Re: [CR]Frame Alignment Obsession?


Example: Racing:Wayne Stetina

To: feldmanbike@YAHOO.COM
Cc: jschaer@columbus.rr.com, rabbitman@mindspring.com, classicrendezvous@bikelist.org
Date: Wed, 19 Dec 2001 12:03:58 -0500
Subject: Re: [CR]Frame Alignment Obsession?
From: Richard M Sachs <richardsachs@juno.com>


imperfection is perfection e-RICHIE in chester

On Wed, 19 Dec 2001 08:35:46 -0800 "feldman" <feldmanbike@yahoo.com> writes:
> 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" <jschaer@columbus.rr.com>
> To: "garth libre" <rabbitman@mindspring.com>;
> <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