Re: [CR]stress riser


Example: Events
Date: Thu, 16 May 2002 08:41:51 -0400
From: "Daniel Artley" <dartley@co.ba.md.us>
To: <classicrendezvous@bikelist.org>
Subject: Re: [CR]stress riser


I would be interested in hearing how these cracks progress when the failure actually occurs. I first heard about all the failures at the spider on Campy cranks from Bicycle Classics website, but I've never actually heard an account of the failure occuring until this report. Jim's crank failing at the pedal would make for a catastophic failure, but what happens when the cranks fail where all these cracks that have been warned about happen, right at the spider. I've always felt that it wouldn't be that disastrous since the chainring(s) would hold the rest of the crank together. A failure at the taper would probably progress slowly enough to warn the rider before failure, wouldn't it?

Dan Artley Parkton, Maryland
>>> "Jim McCoin" <j.mccoin@attbi.com> 05/15/02 07:23PM >>> I would bet a few bucks that the small line in the web shown in the photo is the beginning of a crack , as a youngster hanging out at the American Cyclery, that was one of the many things I learned about . Oscar would knock the edge off the stress riser with a small jewelers file to prevent cracks from beginning and file through the cracks to stop them from spreading .

The sad thing is that the premier equipment manufacturer in the world , at that time , would let a part out with such an obvious flaw ,

I think the ones that are the most dangerous are the ones you don't see down around the pedal area . When mine broke it was obvious that it had been cracked for some time and was slowly working its way through the arm , the crash was spectacular .

The last arms I have purchased have been dye penetrant tested before I use them , its not as fool proof as Xray but a lot less expensive .

Jim McCoin
Fremont Ca.