RE: [CR]RE: Stainless Tubes

(Example: Events:Cirque du Cyclisme:2004)

Content-class: urn:content-classes:message
Subject: RE: [CR]RE: Stainless Tubes
Date: Tue, 14 Nov 2006 09:41:32 -0800
In-Reply-To: <8E538912BF637740BA7EFEC3FA2BE341A42F6C@G3W0069.americas.hpqcorp.net>
Thread-Topic: [CR]RE: Stainless Tubes
Thread-Index: AccHnR9w5AVRGom0RMufV9fwcxSc+wAUMkxgAAkAn+A=
From: "Mark Bulgier" <Mark@bulgier.net>
To: <classicrendezvous@bikelist.org>


Gary Watts wrote:
> Relative to the Crescent reference and stainless bikes, the
> stainless series that were available in the 1970's (mostly
> 300 and perhaps 400 series) aren't all that strong in terms of
> tensile strength compared to hardened cr-moly steels. I
> owned a Crescent in that era but not the stainless model. I
> suspect that the BB was pretty flexible, much like the Ti
> bikes of that era. That may well be why the 2 gentlemen you
> mentioned liked the bike; cushy ride quality.

Hmm, though I did ride a Crescent Stainless, that's irrelevant because it was so long ago and I don't remember a thing about the ride. So the following is pure conjecture, but I'd bet money that they were heavy and stiff. That goes naturally with low-strength steel -- you have to use more of it.

The inherent stiffness of the material, Young's Modulus, is close to a constant among all bike steels including stainless. And since tube diameters were standard, and frame geometry was fairly standard, you'll have a pretty much linear inverse relationship between frame stiffness and strength of the steel, if they're designed to be "strong enough" (leaving that undefined for now).

That's right, strong steel = whippy frame, weak steel = stiff frame. It doesn't have to be that way (there are counterexamples), but the correlation is very strong.

Mark Bulgier
Seattle WA USA