The Basics of Wheel Alignment and Wheelbuilding

Tim McNamara wrote:
jim beam writes:


wrote:

snip

Spoke-squeezing is an intriguingly mysterious subject to
research. I remain agnostic, wavering one way and the other, but
haven't seen any experimental data or analyses involving bicycle
spokes. If you have the 3rd edition, perhaps you could peek at the
Wiedemer stuff and give me your thoughts on it?

you may also want to consider this question:

q: elevator safety certification requires loading the cab to double
it's "safe working load". this is to test the wire ropes that
suspend it. the reason is that fracture mechanics predict that this
process will typically reveal by failure any latent flaws. but, if
we extend spoke squeezing theory, wouldn't this overload procedure
also prevent fatigue of elevator cables?

a: no. elevator cables still fatigue and need regular testing,
inspection & replacement.


Of course they fatique. They are constantly being wound around a drum
and unwound with a large weight dangling on the end. This doesn't
happen with spokes. Spokes are one fairly thick wire under a fairly
small load, elevator cables are thin-stranded cables with internal
friction, corrosion challenges, etc.

Additionally, a spoke supports a load much differently than an
elevator cable, as has been discussed and verified- independently of
Brandt, BTW- by finite element analysis.

I see you're keeping the fine art of red herrings alive.


the bottom line is that there is no quantification or testing of
this spoke squeeze theory. squeezing "as hard as you can" is no
more scientific than building with spoke tension "as high as the rim
can bear". i would suggest to you that the reason academics "change
the subject and get back to "serious" work" is because this theory
is mere speculation - it's author has shown no basis in statistical
fact, and most definitely not by metallurgical analysis.


And it's easy to take cheap shots when he's out of town and not able,
therefore, to respond. I don't quite know why it sticks in your craw
so much to admit even the possibility that Jobst is right, and it's an
interesting psychological problem especially when combined with your
anonymity behind a boozy screen name. But if you're going to
seriously critique his work and not just take potshots, come up with a
quantified and testable alternative analysis. Prove him wrong. Put
up or shut up. Frankly, jim beam old buddy old pal, I don't think you
have the stuff.

tim, you're like a drunken finnean looking for a bit of bare-knucked
sport on his way home from a bar. read what i said when you're sober,
then show me one single piece of metallurgical evidence to support
brandts bullying assertions. or your allusions to superior mental
health come to that.

jim beam wrote:
wrote:

Second, do spokes in well-built (by whatever means) wheels
require constant inspection and replacement?

if you read the instructions that come with all these expensive
pre-built wheels yes! but, that's only a cursory visual inspection.
it's just like the contrasts between the safety & inspection regimes for
cars vs planes, wheel spokes are not usually considered a high fatality
risk, so there's no reason to subject them to a rigorous expensive
certification procedure.

How do you inspect your spokes? I can't imagine that it is very
easy to see signs of imminent failure. Well-built wheels don't
require "constant" spoke replacement.

Carl, did you see in the discussion at
http://yarchive.net/bike/stress_relieve.html
the article containing this quote and link

"For some results of some actual residual stress measurements I did on
7050 aluminum plate before and after stretching see:
http://www.lanl.gov/residual/alplate.pdf
The residual stress was reduced by about a factor of 10 by the stress
relief process."

After hundreds of exchanges previously in this newsgroup the questions
originally about tied and soldered wheels, what difference they made and how
a wheel is loaded/supported/hangs/stands on or from its tyre/rim/spoke(s)
was reduced mostly to the semantics of the English language and whether
appropriate engineering terms were being used/abused. I fear the same may
happen again.
So here it is, how to build a wheel. Ignore JBs "stress releiving" it
is not required. When the spoke is relaxed, form the bend at the crossing,
oil the nipples with linseed and tighten to a point where the riders full
weight does not releive the bottom spoke. This is using a method of minimal
tension not only provides a wheel which will fail safe but also maintains a
ridable wheel in the event of impact damage resulting in spoke loss.
Severre buckling is eliminated. Spoke quality is not an issue.
The pre-forming of the spoke reduces the side to side bending which
occurs at the hub interface to a minimum thus allowing maximum life.
If I want to ride a rock strewn bridleway I will, with 20mm wide rims.
This is not asking for the impossible. I've done it safe in the knowledge
that my wheels will not buckle due to incorrect build. It was only through
cycling that road improvements came about in England with a smooth sealed
surface. If you look at early high-wheelers they had 20mm wide rims, so for
reliability there is no reason why a 27" wheel would require anything of
larger section. Those wheels where built for rough roads. This is a change
of my belief of 5+ years ago, when I thought a wider rim was required to
prevent buckling. Experience has since demonstrated that wheels built with
pre-formed spokes grossly outperform those built with ignorance. So all
in all rim width is dependant only on tyre choice.
Perhaps some 7oz rims may eventually become available again. Try using
JB's method on that and you may as well burn your money, followed by the
book.
TJ

jim beam:

First, how much do elevator cables resemble spokes?

obviously, rope is multistrand, a spoke is single strand, but the
materials & applications are the same.

