RE: [CR]Stress cracks on Super Record cranks?


Example: Production Builders:Peugeot:PY-10

Subject: RE: [CR]Stress cracks on Super Record cranks?
Date: Sun, 15 Oct 2006 22:57:38 -0700
In-Reply-To: <ea2e86bf0610151959p3a841facgf934d03fafdcf442@mail.gmail.com>
Content-class: urn:content-classes:message
Thread-Topic: [CR]Stress cracks on Super Record cranks?
Thread-Index: Acbwzw+ippV2RkDSS2aGMa98qL69TwAFxLCw
From: "Mark Bulgier" <Mark@bulgier.net>
To: "ryan hildebrand" <greengate@gmail.com>, <classicrendezvous@bikelist.org>


Yes, I believe those are cracks. While it might be possible for some other kind of surface mark to look like that, I doubt it.

If you catch the cracks while they're shallow enough, you can file away all the cracked metal, leaving the edge rounded and smooth, and have a potentially better than new crank. Yours look like they've progressed too far though.

For a good description, with pictures, of what might happen (to the crank, not to you) if you keep riding them, check out: http://materials.open.ac.uk/mem/mem_ccf4.htm Another good webpage for fatigue crack pictures: http://pardo.net/bike/pic/fail-009/000.html Check out the Campy crank about 1/3 down the page.

Mark Bulgier Seattle WA USA


> -----Original Message-----
> From: classicrendezvous-bounces@bikelist.org
> [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of
> ryan hildebrand
> Sent: Sunday, October 15, 2006 7:59 PM
> To: classicrendezvous@bikelist.org
> Subject: [CR]Stress cracks on Super Record cranks?
>
> While cleaning my bike today I noticed some very small marks on my
> 1979 Super Record spider:
>
> http://www.flickr.com/photos/90152663@N00/270880179/
>
> http://www.flickr.com/photos/90152663@N00/270881016/
>
> http://www.flickr.com/photos/90152663@N00/270881014/
>
> http://www.flickr.com/photos/90152663@N00/270880178/
>
> Are these stress cracks? How worried should I be? Please advise!
>
> Ryan Hildebrand
> Costa Mesa, Calif.