hidden]...

:::::
:::::: You edited the message wrong. It went like this:
::::::
::::::: But how do you "ruin" the rim? Did it become
::::::: impossible to true after?
:::::::
:::::: Yes.
:::
::: <snip>
:::
::::: When you say the rim was "not truable," by whom was it
::::: not truable?
:::::
:::: The rims were declared not truable by the service
:::: department of LBS. I was shocked and asked that more
:::: senior techs give a second opinion and all the techs
:::: agreed. With the Open Pro rim one spoke actually pulled
:::: through the rim and it was instant trash.
:::
::: I'd have been shocked and skeptical to say the least.
::: Now, I don't like the Open Pro or any anodized rims,
::: having had a string of failures in which the rims
::: cracked around the spoke holes. I've cracked an Open
::: Pro, but the spoke didn't pull through the rim- it
::: couldn't because there's a big metal socket around the
::: nipple. If it had, there's have been a hole bigger than
::: 1 cm across left in the rim and it would have probably
::: been a very dramatic catastrophic failure. Such a
::: failure isn't from the wheel build but from a flaw in
::: the rim.
:::
::
:: Yep, you have it right. The metal socket, and spoke,
:: pulled right through the rim. You were also right that it
:: was catastropic to me. I was going up a steep hill and
:: suddenly there was a bang. I tried riding home but there
:: was no way. I called a friend to get me.
::
::
:::: I weigh 245 lbs so I think that I am seeing problems
:::: that lighter riders never see.
:::
::: Touring cyclists put these loads on wheels all the time.
::: It's nothing new. And they get thousands of miles of trouble-
::: free performance. Unless you're doing lots of sideways
::: skids, slamming into curbs and potholes, etc, this
::: shouldn't be a problem. A properly built 36 spoke wheel
::: ought to be able to support close to an 800 pound load
::: before collapsing.
:::
:::: The thing that is frustrating to me is that I took
:::: appropriate steps to getting wheels built. I went to
:::: good shops, explained my situation with breaking rear
:::: spokes, always took the shops recommendations as to the
:::: best parts for me, asked that the wheels be built by
:::: their best wheel builder, and brought the wheels back
:::: to the shop for maintenance if there was any sign loose
:::: spokes or being out of true but I still did not get a
:::: wheel to last 500 miles. Most of the replies are either
:::: "build your own wheels, it not rocket surgery", or "the
:::: person who built your wheels didn't know what they were
:::: doing." If it isn't hard how come I got three crappy
:::: wheels?
:::
::: You may have gotten three bike shops that think they
::: know how to build wheels, but really don't. If I was to
::: recommend a wheel to you, it would be a 36 spoke Ultegra
::: hub, with DT 14-15 gauge double butted spokes, and a
::: Mavic MA2 rim (which you're not going to find, in all
::: likelihood, it being out of production). Properly built,
::: I'd be nothing but astonished if that didn't work well
::: for you for many many more than 500 miles. You'd need to
::: go with a different rim, perhaps a Torelli Master which
::: is similar to an MA2.
::
:: This is interesting. You described the exact wheel that
:: one of the shops built, but to be accurate I am not sure
:: that spokes were DT. I think that they were DT but not
:: 100% sure. The rest of the wheel is accuate..with a 3X
:: pattern.
::
:::
:::: I am also frustrated that there is an elitist attitude
:::: that hand built wheels are the only way to go and that
:::: only fools buy ready made wheelsets.
:::
::: You're reading more into people's comments than
::: there is.
:::
:::: I have had much more fun on my rides since I switched
:::: to the Ksyrium Elite rear wheel.
:::
::: And good luck to you- and carry a cell phone. If you
::: break a spoke, those wheels will be instantly
::: unrideable.
::
:: I think that I will leave the cell phone comment alone.
:: There is a cell phone thread that is running already.

Having a cell phone with you is not the same as using it
while riding.

Quoted message said:

Standard rim:
nashbar.comprofile moreimages.cfmOpen ↗

Is it just me, or does that "touring" wheelset have single-
wall rims?

--
Phil, Squid-in-Training

Quoted message said:

Old Crow or was it Wild Turkey said:

Quoted message said:

My reference to a kink is one induced by, for instance, a
wheel collapse in which a spoke is doubled back on itself
or one in which the wheel fell on an unoccupied pedal and
got snagged by a projecting part in a crash. These are
sharp bends in the middle of a spoke. Ones that cannot be
straightened by anything but a hammer and smooth surface
to fatten the kink, and even then it is doubtful to be
durable. In effect an unsupported "elbow".

Quoted message said:

Understood, but there are two types of "sharp" bend. The
bending that has a comparatively large radius like a
straightened paper clip, or the minor bend which has a
very small radius like a chain gouge. The smaller the
radius, the greater the stress concentration & the greater
fatigue propensity. The large radius bend induces similar
effects in the material to "correcting the line".

Quoted message said:

Quoted message said:

>>Even smooth bends have practically no effect on spoke
>>life. Replacement spokes must often be bent to insert
>>them into the hub. The main thing is to stress relieve
>>them after truing. That's what assures durability for
>>high quality spokes.

Quoted message said:

Quoted message said:

>Interesting qualification - that high quality spokes
>assure durability. Can it therefore be inferred that you
>don't feel confident that "stress relief" has the same
>magical properties of infinite fatigue life on poor
>quality spokes? If so, what would be the differentiator?

Quoted message said:

Quoted message said:

I see you didn't live in the days of Stella and Robergel
spokes from which I discovered the benefits of stress
relieving.

Quoted message said:

But I'm not too old to still find wheels with these spokes
at swap meets.

So? What is it that is unclear about why these spokes fail
so rapidly and why stress relieving reduces their failure
rate as you see it?

i don't think your version of "stress relief" brings any
metallurgical change to the spokes, but it definitely builds
a stronger more evenly tensioned wheel. see below for my
experiment last summer.

as explained before, one reason for failure of these spokes
is their "dirty" steels. another is the use of chrome
plating. chrome is brittle and cracks when the spokes get
bent during build. these cracks are /classic/ fatigue
initiators.

Quoted message said:

Quoted message said:

Quoted message said:

These spokes broke after such short duty that a large
statistical trend was discernable by stress relieving
although that did not stop spoke failures entirely. It
was with the advent of DT spokes that truly durable
spokes became available. Now there are several brands
that work well.

Quoted message said:

Yes, there are now several brands that work well. But
their long life is not the product of "stress relief";
it's the fact that in the 70's, it became economic to mass
produce vacuum degassed steels. Ultra-clean materials like
this are substantially more fatigue resistant because this
process virtually eliminates inclusions, thereby removing
a significant source of fatigue initiation.

Oh? So how do you explain the reports of repeated failures
in wheels with these spokes, ones built by people who, as
you, don't believe that stress relief is useful or don't
know about it.

which brand of spokes? the people i've asked for info on
which brand of spoke they've been breaking here on r.b.t.
either don't seem to know or will only admit to pre-built
wheels which usually use no-name cheapo stuff. the broken
d.t.'s i have are all victims of chain gouge, so i don't
think they're much of a data point. and when spokes /do/
break, the wheels usually get rebuilt with high quality
after market replacements, and miraculously, their problems
seem to disappear! coincidence?

Quoted message said:

How about an experiment? One that I have done. I take it
that you have access to materials testing equipment from
what you write. Take a spoke and manually give it some
kinks with as small a radius as you can. Tension that
spoke to customary service tension in a tensile tester
using a simulated 3mm flange hole and holder for a spoke
nipple. I think you'll notice that when relaxed again, the
spoke will still have kinks,

agreed - i can repeat this experiment if you like.
probably won't have time to do it for several weeks, but
it's easily done.

Quoted message said:

kinks that in service would lead to fatigue failure.

not necessarily more so than a spoke that's been bent to
"correct the line" or a spoke that's crossing another,
particularly if that crossing is closer to the hub than
normal like 2x on a 32 spoke wheel. depends on the extent of
the kink doesn't it!