Materials may be the same but "applications" are not. That "rope" is
subjected to turns and loads on pulleys, as you admit below.

it's only the practical issues
of price, of needing a spoke that resists torque sufficiently to be able
to tighten a nipple and indeed, ability to thread a nipple in the first
place that lead to the use of single strand.

This made-up story doesn't even look nor sound good. Spokes still do
twist, and a threaded nipple is not the only way to have an adjustable
tightening mechanism on a rim.

Does it matter that they bend
around pulleys in a constant side-to-side flexing different
than spokes?

yes, and those pulleys cause wear and bending stresses, but that's why
you use multi-strand in the first place.

Hence spokes and cable are not the same "application".

also, one strand breaking in a
rope of 100 leaves 99 others - pretty comforting.

Nonsense. If a cable is loaded such that a strand breaks, the effective
cross section of the cable is reduced and hence the load results in a
higher stress for the remaining strands, which will rapidly lead to
failure of the cable. If a strand was broken by other than a load (eg
cut), the same effect on cross section will be observed. You can't cut
a strand on a solid spoke.

and there's a small
degree of freedom to move between strands which reduces cross sectional
stress considerably.

Again, nonsense. What can move between strands? The only way to move
loads between strands is if the strands are able to move along the
cable's length. This is a bad event since the strands will not take up
the load evenly amongst themselves.

Second, do spokes in well-built (by whatever means) wheels
require constant inspection and replacement?

if you read the instructions that come with all these expensive
pre-built wheels yes! but, that's only a cursory visual inspection.
it's just like the contrasts between the safety & inspection regimes for
cars vs planes, wheel spokes are not usually considered a high fatality
risk, so there's no reason to subject them to a rigorous expensive
certification procedure.

In other words, no.

Trevor Jeffrey:

After hundreds of exchanges previously in this newsgroup the questions
originally about tied and soldered wheels, what difference they made and how
a wheel is loaded/supported/hangs/stands on or from its tyre/rim/spoke(s)
was reduced mostly to the semantics of the English language and whether
appropriate engineering terms were being used/abused. I fear the same may
happen again.

You've just started it by your poor writing skill.

So here it is, how to build a wheel. Ignore JBs "stress releiving" it
is not required. When the spoke is relaxed, form the bend at the crossing,
oil the nipples with linseed and tighten to a point where the riders full
weight does not releive the bottom spoke.

Just how do you do this, and how do you account for the dynamic loads
put on the wheel which exceed the static rider/bike weight?

This is using a method of minimal
tension not only provides a wheel which will fail safe

What the hell is "a wheel which will fail safe"?

but also maintains a
ridable wheel in the event of impact damage resulting in spoke loss.

Uhhhh, headache.....

Severre buckling is eliminated.

Since buckling is also load magnitude dependent, "severre" buckling
cannot be avoided if the load is high enough, and especially since you
only tensioned the spokes enough to take up your static weight.

Spoke quality is not an issue.

Plastic spokes will be fine then.

Trevor Jeffrey wrote:
So here it is, how to build a wheel. Ignore JBs "stress releiving" it
is not required. When the spoke is relaxed, form the bend at the crossing,
oil the nipples with linseed and tighten to a point where the riders full
weight does not releive the bottom spoke. This is using a method of minimal
tension not only provides a wheel which will fail safe but also maintains a
ridable wheel in the event of impact damage resulting in spoke loss.
Severre buckling is eliminated. Spoke quality is not an issue.

So, how do I determine when the rider's full weight will not unload a
spoke? Do I measure that at rest? Or perhaps while dropping the laden
bike off a 2 foot high ledge? The point is that wheels are subject to
dynamic loads and you cannot predict whether those loads will unload
bottom spokes. So you tension spokes as highly as possible to handle the
highest radial load possible.

I'm looking forward to your alternative rigorous analysis of spoked
wheels, preferably published in book form. You and 'Jim Beam' might
collaborate on that work.

--
Todd Bryan
Santa Barbara, CA
bryan at cs dot utk dot edu

Jose Rizal wrote:
jim beam:


First, how much do elevator cables resemble spokes?

obviously, rope is multistrand, a spoke is single strand, but the
materials & applications are the same.


