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. Sorry, but I don't have access to a digitle camera at the moment so I can't help with jpegs. Is that enough for anyone to have ideas of what it's for, when it was used, etc.
As always, thanks in advance,
Eric Elman