Quoted message said:

Now, tension the spoke to the yield stress and relax it
again. I think you'll see a perfectly straight spoke with
no residual stress. If that is not stress relieving, then
you may have abetter word for
it. Let me know what you find.

well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even then,
that would typically be done immediately after initial
deformation to prevent any possible aging effects. on a
296mm spoke, if we're conservative, 1% means 3mm elongation
making it unusable for its originally intended purpose.
being as we're not getting strain of that magnitude, you
can't contend that there's true metallurgical stress relief
in a wheel build.

Quoted message said:

Quoted message said:

A traditional steel for example may have half the
fatigue limit in the transverse axis of a rolled sheet
compared to its longitudinal axis. The same alloy
composition, but vacuum degassed, may have very similar
fatigue limits in both orientations. When first seen,
the observation of this effect sparked a hunt for
explanation. Electron microscopy subsequently confirmed
fatigue initiation at tiny inclusions previously thought
to be insignificantly small.

So what does this have to do with stress relieving or not?

i'm trying to tell you /why/ modern spokes have such good
fatigue characteristics!!!

Quoted message said:

Quoted message said:

Quoted message said:

As I have described here often, spoke wire must be
ductile enough to withstand cold forming yet retain a
sufficiently high yield strength to resist fatigue
failures at normal spoke loadings. This had not been so
before DT spokes so there is where you should look for
the answer. Redaelli, Berg, and Prym spokes also did not
survive long even with stress relieving although it
extended their service life.

I see you have no comment on the high ductility and high
tensile strength of DT spoke wire.

what's to comment? you're the guy that was telling me a
while back that
d.t. spokes were fully hard. you didn't respond to links
showing the tensile strength differences between 2.0
straight gauge, 2.0/1.8/2.0 butted and 2.0/1.5/2.0
butted - which are directly attributable to continued
work hardening.

google.comgroupsOpen ↗
newssvr27.news.prodigy.com&output=gplain

Quoted message said:

Quoted message said:

Quoted message said:

>It's interesting how you're so very careful with your
>claims; when challenged you fall back on your personal
>use of just one brand of top quality spoke, as if it
>were proof across the whole mechanical/materials
>spectrum.

Quoted message said:

Quoted message said:

You create these characterizations of thin air to your
liking. Every so often someone with your attitude shows
up here on wreck.bike to attack what has been discovered
about bicycle parts apparently trying to defend myth and
lore from days gone by. I can't see any other goal but
then you never said what you believe is the cause of
failures. Instead of beating around the bush and
insinuating and alluding to some agenda, how about
stating what it is you believe is occurring.

Quoted message said:

What causes failures is well known. It's what alleviates
them that seems to be the issue here. All that "stress
relief" achieves is a wheel that is fully bedded in before
riding. Spokes do not therefore loosen and others do not
therefore carry disproportionate load. In that respect,
the practice referred to as "stress relief" is a good
thing, and thoroughly to be commended. But the business of
fatigue mitigation itself is achieved in the spoke
manufacturers factory, not the wheel builders bench.

"Well known"? From what you just said, it seems not to be.

the causes of fatigue are quite well known to
metallurgists & materials engineers. there's tons of stuff
about that on the web.

Quoted message said:

Bedding in is already complete when spokes are tensioned

i absolutely disagree. my hefty #210 hindquarters most
definitely are able to untrue a wheel that has not been
properly bedded in. quickly too. that's where the
benefits of the "stress relief" wheel build process are
most apparent.

Quoted message said:

and even if it weren't, subsequent bedding in from use
cannot relax the tension of a spoke, the change in length
being insignificant compared to spoke elastic stretch from
tensioning.

this is not my experience. last summer, i /did/ build a
wheel, deliberately without "stress relief". it was evenly
tensioned and perfectly true before leaving the house. i
took care to ensure no spoke had any twist by marking them
on one side before assembly so any torque could easily be
seen. it did not "ping" while riding. it was ~6mm out of
true after riding around just one block and some of the
spokes were almost completely slack. clearly there was
measurable yielding of /something/. as i think we both
agree that spokes are loaded to less than a third of their
yield, it had to be something else - yielding of soft
aluminum hub holes & rim holes. hence the need to
/properly/ bed wheels in.

Quoted message said:

However, even if it did, your model of overloaded spokes
cannot explain the failure of left side spokes in rear
wheels that have as little as half the tension of those
on the right.

why not? if it means the spokes get higher cyclic load
limits, i.e. the difference between the maximum & minimum
loads, or even /negative/ loads, i don't see any disparity
at all! i have examples of spoke failures where the elbows
have fatigued from both the inside out, /and/ outside in!
clearly in this situation, poor tension is a contributor.

Quoted message said:

Beyond these considerations, high spoke tension is
generally in the range of 1/3 the yield stress of a
spoke.

which just happens to be about the same stress level we
commonly see for fatigue limits [_not_ to be confused with
an endurance limits]. funny coincidence that.

Quoted message said:

Would you explain your understanding of spoke failure in
this respect?

Quoted message said:

The explanation of "local yielding" you've presented as
theory on how to eliminate fatigue is unfortunately built
on some gross misconceptions. You assert that the steel in
spokes exhibits the same properties as mild steel, i.e.
the exhibition of yield and deformation without work
hardening as a method of reducing residual stress.

Where do you find that "unfortunate" scenario? I haven't
proposed anything of the sort. I see a straw man raising
his head. Where is Ray Bolger when we need him. He's
probably out there on a yellow brick road commiserating
heart warmingly with a tin man.

i don't have your book in front of me, but you show a
stress/strain graph for mild steel, i.e. one that
exhibits strain aging, then iirc, go on to discuss
yielding without work hardening. if you knew the
distinction between a material that exhibits strain
aging, mild steel, and one that doesn't, stainless steel,
you wouldn't have made that error.

Quoted message said:

Quoted message said:

Reality is, stainless steel spoke wires /do/ work harden
immediately from yield, as the real-life spoke
stress/strain graphs in the back of your book show.
"Stress relief" therefore has the ability to not only
continue increasing the dislocation density of the
material [which /increases/ lattice stresses] at any point
where it does yield, [/if/ it yields, and that's
conjecture], but to also activate slip bands and initiate
cumulative damage effects.

I am reminded of Richard Feynman's appropriate words: "If
you can't explain it in plain English, you probably don't
understand it yourself."

"plain english" is relative. there are certain concepts that
have their own names. "dislocation" is one that is
fundamental to deformation theory, much like the host of sub-
atomic particle names are to fundamental to the physics of
matter. there's no avoidance possible. likewise "lattice".
atoms in a crystal are arranged in a lattice. that's pretty
plain. these terms are all googleable.

Quoted message said:

Quoted message said:

The closest analogy to your explanation is something
called "coaxing" where a component is progressively loaded
and fatigue limits improved, but unfortunately, this
effect is only present in materials that exhibit strain
aging. Stainless steel is not one of them.

I see. Now it is specifically stainless steel that makes
spokes not fail.

you're putting words in my mouth. high quality stainless
steel can be fatigue resistant. mild steel can be fatigue
proof in certain circumstances. two very different things.
stainless steel has no endurance limit and therefore can
never be fatigue proof.

Quoted message said:

Are you proposing that other steel components on
bicycles, such as axles, cables, frames and the like,
would be more durable in such alloys?

the appropriate alloys are used already. prime examples are
the stainless steels used to make good spokes and control
cables because of corrosion resistance. corrosion resistance
preserves surface quality and good surface quality is a
primary fatigue mitigator.

Quoted message said:

Quoted message said:

So, you want to know my agenda? Update your book and get
rid of the glaring materials theory errors! And please
include the differential spoke tension formula for dished
wheels while you're at it.

What sort of "differential spoke tension formula" are you
suggesting and for what would this be useful, considering
that the difference is dependent on the hub offset,
something that cannot be changed.

i know hub offset can't be changed - that's not the
question. i've seen it asked a number of times on r.b.t.,
why are measurements are given for the drive side of a
dished rear wheel, but not the non-drive side? if someone
has just built their first wheel, have a shiny new
tensiometer in their hand, are they not curious what the
deal is with the spokes they've not had comparison
measurements for? publishing the tension differential
formulae in the same way you did for spoke length
calculation allows the curious to understand /why/ there is
a difference in tension, and if necessary, to calculate what
it would be for any given hub/rim combination.

