Re: [CR] Unusual FR Peugeot PX-10--gold color / steerer integrity

(Example: Framebuilding:Tubing:Falck)

Date: Thu, 22 Apr 2010 09:46:27 +0000 (GMT)
From: "Hugh Thornton" <hughwthornton@yahoo.co.uk>
To: Classic Rendezvous <classicrendezvous@bikelist.org>
In-Reply-To: <2D41DACA-1FC3-4EF7-A9C7-220439F12B91@att.net>
Subject: Re: [CR] Unusual FR Peugeot PX-10--gold color / steerer integrity


Well, I got it wrong - it seems manufacturers did actually put wood up the steerers themselves, which I find strange from a product liability point of view.  I know that this was done after purchase by many European racers.

Probably the worst case scenario fork failure is the fracture of the steering tube just above the fork crown, resulting in total collapse of the front end.  Such a failure could occur as a result of bending stresses in the tube from the rider's weight, braking and road inputs.  There is no doubt that a wood dowel stuffed up the steerer would mitigate the effects of such a failure because it will be held in place by the brake attachment and will keep the fork more or less in place. 

Does anybody know if there is a greater incidence of breakage of French steerers than British-sized ones?  The French steerers are 25.0mm outside diameter and 22.0mm inside diameter, whereas the British size is 25.4mm OD and 22.2mm ID.  The French steerer therefore has a slightly smaller OD and a slightly thinner wall, both of which will increase the maximum stress in the steerer. 

In normal usage, I would expect the stresses to be low enough that the fork will last indefinitely, but a combination of overheating the tube during manufacture and a heavy rider and lots of riding on rough roads and pave might ultimately prove too much and result in a fracture.

Hugh Thornton
Cheshire, England


--- On Thu, 22/4/10, Jon Spangler wrote:


From: Jon Spangler <jonswriter@att.net> Subject: Re: [CR] Unusual FR Peugeot PX-10--gold color To: "Dale Brown" <classicrendezvous@bikelist.org> Cc: "Hugh Thornton" <hughwthornton@yahoo.co.uk> Date: Thursday, 22 April, 2010, 4:51

Hugh and all,

The word during the 1970s at my LBS and avid Peugeot dealer, Collins' Cycle Shop in Eugene, OR, was that the wooden dowel plug was there to keep water and crud out of the steer tube and head tube. I never heard anything at all about the wood being a reinforcement for the steer tube or the head tube, and do not think it would make that much difference in the strength at all. 

Could it have been placed there in part to help damp some road vibration? This possibility never even occurred to me until I was composing this email, but it makes as much sense as any other rationale I have seen. (Of course it doesn't make any *more* sense than other explanations either...)

I never imagined that my post about this bike's color would have such "legs," BTW. Life is full of surprises....

Jon Spangler tired of writing pro bono press releases and publicity flyers all day--even for a cause i believe in--in Alameda, CA

Message: 6 Date: Wed, 21 Apr 2010 16:54:00 +0000 (GMT) From: Hugh Thornton <hughwthornton@yahoo.co.uk> Subject: Re: [CR] Unusual FR Peugeot PX-10--gold color To: classicrendezvous@bikelist.org Message-ID: <467636.22593.qm@web25904.mail.ukl.yahoo.com> Content-Type: text/plain; charset=iso-8859-1

My 1975 PX and 1976 PY both have wood dowel inserted in the bottom of the steerer.? Both bikes were purchased from France.? French and other European racers loved to stuff wood up their steerers to guard against breakage.? Maybe their steerers were more likely to break because of their miles of pave, or maybe it was just a tradition that started a century ago when roads and steel quality were worse. ? I would be surprised if a manufacturer put a wood dowel in from new - that is like saying that their product is defective in design or manufacture so it needs a bit of wood to hold it together?(although Bianchi did get away with injecting rigid foam into their aluminum frames, but that is OT).? Mind you, I am not saying that Peugeot were not silly enough to put a bit of wood up - but think of the potential liability suits in the US if the wood were to rot and the steerer to break!? Or if the steerer broke on a bike not fitted with the wood - they would not have a leg to stand on if they fitted wood to some models and not others.? Far better not to fit it and blame the user for crashing or misusing the bike if the steerer breaks. ? Hugh Thornton Cheshire, England

Jon Spangler
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