A mate of mine's SR 11 carbon rear mech failed at the w/e.........it seems to have sheared around the hanger bolt, went into the spokes and damaged the carbon chainstays.

And before anyone asks my mate is a top class wheel builder/cycle mechanic/ex racer - he's set more gears up over the last 30 odd years than we've had hot dinners

Does anyone have a similar experience ?

No problems with mine.

Which one is it - the all carbon version, or the alluminium/carbon pre 2011 model?

Had the bike been crashed or knocked at over at any point prior to this?

Super Record - all carbon version.

happened last sunday. 12kph on an uphill road as i shifted to my 2nd to the last (23) cog. 13mos old rd, no crash.
good thing rd didnt swing towards the spokes/ wheel.
rd now with local campy distributor for warranty claim.

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@farm_lim

looks horrid!
thank goodness nothing happened to the wheelset, hopefully no issues with the chainstays as well.
seriously hoping Campagnolo is taking note on such failures.

Btw, you mentioned that you shifted from 2nd to last cog? which means from a 12/13th to 23rd?

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Thanks for the pic...........

I've not yet seen what happened to my mates mech yet or seen any pics.............will post a pic when I see him at the w/e...............but from what he says looks similar to what happended to him.

I'm suspecting that there isn't enough carbon around the gear hanger bolt for the forces involved.

That doesn't look nice. In worst case scenario, the hanger should have broken :-s

i'd read that as though he is going from the 21t sprocket & upshifting to the 23t sprocket, thus beginning in the 2nd to last & then moving to last sprocket when the RD fails..

This looks like a simple case of the limit screw not set correctly. The rear derailleur touches a spoke and gets pulled by the spoke. This usually results in the rear derailleur being pulled out and often jammed into the seatstay breaking the frame. Happens all the time and has been happening for some 50+ years. Of course back then the frames were not made out of carbon did not break so easily.

He should count himself lucky that he did not break his frame.

Forensics. Look at all the crack surfaces under magnification. If the crack propagated due to a surface flaw you can see dirt on the crack surfaces, as it was accumulated over time. In some cases you can even find the start of the crack, right at the flaw.

If this failure was the result of poor mechanical alignment and the derailleur was grabbed by a spoke/s then all surface could be clean.

Even the best make mistakes, sometimes costly.

Sure does not look like it just 'broke'. Something forced it to look like that.

My description above comes from my experience with a very similar occurrence.

Someone bumped me from behind while in a big group. I didn't think anything of it because my bike was functioning properly. A day or two later my derailleur came apart and opened up into my wheel, locking it up during high speed section.

Turns out the carbon fiber parallelogram fractured around the area of two attachment pins. The impact that happened earlier had started the cracks. Usage forced the cracks to propagate until failure.

I've learned it pays to check this mechanism out periodically. Having your back wheel lock up can be a nuisance.

@maverick
sorry for confusing you. yes mr_tim is right. was shifting from 21 (3rd to last) to 23 (2nd to last) when it happened.

@sedluk
rd didnt touch a spoke at all, i wasnt even on the last cog yet and rd didnt get into the wheels as ive said initially. yes, im lucky!

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Hi there

yep happened to mine too. Exactly the same problem - glad I am not alone!

And it's nowt to do with the limit screw. I was in the 16 sprocket at the back and changing up to the 18. So middle of the cassette. Mine DID go into the rear wheel causing damage and ripping the cage to bits - hence until now I couldn't be sure of the reason for the failure. Also had the aluminium jockey wheel bolts strip their thread early on but the good people at Primera were decent enough to swap those for 2010 ti ones. No problem with those since.

My bike is in with Primera right now who are sorting it for me. Because I was in Europe, the problem meant an expensive taxi ride, cosmetic (I hope) damage to the frame and wheel,and two months without my best bike. I also lost 2 months riding that bike in 2011 because of the jockey wheel bolts.

Hope to have it sorted soon.

I had a bloke come in shop with a chorus mech all carbon that gave up in a similar way. I suppose the aluminium cages were more likely to bend before breaking you normally had a bit of warning.

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