rebuild wheel or not?

Certainly do not throw the wheels away, unless you're so rich you can
afford it!

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.

Have a competent wheel builder look at them, if they were improperly
built he may be able to fix them. If they are simply not strong enough
for your weight, strength or use, he can rebuild or replace as necessary
to better suit you and your needs.

- -

"May you have the wind at your back.
And a really low gear for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner
http://www.geocities.com/czcorner

mark-<< Campagnolo
Daytona hubs, Mavic Open Pro >><BR><BR>
<< 2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? >><BR><BR>

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.

You can try to remove all tension and re-do it all, with stress relieving and
attempting to get the tension as equal as possible.

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

On 30 Jul 2004 08:40:36 -0700, [email hidden] (Mark Runacres)

Quoted message said:

I have a set of wheels that came with my bike when I bought it: Campagnolo
Daytona hubs, Mavic Open Pro rims and 32 flat (aero) DT Swiss spokes. The
rear wheel is laced three-cross on the drive side, radial on the non-drive
side. After 6000 km without problems, I broke two spokes of the rear wheel
over the last few hundred kms. I don't trust these wheels. Should I
1. just throw away the wheels ?
2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? I know one isn't suppose to lace the same hub in
different patterns, but is this really a problem after 6000km, if I
inspect the hubs for cracks, from time to time?
3. Try to stress-relieve the wheels and hope that fixes the problem?

I am assuming I can continue to use the (radially spoked) front wheel.
Thanks in advance for your advice.

With good quality hubs and spokes like yours, broken spokes are most
often caused by the builder's failure to stress relieve them.

The fact that your spokes are bladed means it might have been
uncomfortable to stress relieve them.

I'd suggest wearing thick, padded leather gloves to stress relieve the
spokes. Squeeze really hard. Try to break any other spokes that are
about to break.

Then re-tension, true, round and dish, and as Peter says, "go ride".

Mark Runacres said:

I have a set of wheels that came with my bike when I bought it: Campagnolo
Daytona hubs, Mavic Open Pro rims and 32 flat (aero) DT Swiss spokes. The
rear wheel is laced three-cross on the drive side, radial on the non-drive
side. After 6000 km without problems, I broke two spokes of the rear wheel
over the last few hundred kms. I don't trust these wheels. Should I
1. just throw away the wheels ?

no.

Quoted message said:

2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? I know one isn't suppose to lace the same hub in
different patterns, but is this really a problem after 6000km, if I
inspect the hubs for cracks, from time to time?

respokeing crossed to another crossed pattern is ok, but respoking
radial to crossed exerts stress on the part of the hub hole that was
notched in exactly the right orientation for fatigue. i guess if you
inspect regularly, it'll be ok, but from a purist viewpoint, it's a bad
plan.

Quoted message said:

3. Try to stress-relieve the wheels and hope that fixes the problem?

well, you don't say /which/ spokes broke. drive side or non-drive side?
were the wheels tensioned correctly? i personally see no
metallurgical benefit to what's termed "stress relief" in this
application, but it definitely helps make sure spokes are bedded in to
hubs & rims, so it's a good thing to do.

Quoted message said:

I am assuming I can continue to use the (radially spoked) front wheel.
Thanks in advance for your advice.

you may also want to consider a different spoke. d.t. don't publish
fatigue ratings for their products, but sapim do. that in itself is not
convincing, but to my way of thinking, it indicates greater confidence
in what they do.

jim beam said:

Mark Runacres said:

I have a set of wheels that came with my bike when I bought it: Campagnolo
Daytona hubs, Mavic Open Pro rims and 32 flat (aero) DT Swiss spokes. The
rear wheel is laced three-cross on the drive side, radial on the non-drive
side. After 6000 km without problems, I broke two spokes of the rear wheel
over the last few hundred kms. I don't trust these wheels. Should I
1. just throw away the wheels ?

Send the hubs to me....

Quoted message said:

Quoted message said:

2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? I know one isn't suppose to lace the same hub in
different patterns, but is this really a problem after 6000km, if I
inspect the hubs for cracks, from time to time?

OK, the pattern is not _that_ unreasonable, so you can re-use it. If you
want to do the left-side spokes with a semi-tangential pattern, it'll be
all right. Most of the stresses are on the right-side flange, anyway. I
would use 14/15 round spokes, though.

Quoted message said:

Quoted message said:

3. Try to stress-relieve the wheels and hope that fixes the problem?

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.

