rebuild wheel or not?

trust these wheels. Should I
1. just throw away the wheels ?

I will pay shipping to have them sent to me... I will dispose of them
properly, as the grease inside is highly toxic and cannot be simply thrown
away in any dump.

--
Phil, Squid-in-Training

jim beam wrote:
wrote:

On Fri, 30 Jul 2004 20:21:16 -0700, jim beam
wrote:


David L. Johnson wrote:



[snip]


I don't trust bladed spokes as much as round ones.


why? if sapim's spoke fatigue tales are anything to go by, their
bladed spokes have a much better fatigue life than their round ones.



Dear Jim,

I'm wondering why bladed spokes would resist fatigue better
than round ones. Do you have a link to the Sapim stuff?


http://www.seetool.be/sites/sapim/in...=fatiguetes t


to be honest, i don't know for sure why that would be, but i'd guess
it's something to do with the bending component present at the spoke
elbow. a bladed spoke would be able to exert less bend in the plane of
the blade compared with a round spoke.


Don't both kinds of spokes have roughly similar ends, where
most failures occur?


yes. but i have noticed for example that the surface finish on sapim's
unbutted spokes is not as good as their butted ones, so maybe they also
finish their bladed spokes even more carefully. they certainly should
for the price they charge!


Do the bladed spokes benefit from work-hardening?


no more than ordinary spokes benefit from normal butting.


Are they--the proper word escapes me--stretchier in the
fashion of double-butted spokes being stretchier than
straight spokes?


if the material in the bladed section is less, yes. it's simply a
function of cross section area. usine the formula for an elipse is
probably a good approximation.


And if they are indeed more fatigue-resistant, are bladed
spokes usually subjected to the spoke-squeezing process so
often mentioned on rec.bicycles.tech? (Somehow I have
trouble imagining squeezing bladed spokes together, even
with gloves, but maybe it's not as bad as I think.)

There are different ways of pulling on the spokes. One is pinching the
pairs together, in the same plane as the one in which the lie; the other
is to push or pull each one at right angles to the plane. With bladed
spokes this is more comfortable to the hands. What's important is that
each spoke is given a temporary and significant increase in tension . . .


mavic recommend a different method: pressing the hub axle hard against
a flat surface while pressing on the rim. it achieves over-tension
therefore bedding in the spokes, but does not mean touching the spokes.
it seems to work quite well if repeating until the wheel stays in true
is any indication - just as well as spoke squeezing at any rate.

Agree that this works very well, too.

[also referring to other postings in this thread] Having built with
straight-gauge, butted, and bladed, I don't understand the hullaballoo
about the durability of bladed vs. straight, or whether tension ratings
are published on the web site for Sapim, DT, or whoever. The bladed ones
I use are DT Aero Speed. At both elbow and threaded ends, they're round
in cross-section, just as any "normal" spokes are. With a cross-section
of 2,3 * 1,2 mm (IIRC), they don't require that the hub holes are filed.
They're also flat enough so that the user *thinks* that he/she will ride
faster with them. A good buy at one USD dollar/spoke here in Europe.

The wheelset I've built have very high spoke tension, using the DT Aero
Speed spoke. Performed usual stress-relieving measures in all cases.
Have ridden on all types of roads and find them to be very durable so
far. OK - the jury's out on actual endurance because these wheels have
not quite gone 3000 km. But I foresee no problems. I've not had to
adjust the true/roundness since a trivial touch-up after the first ride.

(for those wondering: other gear on this wheelset is: brass nipples,
Mavic OP Ceramic, Campag Record 32h, Veloflex Master, all supporting
rider (me) weighing 74 kg (160 lb) who is decent sprinter. Lacing is x2
on front (290 mm), x3 DS (293 mm), x1 NDS (284 mm). Gives a good
wheelset for long rides and impressing friends and neighbours).

YMMV.

/Robert

jim beam wrote:

mavic recommend a different method: pressing the hub axle hard against a
flat surface while pressing on the rim. it achieves over-tension
therefore bedding in the spokes, but does not mean touching the
spokes.

FWIW, I tacoed a (dished rear) wheel doing this once. How do they suggest
holding the rim while doing this? You need to apply many times the force
that squeezing opposing pairs of spokes by hand requires, in order to
overtension the spokes an equal amount.

Is there some reason touching the spokes is to be avoided?

--
Benjamin Lewis

A small, but vocal, contingent even argues that tin is superior, but they
are held by most to be the lunatic fringe of Foil Deflector Beanie science.

(Chris Zacho "The Wheelman") wrote in message ...


You didn't mention how heavy or strong you are, but this might be the
problem. Also, wheels laced like this are normally designed for time
trials, which usually do not involve any realy hard pedalling, as would
be encountered in sprinting or hill climbing.

