Ksyrium rim cracks
Alexei Pavlov
after sunday race i noticed that on my rear ksyrium wheel rim cracked
in 2 drive side spokes which are next to each other..
I'll post pics later.. By the way i weight 225 lbs.. And use them as
race-only wheelset.. I ahad them for 1 year.. and now this..
I was wonder if mavic will warranty the whole wheel or just a rim..
Alexei
Qui si parla Campagnolo
sounds like you do BUT-<< after sunday race i noticed that on my rear ksyrium
wheel rim cracked
in 2 drive side spokes which are next to each other..
I'll post pics later.. By the way i weight 225 lbs.. And use them as
race-only wheelset.. I ahad them for 1 year.. and now this.. >><BR><BR>
<< I was wonder if mavic will warranty the whole wheel or just a rim..
>><BR><BR>
If < I year old and you have proof you are the original purchaser, they will
rebuild them, new rim/spokes-Takes about 3 weeks...if more than a year, rebuild
is about $275...
Your weight has nothing to do with them cracking...
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Alexei Pavlov
Well, i guess my weight has something to do with it, since, my regular
training 36 spoke rear wheel (campy montreal 76 rim 36 spokes , d/a
hubs, 14g spokes) cracked at nipple eyelets for 2nd time now..
First time after it was hand-buld, it cracked in 4 month, and we
thought it is because of stress-relive (sheldon brown method) of the
spokes.. So they replaced the rim.. and again , i have hairline cracks
all over the rim..
As far as weight goes i think it is detrimental, that weight and
accelerations put loads of stress on wheels, so i bet 150lbs riders
will have much fewer problems with wheels then 225 lbs rider..
Thanks for the info!
Alexei
On 12 Aug 2003 12:37:27 GMT, vecc...@aol.com (Qui si parla
Craig.
news:32cijv4ksrsbd0d71...@4ax.com...
> Hello Peter!
>
< snip >
>
> As far as weight goes i think it is detrimental, that weight and
> accelerations put loads of stress on wheels, so i bet 150lbs riders
> will have much fewer problems with wheels then 225 lbs rider..
I weigh less than 150lbs and have had the same problem twice - both times
with 32-spoke Open Pro rims. In my case I suspect it's because the wheels
were badly built but I don't know for sure.
Craig.
Tom Nakashima
I've gone through quite a few Mavic MA-2's, and Open 4s, never seen a rim
crack from just riding or hard braking.
-tom
"Craig." <porte...@hotmail.com> wrote in message
news:rIb_a.2784$z7.4...@wards.force9.net...
jobst....@stanfordalumni.org
> Your weight has nothing to do with them cracking...
Oh yes it does. The greater th cyclic stress change, the greater the
greater the rate of fatigue failures are. This IS a fatigue failure.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
jobst....@stanfordalumni.org
> Are these cranks in the rim itself, or the anodizing? I've gone
> through quite a few Mavic MA-2's, and Open 4s, never seen a rim
> crack from just riding or hard braking.
If the cracks are visible, they are in the metal, regardless of
anodizing. The MA-2 may not have cracked but had you used the
identical rim with black anodizing, you would most likely had cracks.
That rim would have been a MAVIC G-40 rim.
jobst....@stanfordalumni.org
> Your weight has nothing to do with them cracking...
Oh yes it does. The greater the cyclic stress change, the greater the
rate of fatigue failures. This IS a fatigue failure.
Donald Gillies
>Hi!
>Alexei
Welcome to the world of planned obsolescence. There is a good reason
why some people think the "Rivendell" way is the right way to build
bicycles. All components should be simple. All should be
interchangeable. All should be offered in the aftermarket. All
should be affordable to replace. If this were a normal set of wheels
you'd be talking about a $100 repair ($60 for mavic open pro, $40 to
relace it.)
sorry for your misery but i'd recommend going with a normal wheel
rather than paying the $275 to get the fragile high tech wheel put
back into its original fragile state.
- Don Gillies
San Diego, CA
Qui si parla Campagnolo
regular
training 36 spoke rear wheel (campy montreal 76 rim 36 spokes , d/a
Cracking with these rims is pretty common and 14g spokes don't really help,
IMHO-
Suggest Velocity Deep V, CXP-33, 36 dbl butted spokes, DA or Campagnolo hubs...
Qui si parla Campagnolo
the greater the
rate of fatigue failures. This IS a fatigue failure.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA >><BR><BR>
<< Oh yes it does. The greater the cyclic stress change, the greater the
rate of fatigue failures. This IS a fatigue failure.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA >><BR><BR>
Do you know you get two posts for every single post you submit?
just for info...
