From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: truing stand adjustment
Date: 23 Sep 1996 15:18:34 GMT

Jason Plum writes:

> I just recieved my park truing stand in the mail and I am having
> problems with it's self centering claims.  The wheel is centered
> between the calipers when the hub is oriented one direction, but
> in the other, it is off center of the calipers.

That's the method for adjusting the stand.  You tweak the stand until
it gives the same reading in both orientations of the wheel.  You
don't need a special gauge or a perfectly centered wheel to do this,
only a true one.  You need only adjust the stand to give the same
reading in both orientations.  That said, there is probably no stand
that can consistently do this even if you have it "dialed in" because
the variability of a few 0.0001 inch in clamping will give significant
differences at the rim that are major compared to what most wheel
builders consider good.  Flip the wheel over to check it.

Jobst Brandt      <jbrandt@hpl.hp.com> 

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Truing stand questions
Date: 28 Jul 2000 00:57:08 GMT

David L. Johnson writes:

> My experience is contrary to this.  I used to only use my frame to
> true/dish wheels, then I got a truing stand and was amazed how much
> more convenient it was.  I made myself a dishing tool, and was
> shocked how inaccurate the old method of flipping the wheel around
> really is.  Every time you flip the wheel around you position it
> slightly differently.  A dishing tool can much more easily determine
> the proper center.

This is also my experience.  Although I built many wheels in a
bicycle, even a rudimentary stand is more convenient.  I find the
centering was accurate enough but difficult to accomplish by reversal
in the frame/fixture because other things change.  A centering bridge
(aka dishing tool) is a must for me.  It is accurate and gives
resolution to 0.1mm because it is doubly differential.  That is the
error is magnified fourfold and appears as clearance between one end
of the bridge.  You can resolve less than a half millimeter easily.
That gives an error of 0.1mm or 0.004".  Not that you need this but it
shows how this apparently crude instrument is a high precision tool.

Jobst Brandt      <jbrandt@hpl.hp.com>