Re: [CR] Predicting Campy Crank failure

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From: <GPVB1@cs.com>
Subject: Re: [CR] Predicting Campy Crank failure
To: classicrendezvous@bikelist.org
Date: Sun, 22 Sep 2002 15:55:50 EDT

All:

Ben was kind enough to send me very nice jpegs of the 175 cranks in question.

The crack at the arm-to-spider junction is probably the longest (on an NR/SR crank) that I've seen. He was wise to stop riding it IMO.

The crank also looks to have led a pretty rough life. Lots of severe marks on the pedal end of the arm, un-shipped chain marks, deep front derailleur gouge mark, toestrap rub marks, etc. It has also been filed in the usual manner at the spider joints - not sure when this was done vis-a-vis crack formation. This part really fits the pattern that I've seen of which ones develop significant cracks, and potentially break.

Ben, would you be willing to tell us your weight and height, and your history of other part breakage (if any, just curious...)?

Regards,

Greg Parker A2 MI USA

In a message dated 9/22/02 3:04:50 PM Eastern Daylight Time, Ben Sanford wrote:


> 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.
>
> Ben Sanford
> Falls Church, VA
>
> -----Original Message-----
> From: Mark Bulgier [mailto:mark@bulgier.net]
> Sent: Saturday, September 21, 2002 11:26 PM
> To: 'Ben Sanford'; Classicrendezvous@bikelist.org
> Subject: RE: [CR]Predicting Campy Crank failure
>
>
> Ben Sanford wrote:
>
> > Mine that broke was an undated track crank just marked
> > "165 PISTA" with the 144mm bolt circle.
>
> That would be a late model, right? I don't remember when they went to 144
> for track but it was quite a few years after road went to 144. the Campy
> Timeline on Velo-Retro is silent on the matter unless I read it too quickly.
>
> > The crank broke at the eye where the pedal mounted.
>
> That's the most common location for a break, as opposed to a crack. The
> spider cracks are quite common but rarely result in a rider down.
>
> > I had previously retired a 175mm SR road crank due
> > to a crack at the spider.
>
> Are you sure that right with the spider crack is too bad to be filed? Do
> you know what I mean, filing with a chainsaw file or needle file to the full
> depth of the crack or a little beyond? This has saved many a cracked Campy
> crank, and I've never heard of one breaking there after having been filed.

>

> Mark Bulgier

> Seattle, Wa

> USA