Velocity Wheels - Any Good?

In article , says...

My question is: are Velocity wheels reliable?
Would I do better going elsewhere, & if so where?
I'd like to get plain to heavier-duty wheels. I'm not into 32, 28, or
24 hole, radial spoking, carbon-fiber spokes, aero rims, & the like.
I'd like to get a set for 27" clinchers (~90 lbs ish pressure), and a
set for 700C clinchers (~120 lbs ish pressure). The 27" should be for a
freewheel, and the 700C should be for a cassette. Sealed hubs would be
nice.
I've got a pair of rims that I got from Nashbar around 1990. Yow, these
are great! The rear is 40 hole, cross 4, low flange sealed hub; the
front is 36 hole, cross 4 (I think), sealed hub.

Velocity makes some nice rims. But I would not buy these wheels. Simply
because they are built up with 14G spokes. Double butted spokes would be a
better choice for a more reliable wheel.
-----------------
Alex __O
_-\,_
(_)/ (_)

Paul Kopit writes:

Velocity makes some nice rims. But I would not buy these wheels.
Simply because they are built up with 14G spokes. Double butted
spokes would be a better choice for a more reliable wheel.

The straight guage spoked wheel will be just as reliable as a wheel
with butted spokes. You are perpetuating a theory and not a hard,
proven fact.

14gauge or 2.0mm diameter spokes are 1.5x as stiff as 1.8-1.6mm swaged
spokes. Noting that in a 32 or 36 spoke wheel, load distribution is
over about four spokes and the amount of load sharing is dependent on
spoke elasticity, what do you have to support your contention?

What is the theory that is unproven about this? Have you made an
effort to assess the theory's validity by measuring spoke tension on
spokes in the load affected zone of the wheel? This can be done
qualitatively by tone of plucked spokes and quantitatively with a
tensiometer. Better yet is by computer (FEA) analysis, the results of
which have been published.

On what do you base your claim?

Jobst Brandt

Palo Alto CA

On Fri, 22 Aug 2003 18:44:13 GMT,
wrote:

What is the theory that is unproven about this? Have you made an
effort to assess the theory's validity by measuring spoke tension on
spokes in the load affected zone of the wheel? This can be done
qualitatively by tone of plucked spokes and quantitatively with a
tensiometer. Better yet is by computer (FEA) analysis, the results of
which have been published.

On what do you base your claim?

I repeat:

, The straight guage spoked wheel will be just as reliable as a
wheel with butted spokes. You are perpetuating a theory and not a
hard, proven fact.

You often have stated that higher numbers of thin spokes are better
than smaller number of heavier spokes. That makes great sense to me.
Last response to one of my posts, you mentioned that butted spokes
will not fatigue as quickly as straight guage spokes. An example of
fatigue was notching at the nipple end where the threads start. Most
spokes don't seem to break that way. Your own spokes have gone tens
of thousands of miles without that happening. You are far more expert
than I. Assuming that the butted spokes, at high tension need to be
butted, why do the non drive spokes need butting?

Well built wheels with straight guage spokes seem to last 'til the
rims wear thin and spokes don't seem to wear out.

Have Mavic or Wheelsmith proven that their butted spokes are more
reliable? The emphasis is that butted spokes weigh less.

Paul Kopit writes:

The straight guage spoked wheel will be just as reliable as a
wheel with butted spokes. You are perpetuating a theory and not a
hard, proven fact.

What is the theory that is unproven about this? Have you made an
effort to assess the theory's validity by measuring spoke tension
on spokes in the load affected zone of the wheel? This can be done
qualitatively by tone of plucked spokes and quantitatively with a
tensiometer. Better yet is by computer (FEA) analysis, the results
of which have been published.

On what do you base your claim?

You often have stated that higher numbers of thin spokes are better
than smaller number of heavier spokes. That makes great sense to me.
Last response to one of my posts, you mentioned that butted spokes
will not fatigue as quickly as straight guage spokes. An example of
fatigue was notching at the nipple end where the threads start. Most
spokes don't seem to break that way. Your own spokes have gone tens
of thousands of miles without that happening. You are far more expert
than I. Assuming that the butted spokes, at high tension need to be
butted, why do the non drive spokes need butting?