--

David L. Johnson

__o | Become MicroSoft-free forever. Ask me how.
_`\(,_ |
(_)/ (_) |

David L. Johnson said:

jim beam said:

Mark Runacres said:

I have a set of wheels that came with my bike when I bought it: Campagnolo
Daytona hubs, Mavic Open Pro rims and 32 flat (aero) DT Swiss spokes. The
rear wheel is laced three-cross on the drive side, radial on the non-drive
side. After 6000 km without problems, I broke two spokes of the rear wheel
over the last few hundred kms. I don't trust these wheels. Should I
1. just throw away the wheels ?

Send the hubs to me....

Quoted message said:

Quoted message said:

2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? I know one isn't suppose to lace the same hub in
different patterns, but is this really a problem after 6000km, if I
inspect the hubs for cracks, from time to time?

OK, the pattern is not _that_ unreasonable, so you can re-use it. If you
want to do the left-side spokes with a semi-tangential pattern, it'll be
all right. Most of the stresses are on the right-side flange, anyway. I
would use 14/15 round spokes, though.

Quoted message said:

Quoted message said:

3. Try to stress-relieve the wheels and hope that fixes the problem?

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.

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.

Quoted message said:

it's a good thing to do.

jim beam said:

David L. Johnson wrote:

[snip]

Quoted message said:

Quoted message said:

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?

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

Do the bladed spokes benefit from work-hardening?

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

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.)

Carl Fogel

On Fri, 30 Jul 2004 22:48:46 -0400, "David L. Johnson"
<[email hidden]> wrote:

[snip broken-spoke details]

Quoted message said:

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.

Dear David,

Do you find most broken spokes on the non-drive side?

My impression (and experience) is that spokes break most
often at the elbow on the drive side.

As I understand it, the spokes on both sides de-tension
roughly the same amount as they pass under the axle, but the
drive-side ones break more often because they are under
greater tension to make up for their shallow angle to the
rim.

Carl Fogel

Quoted message said:

jim beam said:

David L. Johnson wrote:

[snip]

Quoted message said:

Quoted message said:

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/index.php?st=products&sub=spokes&detail=fatiguetest

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.

Quoted message said:

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!

Quoted message said:

Do the bladed spokes benefit from work-hardening?

no more than ordinary spokes benefit from normal butting.

Quoted message said:

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.

Quoted message said:

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.)

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.

Quoted message said:

Carl Fogel

carlfogel said:

On Fri, 30 Jul 2004 22:48:46 -0400, "David L. Johnson"
<[email hidden]> wrote:

[snip broken-spoke details]

Quoted message said:

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.

Dear David,

Do you find most broken spokes on the non-drive side?

My impression (and experience) is that spokes break most
often at the elbow on the drive side.

Depends on the cause. This was a wheel that had few miles on it, and if
spokes are breaking already I would bet it's from complete de-tensioning,
which is more likely on left-side spokes since they have less tension to
begin with. This is also more likely with wheels that are too loose to
begin with.

--

David L. Johnson

__o | The lottery is a tax on those who fail to understand
_`\(,_ | mathematics.
(_)/ (_) |

Quoted message said:

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 said:

Quoted message said:

jim beam said:

David L. Johnson wrote:

[snip]

Quoted message said:

> 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/index.php?st=products&sub=spokes&detail=fatiguetest

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.

Quoted message said:

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!

Quoted message said:

Do the bladed spokes benefit from work-hardening?

no more than ordinary spokes benefit from normal butting.

Quoted message said:

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.

Quoted message said:

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 . . .

Quoted message said:

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 said:

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.

[email hidden] (Chris Zacho "The Wheelman"😉 wrote in message news:<[email hidden]>...

Quoted message said:

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.

[email hidden] (Qui si parla Campagnolo ) wrote in message news:<[email hidden]>...

Quoted message said:

mark-<< Campagnolo
Daytona hubs, Mavic Open Pro >><BR><BR>
<< 2. have them rebuilt in a more sensible pattern, using the same hub and rim,
but different spokes? >><BR><BR>

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

Quoted message said:

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

Quoted message said:

Quoted message said:

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 said:

jim beam said:

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.

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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 said:

"David L. Johnson" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

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

Quoted message said:

Quoted message said:

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 said:

Benjamin Lewis said:

jim beam said:

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.

Quoted message said:

Quoted message said:

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