Quoted message said:

The graphic description in the book makes that fairly
clear as wheel as what the results are.

Jobst Brandt [email hidden]

RWM said:

"Tim McNamara" <[email hidden]> wrote in message news:m28yf7narh.fsf@Stella-
Blue.local...

Quoted message said:

Quoted message said:

Quoted message said:

You edited the message wrong. It went like this:

>But how do you "ruin" the rim? Did it become impossible
>to true after?
>

Yes.

OK, this is making less and less sense. I've had to ride
home on broken spokes more than 50 miles on occasion, and
over 10 miles on several occasions- happily not in years.
I've never ruined a rim by riding on it with a broken spoke-
and I've weighed over 195 lbs since I was a sophomore in
high school back in 1974. I built my first wheels in 1978
and finally retired those in 1994. I don't recall any
spoke breakages in those wheels, but I have had spokes
break in OEM prebuilt wheels and in one wheel I built
using cheap Asahi spokes; otherwise I find 32 spoke wheels
quite adequate.

When you say the rim was "not truable," by whom was it not
truable?

Basically it sounds like your wheels have been built up by
people who didn't know what they were doing- how to
properly tension the spokes, remove spoke windup and
stress relieve them to prevent breakage. A wheel should go
50,000 miles at least without breaking a spoke, IMHO. This
is not hard to achieve once the principles and procedures
of good wheel building are known.

The rims were declared not truable by the service
department of LBS. I was shocked and asked that more
senior techs give a second opinion and all the techs
agreed. With the Open Pro rim one spoke actually pulled
through the rim and it was instant trash.

I weigh 245 lbs so I think that I am seeing problems that
lighter riders never see.

The thing that is frustrating to me is that I took
appropriate steps to getting wheels built. I went to good
shops, explained my situation with breaking rear spokes,
always took the shops recommendations as to the best parts
for me, asked that the wheels be built by their best wheel
builder, and brought the wheels back to the shop for
maintenance if there was any sign loose spokes or being
out of true but I still did not get a wheel to last 500
miles. Most of the replies are either "build your own
wheels, it not rocket surgery", or "the person who built
your wheels didn't know what they were doing." If it isn't
hard how come I got three crappy wheels?

all 3 shops were crappy. here in the bay area, i've only
come across 1 shop that really knows how to build a wheel
that stays true under my
#210 weight. i slightly bent a wheel in a crash and i took
#it to 3 of
the "best" shops in the area for repair. all 3 declared it
bent beyond hope. finally, i took it to its original
builder, and he had it back in shape in no time! i'd
originally avoided him because he was expensive and i wanted
to see whether anyone else knew their stuff. false economy.

Quoted message said:

I am also frustrated that there is an elitist attitude
that hand built wheels are the only way to go and that
only fools buy ready made wheelsets. I have had much more
fun on my rides since I switched to the Ksyrium Elite
rear wheel.

the ksyiriums with the big fat alloy spokes do seem to
fail. i've passed a number of riders limping home with
those things flopping about. but they /are/ ridable if
you open the brake caliper right up; if you want to ride
them, go right ahead! and the ones with the steel spokes
seem to be fine.

ignore the elitist attitude. there's people that that feel
qualified to criticize equipment they've never used in every
field, not just bikes.

"jim beam" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

[email hidden] wrote:

Quoted message said:

Quoted message said:

Now, tension the spoke to the yield stress and relax it
again. I think you'll see a perfectly straight spoke
with no residual stress. If that is not stress
relieving, then you may have abetter word for
it. Let me know what you find.

well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even then,
that would typically be done immediately after initial
deformation to prevent any possible aging effects. on a
296mm spoke, if we're conservative, 1% means 3mm
elongation making it unusable for its originally intended
purpose.

But the lower end of that limit quite plausible, right?
Fully tensioned spokes do exhibit loaded elongations of
around 1% and so the stress-relief procedure described in
Jobst's book is taking the spokes to about 1.5% or 2%
strain, clearly within your specified range.

Regarding aging effects, these can be very slow for
stainless steels. Are you sure they are important in this
application for such high purity stainless steels as DT (for
example) are using?
--
Mark South: World Citizen, Net Denizen

"Mark South" <[email hidden]> wrote in message
"]news:[email hidden]...

I'm sorry, I have made a mistake or two in the following,
which I attribute to my inability to leave numbers alone no
matter how short of sleep I am.

Quoted message said:

"jim beam" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

[email hidden] wrote:

Quoted message said:

Quoted message said:

Now, tension the spoke to the yield stress and relax
it again. I think you'll see a perfectly straight
spoke with no residual stress. If that is not stress
relieving, then you may have abetter word for
it. Let me know what you find.

well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even
then, that would typically be done immediately after
initial deformation to prevent any possible aging
effects. on a 296mm spoke, if we're conservative, 1%
means 3mm elongation making it unusable for its
originally intended purpose.

But the lower end of that limit quite plausible, right?
Fully tensioned

spokes

Quoted message said:

do exhibit loaded elongations of around 1% and so the stress-
relief procedure described in Jobst's book is taking the
spokes to about 1.5% or 2% strain, clearly within your
specified range.

I overestimated, sorry. That should have been:

But approaching the lower end of that limit is quite
plausible, right? Fully tensioned spokes do exhibit loaded
elongations approaching 1% and so the stress-relief
procedure described in Jobst's book is taking the spokes to
in the region of 1% strain, close to your specified range.

Quoted message said:

Regarding aging effects, these can be very slow for
stainless steels. Are you sure they are important in this
application for such high purity stainless steels as DT
(for example) are using?

That question stands.
--
Mark South: World Citizen, Net Denizen

Mark South said:

"Mark South" <[email hidden]> wrote in message
"]news:[email hidden]...

I'm sorry, I have made a mistake or two in the following,
which I attribute to my inability to leave numbers alone
no matter how short of sleep I am.

Quoted message said:

"jim beam" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

[email hidden] wrote:

Quoted message said:

>Now, tension the spoke to the yield stress and relax it
>again. I think you'll see a perfectly straight spoke
>with no residual stress. If that is not stress
>relieving, then you may have abetter word for
>it. Let me know what you find.

well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even then,
that would typically be done immediately after initial
deformation to prevent any possible aging effects. on a
296mm spoke, if we're conservative, 1% means 3mm
elongation making it unusable for its originally intended
purpose.

But the lower end of that limit quite plausible, right?
Fully tensioned

spokes

Quoted message said:

do exhibit loaded elongations of around 1% and so the stress-
relief procedure described in Jobst's book is taking the
spokes to about 1.5% or 2% strain, clearly within your
specified range.

I overestimated, sorry. That should have been:

But approaching the lower end of that limit is quite
plausible, right? Fully tensioned spokes do exhibit
loaded elongations approaching 1% and so the stress-
relief procedure described in Jobst's book is taking the
spokes to in the region of 1% strain, close to your
specified range.

there's elastic & plastic strain. metallurgical stress
relief is only achieved in the 1-3% /plastic/ strain region.
it's easy to get elastic spoke elongations in the 1mm range,
but that's only ~1/3 of 1% but again, it needs to be
_plastic_ strain to achieve relief.

Quoted message said:

Quoted message said:

Regarding aging effects, these can be very slow for
stainless steels. Are you sure they are important in this
application for such high purity stainless steels as DT
(for example) are using?

That question stands.

i don't believe it's important to us as consumers. i just
mention it because in the factory, to make a difference in
reducing residual stress after a drawing operation, the
second stress relief drawing needs to take place pretty much
immediately. otherwise aging can reduce effectiveness.
depends on alloy.

Old Crow or was it Wild Turkey said:

Quoted message said:

So? What is it that is unclear about why these spokes
fail so rapidly and why stress relieving reduces their
failure rate as you see it?

Quoted message said:

I don't think your version of "stress relief" brings any
metallurgical change to the spokes, but it definitely
builds a stronger more evenly tensioned wheel. See below
for my experiment last summer.

I don't see your experiment below or are you referring to
the URL with wreck.bike exchange?

