Carbon fiber spokes + Alloy Rim = DISASTER(for MAVIC users)

Discuss light weight issues concerning road bikes & parts.
nemeseri
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by nemeseri

This is very disturbing, especially after I read the 2009 velonews article. Wow. Just wow.

by Weenie


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kgt
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by kgt

Sorry, I don't believe that. Maybe extreme bad luck in your case but, no, Mavic wheels do not collapse like that. Not even no name chinese crapy wheels snap like that.
Last edited by kgt on Tue Nov 14, 2017 11:03 am, edited 1 time in total.

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kidrob
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by kidrob

kgt wrote:Sorry, I don't believe that. Maybe extremely bad luck in your case but, no, Mavic wheels do not collapse like that. Not even no name chinese crapy wheels snap like that.

second that

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573
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Location: West Sussex, UK.

by 573

The more I look, the more this looks like rubbish. The second one pictured which I've copied below, there aren't even any broken spokes! The aluminium rim has supposedly just folded over for no reason? I'm not buying that.


Image
Image

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kgt
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by kgt

Or someone is good at photoshop...

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Sjoerd
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by Sjoerd

Was the GoPro on the Focus bike recording at the time of the failing of the wheel?

ohhyeok90
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by ohhyeok90

573 wrote:The more I look, the more this looks like rubbish. The second one pictured which I've copied below, there aren't even any broken spokes! The aluminium rim has supposedly just folded over for no reason? I'm not buying that.


Ksyrium has carbon spoke on NDS and alloy spoke on DS. I think this is the reason why spokes didn't broken, not like front R-sys wheel which made up with all carbon spokes

kgt wrote:Or someone is good at photoshop...


I understand. First time I saw it, I don't understand either.

If it is 'no name chinese crapy wheels' maybe I understand, but Mavic wheel folding like that?

I still can't understand why this is happened. but it happened.

believe or not is your choice but if you using same wheels, I want to wish you good luck.


I don't want to hear 'photoshop' or something like that anymore.

everything I say is truth, and if I'm lying, Mavic can sue me.

There is no reason lying. I just want to know why. because there is more friends using those wheels around me. I want them to feel safe.
Last edited by ohhyeok90 on Tue Nov 14, 2017 1:46 pm, edited 2 times in total.

wingguy
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by wingguy

On that 125 rear there are 3 carbon spokes in the folded section, and only the middle one looks broken (has a kink in it) the other two are bowed just like the alloy spokes. So the OP thinks that one broken spoke caused the wheel to fold in half? Far more likely the broken spoke is a result of the damage, not the cause.

ohhyeok90
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Joined: Sun Nov 08, 2015 2:24 am

by ohhyeok90

Sjoerd wrote:Was the GoPro on the Focus bike recording at the time of the failing of the wheel?


If there is recording file, Mavic or Amersports weren't ignore it...

here is more pics.

Image

Image

Image

Image

ohhyeok90
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by ohhyeok90

wingguy wrote:On that 125 rear there are 3 carbon spokes in the folded section, and only the middle one looks broken (has a kink in it) the other two are bowed just like the alloy spokes. So the OP thinks that one broken spoke caused the wheel to fold in half? Far more likely the broken spoke is a result of the damage, not the cause.


road is too clear to damage or impact spoke.

I guess there is imbalnce between carbon spokes and ally spokes or unlike carbon rims, alloy rim fail to stand carbon spokes's storng tension(fatigue failure?).

cause would be internal structure, not other outside facts. I think.

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kgt
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by kgt

I may be wrong but the third photo of the first post looks like photoshop to me. Even the size of the rear wheel seems huge.

ohhyeok90
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Joined: Sun Nov 08, 2015 2:24 am

by ohhyeok90

kgt wrote:I may be wrong but the third photo of the first post looks like photoshop to me. Even the size of the rear wheel seems huge.


That's what 'Perspective' is.

joejack951
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by joejack951

Given how folded those aluminum rims are, if these failures are real they appear to be the result of improperly heat treated aluminum, or aluminum that has not been heat treated at all (T0 condition, straight off the extruder). 6000 or 7000 series aluminum in the T6 condition will not deform anywhere near that much without cracking in my experience both fabricating with the metal and with bicycle rims. I was rear ended riding a Mavic Open Pro rim and the rim broke into several pieces from the impact (I can supply pics). There were virtually no signs of bending before breaking. Those creases in the rim in the images above are simply so far beyond what heat treated aluminum will allow that I have to conclude that they are either fake (and pretty good ones at that) or the rims were not treated.

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573
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by 573

ohhyeok90 wrote:
Ksyrium has carbon spoke on NDS and alloy spoke on DS. I think this is the reason why spokes didn't broken, not like front R-sys wheel which made up with all carbon spokes


Just for reference, the R-SYS SLR also has alloy spokes on the rear DS.

antonioiglesius
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Joined: Sat Oct 15, 2016 9:08 pm

by antonioiglesius

Are the wheels serviced/tensioned by the same person? If the spoke tensions are out of wack, can that cause this type of failure?

(Edit: Ok OP mentioned this earlier).

Can temperature differences between when the spokes are tensioned, versus when they are ridden, make a significant difference to the effective tension? I'd imagine carbon and metal don't expand/contract the same amount?
Last edited by antonioiglesius on Tue Nov 14, 2017 7:15 pm, edited 1 time in total.

by Weenie


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