Re: [CR]Broken cranks


Example: Racing:Jean Robic

From: GPVB1@cs.com
Date: Sun, 8 Feb 2004 02:06:09 EST
Subject: Re: [CR]Broken cranks
To: classicrendezvous@bikelist.org


Oh puh-leeze, what a load of baloney. Did you even look at the links Chuck provided? Virtually every brand of cranks from back then would break if ridden long enough by the right person, frequently at or near the pedal eye. Every aluminum part ever made by man has a fatigue limit. Design always involves compromises. Weight vs. durability is just one of them. Literally millions of Record cranks were manufactured from 1958 to about 1987. An extremely small portion of them have now broken - after nearly fifty years of usage in some cases! So have Sugino, Stronglight, TA, Shimano, Gipiemme, Ofmega, Galli, Nervar, SR, etc. etc. etc.... On a per-mile basis, the Campy cranks may have broken less often than some of the others!

Enough BS. We've discussed this issue ad nauseam several times in the past on CR. Let's nip this in the bud now. Certain riders (Jobst Brandt apparently among them) seem to break lots of stuff - cranks, BB spindles, hub axles, frames, saddle frames, bars, stems, etc. etc. Most everyone else never breaks anything (in fatigue). It apparently has to do with pedaling style, plus mega-miles of use in most cases. Do any of those broken cranks on Damon Rinard's site look like they didn't have piles of miles on them when they finally failed?

Just as Chuck hasn't, I've never, ever seen a Campy crank fail at the arm-to-spider junction. Crack, yes; fail, no. Cracks aren't necessarily fatal, as long as they don't propagate too far. If you knew how many cracks there were in that last 37-year-old McDonnell Douglas DC-9 you flew on, you'd probably freak. In the commercial aircraft business, cracks are a way of life. (Note that those 'planes are made primarily out of aluminum...). They have procedures to deal with them, but they don't throw the jumbo jet away or curse its design beacuse it has little cracks!

Note that Jobst has caught his cracked cranks pre-failure almost every time. Note also how many brands are represented on Damon's site....

Greg Parker in the no baloney zone Ann Arbor, Michigan


> Date: Sat, 7 Feb 2004 20:43:16 -0600
> From: "jerrymoos" <jerrymoos@sbcglobal.net>
> To: <classicrendezvous@bikelist.org>
> Subject: Re: [CR]Broken cranks
>
>
> This demonstrates another fallacy in the myth of Campy superiority. Campy
> cranks were acknowledged to be made of harder alloy than Stronglight or TA.
> Did this make them better? Well, they wore less and showed less wear after
> the same number of miles. Better, right? Maybe not. The harder Campy
> alloy was also more brittle, so they suffered brittle stress cracking,
> notably at the junction of spider and right arm or at the pedal hole. This
> type of failure is almost unheard of with the softer Stronglight or TA
> cranks. Of course TA and especially Stronglight arms, being softer, had a
> greater tendency to seize up on the axle. But this could be prevented by
> applying a very light film of grease to the axle when installing them. The
> familiar Campy pattern - great quality control, stupid design.
>
> Regards,
>
> Jerry Moos
> Houston, TX
>
>
> ----- Original Message -----
> From: "Chuck Schmidt" <chuckschmidt@earthlink.net>
> To: <classicrendezvous@bikelist.org>
> Sent: Saturday, February 07, 2004 7:15 PM
> Subject: [CR]Broken cranks
>
>
> ><http://pardo.net/pardo/bike/pic/fail/000.html>
> >
> ><http://pardo.net/pardo/bike/pic/fail/FAIL-008.html>
> >
> ============================================================================
> =====