RE: [CR]Wheelbuilding Questions - valve stem holes


Example: Production Builders:Frejus

Date: Wed, 03 Dec 2008 11:50:13 -0500
To: <classicrendezvous@bikelist.org>
From: John Betmanis <johnb@oxford.net>
Subject: RE: [CR]Wheelbuilding Questions - valve stem holes
In-Reply-To: <249DDD9704676C49AE6169AE3D2D9F4ECDB6EF@Exchange-SVR>
References: <8CB22D27AEDB6F8-1224-127D@webmail-de07.sysops.aol.com> <249DDD9704676C49AE6169AE3D2D9F4ECDB6EC@Exchange-SVR>


At 10:27 AM 03/12/2008 -0600, John Hurley wrote:
>One interesting thought
>regarding valve stem holes was that you can always turn a Schrader rim
>into a Presta rim by simply drilling a second hole. I'm not convinced,
>however, that a Presta valve would mind using an oversized hole instead
>of the usual 6mm.

Wasn't the original question whether a Presta hole cam be drilled out fot a Schrader valve? Of course it can, if you're careful. Best done in a drill press. You don't want the drill to grab or end up with a 5-sided hole. My question would be, why would you want to use a Schrader valve tube? Most on-topic good quality vintage bikes used Presta valves. To this day, Schrader valves are only found on mountain bikes, children's bikes and department store bikes.

As for using a Presta valve in a Schrader hole, I too doubt if it would be a problem in the real world, although it wouldn't look "right". There are bushings and grommets available to take up the gap. I certainly wouldn't drill a second hole. Personally, I'd make a couple of aluminum bushings with a thin flange on the inside of the rim. I don't usually use them, but a nut on the outside would hide any evidence of the bushing.

John Betmanis
Woodstock, Ontario
Canada