It looks like the bolt that actually holds the cranks together is busted. Does anyone know if this is something user serviceable or is it new cranks time?
thanks!
Campag ultra-torque cranks busted
Moderator: robbosmans
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highdraw
Never seen it before. 2000W Tom Bonnen has ridden UltraTorque Campy cranks multiple seasons without issue.
I have 10 years on mine.
Speculation is, crank failure occurred because of either under torque resulting in insufficient thread penetration and/or hirth joint teeth engagement or...over torquing the center bolt causing the bolt or thread to yield.
How often do you service the crank and check center bolt torque? Did you use a torque wrench? What torque did you apply?
The hirth joint is spoiled so new crank time.
I have 10 years on mine.
Speculation is, crank failure occurred because of either under torque resulting in insufficient thread penetration and/or hirth joint teeth engagement or...over torquing the center bolt causing the bolt or thread to yield.
How often do you service the crank and check center bolt torque? Did you use a torque wrench? What torque did you apply?
The hirth joint is spoiled so new crank time.
Nah no injury, I seemed to land on the saddle when it happened.
It was actually serviced not too long ago... I've no idea if the shop used a torque wrench when putting it back together though.
Thanks for replies guys, just wanted to check if anything of it is salvageable before consigning it to the trash. New cranks all round!
It was actually serviced not too long ago... I've no idea if the shop used a torque wrench when putting it back together though.
Thanks for replies guys, just wanted to check if anything of it is salvageable before consigning it to the trash. New cranks all round!
I'm just curious why there is a piece of wood in the teeth? Maybe it is not wood, but it does not appear to be the tooth of the joint.
Yes indeed, The bolt appears to have failed. I would suspect the bike mechanic and his skill with a torque wrench [or lack of a torque wrench]. The teeth do not appear to be damaged so I would install a bolt and check the teeth engagement.
Yes indeed, The bolt appears to have failed. I would suspect the bike mechanic and his skill with a torque wrench [or lack of a torque wrench]. The teeth do not appear to be damaged so I would install a bolt and check the teeth engagement.
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ferrarista
- Posts: 1202
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I've seen this once before,but the bolt was not tight enough. The teeth got completely damaged.
Clean it up and take off the bolt so you can check if the joint is damaged.
If the joint is ok, you would just have to buy a new bolt. Apply grease or anti-seize on the bolt threads and use a torque wrench to the recommended torque. If its damaged, you could try to pass it under warranty if you have the original bill and its less than 4 years since you bought it .
Clean it up and take off the bolt so you can check if the joint is damaged.
If the joint is ok, you would just have to buy a new bolt. Apply grease or anti-seize on the bolt threads and use a torque wrench to the recommended torque. If its damaged, you could try to pass it under warranty if you have the original bill and its less than 4 years since you bought it .
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graeme_f_k
- Shop Owner / Manufacturer
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Sorry to hear that this has happened and pleased that you were not injured ...
The most common reason that we see for this very, very rare failure is under- or over-torque of the bolt, or re-installation of a bolt whose (normally captive) compression washer has failed, usually due to a previous over-torquing of the bolt.
You will need to examine the Hirth joint very carefully indeed to check for damage - it only takes very small deformations to cause big problems with the joint retaining it's integrity. On a personal level I would be very dubious indeed about re-installation and from a professional perspective I would definitely not advise it.
We would examine the cranks and bolt in order to try and diagnose the reason for the failure but of course, if the cause can be shown to be under- or over-torque of the bolt or some other failure of correct maintenance practice, we would not be able to warranty the product.
HTH
Graeme
Velotech Cycling Ltd - Main Campagnolo Service Centre, UK
The most common reason that we see for this very, very rare failure is under- or over-torque of the bolt, or re-installation of a bolt whose (normally captive) compression washer has failed, usually due to a previous over-torquing of the bolt.
You will need to examine the Hirth joint very carefully indeed to check for damage - it only takes very small deformations to cause big problems with the joint retaining it's integrity. On a personal level I would be very dubious indeed about re-installation and from a professional perspective I would definitely not advise it.
We would examine the cranks and bolt in order to try and diagnose the reason for the failure but of course, if the cause can be shown to be under- or over-torque of the bolt or some other failure of correct maintenance practice, we would not be able to warranty the product.
HTH
Graeme
Velotech Cycling Ltd - Main Campagnolo Service Centre, UK
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC
Pls contact via velotechcycling"at"aim"dot"com, not PM, for a quicker answer. Thanks!
Head Tech, Campagnolo main UK ASC
Pls contact via velotechcycling"at"aim"dot"com, not PM, for a quicker answer. Thanks!
Just curious Graeme, is it even possible to determine whether the bolt was under or over torqued at this point? I'm interested in learning, at a high level, how you would even go about determining that?
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
I would hazard a guess that an overtorque of the bolt would result in shear failure fracture at the bolt, whereas an undertorque would cause the bolt to fail due to fatigue over time. So, if you examine the fracture surface of the failed bolt, you might see this. Fatigue is exhibited by parallel lines as the fracture progresses across the surface, whereas a sudden fracture due to overtorque would not have the lines.
Thx, I think I would just ask the installer if he used a torque wrench or not 
. Or just warranty the thing in good faith. The crank is pre 2011 vintage for sure.
. Or just warranty the thing in good faith. The crank is pre 2011 vintage for sure.Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
Glad you're not hurt. I'm also curious about the debris - did the crank come out and fall on the ground? I'm not sure how to explain all the crap on the teeth, particularly the drive side with those blobs that look like the stuff I pull off my derailleur pulleys. Every time I've serviced mine, it's clean as a whistle in there. Edit: what's with all that nasty looking gray grease all over it? Did the shop do that? The bearings only need sewing machine oil, or nothing at all, right?
goodboyr wrote:No torque wrench could be either under or over torque.
Exactly... don't really care if it was under or over, it would just be my first question to the installer... Was a torque wrench used? And did you torque it to spec? If not, well...
I always torque that bolt to 50Nm, right in the middle of the spec range of 40-60Nm. Never had a problem.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ
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So when it happened I was going uphill, but just out of the saddle, so I dropped down into it. All good.
The left arm came out and was still attached to the pedal so I kinda had to step on it slightly to get off the bike at the side of the road. The right arm dropped out just after that. The debris is just some dusty, gritty thing from the side of the road (lots of trees, pine needles etc..).
I'll give it a good clean up and see what state things are in.
The cranks are definitely pre 2011 models. They have served me well!
Graeme - is there a service centre in Sydney? Is it worth sending them off for a look see? I don't have original receipts though.
Marty
The left arm came out and was still attached to the pedal so I kinda had to step on it slightly to get off the bike at the side of the road. The right arm dropped out just after that. The debris is just some dusty, gritty thing from the side of the road (lots of trees, pine needles etc..).
I'll give it a good clean up and see what state things are in.
The cranks are definitely pre 2011 models. They have served me well!
Graeme - is there a service centre in Sydney? Is it worth sending them off for a look see? I don't have original receipts though.
Marty
