Tubular rim that would not crack

My Mavic Reflex (silver) rear rim just pulled an eylet out with a lot
of cracks around all drive side eylets. Was ridden about 6000 km since
2006. The same thing happened to the Mavic 4CD I had earlier. The
front rim (Wolber, a slight aero section) has been totally trouble
free (has been true, not a single crack or a broken spoke) for 21
years and at least 30 000 km. I'm not heavy (77 kg, 170 lbs) and I
never get dents on the rims.

I'm hoping to find a rim, that would last as long as I have that bike.
Which tubular rim would you recommend. I would like to keep the hub,
which is for 32 spokes, and the rim should not be expensive (hopefully
less than 50 $/€) and available in Europe. I'm going to build it. It
would be a plus, if the rim would have the same spoke diameter and I
could use the old spokes.

On Nov 9, 10:18*am, Joakim Majander
wrote:
My Mavic Reflex (silver) rear rim just pulled an eylet out with a lot
of cracks around all drive side eylets. Was ridden about 6000 km since
2006. The same thing happened to the Mavic 4CD I had earlier. The
front rim (Wolber, a slight aero section) has been totally trouble
free (has been true, not a single crack or a broken spoke) for 21
years and at least 30 000 km. I'm not heavy (77 kg, 170 lbs) and I
never get dents on the rims.

I'm hoping to find a rim, that would last as long as I have that bike.
Which tubular rim would you recommend. I would like to keep the hub,
which is for 32 spokes, and the rim should not be expensive (hopefully
less than 50 $/€) and available in Europe. I'm going to build it. It
would be a plus, if the rim would have the same spoke diameter and I
could use the old spokes.

It's more a question of what can you get hold of. Have a particular
tyre section in mind and use a coin or similar to check that the tyre
bed radius is suitable. At your weight I think that 24mm (to allow
some spread of the stomach) or possibly 23mm is suitable on a rear
tyre predominantly for hard surface use. A 14oz rim is overdoing it
unless hard touring so a 12oz, or 330g, will be more than adequate. A
channeled tyre bed into which a projecting tyre seam can fit means you
can use cheap tubulars without problems. Anything with 19,20 or 21 in
its model nomenclature is probably to fit a narrow tyre of that
dimension and should be avoided.

I've used an Open4 CD 32 spoke rear wheel for at least 40 000km
without any crazing of the rim surface. I had it on a MA40 rear, yet
nothing developed past the surface crazing and I'd ridden that one at
least 50 000km . Both were on 32 spoke 1.6mm crossed 3 at above your
weight, up to 10kg heavier for most of the Open 4's work and they were
the earliest lighter section models at around 380g. It was a 7-speed
compact freewheel with 127mm frame spacing.
1.6mm spokes are enough, but I do have a particular fondness for
straight 1.8mm in the rear wheel.

Good reliable wheels can be made at this weight and the 4CD is
probably inherently a little weaker than a 330g sprint rim.

If you tend to use the rear as a drag brake, you may want to consider
a thicker wall which will take you to 390g and over for a sprint rim.
Alternately if you can find wall thickness specification, look for
1.1mm and 1.2mm for the heavier rims suitable for much braking in crap
conditions. If you find good prices, buy spares. Use the spare rims
to store your spare tyres. This makes it easier to mount thetyre to a
high standard when the time comes.

I can get hold of at least Mavic Reflex (not very keen on, since I
just broke one), Mavic CX18 and Campa Seoul 88. LBS told they have
plenty of other options as well. Since it will take some time for me
to build the wheel (last time was 2006), I would like to carefully
choose a good rim.

Mavic Reflex is 360 or 375 g depending on the source and 21 mm wide.
The GP4 (forgot the GP in the first post) I had was at least as heavy
and 20 mm wide. So those should not have been too light, but they
cracked. GP4 lasted much longer, maybe 20 000 km (I had Open 4 rim for
a while). I thought the problem with GP4 was anodizing and thus bought
the silver Reflex only to find out it was worse.

What would it help to have a 24 mm wide rim? I have never seen one and
I use 22 mm tubulars, which fit nicely to 20-21 mm rims. I don't like
cheap tubulars, since they puncture easily and are close to impossible
to repair. I use Continental Sprinter (about 30 € each, last ~2000 km
rear and at least 10 000 km front). No problems mounting them straight
from the package.

Never had a problem with rim sidewall wear.

On Wed, 09 Nov 2011 02:18:10 -0800, Joakim Majander wrote:

My Mavic Reflex (silver) rear rim just pulled an eylet out with a lot of
cracks around all drive side eylets. Was ridden about 6000 km since
2006. The same thing happened to the Mavic 4CD I had earlier. The front
rim (Wolber, a slight aero section) has been totally trouble free (has
been true, not a single crack or a broken spoke) for 21 years and at
least 30 000 km. I'm not heavy (77 kg, 170 lbs) and I never get dents on
the rims.

