Re: [CR]Frame Alignment Obsession?


Example: Events:Eroica

From: "feldman" <feldmanbike@yahoo.com>
To: "Jon M. Schaer" <jschaer@columbus.rr.com>, "garth libre" <rabbitman@mindspring.com>, <classicrendezvous@bikelist.org>
References: <000a01c1881e$3f4ea680$0ab256d1@Marta> <00b501c18853$b9411d80$700b1841@columbus.rr.com>
Subject: Re: [CR]Frame Alignment Obsession?
Date: Wed, 19 Dec 2001 08:35:46 -0800


I'd find it interesting to take a measurement survey across a variety of frames, vintage and modern and all materials. The errors measurable might be surprising.

David Feldman
Vancouver WA


----- Original Message -----
From: "Jon M. Schaer"
To: "garth libre" ;


<classicrendezvous@bikelist.org> Sent: Tuesday, December 18, 2001 10:09 PM Subject: Re: [CR]Frame Alignment Obsession?


> ----- Original Message -----
> >>>
> When I got home and put the wheel on frame it still was a shade off from
> having the rear wheel centered under the brake bolt of the bridge. It is a
> shade over 1 mm off. Others can not see it, as 1 mm is such a small
> difference. Finally I just took a ruler and measured the distance from the
> center of the braze on bolt holder to the inside face of the seat stays and
> there was the 1 mm difference.
> >>>
>
> By that description it sure sounds like the bridge is off. It is possible
> that, though the hole is not centered between the seat stays, that it is on
> the center plane of the frame. But in this case, the wheel would probably
> look correct at the hole, but closer to one seat stay. This condition could
> be checked on a frame table, or with a surface gauge and some long
> indicators, off of the BB shell faces.
>
> Either way, I honestly would not hassle over a 1mm vertical lean error. I
> would use no-hands riding as the guidepost. You can detect pretty subtle
> errors, but it depends on where the error is, and rear wheel lean doesn't
> stand out much. I've seen more error than that on many big-name carbon
> forks, and the owners couldn't even tell.

>

> Jon Schaer

> Columbus, OH