Re: [CR]Oschner Frame - French Threading - Seek larger French threaded frame

Example: Racing:Roger de Vlaeminck

Date: Wed, 6 Oct 2004 08:19:46 -0700 (PDT)
From: Jerome & Elizabeth Moos <>
Subject: Re: [CR]Oschner Frame - French Threading - Seek larger French threaded frame
To: John Clay <>,
In-Reply-To: <>

I don't think there is any such thing as French dropout threading. Threaded dropouts are usually compatible with Campy and virtually all other derailleurs. Some French bikes, however, had Simplex dropouts with a unthreaded whole. These used a nut on the inside of the dropout to secure the RD upper pivot bolt. Simplex and some Huret RD's were supplied with such a nut. It is possible to tap a Simplex DO for a Campy derailleur, but you also have to file a notch in the DO to provide a stop for the Campy RD body. That's a lot of trouble - it's easier to just buy a Simplex all alloy SLJ RD, which is still easy to find on eBay, and which is IMHO far superior to Campy NR.

There's no guarantee that a French BB means French dimensions all around, but an all French frame takes a different thread on the HS adjustable cup and locknut, and a slightly smaller stem quill diameter (22.0mm rather 22.2mm). French tubes (even the French version of 531) were also a different OD and ID, meaning a different FD clamp, a smaller seatpost (usually 26.2, 26.4 or 26.6), and sometimes it's a bit difficult to install Campy clampon brake cable clips.

I seem to recall maybe some Oschners were made in Switzerland. If that's the case, are you sure the BB isn't Swiss threaded? Swiss was the same as French BB thread except that the right side cup is left hand thread rather than right hand thread. Swiss thread applied only to BBs, but bikes with Swiss BB could have any combination of French, Englis or Italian dimensions elsewhere.

You can read more about all this on Sheldon Brown's web site.


Jerry Moos Houston, TX

John Clay <> wrote: I just learned that my Oschner frame has French BB and pedal threading. Big bummer. Would the rear derailleur hanger also be French threaded? Would the headset be a different diameter and are there any other differences that matter if trying to put the SR group set on another frame?

Since what I'm after is an old (mint) SR equipped bike would it be wiser to sell this mint Oschner complete with SR, and find something else with the groupset I want and friendlier threading and tubing dimensions, or try to transplant the groupset to some other frame that's larger (56)? If the latter, can ya'll recommend frames for sale, or makers that I should be on the lookout for other than Peugot? I'd prefer rando or touring geometry as opposed to racing. The Oschner is straight gauge Columbus tubing.

Thanks for any info
John Clay
Tallahassee, FL