I've noticed this dropout pattern myself. It appears to be gone from Peugeots by 1972-73 or so ... but lived on a while longer on some Gitane TdFs.
Looking at it, my suspicion is that it was meant to speed up wheel changes, as the forward contour of the left dropout extension mirrors the shape of the Simplex hanger ear on the right dropout. Does this make sense? During a wheel change, one could simultaneously pull up and back on the new wheel and use the guides to align it as it went - or am I just making this up?
Russ -----Original Message----- From: David Goerndt <davidg@iag.net> To: Eric Elman <tr4play@home.com>; classicrendezvous@bikelist.org <classicrendezvous@bikelist.org> Date: Tuesday, January 16, 2001 6:33 PM Subject: Re: [CR]Simplex DO Question
>: [CR]Simplex DO Question
>
>
>> I have what I presume to be a 1970 Peugeot PX-10 frameset based on decals
>> and date stamp on rear Simplex derailleur. The left rear Simplex dropout
>is
>> odd - can anyone tell me more about it? Hanging down from the front edge
>> (section of metal which the axle would rest on) is a 3/4" tang protruding
>> down from the leading edge. It's about 1/4" wide at the top and narrows
>to
>> a gentle point - sort of the shape of a sharks tooth.
>
>
>Eric,
>
>I've noticed this too. All my Peugeot's have it, including the '56 PLX-10.
A
>later '72 or '73 frame doesn't have it.
>
>David Goerndt