Tom Nakashima
I know you said "most likely" and "may not have cracked."
Mavic made two similar rims, the MA-2 and the G-40, only the G-40 is black
anodized and has more potential to crack? So it is the anodizing which
weakens the rim?
If you can lead me to an FAQ or literature on this I would love to read it..
Just curious, what happens when the rims crack? Can they collapse at
anytime?
-tom
<jobst....@stanfordalumni.org> wrote in message
news:Vgj_a.11243$dk4.4...@typhoon.sonic.net...
Paul Southworth
Alexei Pavlov <whoc...@aol.com> wrote:
>Hello Peter!
>
>Well, i guess my weight has something to do with it, since, my regular
>training 36 spoke rear wheel (campy montreal 76 rim 36 spokes , d/a
>hubs, 14g spokes) cracked at nipple eyelets for 2nd time now..
>
>First time after it was hand-buld, it cracked in 4 month, and we
>thought it is because of stress-relive (sheldon brown method) of the
>spokes.. So they replaced the rim.. and again , i have hairline cracks
>all over the rim..
>
>As far as weight goes i think it is detrimental, that weight and
>accelerations put loads of stress on wheels, so i bet 150lbs riders
>will have much fewer problems with wheels then 225 lbs rider..
Next I would be going to a beefy stiff rim, like a CXP-33 with at
least 32 spokes in back. You could also try a mail-order guru
wheelbuilder - if you do, start by asking them what they think is
the best wheel they can build for you.
--Paul
M-Gineering import & framebouw
>
> A little confused now,
> I know you said "most likely" and "may not have cracked."
> Mavic made two similar rims, the MA-2 and the G-40, only the G-40 is black
> anodized and has more potential to crack? So it is the anodizing which
> weakens the rim?
> If you can lead me to an FAQ or literature on this I would love to read it..
> Just curious, what happens when the rims crack? Can they collapse at
> anytime?
> -tom
Aaarch!!, not again ;)
http://groups.google.nl/groups?q=rim+crack+anodizing&ie=ISO-8859-1&hl=nl&btnG=Google+zoeken
290 hits
--
Marten
gwhite
Tom Nakashima wrote:
>
> A little confused now,
> I know you said "most likely" and "may not have cracked."
> Mavic made two similar rims, the MA-2 and the G-40, only the G-40 is black
> anodized and has more potential to crack? So it is the anodizing which
> weakens the rim?
The anodizing is brittle/hard. Cracks begin there. The anodizing molecules are
very similar (high coherency) in physical dimension to the underlying Al
crystals, thus the two bond well and any cracks in the brittle anodizing shell
are propagated into the underlying Al crystals.
Tom Nakashima
Center, they said they've never seen cracks in the anodizing. We're going
to run a test on .062" aluminum, have it black anodized then bend it to see
if cracks occur. Any suggestions for other test, we also have a Rockwell
hardness tester here.
-tom
"gwhite" <gwh...@ti.com> wrote in message news:3F3A789F...@ti.com...
jobst....@stanfordalumni.org
>>> Are these cranks in the rim itself, or the anodizing? I've gone
>>> through quite a few Mavic MA-2's, and Open 4s, never seen a rim
>>> crack from just riding or hard braking.
>> If the cracks are visible, they are in the metal, regardless of
>> anodizing. The MA-2 may not have cracked but had you used the
>> identical rim with black anodizing, you would most likely had
>> cracks. That rim would have been a MAVIC G-40 rim.
> A little confused now, I know you said "most likely" and "may not
> have cracked." Mavic made two similar rims, the MA-2 and the G-40,
> only the G-40 is black anodized and has more potential to crack? So
> it is the anodizing which weakens the rim? If you can lead me to an
> FAQ or literature on this I would love to read it.. Just curious,
> what happens when the rims crack? Can they collapse at anytime?
Crack generation is not a sudden event but a fatigue failure that take
many thousands of stress cycles (loaded wheel rotations) to develop.
The cracks are especially easy to see on dark anodized rims and it is
the crazed surface of the anodizing that initiates crack development.
It is much like bending the knee having a scab. The hard, inelastic
scab cracks and tears the redeveloping skin beneath, causing bleeding.
In contrast, after soaking the scab in water it can often be removed
and the knee bent without tearing the skin.
Anodizing is a hard and brittle ceramic coat that already is crazed
from rolling the rim into a hoop. Additional (mostly invisible)
cracking occurs when sockets and eyelets are riveted into place.
