I'm trying to build up a classic Alan made Guerciotti cross frame, but I've ran into a bit of a problem. The seat tube is exactly 30mm in diameter with no braze ons for a derailleur. This seems to be a nonexistant size between the 1 1/8 and 1 1/4 sizes I know. There is a pully on the frame for running a bottom pull derailleur from the cable stop in the seat post clamp lug, so it can't be that it was just intended for a single ring. Anyone run into this or know of a company that made a derailleur in that size?
Nathan Loop
Richmond, VA USA