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Colnago carbon-fiber crank failure. From the picture, the crank appears to be hollow with a foam core and an aluminum insert for the pedal threads.
Posted December 2003 as http://www.serotta.com/forum/attachment.php?s=9935a2edb6ddd7313fbc15725168c6ce&postid=6286 in the message Broken Colnago Carbon Crank with the text by member MGS9500:
To show a previous interesting problem with carbon cranks, these are my cranks off a Colnago bike. They failed while climbing a hill.
I have never seen a crank other than the Colnago fail in this fashion.
A follow-up post suggests some Colnago cranks were recalled.
A further follow-up by the original poster says
I sent the cranks back to the shop that sold them. They took them to Trialtir which apparently told them they had never seen a failure like this.
I was given the option of a new Colnago crank with a "new design", or a full refund. They did not explain why a "new design" was necessary if there was no problem being reported with the cranks.
Needless to say, having had a catastrophic failure, I opted to exchange them for Campy Carbon, which were at the time, equally priced.
I have never heard of a Campy Carbon failure.
The cranks do look like they are a "clamshell" design around a foam core, with superficial layering to bond the clamshell together.
All in all, not a great design. One wonders how a bike maker like Colnago would accept such a design, knowing their experience with carbon monocoque frames.[...]
A yet further follow-up by another poster says
i had to replace the left crank arm on my serotta 30th anniversary bike. it was the first generation campy crank. the aluminum insert bonded into the crank arm for attachment to the BB spindle managed to come loose. didn't completely fail but the noise was very bad and in the 4 miles i had to ride back it was only getting worse. campy replaced the crank arm no questions asked.
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