Quoted message said:

As explained before, one reason for failure of these
spokes is their "dirty" steels. Another is the use of
chrome plating. Chrome is brittle and cracks when the
spokes get bent during build. These cracks are /classic/
fatigue initiators.

Oh, you mean like anodizing on aluminum rims? Actually the
old spokes I listed were not chromed except Berg. Their
durability increase was what led me to stress relief.

I think you are missing a logical point of why spokes fail
where they
do. They break at the ends for good reasons. Thread
failures are probably the best place to look. For a
spoke to fail in fatigue it must be operating (cyclic
loading) near its yield stress. Since the tension load
on a spoke is far below yield it cannot be the cause,
there must be an additional stress to cause a failure.
That stress is a residual stress from manufacturing and
installation. DT as well as other spokes fail in the
threads but if they are stress relieved, their threads
do not fail.

By overloading a spoke temporarily, high stress points must
yield so that when the overload is relaxed, the peak stress
becomes lower than it was. This margin is what makes spokes
last longer when stress relieved. That does not mean all
residual stress is removed but the highest stress is reduced
and that is enough to reduce failures.

Quoted message said:

Quoted message said:

Quoted message said:

Yes, there are now several brands that work well. But
their long life is not the product of "stress relief";
it's the fact that in the 70's, it became economic to
mass produce vacuum degassed steels. Ultra-clean
materials like this are substantially more fatigue
resistant because this process virtually eliminates
inclusions, thereby removing a significant source of
fatigue initiation.

Quoted message said:

Quoted message said:

Oh? So how do you explain the reports of repeated
failures in wheels with these spokes, ones built by
people who, as you, don't believe that stress relief is
useful or don't know about it.

Quoted message said:

Which brand of spokes? The people I've asked for info on
which brand of spoke they've been breaking here on r.b.t.
either don't seem to know or will only admit to pre-built
wheels which usually use no-name cheapo stuff. The broken
d.t.'s i have are all victims of chain gouge, so i don't
think they're much of a data point. And when spokes /do/
break, the wheels usually get rebuilt with high quality
after market replacements, and miraculously, their
problems seem to disappear! coincidence?

No dice. People have failures with DT and Sapim spoke and
have reported about that here. I have had a DT spoke fail
near the rim where I had gotten a hardwood stick in the
front wheel that cause an endo and a kink that was visible
but had no scratch on it. I thought nothing of it before it
broke because the spoke was essentially straight to the eye.
It obviously had residual stress or it would not have broken
in fatigue a few thousand miles later.

Quoted message said:

Quoted message said:

How about an experiment? One that I have done. I take it
that you have access to materials testing equipment from
what you write. Take a spoke and manually give it some
kinks with as small a radius as you can. Tension that
spoke to customary service tension in a tensile tester
using a simulated 3mm flange hole and holder for a spoke
nipple. I think you'll notice that when relaxed again,
the spoke will still have kinks,

Quoted message said:

Agreed - I can repeat this experiment if you like.
Probably won't have time to do it for several weeks, but
it's easily done.

I'm sure you can comment on it even if you haven't
performed it yet. Do you believe the results would be as I
described above? If so how do you account for the spoke
being straight after being stressed to yield? Do you agree
that his removes residual stress? For instance, if you bend
a spoke and get only partial spring back, do you agree that
this shows residual stress where the outer fibers went
beyond yield while the inner ones that did not and try to
return to the original shape while the outer ones resist.
Is that not residual stress, and if so why do you believe
it is not additive to a subsequent tensile load on the
installed spoke?

That is what this experiment is intended to demonstrate. I
have inadvertently done this when I charted the stress
strain curves for "the Bicycle Wheel" in which less than
perfectly straight spokes became straight from stretching
them beyond yield.

Quoted message said:

Quoted message said:

kinks that in service would lead to fatigue failure.

Quoted message said:

Not necessarily more so than a spoke that's been bent to
"correct the line" or a spoke that's crossing another,
particularly if that crossing is closer to the hub than
normal like 2x on a 32 spoke wheel. Depends on the extent
of the kink doesn't it!

I'm sure you can come up with a spoke lacing that is more
damaging than conventional cross patterns. However, we have
not seen failures in common interleaved spoke lacings. I
have never seen a failure at a crossing point so let's drop
that one. We have seen many failures at the elbows, heads
popping off, and thread failures as well as mid spoke
failures from smooth kinks, ones that had no knick or gouge.

Quoted message said:

Quoted message said:

Now, tension the spoke to the yield stress and relax it
again. I think you'll see a perfectly straight spoke with
no residual stress. If that is not stress relieving, then
you may have abetter word for
it. Let me know what you find.

Quoted message said:

Well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even then,
that would typically be done immediately after initial
deformation to prevent any possible aging effects. On a
296mm spoke, if we're conservative, 1% means 3mm
elongation making it unusable for its originally intended
purpose. Being as we're not getting strain of that
magnitude, you can't contend that there's true
metallurgical stress relief in a wheel build.

Oh but yes. As I mentioned, for a fatigue failure to occur
requires high stress, stress that spoke tension alone does
cannot cause. Spokes fail. Ergo, there is high stress.
Overloading a spoke to relieve that stress causes local
yield because the stress is high.

Quoted message said:

Quoted message said:

Quoted message said:

A traditional steel for example may have half the
fatigue limit in the transverse axis of a rolled sheet
compared to its longitudinal axis. The same alloy
composition, but vacuum degassed, may have very similar
fatigue limits in both orientations. When first seen,
the observation of this effect sparked a hunt for
explanation. Electron microscopy subsequently confirmed
fatigue initiation at tiny inclusions previously thought
to be insignificantly small.

Quoted message said:

Quoted message said:

So what does this have to do with stress relieving
or not?

Quoted message said:

I'm trying to tell you /why/ modern spokes have such good
fatigue characteristics!!!

We are talking about failures, not how good spokes are.
Besides, it is documented that the good spokes fail.

Quoted message said:

Quoted message said:

Quoted message said:

> As I have described here often, spoke wire must be
> ductile enough to withstand cold forming yet retain a
> sufficiently high yield strength to resist fatigue
> failures at normal spoke loadings. This had not been so
> before DT spokes so there is where you should look for
> the answer. Redaelli, Berg, and Prym spokes also did
> not survive long even with stress relieving although it
> extended their service life.

--- no response

Quoted message said:

Quoted message said:

I see you have no comment on the high ductility and high
tensile strength of DT spoke wire.

Quoted message said:

What's to comment? You're the guy that was telling me a
while back that
d.t. spokes were fully hard. You didn't respond to links
showing the tensile strength differences between 2.0
straight gauge, 2.0/1.8/2.0 butted and 2.0/1.5/2.0
butted - which are directly attributable to continued
work hardening.

You're the one who did not believe that the ductility shown
in the stress strain curve of the DT spoke that stretched
horizontally right off the chart was not real and that this
showed strain hardening. As I pointed out, you were assuming
there was a significant reduction in cross section from this
stretching but for a 300mm long spoke a few .1mm does not
make a significant change in cross section. The spokes were
not necking locally.

Quoted message said:

google.comgroupsOpen ↗
40newssvr27.news.prodigy.com&output=gplain

Quoted message said:

Quoted message said:

Quoted message said:

What causes failures is well known. It's what alleviates
them that seems to be the issue here. All that "stress
relief" achieves is a wheel that is fully bedded in
before riding. Spokes do not therefore loosen and others
do not therefore carry disproportionate load. In that
respect, the practice referred to as "stress relief" is
a good thing, and thoroughly to be commended. But the
business of fatigue mitigation itself is achieved in the
spoke manufacturers factory, not the wheel builders
bench.

Quoted message said:

Quoted message said:

"Well known"? From what you just said, it seems not to
be.

Quoted message said:

The causes of fatigue are quite well known to
metallurgists & materials engineers. There's tons of stuff
about that on the web.

You seem to attribute durability to "bedding in" rather than
stress relief. I propose there is no bedding in after a
spoke is tensioned, the aluminum having yielded or a point
where contact area is large enough to sustain the load. If
you unspoke a stress relieved wheel and one whose spokes
have not been loaded by this process, you will find no
visible difference n the dimples made by their spokes
although there is a minuscule change. This is not what
prevents spoke failures and especially not on the threaded
end of spokes.