I'm hoping to find a rim, that would last as long as I have that bike.
Which tubular rim would you recommend. I would like to keep the hub,
which is for 32 spokes, and the rim should not be expensive (hopefully
less than 50 $/€) and available in Europe. I'm going to build it. It
would be a plus, if the rim would have the same spoke diameter and I
could use the old spokes.

The cracks around the eylets are due to too much tension in the spokes.
The rear wheels have more tension on three counts: the dish causes a
smaller driving side bracing angle which requires more tension for the
same amount of lateral support; rider supplied torque is transmitted
through the pulling spokes by means of increased tension; the imbalance
of bracing angles between the driving and non driving side means the non-
driving side spokes have barely enough tension to resist nipples coming
loose. The compensation for the last item is to over tighten the driving
side spokes thereby increasing the tension in non-driving side so that
the nipples don't come loose.

Here are a couple of techniques to reduce spoke tension without
compromising wheel strength.

Go to 36 or 40 spokes on the rear instead of 32 spokes. This will permit
a 12.5% or 25% reduction in individual spoke tensions without
compromising wheel strength.

This still leaves the imbalance of spoke tensions between driving and non-
driving side spokes due to the dishing angle. The second technique is to
use narrower gauge spokes on the non-driving side. So, if you have 14 ga
on the driving side, use 15 ga on the non-driving side. What this will do
is increase the stress (tension per unit area) in the non-driving side.
The spoke threads have the same area for 14 and 15 ga spokes. Therefore,
there will be more resistance to to nipple coming loose despite the spoke
having less tension.

This all supposes that the wheels are well built - especially having
equalized tensions. You may want to verify which driving side spokes on
the driving side cracked the rim. Were they all pulling spokes or were
did some static spokes also crack the rim and some pulling spokes did
not. If the latter, I'd chalk that up to uneven tension.

Stephen Bauman

On Nov 9, 1:49*pm, Joakim Majander wrote:
I can get hold of at least Mavic Reflex (not very keen on, since I
just broke one), Mavic CX18

Too narrow, for trialling with a skinny tyre (18-20mm) only.

and Campa Seoul 88. LBS told they have

Campag made some wonderful rims, but that's another trialling rim if
I'm not mistaken.

plenty of other options as well. Since it will take some time for me
to build the wheel (last time was 2006), I would like to carefully
choose a good rim.

Mavic Reflex is 360 or 375 g depending on the source and 21 mm wide.

Should be a good choice.

The GP4 (forgot the GP in the first post) I had was at least as heavy
and 20 mm wide. So those should not have been too light, but they
cracked. GP4 lasted much longer, maybe 20 000 km (I had Open 4 rim for
a while). I thought the problem with GP4 was anodizing and thus bought
the silver Reflex only to find out it was worse.

You've really tried hard to break a GP4. They comprised 1/2 the
wheels in the pack during my time racing. They were chosen because
3rd cat riders had the most difficulty in breaking them. They are
about the same as the professional SSC, but were 1/2 the price and
obtainable. Not as robust an alloy, but if you don't make a habit of
denting rims, it doesn't matter.

Dont worry too much about anodising except if you are going to ride
through gravel. A hard anodised rim is then most advisable.

What would it help to have a 24 mm wide rim? I have never seen one and
I use 22 mm tubulars, which fit nicely to 20-21 mm rims. I don't like

Not a 24mm rim, a rim bed radius to match the tyre so that it stays
stuck in the bends. If you use 22mm then the rim bed should also have
an 11mm radius. The rim width is probably going to be 20mm or 21mm if
it's supposed to be an aero varient for a 22mm tyre.

cheap tubulars, since they puncture easily and are close to impossible
to repair. I use Continental Sprinter (about 30 € each, last ~2000 km

I didn't realise they were so poor for mileage. My, things have
changed.
There's a good point to going for a wider tyre with a patterned tread
and harder rubber (usually the carbon black option, not the gummy).
It's probably about time you tried something other than Conti's
Challenge, Vittoria, Hutchinson. Allesandro.

rear and at least 10 000 km front). No problems mounting them straight
from the package.

Yes, they do have that going for them. A stretchy base tape makes
fitting one as a spare quite easy. I've got a Conti training tub and
it's lasted me 8 years because it's such a poor performer. I delay
putting it on and cut the ride short, so it's probably not done 100
miles. All is not lost with it, the sidewall coating is breaking up
and it might make a decent front tyre once I've stripped all the
coating and replaced it with plain latex. I might even go the whole
hog and strip the tread to get that on a plain latex footing. It's a
long job and I could just spend between 30 and 50 pounds on a good
racing tub and not get upset about it, yet I find pleasure in doing
the sidewall and base-tape, but I don't know that I can safely lift
the tread. I've yet to see whether I can straighten the seam. If it
requires a restitch to get the seam straight, I'll probablly give up
on it.


