Re: [CR]drop-out dimension question

(Example: History:Norris Lockley)

Date: Wed, 27 Jun 2007 08:00:49 -0700 (PDT)
From: "Fred Rednor" <>
Subject: Re: [CR]drop-out dimension question
In-Reply-To: <>

> How much variation is there in the opening of
        > front drop-outs? I guess, my question is, was
        > there a change over time, or were front forks
        > built to accommodate specific axle diameters?
        > I ask because I have a 1950's path-racer bike
        > where the front fork readily takes a Chater
        > Lea front hub, but placing a Campagnolo track
        > hub, or any other hub for that matter, into
        > it won't fit and that lack of fitting is not
        > related to the axle nuts, but rather the
        > diameter of the axle. Measuring shows a
        > difference of approximately six-tenths of a
        > milimeter: the Chater Lea measure ~7.6 mm and
        > the other hubs ~8.2. The rear on the bike
        > accommodates any rear hub.
        > Would opening the drop-outs slightly be advised?
        > And if so, recommendations on accomplishing that,
        > other than carefully? Tom,
     The Chater Lea front hubs use a 5/16 inch axle, which works out to your 7.6mm once you allow for cutting the threads, and so forth. This is actually common for older British hubs - I'm pretty certain that Airlite and Racelite hubs use similar 5/16" axles. Even a fair number of non-NJS Japanese track hubs use that size.
     So rather than open up the dropouts, why not file small flats at the end of the axles. That must have been common at one time, too, because I've seen hubs whose axles came from the factory with machined flats. You might not want to do that to the original Campagnolo axles, so you might want to replace it with a substitute from Wheels Manufacturing or something similar.
      Fred Rednor - Arlington, Virginia (USA)