The funny thing is, I've never seen a first-hand report of a Campy R/SR arm (of any flavor or vintage) breaking right at the arm-to-spider junction. The vast majority of the ones that fail seem to do so at or very near the pedal eye (which certainly makes sense from a stress-concentration viewpoint). My informal CR survey last year turned up precisely zero vintage aluminum cranks (of any brand) that broke at the arm-to-spider junction. It actually surprised me a bit - I thought there would at least be *some* that broke there. Lots of cracks there, but no failures.... I think the bottom line is: examine your vintage cranks (of any brand) around the pedal eyes very closely and frequently for cracks that radiate outward from the pedal thread, or for any cracks in that general area. These can be fatal. There is virtually always a crack before there is a failure. The R/SR arms were forged, then machined, BTW, not cast, AFAIK. Greg Parker Dexter, Michigan, USA
Date: Thu, 17 Mar 2005 08:13:25 -0500 From: "Daniel Artley" <dartley@co.ba.md.us> To: <classicrendezvous@bikelist.org> Subject: Re: [CR]engraved vs. etched campy crankarms
I once spoke to a Campagnolo USA rep about the non fluted cranks after getting one in the mail to drill and tap for a 74 mm bolt circle triple. Of course I wanted the classic fluted one. The rep told me that the newer lazer etched cranks when molded, had an electrical charge passed through the casting that alligned the molecules along the lines of the spider and as a result was actually stronger than the older milled cranks. If you check closely, the sharp edged stress riser at the base of the arm and spider is not a sharp edge on the lazer etched model either. I can't say that this information also relates the the engraved cranks.
That crank looks good on my not quite on topic road/path fixed gear, a keeper of the flame only in geometry.
Dan Artley
Parkton, Maryland
>>> Jay Sexton jvs@sonic.net> 03/16/2005 8:19:06 PM >>
Is there any truth to the story I have heard that the etched and/or the engraved versions of Campy crank arms broke due stress fractures from these processes?
What are the locations of the logos on engraved and etched crank arms?
Jay Sexton
Sebastopol, CA