Never had a problem with rim sidewall wear.

No, you break them instead. You are going to have to use much lower
spoke tension than you have been using. Use a threadlock and start
with a light tension. Only work up the tension in half turns on the
right and whatever on the left until you have the wheel stability you
require. It's easier if you use 2.0mm or 1.8mm spokes and start off
really loose to get a feel what a slack wheel is. You should not have
to think about it, a wheel with really slack spokes IS not a wheel
which copes with camber, climbing, cornering or sprinting. The feel
of the wheel should prevent the urge from attempting any of these
risky activities. It'snot high brow, it's obvious when a wheel is
loose. Just add a little tension and try riding again. As soon as
the wheel is stable for your most difficult surface, you can either
leave it at that or fine tune the tension for greatest speed over that
rough road. If you used boiled linseed oil as your threadlock, you
can also add a ldrop more to the spoke and nipple junction now that
you've finished.

Yes probably too much tension for this rim, but still just on the
limit for the NDS nipples to come loose. The first cracks came during
autumn 2007 and I measured then 1400 N on DS and 700 N on NDS and 1000
N on my Wolber front wheel. Very even on both. The spokes are butted
1.8/2.0 mm in the rear wheel.

The one nipple that came through the rim is a "pushing" spoke and
every single DS eylet has cracks around it. And even most NDS eylets
have cracks!

I understand that 1400 N is quite much, but what explains NDS cracks?
I think this Reflex (maxtal) rim is just very bad one!

Since I'm planning to keep the hub, going to 36 spokes is not an
option.

I don't think rider torque is a big issue here. Hub flange radius is
about 1/8 of the crank length and at smallest gear you have about 1:2
gearing. Thus the force at the flange radius is about 4 times your
weight when you stand on the pedal, which is about the maximum that
you can get. Thus for me that would be about 3000 N. Since I have 16
DS spokes (due to pretension "pushing" spokes work as well), this
would less than 200 N/spoke and some of that would go through NDS side
as well.

Stephen Bauman wrote:
On Wed, 09 Nov 2011 02:18:10 -0800, Joakim Majander wrote:

My Mavic Reflex (silver) rear rim just pulled an eylet out with a lot of
cracks around all drive side eylets. Was ridden about 6000 km since
2006. The same thing happened to the Mavic 4CD I had earlier. The front
rim (Wolber, a slight aero section) has been totally trouble free (has
been true, not a single crack or a broken spoke) for 21 years and at
least 30 000 km. I'm not heavy (77 kg, 170 lbs) and I never get dents on
the rims.

I'm hoping to find a rim, that would last as long as I have that bike.
Which tubular rim would you recommend. I would like to keep the hub,
which is for 32 spokes, and the rim should not be expensive (hopefully
less than 50 $/€) and available in Europe. I'm going to build it. It
would be a plus, if the rim would have the same spoke diameter and I
could use the old spokes.

The cracks around the eylets are due to too much tension in the spokes.
The rear wheels have more tension on three counts: the dish causes a
smaller driving side bracing angle which requires more tension for the
same amount of lateral support; rider supplied torque is transmitted
through the pulling spokes by means of increased tension; the imbalance
of bracing angles between the driving and non driving side means the non-
driving side spokes have barely enough tension to resist nipples coming
loose. The compensation for the last item is to over tighten the driving
side spokes thereby increasing the tension in non-driving side so that
the nipples don't come loose.

Here are a couple of techniques to reduce spoke tension without
compromising wheel strength.

Go to 36 or 40 spokes on the rear instead of 32 spokes. This will permit
a 12.5% or 25% reduction in individual spoke tensions without
compromising wheel strength.

This still leaves the imbalance of spoke tensions between driving and non-
driving side spokes due to the dishing angle. The second technique is to
use narrower gauge spokes on the non-driving side. So, if you have 14 ga
on the driving side, use 15 ga on the non-driving side. What this will do
is increase the stress (tension per unit area) in the non-driving side.
The spoke threads have the same area for 14 and 15 ga spokes. Therefore,
there will be more resistance to to nipple coming loose despite the spoke
having less tension.

I don't understand this explanation at all. The only reason for using
thinner spokes on the non-drive side that I can think of is that they
will elongate slightly further given the same applied tension. They are
a lighter spring. Jobst mentions this in his book, IIRC. They don't
loose tension as quickly when the wheel is pushed to the left.

This all supposes that the wheels are well built - especially having
equalized tensions. You may want to verify which driving side spokes on
the driving side cracked the rim. Were they all pulling spokes or were
did some static spokes also crack the rim and some pulling spokes did
not. If the latter, I'd chalk that up to uneven tension.