Well built wheels with straight guage spokes seem to last 'til the
rims wear thin and spokes don't seem to wear out.

Have Mavic or Wheelsmith proven that their butted spokes are more
reliable? The emphasis is that butted spokes weigh less.

So back to the question, on what do you base the claim that thick
straight gauge spoked wheels are as reliable as ones with thin swaged
spokes. I have explained that extensively here, shown measurements
and computation and published the whole lot. You can get the book in
most bicycle shops and many libraries, or you could purchase it and
make good use of it in building durable wheels from:

http://www.avocet.com/wheelbook/wheelbook.html

By the way, it "gauge" if you insist on using this archaic measure for
spoke diameters.

Jobst Brandt

Palo Alto CA

Have Mavic or Wheelsmith proven that their butted spokes are more
reliable?

sapim have. check this site:

http://seetool.be/sites/sapim/index....=fatiguetes t

these fatigue tables are for 0-80kg load - a far greater load cycle than
seen in use - so you should see considerably greater life.

it's more of a manufacturing thing than anything else. straight gauge
spokes are the lowest quality. just like cheap vs. expensive bolts or
bearings, you get what you pay for.

jb

Jim Beam writes:

Have Mavic or Wheelsmith proven that their butted spokes are more
reliable?

Sapim have. Check this site:

http://seetool.be/sites/sapim/index....=fatiguetes t

These fatigue tables are for 0-80kg load - a far greater load cycle
than seen in use - so you should see considerably greater life.

It's more of a manufacturing thing than anything else. Straight
gauge spokes are the lowest quality. Just like cheap vs. expensive
bolts or bearings, you get what you pay for.

DT and Sapim spokes are at the limit of work hardening before they are
swaged. There is no increase in strength but rather a reduction in
area. Whether the fatigue charts are believable is damaged by the
claims of increased strength:

# Sapim butted spokes have two major benefits: less weight and more
# strength! Technological advances using cold forging (SAPIM Forging
# Technology) 'stretch' the spoke, retaining the linear molecular
# structure of the material, thereby increasing the spoke strength at
# the middle by at least 48%.

The cross sectional area is reduced by 1/3 so the stress increases 50%
but that does not mean the spoke has a higher ultimate strength. Such
claims don't do their credibility any good. Since only the mid
sections of spokes are modified by swaging, the spokes still break at
their ends. I am not sure what they are measuring. If the test is of
a whole wheel, then it is possibly correct but not in a tensile tester
with a fixed load.

Jobst Brandt

Palo Alto CA

DT and Sapim spokes are at the limit of work hardening before they are
swaged. There is no increase in strength but rather a reduction in
area.

say /what/???? so what happens to the dislocation density then? you
/do/ know about dislocations don't you jobst?

and how are /you/ able to tell they're at the limit of cold work just by
looking at them? this one i've just got to hear!

oh, and sapim butted spokes are *drawn*, not swaged.

The cross sectional area is reduced by 1/3 so the stress increases 50%
but that does not mean the spoke has a higher ultimate strength. Such
claims don't do their credibility any good.

u.t.s. is measured by stress/area. by that definition, the strength
/is/ increased, and there's no reason why the u.t.s. of that spoke can't
be greater than an unbutted spoke if it continues to work harden. if
you're trying to say the /elasticity/ of the whole spoke increases as
area decreases, that would be true, but you're not being clear.

I am not sure what they are measuring.

individual spokes, fatigue loaded, between zero and 80 kg each cycle, as
per the number of cycles in the chart.

jb

Paul Kopit wrote in message . ..
I repeat:

The straight guage spoked wheel will be just as reliable as a
wheel with butted spokes.

Is accelerated rim cracking a form of reduced reliability? Wouldn't
you expect rims to crack earlier when laced with stiffer spokes?

yes.

Jim writes of Jobst... you clearly don't fully understand all the features of
the stress/strain
graphs you publish in your own book. BRBR


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