Materials may be the same but "applications" are not. That "rope" is
subjected to turns and loads on pulleys, as you admit below.


it's only the practical issues
of price, of needing a spoke that resists torque sufficiently to be able
to tighten a nipple and indeed, ability to thread a nipple in the first
place that lead to the use of single strand.


This made-up story doesn't even look nor sound good. Spokes still do
twist, and a threaded nipple is not the only way to have an adjustable
tightening mechanism on a rim.

what method do you propose? the threaded nipple method is cheap,
reliable and has stood the test of time. and of course spokes still
twist, but not as much as the equivalent multi-strand. brake cable's
about the same as a spoke, try the comparision.



Does it matter that they bend
around pulleys in a constant side-to-side flexing different
than spokes?

yes, and those pulleys cause wear and bending stresses, but that's why
you use multi-strand in the first place.


Hence spokes and cable are not the same "application".

maybe your definiton of tension is different to mine.



also, one strand breaking in a
rope of 100 leaves 99 others - pretty comforting.


Nonsense. If a cable is loaded such that a strand breaks, the effective
cross section of the cable is reduced and hence the load results in a
higher stress for the remaining strands, which will rapidly lead to
failure of the cable. If a strand was broken by other than a load (eg
cut), the same effect on cross section will be observed. You can't cut
a strand on a solid spoke.

read some fracture mechanics. crack propagation in a single piece leads
to failure of the whole. fracture of a single strand does not. next
time you fly, check out the skin of the plane and notice that it's made
of many parts riveted together. is this because manufacturers can't
weld? no, it's because crack proagation in one piece does not propagate
to the whole - it's a policy of fracture containment.



and there's a small
degree of freedom to move between strands which reduces cross sectional
stress considerably.


Again, nonsense. What can move between strands? The only way to move
loads between strands is if the strands are able to move along the
cable's length. This is a bad event since the strands will not take up
the load evenly amongst themselves.

take a cable and cut the end exactly square. then bend it about some
kind of mandrel. notice how the end is no longer square and the strands
are staggered? they move relative one to another. this is why rope is
flexible.



Second, do spokes in well-built (by whatever means) wheels
require constant inspection and replacement?

if you read the instructions that come with all these expensive
pre-built wheels yes! but, that's only a cursory visual inspection.
it's just like the contrasts between the safety & inspection regimes for
cars vs planes, wheel spokes are not usually considered a high fatality
risk, so there's no reason to subject them to a rigorous expensive
certification procedure.


In other words, no.

Benjamin Weiner wrote:
jim beam wrote:

wrote:


Second, do spokes in well-built (by whatever means) wheels
require constant inspection and replacement?


if you read the instructions that come with all these expensive
pre-built wheels yes! but, that's only a cursory visual inspection.
it's just like the contrasts between the safety & inspection regimes for
cars vs planes, wheel spokes are not usually considered a high fatality
risk, so there's no reason to subject them to a rigorous expensive
certification procedure.


How do you inspect your spokes? I can't imagine that it is very
easy to see signs of imminent failure.

absolutely correct, the chances of you getting a visual on a spoke
fatigue crack are slim to zero. but pre-built wheels come with an
ass-covering "regular inspection" warning just the same. about the only
thing you can do for spokes short of spending a huge amount of money, is
just do a visual inspection for nicks & dents which could be fatigue
initators, and do a "ping" test for anything loosening up.

Well-built wheels don't
require "constant" spoke replacement.

Carl, did you see in the discussion at
http://yarchive.net/bike/stress_relieve.html
the article containing this quote and link

"For some results of some actual residual stress measurements I did on
7050 aluminum plate before and after stretching see:
http://www.lanl.gov/residual/alplate.pdf
The residual stress was reduced by about a factor of 10 by the stress
relief process."

sure, metallurgical stress relief is very important, particularly when
trying to mitigate distortion of components machined out of 70mm chunks
of aluminum like that described above, but that material is entirely
different from a piece of high tensile wire. how often do you go about
comparing church bells to bicycles? they both have about as much in common.

jim beam writes:

Tim McNamara wrote:
jim beam writes:

wrote:

snip

Spoke-squeezing is an intriguingly mysterious subject to
research. I remain agnostic, wavering one way and the other, but
haven't seen any experimental data or analyses involving bicycle
spokes. If you have the 3rd edition, perhaps you could peek at the
Wiedemer stuff and give me your thoughts on it?

you may also want to consider this question:

q: elevator safety certification requires loading the cab to double
it's "safe working load". this is to test the wire ropes that
suspend it. the reason is that fracture mechanics predict that
this process will typically reveal by failure any latent flaws.
but, if we extend spoke squeezing theory, wouldn't this overload
procedure also prevent fatigue of elevator cables?

a: no. elevator cables still fatigue and need regular testing,
inspection & replacement.