Another technique is to employ the 2:1 lacing as seen on Fulcrum wheels.
Twice as many spokes on the drive side. With a 32 spoke hub and 24
spoke rim, you can use 16 spokes on the drive side and 8 on the other
side, giving 24 spokes total.

If you can get a 48 spoke hub and 36 spoke rim, you can do 24 + 12 - 36
arrangement.

If the hub will support radial lacing, you can do what Mavic do with
their Ksyrium wheels, i.e. radial lacing on the drive side and crossed
on the other side.

Maybe 1x on the drive side to 3x would also help, if a radial spoke
pattern is not recommended for the hub of choice.

--
JS

Joakim Majander wrote:
Yes probably too much tension for this rim, but still just on the
limit for the NDS nipples to come loose.

Thread lock Loctite or boiled linseed on the nipple threads at build
time. You don't need as much tension to stop them coming loose.

--
JS.

On Wed, 09 Nov 2011 11:42:53 -0800, Joakim Majander wrote:

Yes probably too much tension for this rim, but still just on the limit
for the NDS nipples to come loose. The first cracks came during autumn
2007 and I measured then 1400 N on DS and 700 N on NDS and 1000 N on my
Wolber front wheel. Very even on both. The spokes are butted 1.8/2.0 mm
in the rear wheel.

The one nipple that came through the rim is a "pushing" spoke and every
single DS eylet has cracks around it. And even most NDS eylets have
cracks!

I understand that 1400 N is quite much, but what explains NDS cracks? I
think this Reflex (maxtal) rim is just very bad one!

Since I'm planning to keep the hub, going to 36 spokes is not an option.

I don't think rider torque is a big issue here. Hub flange radius is
about 1/8 of the crank length and at smallest gear you have about 1:2
gearing. Thus the force at the flange radius is about 4 times your
weight when you stand on the pedal, which is about the maximum that you
can get. Thus for me that would be about 3000 N. Since I have 16 DS
spokes (due to pretension "pushing" spokes work as well), this would
less than 200 N/spoke and some of that would go through NDS side as
well.

It's impossible for me to diagnose a wheel without seeing and feeling it.
NDS spokes causing a cracked rim could be due to unequal tension on the
NDS. It's purely speculative without my seeing and feeling the rim.

You've got a 2:1 ration in spoke tension between the DS and NDS on the
rear wheel. That's due to the geometry of the hub and rim. It's something
you cannot change.

However, you can maintain the friction force that prevents the nipples on
the NDS from unwinding while reducing spoke tension. As I stated in my
previous post, you reduce the spoke gauge on the NDS. You are using 14/15
butted spokes. Keep the 14/15 butted spokes on the DS but go to 15/17
butted spokes on the NDS. The tension will remain 700 N but the stress
(force/area) will be increased by a factor of (1.8/1.5)^^2 or 1.44.

The contact area between the treads of the nipple and spoke will be
approximately the same. So the force on the threads will be 44% greater
for the same spoke tension. This will permit you to reduce overall spoke
tension in the neighborhood of 30% on both the DS and NDS. This will put
the DS spoke tension in the neighborhood of 1000 N and the NDS spoke
tension around 500 N. This would make spoke tension no more than on your
front wheel, which you say has no problems.

If you really think it's the rim and not the spokes, you could rebuild
exactly what you have now but swap rims. I would not want to sacrifice a
Wolber rim. Wolber is a tire maker that bought out Super Champion, a rim
maker. I use Super Champion Arc-en-Ciel tubular rims. I agree they do not
wear out.

Stephen Bauman

Stephen Bauman wrote:

However, you can maintain the friction force that prevents the nipples on
the NDS from unwinding while reducing spoke tension. As I stated in my
previous post, you reduce the spoke gauge on the NDS. You are using 14/15
butted spokes. Keep the 14/15 butted spokes on the DS but go to 15/17
butted spokes on the NDS. The tension will remain 700 N but the stress
(force/area) will be increased by a factor of (1.8/1.5)^^2 or 1.44.

With the same tension, the stress is only increased in the thin middle
section, not at the thread, therefore the friction is identical.

The only difference is that the thin middle section of the spoke
stretched elastically further under static conditions, and can therefore
maintain some tension when the rim is pushed to the left, which acts to
reduce the tension in the NDS spokes. It also means the rim can be
pushed to the right more easily - i.e. the wheel is less stiff laterally
in one direction.

Please, read The Bible. http://www.icelord.net/bike/thebicyclewheel.pdf

Page 81.

The contact area between the treads of the nipple and spoke will be
approximately the same. So the force on the threads will be 44% greater
for the same spoke tension.

No, with the same tension and thread diameter, only the stress in the
middle section of a butted spoke is higher.

--
JS.