Quoted message said:

Quoted message said:

Bedding in is already complete when spokes are tensioned

Quoted message said:

I absolutely disagree. My hefty #210 hindquarters most
definitely are able to untrue a wheel that has not been
properly bedded in. Quickly too. That's where the benefits
of the "stress relief" wheel build process are most
apparent.

Oops. What does your weight have to do with "bedding in?" I
assume you are aware that spoke tension does not increase
from loading the wheel. Driving torque causes minimal almost
imperceptible increases and decreases as does braking.
However, sitting on the bicycle does not bed in spokes.

Quoted message said:

Quoted message said:

And even if it weren't, subsequent bedding in from use
cannot relax the tension of a spoke, the change in length
being insignificant compared to spoke elastic stretch
from tensioning.

Quoted message said:

This is not my experience. Last summer, I /did/ build a
wheel, deliberately without "stress relief". It was evenly
tensioned and perfectly true before leaving the house. I
took care to ensure no spoke had any twist by marking them
on one side before assembly so any torque could easily be
seen. It did not "ping" while riding. It was ~6mm out of
true after riding around just one block and some of the
spokes were almost completely slack. Clearly there was
measurable yielding of /something/. As I think we both
agree that spokes are loaded to less than a third of their
yield, it had to be something else - yielding of soft
aluminum hub holes & rim holes. Hence the need to
/properly/ bed wheels in.

Quoted message said:

Quoted message said:

However, even if it did, your model of overloaded spokes
cannot explain the failure of left side spokes in rear
wheels that have as little as half the tension of those
on the right.

Quoted message said:

Why not? If it means the spokes get higher cyclic load
limits, i.e. the difference between the maximum & minimum
loads, or even /negative/ loads, I don't see any disparity
at all! I have examples of spoke failures where the elbows
have fatigued from both the inside out, /and/ outside in!
Clearly in this situation, poor tension is a contributor.

How can a lowly tensioned spoke have higher cyclic loads. It
can only go from zero to the low tension of the left side
that is often 1/2 or less that of the right side of a rear
wheel. Cyclic load is irrelevant to fatigue if it is a tiny
fraction of the yield stress.

Quoted message said:

Quoted message said:

Beyond these considerations, high spoke tension is
generally in the range of 1/3 the yield stress of a
spoke.

Quoted message said:

Which just happens to be about the same stress level we
commonly see for fatigue limits [_not_ to be confused with
an endurance limits]. Funny coincidence that.

Fatigue limit

Definition: The maximum value of the applied alternating
stress which a test piece can stand indefinitely.

Endurance limit

Definition: The maximum value of the applied alternating
stress which a test piece can stand indefinitely. Rigid,
elastic, low damping materials such as thermosetting
plastics and some crystalline thermoplastics do not exhibit
an endurance limit. Also known as FATIGUE LIMIT.

I think you are quibbling. This is not about other materials
but about steel spokes.

Quoted message said:

Quoted message said:

Would you explain your understanding of spoke failure in
this respect?

Quoted message said:

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Quoted message said:

The explanation of "local yielding" you've presented as
theory on how to eliminate fatigue is unfortunately
built on some gross misconceptions. You assert that the
steel in spokes exhibits the same properties as mild
steel, i.e. the exhibition of yield and deformation
without work hardening as a method of reducing residual
stress.

Quoted message said:

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Where do you find that "unfortunate" scenario? I haven't
proposed anything of the sort. I see a straw man raising
his head. Where is Ray Bolger when we need him. He's
probably out there on a yellow brick road commiserating
heart warmingly with a tin man.

Quoted message said:

I don't have your book in front of me, but you show a
stress/strain graph for mild steel, i.e. one that
exhibits strain aging, then IIRC, go on to discuss
yielding without work hardening. If you knew the
distinction between a material that exhibits strain
aging, mild steel, and one that doesn't, stainless steel,
you wouldn't have made that error.

I don't know what you are getting at. The stress strain
curves for the two brands of spokes shown are from a tensile
tester. You have criticized these before but I never got the
thrust of your complaint. Besides, what has this got to do
with stress relief?

Quoted message said:

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Reality is, stainless steel spoke wires /do/ work harden
immediately from yield, as the real-life spoke
stress/strain graphs in the back of your book show.
"Stress relief" therefore has the ability to not only
continue increasing the dislocation density of the
material [which /increases/ lattice stresses] at any
point where it does yield, [/if/ it yields, and that's
conjecture], but to also activate slip bands and
initiate cumulative damage effects.

Quoted message said:

Quoted message said:

I am reminded of Richard Feynman's appropriate words: "If
you can't explain it in plain English, you probably don't
understand it yourself."

ibid

Quoted message said:

"Plain English" is relative. There are certain concepts
that have their own names. "Dislocation" is one that is
fundamental to deformation theory, much like the host of
sub-atomic particle names are to fundamental to the
physics of matter. There's no avoidance possible. Likewise
"lattice". Atoms in a crystal are arranged in a lattice.
That's pretty plain. These terms are all googleable.

You needn't go into metallurgical jargon to explain what is
being discussed on a public forum such as this. Withdrawing
into such language obscures what is being said and readers
are not going to study etymology tomake sense of it. Jargon
is used in the trade to be concise and brief, however each
such words can be explained in common usage English as they
are in a dictionary. On wreck.bike abbreviations like QR or
Freehub are bike jargon known to most readers of the group
but unknown outside. I'm sure I can explain such devices
without using those terms. You can too.

Quoted message said:

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The closest analogy to your explanation is something
called "coaxing" where a component is progressively
loaded and fatigue limits improved, but unfortunately,
this effect is only present in materials that exhibit
strain aging. Stainless steel is not one of them.

Quoted message said:

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I see. Now it is specifically stainless steel that makes
spokes not fail.

Quoted message said:

You're putting words in my mouth. High quality stainless
steel can be fatigue resistant. Mild steel can be fatigue
proof in certain circumstances. Two very different things.
Stainless steel has no endurance limit and therefore can
never be fatigue proof.

By the way, you didn't explain what "coaxing" is and how it
affects spokes.

If you want to talk about steel manufacture and alloying you
should probably take that to another forum. We are talking
about stress reliving and spoke failure, specifically high
quality stainless steel spokes, ones that have failed.

Quoted message said:

Quoted message said:

Are you proposing that other steel components on
bicycles, such as axles, cables, frames and the like,
would be more durable in such alloys?

Quoted message said:

The appropriate alloys are used already. Prime examples
are the stainless steels used to make good spokes and
control cables because of corrosion resistance. Corrosion
resistance preserves surface quality and good surface
quality is a primary fatigue mitigator.

Corrosion is another matter. I haven't seen any crank
spindles of stainless steel or their bearing cones. I am
aware that stainless instrument bearings are available but
they have significantly lower load limits and wear life.

Quoted message said:

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Quoted message said:

So, you want to know my agenda? Update your book and get
rid of the glaring materials theory errors! And please
include the differential spoke tension formula for
dished wheels while you're at it.

Quoted message said:

Quoted message said:

What sort of "differential spoke tension formula" are you
suggesting and for what would this be useful, considering
that the difference is dependent on the hub offset,
something that cannot be changed.

Quoted message said:

I know hub offset can't be changed - that's not the
question. I've seen it asked a number of times on r.b.t.,
why are measurements are given for the drive side of a
dished rear wheel, but not the non-drive side? If someone
has just built their first wheel, have a shiny new
tensiometer in their hand, are they not curious what the
deal is with the spokes they've not had comparison
measurements for? Publishing the tension differential
formulae in the same way you did for spoke length
calculation allows the curious to understand /why/ there
is a difference in tension, and if necessary, to calculate
what it would be for any given hub/rim combination.

I think that is a curiosity. The only thing that counts is
the right side tension, the other side being dependent and
of little consequence.

Quoted message said:

Quoted message said:

The graphic description in the book makes that fairly
clear as wheel as what the results are.

Jobst Brandt [email hidden]

jim beam <[email hidden]> wrote in message

Quoted message said:

there's elastic & plastic strain. metallurgical
stress relief is only achieved in the 1-3% /plastic/
strain region.