Of course they fatique. They are constantly being wound around a
drum and unwound with a large weight dangling on the end. This
doesn't happen with spokes. Spokes are one fairly thick wire under
a fairly small load, elevator cables are thin-stranded cables with
internal friction, corrosion challenges, etc. Additionally, a
spoke supports a load much differently than an elevator cable, as
has been discussed and verified- independently of Brandt, BTW- by
finite element analysis. I see you're keeping the fine art of red
herrings alive.

the bottom line is that there is no quantification or testing of
this spoke squeeze theory. squeezing "as hard as you can" is no
more scientific than building with spoke tension "as high as the
rim can bear". i would suggest to you that the reason academics
"change the subject and get back to "serious" work" is because this
theory is mere speculation - it's author has shown no basis in
statistical fact, and most definitely not by metallurgical
analysis.

And it's easy to take cheap shots when he's out of town and not
able, therefore, to respond. I don't quite know why it sticks in
your craw so much to admit even the possibility that Jobst is
right, and it's an interesting psychological problem especially
when combined with your anonymity behind a boozy screen name. But
if you're going to seriously critique his work and not just take
potshots, come up with a quantified and testable alternative
analysis. Prove him wrong. Put up or shut up. Frankly, jim beam
old buddy old pal, I don't think you have the stuff.

tim, you're like a drunken finnean looking for a bit of bare-knucked
sport on his way home from a bar.

"Finnean?" Did you mean "Fenian"? Nice reference though.

read what i said when you're sober, then show me one single piece of
metallurgical evidence to support brandts bullying assertions. or
your allusions to superior mental health come to that.

You'd have to take that up with the author of the book, eh? But as
usual you're ducking and weaving, casting rocks and aspersions and
then crying foul when you get treated the way you treat others. Stop
being a whiner and step up to the plate. If you can disprove Brandt's
theory, then do so. Put up or shut up. If you can't disprove his
ideas, then accept that he may in fact be right. I'll say it again- I
don't think you have the stuff. If you did, you would have actually
disproven Brandt a long time ago.

All I can say, not being an engineer, is that the wheels I've built
with his method have performed admirably, better than wheels I've
bought built according to the Wheelsmith specs and much better than
wheels I have bought built to who knows what specs (e.g., OEM wheels).
I'll settle for my 50,000 to 60,000 miles without a spoke breakage and
rarely having to true a wheel- even 9 speed wheels built with MA2
rims. At my weight (215 lbs, give or take 10), I'm pleased with the
results.

The type of guttersniping you indulge in does not advance the
discussion one whit. Over the years we've had recurrent posters with
the gunslinger mentality who come into town aiming to knock off the
big guy. You seem to be just another one of this species. I suspect
that many of those posters have been the same person hiding behind
different personae, due to consistencies in writing style and
conceptual framework. You don't raise chickens, by any chance?

As far as comparative mental health, not having met you I can't say
for sure. However, at least I don't have an obsessive hatred of
someone on the Internet with a need to continue to attack that person
over and over and over- even when I can't prove that person wrong.

Todd Bryan wrote in message ...
So, how do I determine when the rider's full weight will not unload a
spoke? Do I measure that at rest? Or perhaps while dropping the laden
bike off a 2 foot high ledge? The point is that wheels are subject to
dynamic loads and you cannot predict whether those loads will unload
bottom spokes. So you tension spokes as highly as possible to handle the
highest radial load possible.


The fear of loose spokes is unfounded. As long as lateral stability is
maintained the spokes are tight enough. The requirement to measure the
tension in the spokes by plucking or gauge is not required using the method
of wheel building I have described. If it is found that the wheel becomes
wobbly it is a simple matter to turn each nipple 1/4 turn to shorten their
effective length.
The use of a drying oil assists in the tensioning of spokes and the
prevention of the nipples unwinding in use.
No I do not tension spokes as high as possible. I presume therefore
that you do and so pre-load the rim so there is a tendency to buckle. There
is no advantage in pre-loading spokes and rims, it only lessens the load
capacity of the wheel before buckling.
A rigorous analysis is not required, all has been presented. I could
tidy it up, add some detail, some pictures and some waffle here and there,
but I doubt that I'd really want to do it. Why don't you do it? Give it a
hardback cover and overprice it. With a bit of luck you may just cover the
publication costs after a few years.
Call it "The Bicycle Wheel Revealed"
TJ