I am rather light (65 kg, 145 lbs) and not extremely strong. Just a
trained recreational cyclist.

(Qui si parla Campagnolo ) wrote in message ...
mark- Campagnolo
Daytona hubs, Mavic Open Pro BRBR
2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? BRBR

If you are breaking spokes it may be due to a 'deformed' or otherwise bent rim
that is causing a place of lower than optimum tension. Bebuild with a new rim,
14/15 spokes.

The rim looks fine. The wheel was perfectly true before I broke the
first spoke and is true again now. It was very much out of true after
I broke the spoke, obviously. Can this damage the rim in a way that is
not obvious to see?

If I use a new rim, on the same hubs, should I keep the spoke pattern?

"David L. Johnson" wrote in message ...
On Fri, 30 Jul 2004 19:16:15 -0700, jim beam wrote:


well, you don't say /which/ spokes broke. drive side or non-drive side?

I bet it was the left side (also known as the contrary-to-drive-side, or
whatever). Those are more likely to be exposed to cycles of complete
de-tensioning, especially if the wheel did not have adequate tension to
begin with, as is often the case. I'd probably replace the spokes if I
were you, just because I don't trust bladed spokes as much as round ones.
it's a good thing to do.

No, it was the right (drive) side, both times. The second spoke broke
near the nipple, where the thread starts.

Benjamin Lewis wrote:
jim beam wrote:


mavic recommend a different method: pressing the hub axle hard against a
flat surface while pressing on the rim. it achieves over-tension
therefore bedding in the spokes, but does not mean touching the
spokes.


FWIW, I tacoed a (dished rear) wheel doing this once.

what was the tension? rims do this anyway if the tension is too high.

How do they suggest
holding the rim while doing this?

"put the hub axle of the wheel on a wooden block and push on opposite
sides of the rim with your hands" there's a pic too, but i can't link
to their web page any more - it's password protected.

You need to apply many times the force
that squeezing opposing pairs of spokes by hand requires, in order to
overtension the spokes an equal amount.

doesn't matter as long as the wheel experinces the same effect.


Is there some reason touching the spokes is to be avoided?

no, but it's uncomfortable doing "spoke squeeze" with bladed spokes, a
point raised earlier in this thread.

Mark Runacres wrote:
"David L. Johnson" wrote in message ...

On Fri, 30 Jul 2004 19:16:15 -0700, jim beam wrote:



well, you don't say /which/ spokes broke. drive side or non-drive side?

I bet it was the left side (also known as the contrary-to-drive-side, or
whatever). Those are more likely to be exposed to cycles of complete
de-tensioning, especially if the wheel did not have adequate tension to
begin with, as is often the case. I'd probably replace the spokes if I
were you, just because I don't trust bladed spokes as much as round ones.
it's a good thing to do.


No, it was the right (drive) side, both times. The second spoke broke
near the nipple, where the thread starts.

ok. the second failure, while it does happen, is comparatively rare.
it could be because the spokes are fractionally too long and there is a
thread binding problem where the nipple has run out of thread. check to
see if the spokes are sticking out of the nipple head at all - they
should be flush with the bottom of the drive slot.

other than that, just replace and make sure the wheel is built properly,
tensioned to spec & tensioned evenly. the two failures are almost
certainly unrelated.

jim beam wrote:

Benjamin Lewis wrote:
jim beam wrote:

mavic recommend a different method: pressing the hub axle hard against
a flat surface while pressing on the rim. it achieves over-tension
therefore bedding in the spokes, but does not mean touching the spokes.
FWIW, I tacoed a (dished rear) wheel doing this once.

what was the tension? rims do this anyway if the tension is too high.

I don't know, but it was well under Jobst's "maximum compressive strength
of rim".

I rebuilt the wheel, and have ridden several hundred kms on it since then
with no problems.

In order to apply the same force per spoke as I do when stress relieving by
squeezing, I'd probably have to stand on the wheel, and maybe jump a bit.

You need to apply many times the force
that squeezing opposing pairs of spokes by hand requires, in order to
overtension the spokes an equal amount.

doesn't matter as long as the wheel experinces the same effect.

In my case it didn't; the rim tacoed.

--
Benjamin Lewis

Seeing is deceiving. It's eating that's believing.
-- James Thurber

mark- The wheel was perfectly true before I broke the
first spoke and is true again now. It was very much out of true after
I broke the spoke, obviously. Can this damage the rim in a way that is
not obvious to see? BRBR

Was it also round?
Breaking a spoke can kill a rim.

mark- If I use a new rim, on the same hubs, should I keep the spoke pattern?
BRBR


yes...

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"