Significant stress relief occurs before 1% applied total
strain. All that is required for stress relief is that under
load the stress range over the spoke cross section is made
smaller. Since stress will unloaded evenly (elastically),
this smaller stress range is retained and the residual
stresses are relaxed. Yes you do need some plastic strain,
since the spoke will load evenly until part of it yields.
Since some of the spoke has tensile residual stress, a
significant portion of the spoke cross-section will have
some plastic strain by the time the applied stress equals
the yield strength, which happens well under 1% strain for
these steels.

Aluminum plate is stretched to 1-3% plastic strain to
achieve a greater degree of stress relief than you can get
at lower levels and to stress relieve in the transverse
direction at the same time. However, significant relief
occurs much earlier. In the below paper recently published
by Alcoa, see Figure 5. Although simplified, it illustrates
the concept. Curve "A" reaches the yield strength before .3%
strain. By 0.6% strain, the whole part has yielded. No
further stress relief occurs with further stretching. In
reality, materials are not perfectly plastic, so further
stress relief does occur for larder strains. However, the
majority occurs before 1% strain.

(Don't let the title fool you. Microstructural effects, etc,
are what limit the stress relief to something like 90-95%
relief instead of 100%. It has little bearing on stress
relief in spokes, which is not trying for 100% relief).
Title:A simplified analysis of the effect of microstructure
gradient on the stress relief of aluminum plates and
extrusions Author:Karabin, ME ; Barlat, F ; Becker, R
Institution:Alcoa Tech Ctr, Journal:INTERNATIONAL JOURNAL OF
MECHANICAL SCIENCES; SEP 2003; v.45, no.9, p.1483-1503

Mike Prime

Rick Warner said:

If they lasted only 500 miles there is a problem, either
in materials or technique. I built a set of 36 spoke
wheels this winter.

he brings up a good point, tho. is your average buyer (who
does not want to build their own wheels) better buying a
prebuilt wheelset or one from an LBS with an essentially
unknown builder? not everyone can or will go out and find
the "best builder" who may or may not be. prebuilt wheels
will (presumably) be consistent and better than N% of shop
built wheels .. and you'll have a major brand standing
behind them. how high N is is a very good question.

Quoted message said:

Took me an evening. Have almost 1000 miles, mostly
'loaded' (e.g., carrying panniers filled with stuff).
Still true as the night I built them, not a complaint from
the spokes.

i've built 4 pairs of wheels now and i'm very glad to have
the experience. in fact i've built all but one pair of the
wheels i'm currently using. there are, however, a lot of
people who should probably not be building their own wheels.
or cooking their own food for that matter.

Quoted message said:

Wait until you pop a spoke on the Ksyrium's. If you are
not near a major city, expect to wait a while if you want
one of those fancy spokes as a replacement.

yea .. i have a pair of campagnolo shamals that it's
horribly easy to get parts for (you can get a 6 spoke mini-
kit easily and the tool to use it at sears). the hubs are
essentially campag record and the manual has a nice
breakdown guide. this complaint is greatly overstated for at
least some brands.
--
david reuteler [email hidden]

Quoted message said:

Old Crow or was it Wild Turkey said:

Quoted message said:

So? What is it that is unclear about why these spokes
fail so rapidly and why stress relieving reduces their
failure rate as you see it?

Quoted message said:

I don't think your version of "stress relief" brings any
metallurgical change to the spokes, but it definitely
builds a stronger more evenly tensioned wheel. See below
for my experiment last summer.

I don't see your experiment below or are you referring to
the URL with wreck.bike exchange?

Quoted message said:

As explained before, one reason for failure of these
spokes is their "dirty" steels. Another is the use of
chrome plating. Chrome is brittle and cracks when the
spokes get bent during build. These cracks are /classic/
fatigue initiators.

Oh, you mean like anodizing on aluminum rims?

yes, like anodizing on rims. but if we don't see rim
fatigue lines actually following cracks in the anodizing,
then it's not the source of failure! exercise proper
analysis of your failures.

Quoted message said:

Actually the old spokes I listed were not chromed except
Berg. Their durability increase was what led me to
stress relief.

I think you are missing a logical point of why spokes fail
where they
do. They break at the ends for good reasons. Thread
failures are probably the best place to look. For a
spoke to fail in fatigue it must be operating (cyclic
loading) near its yield stress.

rubbish. fatigue can occur /well/ below that.

Quoted message said:

Since the tension load on a spoke is far below yield it
cannot be the cause, there must be an additional stress
to cause a failure.

see above. and look at any s-n curve. note the point at
which failures are still occurring. even a mild steel
endurance limit is only about 50% of yield.

Quoted message said:

That stress is a residual stress from manufacturing and
installation. DT as well as other spokes fail in the
threads but if they are stress relieved, their threads do
not fail.

so why do the manufacturers bother to roll high-radius
threads into them then? have you ever looked at one of these
threads under a magnifier?

Quoted message said:

By overloading a spoke temporarily, high stress points
must yield so that when the overload is relaxed, the peak
stress becomes lower than it was. This margin is what
makes spokes last longer when stress relieved. That does
not mean all residual stress is removed but the highest
stress is reduced and that is enough to reduce failures.

so where do things like miner's linear cumulative damage
rule come from
- the life of a component being a function of the number of
cycles at each level of stress?

Quoted message said:

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Quoted message said:

>Yes, there are now several brands that work well. But
>their long life is not the product of "stress relief";
>it's the fact that in the 70's, it became economic to
>mass produce vacuum degassed steels. Ultra-clean
>materials like this are substantially more fatigue
>resistant because this process virtually eliminates
>inclusions, thereby removing a significant source of
>fatigue initiation.

Quoted message said:

Quoted message said:

Oh? So how do you explain the reports of repeated
failures in wheels with these spokes, ones built by
people who, as you, don't believe that stress relief is
useful or don't know about it.

Quoted message said:

Which brand of spokes? The people I've asked for info on
which brand of spoke they've been breaking here on r.b.t.
either don't seem to know or will only admit to pre-built
wheels which usually use no-name cheapo stuff. The broken
d.t.'s i have are all victims of chain gouge, so i don't
think they're much of a data point. And when spokes /do/
break, the wheels usually get rebuilt with high quality
after market replacements, and miraculously, their
problems seem to disappear! coincidence?

No dice. People have failures with DT and Sapim spoke and
have reported about that here.

well, the only sapim failure i can see in a quick google
search is a guy with a powertap hub, but with its huge
flanges causing the spoke angles at the rim to be way
outside normal spec, i think we can safely attribute
failure to that rather than failure of the builder to
"stress relieve".

besides which, /reducing/ fatigue is not /eliminating/
fatigue. /every/ stainless spoke will fail at some point -
it has no endurance limit.

Quoted message said:

I have had a DT spoke fail near the rim where I had
gotten a hardwood stick in the front wheel that cause an
endo and a kink that was visible but had no scratch on
it. I thought nothing of it before it broke because the
spoke was essentially straight to the eye. It obviously
had residual stress or it would not have broken in
fatigue a few thousand miles later.

this gets more & more interesting. what this translates to
is: "i've never had a spoke failure in my 300,000 mile
wheels. apart from the ones that i've replaced because
they broke."

no, it's not "obvious" that it's residual stress. assigning
a failure mode without proper analysis is like you assigning
all rim cracking to anodizing.

Quoted message said:

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How about an experiment? One that I have done. I take it
that you have access to materials testing equipment from
what you write. Take a spoke and manually give it some
kinks with as small a radius as you can. Tension that
spoke to customary service tension in a tensile tester
using a simulated 3mm flange hole and holder for a spoke
nipple. I think you'll notice that when relaxed again,
the spoke will still have kinks,

Quoted message said:

Agreed - I can repeat this experiment if you like.
Probably won't have time to do it for several weeks, but
it's easily done.

I'm sure you can comment on it even if you haven't
performed it yet. Do you believe the results would be as I
described above?

yes, of course!

Quoted message said:

If so how do you account for the spoke being straight
after being stressed to yield?

er, because it's yielded???