These cracks can often be seen by strong illumination in a grazing
incidence. The thicker the anodizing, the greater the initial crack
size.
http://aerade.cranfield.ac.uk/subject-listing/esdu/ES104.html
gwhite
Tom Nakashima wrote:
>
> I just spoke with the plating shop here at the Stanford Linear Accelerator
> Center, they said they've never seen cracks in the anodizing. We're going
> to run a test on .062" aluminum, have it black anodized then bend it to see
> if cracks occur. Any suggestions for other test, we also have a Rockwell
> hardness tester here.
Not really -- the anecdotal evidence of failures does indeed exist for anodized
rims. I am not a MatSci Eng, nor a Civil or Mech Eng. What I know is only
based on a college course in MatSci Eng; the rim failures are consistant with
the basic idea I represented and learned in college. That is the end of what I
have to technically contribute, for the most part. The spoke holes are under
stress *cycles*, not just a single bend. So I suppose a test should
simulate/replicate the real world situation.
Kraig Willet has often posed the question whether a "thin" layer of anodizing
for cosmetic reasons (nice colors) really represents the level of problem of
"thicker" anodizing. I believe it is a fair question (because consumer taste
does matter and a tradeoff may be a fair one in that regard), but those who have
more appropriate technically training than I have seem to shy away from this
more marginal case. I use the terms "thin" and "thick" because I am out of my
field; someone else may be able to quantify these ideas with ease. These
thicknesses and any other issues must be replicated in your tests/simulations.
Personally, I favor non-anodized rims because of the anecdotal evidence and my
limited education in the matter align. I will tolerate a very thin anodizing
layer for my purchases, if things such as price and overall design are otherwise
in good order.
jobst....@stanfordalumni.org
> Well, I guess my weight has something to do with it, since, my
> regular training 36 spoke rear wheel (Campy Montreal 76 rim 36
> spokes , d/a hubs, 14g spokes) cracked at nipple eyelets for 2nd
> time now..
> First time after it was hand-built, it cracked in 4 month, and we
> thought it is because of stress-relive (Sheldon Brown method) of the
> spokes... So they replaced the rim... and again , I have hairline
> cracks all over the rim.
> As far as weight goes I think it is detrimental, that weight and
> accelerations put loads of stress on wheels, so I bet 150lbs riders
> will have much fewer problems with wheels then 225 lbs rider..
I think you would do far better with 1.8-1.6mm swaged spokes in a non
anodized rim. The thicker the spoke, the more concentrated the entire
load becomes on two or so spokes. A well stress relieved wheel with
thin spokes is more durable than one with fat spokes. For one time
loading, the wheel with the heaviest spoke is stronger but collapsing
wheels is not your problem.
jobst....@stanfordalumni.org
> I just spoke with the plating shop here at the Stanford Linear
> Accelerator Center, they said they've never seen cracks in the
> anodizing. We're going to run a test on .062" aluminum, have it
> black anodized then bend it to see if cracks occur. Any suggestions
> for other test, we also have a Rockwell hardness tester here.
I think you'll need to specify depth and "hard anodized" to make a
valid comparison. Cosmetic anodizing can be made thin enough that it
has essentially no effect on cracking much like the light pink rims
from Mavic.
Terry Morse
> I just spoke with the plating shop here at the Stanford Linear Accelerator
> Center, they said they've never seen cracks in the anodizing. We're going
> to run a test on .062" aluminum, have it black anodized then bend it to see
> if cracks occur. Any suggestions for other test, we also have a Rockwell
> hardness tester here.
I know the Stanford ME department has a fatigue test rig (at least
they used to). Fatigue tests are usually done on round bar stock,
but someone in the ME department could give you specifics. The
standard wisdom is that anodizing decreases fatigue life by abot 40%.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
Qui si parla Campagnolo
Accelerator
Center, they said they've never seen cracks in the anodizing. We're going
to run a test on .062" aluminum, have it black anodized then bend it to see
Think it's the combo of anodizing and then slamming eyelets in...
jim beam
existance - even on your precious ma2's.
jim beam
Alexei Pavlov
I agree with you 100%.. Also, when i'm riding 36 spoke front wheel (in
comparison with ksyrium front wheel).. The 36 spoke wheel gives you a
feeling like you "on the rail" and gives me better sprint
accelerations..
Although.. ksyrium is way better for hilly courses, as it is easier to
spin..
Mavic said will replace the wheel and I hope to have it before MBGP..
On 12 Aug 2003 23:23:18 -0700, gil...@cs.ubc.ca (Donald Gillies)
wrote: