Re: [CR] Campy NR early crankset

(Example: Framebuilding:Technology)

From: <gpvb1@comcast.net>
To: classicrendezvous@bikelist.org
Subject: Re: [CR] Campy NR early crankset
Date: Wed, 11 Jan 2006 19:56:09 +0000


Date: Wed, 11 Jan 2006 08:54:53 -0800 (PST) From: Rachael Ramos <ooki1998@yahoo.com> To: classicrendezvous@bikelist.org Subject: [CR] Campy NR early crankset

Hi all, I've read about the stress cracks that plague these cranksets and I think I read somewhere about a possible help. It said that you take a round file to the "sharp" edges between the crankarm and the "star" and round it over a bit. Does anyone know if this works? It almost seems counter-intuitive to eliminate metal from an area that suffers stress cracks.

thanks -George

Yes, it generally works, assuming that the crack is small (or not there yet), and you get all of it removed. What you are doing is trying to stop crack propagation (or avoid it pre-emptively in the case of one that isn't cracked yet). You are eliminating the sharp edges in those areas, and making them smooth, radiused transitions.....

This is just like aircraft fuselage repair where they make modifications (drill holes, etc.) to stop a crack from propagating (progressing). They don't often replace the (aluminum) part, unless necessary. You would freak if you knew how many thousands of cracks there were in the average DC9 fuselage!

But these are all secrets, so don't tell anyone. ;-)

Greg Parker
Dexter, Michigan
http://www.bicycleclassics.com