Quoted message said:

Do you agree that his removes residual stress?

depends on the degree of yielding, and the behavior of the
material! it could introduce residual stress too! just like
"correcting the spoke line" could introduce residual stress
come to that.

Quoted message said:

For instance, if you bend a spoke and get only partial
spring back, do you agree that this shows residual stress
where the outer fibers went beyond yield while the inner
ones that did not and try to return to the original shape
while the outer ones resist. Is that not residual stress,
and if so why do you believe it is not additive to a
subsequent tensile load on the installed spoke?

it can be additive. but by that argument, again, "correcting
the spoke line" is more likely to cause harm than good. your
advice is contradictatory. the fact is, we're not dealing
with a lab sample here, we're dealing with a highly worked
wire with a multitude of surface defects, and an uncertain
operating environment. the reason real world production
focuses on surface quality in a fatigue environment is that
it's the single most prevalent cause of fatigue failure
after incompetent design. then come factors like material
quality, corrosion and damage in service. then you start
getting into the esoteric stuff. a quick manual squeeze on a
spoke being sufficient to exert enough stress to yield the
wire is not an assumption you can make. it's certainly not
one i'd care to propose to my old theory of deformation
professor and keep a straight face.

Quoted message said:

That is what this experiment is intended to demonstrate. I
have inadvertently done this when I charted the stress
strain curves for "the Bicycle Wheel" in which less than
perfectly straight spokes became straight from stretching
them beyond yield.

Quoted message said:

Quoted message said:

kinks that in service would lead to fatigue failure.

Quoted message said:

Not necessarily more so than a spoke that's been bent to
"correct the line" or a spoke that's crossing another,
particularly if that crossing is closer to the hub than
normal like 2x on a 32 spoke wheel. Depends on the extent
of the kink doesn't it!

I'm sure you can come up with a spoke lacing that is more
damaging than conventional cross patterns. However, we
have not seen failures in common interleaved spoke
lacings. I have never seen a failure at a crossing point
so let's drop that one.

no. the crossing is causing the spokes to bend and therefore
be held in a position of elastic strain at that bend point.
that has the same effect as a residual stress. do the math
on how much strain is exerted at that point because of the
bend, then tell me it's insignificant compared to the degree
of residual stress you believe to be present in a good
quality spoke.

Quoted message said:

We have seen many failures at the elbows, heads popping
off, and thread failures as well as mid spoke failures
from smooth kinks, ones that had no knick or gouge.

proper analysis please. "no damage" by what definition? did
you use a magnifier?

Quoted message said:

Quoted message said:

Quoted message said:

Now, tension the spoke to the yield stress and relax it
again. I think you'll see a perfectly straight spoke with
no residual stress. If that is not stress relieving, then
you may have abetter word for
it. Let me know what you find.

Quoted message said:

Well, for the metallurgical definition of stress relief,
that would require between 1% & 3% strain, and even then,
that would typically be done immediately after initial
deformation to prevent any possible aging effects. On a
296mm spoke, if we're conservative, 1% means 3mm
elongation making it unusable for its originally intended
purpose. Being as we're not getting strain of that
magnitude, you can't contend that there's true
metallurgical stress relief in a wheel build.

Oh but yes. As I mentioned, for a fatigue failure to occur
requires high stress,

no. look at any s/n curve.

Quoted message said:

stress that spoke tension alone does cannot cause. Spokes
fail. Ergo, there is high stress.

no. see above. spokes fail, ergo they are made of a material
without an endurance limit, subject to manufacturing
variance and an inconsistent operating environment.

Quoted message said:

Overloading a spoke to relieve that stress causes local
yield because the stress is high.

Quoted message said:

Quoted message said:

>A traditional steel for example may have half the
>fatigue limit in the transverse axis of a rolled sheet
>compared to its longitudinal axis. The same alloy
>composition, but vacuum degassed, may have very similar
>fatigue limits in both orientations. When first seen,
>the observation of this effect sparked a hunt for
>explanation. Electron microscopy subsequently confirmed
>fatigue initiation at tiny inclusions previously thought
>to be insignificantly small.

Quoted message said:

Quoted message said:

So what does this have to do with stress relieving
or not?

Quoted message said:

I'm trying to tell you /why/ modern spokes have such good
fatigue characteristics!!!

We are talking about failures, not how good spokes are.
Besides, it is documented that the good spokes fail.

well that's news! firstly, yes, good spokes fail, but not as
readily as bad spokes!!! secondly, you keep repeating that
your wheels are over 300,000 miles "without spoke failures"
and that "stress relief" eliminates fatigue. isn't that
inconsistent?

Quoted message said:

Quoted message said:

Quoted message said:

>>As I have described here often, spoke wire must be
>>ductile enough to withstand cold forming yet retain a
>>sufficiently high yield strength to resist fatigue
>>failures at normal spoke loadings. This had not been so
>>before DT spokes so there is where you should look for
>>the answer. Redaelli, Berg, and Prym spokes also did
>>not survive long even with stress relieving although it
>>extended their service life.

--- no response

Quoted message said:

Quoted message said:

I see you have no comment on the high ductility and high
tensile strength of DT spoke wire.

Quoted message said:

What's to comment? You're the guy that was telling me a
while back that
d.t. spokes were fully hard. You didn't respond to links
showing the tensile strength differences between 2.0
straight gauge, 2.0/1.8/2.0 butted and 2.0/1.5/2.0
butted - which are directly attributable to continued
work hardening.

You're the one who did not believe that the ductility
shown in the stress strain curve of the DT spoke that
stretched horizontally right off the chart was not real
and that this showed strain hardening.

rubbish. /that/ argument was when you were referring to
figure 15 in your book, not figure 69 to which you are
referring now.

Quoted message said:

As I pointed out, you were assuming there was a
significant reduction in cross section from this
stretching but for a 300mm long spoke a few .1mm does not
make a significant change in cross section. The spokes
were not necking locally.

where have i mentioned necking??? the only reductions in
cross section that i've referred to are the ones from
manufacture - the ones that you were maintaining did not
result in continued work hardening!

Quoted message said:

Quoted message said:

google.comgroupsOpen ↗
40newssvr27.news.prodigy.com&output=gplain

Quoted message said:

Quoted message said:

>What causes failures is well known. It's what alleviates
>them that seems to be the issue here. All that "stress
>relief" achieves is a wheel that is fully bedded in
>before riding. Spokes do not therefore loosen and others
>do not therefore carry disproportionate load. In that
>respect, the practice referred to as "stress relief" is
>a good thing, and thoroughly to be commended. But the
>business of fatigue mitigation itself is achieved in the
>spoke manufacturers factory, not the wheel builders
>bench.

Quoted message said:

Quoted message said:

"Well known"? From what you just said, it seems not to
be.

Quoted message said:

The causes of fatigue are quite well known to
metallurgists & materials engineers. There's tons of stuff
about that on the web.

You seem to attribute durability to "bedding in" rather
than stress relief. I propose there is no bedding in after
a spoke is tensioned, the aluminum having yielded or a
point where contact area is large enough to sustain the
load. If you unspoke a stress relieved wheel and one whose
spokes have not been loaded by this process, you will find
no visible difference n the dimples made by their spokes
although there is a minuscule change. This is not what
prevents spoke failures and especially not on the threaded
end of spokes.

"no visible difference". that not very quantitative.

Quoted message said:

Quoted message said:

Quoted message said:

Bedding in is already complete when spokes are tensioned

Quoted message said:

I absolutely disagree. My hefty #210 hindquarters most
definitely are able to untrue a wheel that has not been
properly bedded in. Quickly too. That's where the benefits
of the "stress relief" wheel build process are most
apparent.

Oops. What does your weight have to do with "bedding in?"
I assume you are aware that spoke tension does not
increase from loading the wheel. Driving torque causes
minimal almost imperceptible increases and decreases as
does braking. However, sitting on the bicycle does not bed
in spokes.

ok, so i'm leaning the bike from side to side on a hill. do
i not increase tension on one side and slacken it on the
other? funny, if i repeat the experiment "in the lab" and
pluck the spokes, i get a higher pitch tone on the loaded
side and a lower tone on the unloaded side. tension does not
increase? just because it's not convenient to your theory
doesn't doesn't mean it's not occurring!

