Where can I find a bolt-on front derailleur boss for an old Aluminum road frame
I'm repainting and rebuilding an old Cannondale aluminum road frame with 9-speed Ultegra and Open Pros laced to 600 hubs and everything's going great so far, except for one thing: The front derailleur mount. The seat tube is 32mm, but it has two bolt holes right at the spot where the front derailleur would clamp on- they look just like bolt-ons for water bottle mounts in that they're a little raised off the surface, so a 32mm FD clamp won't fit on the tube! I have a braze-on FD for the bike, but now I need to track down the derailleur mounting boss. It would look something like a regular FD boss, but it would have two holes so that it could be bolted onto a seat tube. It's for a 1988 Cannondale, if that's any help to anyone.
Please let me know where I can find one! This bike is begging me to ride it!
Try a Cannondale dealer first. I don't know if the company has any obligation to support 1988 product, especially after the bankruptcy, but worth a shot. Should be the same item for many and several years of production. Might be in a junk drawer--saved from a frame that went in for warranty service.
If you're skunked, no shame in using a 31.8 mm clamp=>braze-on mount. Basically, it's a clamp with provision for fitting your bz derailleur. Shimano have made them, as have some others. You should be able to relieve the mount in the area of the fittings, as the Shimano units I've seen had lots of material, but of course it's been a while for me.