Re: [CR]Predicting Campy Crank failure

(Example: History)

From: "Rick Chasteen" <rchasteen@kc.rr.com>
To: <Classicrendezvous@bikelist.org>
References: <GDENKJBOAAOMPKCKENKDKELPCAAA.B.Sanford@cox.net>
Subject: Re: [CR]Predicting Campy Crank failure
Date: Sun, 22 Sep 2002 13:59:43 -0500


----- Original Message -----
From: Ben Sanford
To: Classicrendezvous@bikelist.org
Sent: Sunday, September 22, 2002 8:23 AM
Subject: RE: [CR]Predicting Campy Crank failure



> I purchased the 175mm SR road cranks new in '85, which was close to the last
> year of production. (They are marked 4 in a circle) Unfortunately the
> hairline crack at the spider has progressed about 1/4" so I think it's too
> late to do anything with a file. These cranks had about 33,000 miles of
> use.

Are these the later, non fluted cranks? I wasn't aware that they were prone to breaking at the spider. I have 2 pair of these in fixed gear use and have noted that the shape of the crankarm/spider interface is much different (a radiused corner instead of a more angular one) than that of earlier versions. I assumed this change addressed the stress riser issue.

When a crankarm breaks in the middle, I think the reason is often a groove and therefore weakness cut into the arm from constant front derailleur contact.

Rick Chasteen, Kansas City