Quoted message said:

Quoted message said:

Quoted message said:

And even if it weren't, subsequent bedding in from use
cannot relax the tension of a spoke, the change in length
being insignificant compared to spoke elastic stretch
from tensioning.

Quoted message said:

This is not my experience. Last summer, I /did/ build a
wheel, deliberately without "stress relief". It was evenly
tensioned and perfectly true before leaving the house. I
took care to ensure no spoke had any twist by marking them
on one side before assembly so any torque could easily be
seen. It did not "ping" while riding. It was ~6mm out of
true after riding around just one block and some of the
spokes were almost completely slack. Clearly there was
measurable yielding of /something/. As I think we both
agree that spokes are loaded to less than a third of their
yield, it had to be something else - yielding of soft
aluminum hub holes & rim holes. Hence the need to
/properly/ bed wheels in.

no comment??? do we have to go through the head set bearing
experiment again jobst?

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However, even if it did, your model of overloaded spokes
cannot explain the failure of left side spokes in rear
wheels that have as little as half the tension of those
on the right.

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Why not? If it means the spokes get higher cyclic load
limits, i.e. the difference between the maximum & minimum
loads, or even /negative/ loads, I don't see any disparity
at all! I have examples of spoke failures where the elbows
have fatigued from both the inside out, /and/ outside in!
Clearly in this situation, poor tension is a contributor.

How can a lowly tensioned spoke have higher cyclic loads.
It can only go from zero to the low tension of the left
side that is often 1/2 or less that of the right side of a
rear wheel. Cyclic load is irrelevant to fatigue if it is
a tiny fraction of the yield stress.

you do the math. i have the fatigued spokes for evidence -
elbows fatigued from the inside out, _and_ outside in.
explain that in terms of "zero" tension if you please!

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Beyond these considerations, high spoke tension is
generally in the range of 1/3 the yield stress of a
spoke.

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Which just happens to be about the same stress level we
commonly see for fatigue limits [_not_ to be confused with
an endurance limits]. Funny coincidence that.

Fatigue limit

Definition: The maximum value of the applied alternating
stress which a test piece can stand indefinitely.

Endurance limit

Definition: The maximum value of the applied alternating
stress which a test piece can stand indefinitely. Rigid,
elastic, low damping materials such as thermosetting
plastics and some crystalline thermoplastics do not
exhibit an endurance limit. Also known as FATIGUE LIMIT.

i made the same linguistic error that many do - confusing
fatigue strength and endurance. "fatigue strength" is that
given for a material without an endurance limit at say 10^8
cycles. "endurance strength" is the limit at the s-n curve
goes horizontal. i meant "fatigue strength" for stainless is
in the range ~1/3 yield.

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I think you are quibbling. This is not about other
materials but about steel spokes.

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Would you explain your understanding of spoke failure in
this respect?

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>The explanation of "local yielding" you've presented as
>theory on how to eliminate fatigue is unfortunately
>built on some gross misconceptions. You assert that the
>steel in spokes exhibits the same properties as mild
>steel, i.e. the exhibition of yield and deformation
>without work hardening as a method of reducing residual
>stress.

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Where do you find that "unfortunate" scenario? I haven't
proposed anything of the sort. I see a straw man raising
his head. Where is Ray Bolger when we need him. He's
probably out there on a yellow brick road commiserating
heart warmingly with a tin man.

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I don't have your book in front of me, but you show a
stress/strain graph for mild steel, i.e. one that
exhibits strain aging, then IIRC, go on to discuss
yielding without work hardening. If you knew the
distinction between a material that exhibits strain
aging, mild steel, and one that doesn't, stainless steel,
you wouldn't have made that error.

I don't know what you are getting at. The stress strain
curves for the two brands of spokes shown are from a
tensile tester. You have criticized these before but I
never got the thrust of your complaint. Besides, what has
this got to do with stress relief?

weak dodge. refer to figure 15. /that/ is the incorrect data
on which to build a "stress relief" theory!!!

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>Reality is, stainless steel spoke wires /do/ work harden
>immediately from yield, as the real-life spoke
>stress/strain graphs in the back of your book show.
>"Stress relief" therefore has the ability to not only
>continue increasing the dislocation density of the
>material [which /increases/ lattice stresses] at any
>point where it does yield, [/if/ it yields, and that's
>conjecture], but to also activate slip bands and
>initiate cumulative damage effects.

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I am reminded of Richard Feynman's appropriate words: "If
you can't explain it in plain English, you probably don't
understand it yourself."

ibid

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"Plain English" is relative. There are certain concepts
that have their own names. "Dislocation" is one that is
fundamental to deformation theory, much like the host of
sub-atomic particle names are to fundamental to the
physics of matter. There's no avoidance possible. Likewise
"lattice". Atoms in a crystal are arranged in a lattice.
That's pretty plain. These terms are all googleable.

You needn't go into metallurgical jargon to explain what
is being discussed on a public forum such as this.
Withdrawing into such language obscures what is being said
and readers are not going to study etymology tomake sense
of it. Jargon is used in the trade to be concise and
brief, however each such words can be explained in common
usage English as they are in a dictionary. On wreck.bike
abbreviations like QR or Freehub are bike jargon known to
most readers of the group but unknown outside. I'm sure I
can explain such devices without using those terms. You
can too.

like your references to hertzian math or elastohydrodynamic
separation?

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>The closest analogy to your explanation is something
>called "coaxing" where a component is progressively
>loaded and fatigue limits improved, but unfortunately,
>this effect is only present in materials that exhibit
>strain aging. Stainless steel is not one of them.

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I see. Now it is specifically stainless steel that makes
spokes not fail.

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You're putting words in my mouth. High quality stainless
steel can be fatigue resistant. Mild steel can be fatigue
proof in certain circumstances. Two very different things.
Stainless steel has no endurance limit and therefore can
never be fatigue proof.

By the way, you didn't explain what "coaxing" is and how
it affects spokes.

stormingmedia.usA836913.htmlOpen ↗

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If you want to talk about steel manufacture and alloying
you should probably take that to another forum. We are
talking about stress reliving and spoke failure,
specifically high quality stainless steel spokes, ones
that have failed.

interesting. why don't /you/ post your "research" on
sci.engr.metallurgy? your rim cracking theories would be
particularly well received.

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Are you proposing that other steel components on
bicycles, such as axles, cables, frames and the like,
would be more durable in such alloys?

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The appropriate alloys are used already. Prime examples
are the stainless steels used to make good spokes and
control cables because of corrosion resistance. Corrosion
resistance preserves surface quality and good surface
quality is a primary fatigue mitigator.

Corrosion is another matter. I haven't seen any crank
spindles of stainless steel or their bearing cones. I am
aware that stainless instrument bearings are available but
they have significantly lower load limits and wear life.

no it's not. it's a very significant component in fatigue
initiation. don't go off topic.

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>So, you want to know my agenda? Update your book and get
>rid of the glaring materials theory errors! And please
>include the differential spoke tension formula for
>dished wheels while you're at it.

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What sort of "differential spoke tension formula" are you
suggesting and for what would this be useful, considering
that the difference is dependent on the hub offset,
something that cannot be changed.

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I know hub offset can't be changed - that's not the
question. I've seen it asked a number of times on r.b.t.,
why are measurements are given for the drive side of a
dished rear wheel, but not the non-drive side? If someone
has just built their first wheel, have a shiny new
tensiometer in their hand, are they not curious what the
deal is with the spokes they've not had comparison
measurements for? Publishing the tension differential
formulae in the same way you did for spoke length
calculation allows the curious to understand /why/ there
is a difference in tension, and if necessary, to calculate
what it would be for any given hub/rim combination.

I think that is a curiosity. The only thing that counts is
the right side tension, the other side being dependent and
of little consequence.

yes it is of consequence - it is directly responsible for
campy's "g3" spoking pattern and it's directly responsible
for offset rims. why would manufacturers spend r&d on these
products if it was of no consequence? and why would /you/
say dishless wheels are more stable?

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The graphic description in the book makes that fairly
clear as wheel as what the results are.

Jobst Brandt [email hidden]