From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Runout on Freehub
Date: 30 Sep 1996 16:18:28 GMT

John Everett writes:

> From day one my Dura-Ace freehub has had a bit of runout; in other
> words the cluster wobbles a bit while freewheeling. At first I
> assumed the shop who built the bike had torqued on the cluster
> retainer without the support of a chain whip, thus slightly bending
> the axle. I once asked someone at an LBS about this and he said the
> wobble is designed in to assist chain pickup.

That is a pile of BS!  Freewheels and hubs are made as concentric as
machining reasonably permits.  However, threads do not constitute a
good centering mechanism and since freewheels are made of concentric
components that are mounted on concentric threads, they can easily
acquire some wobble, that as you must have noticed, does not affect
performance at the slow rotational speeds of a bicycle.  That is why
the bicycle industry can use these designs that high speed and
automotive assemblies cannot.

Jobst Brandt      <jbrandt@hpl.hp.com>