Joined: Aug 2003
Posts: 3,520
Likes: 12
From: Colorado Springs, CO
Bikes: 1959 Bottecchia Milano-Sanremo (frame), 1966 Bottecchia Professional (frame), 1971 Bottecchia Professional (frame), 1973 Bottecchia Gran Turismo, 1974 Bottecchia Special, 1977 Bottecchia Special (frame), 1974 Peugeot UO-8
Originally Posted by
sciencemonster
Measuring the chainwheel c-c is about 88-89mm. According to Shelton, that's a 151 BCD. It's a '69 Comp, so I suppose that makes sense, but it means replacing the chainwheels is about impossible. I'd prefer to keep the original hubs rather than replace w/something modern and then have to coldset the frame. It seems a lot easier just to replace the cranks. But in doing research, it seems then that the BB axle would be too short.
Maybe I should just throw on a new derailler to get what I have to work smoother. I just don't like how it changes gears now. If I could get it to change smooth in the back, then I could stick with what I have.
My big concern with that, is buying old deraillers is expensive, and they don't seem to work much better than what I have, and I have no idea if whatever I buy will work with a 32T in back. RIght now I have a Svelte on a hanger as an extention, plugged into the hanger that is built in on the drop out. Pretty sketchy and it doesn't change any better than any other derailer I've tried.
I'd like to just try a good quality modern derailler and see if that fixes everything, but I have no idea what will work.
All very fustrating.
Yeah, you are going to put some thought into this one then. 151bcd is pretty limiting. 110mm bcd would be perfect - those were common during the 80's, definately Shimano and maybe Sun Tour, Sugino, et al. Essentially the same as a modern compact. My Panasonic has a triple Shimano 110/74 that would be just what you need. Of course they don't look quite the same as anything in the 60's but that would be the cheapest way to go. You could also go with a 50mm bcd crank (TA, Stronglight, Nervar) and use TA rings to build a nice 60's period double or triple but that will cost some bucks. For the rear you're in the same boat. Nothing from the 60's is going to shift well over a wide range. 70's Suntour (VGT I think) or Huret Duopar/EcoDuopar will work and keep your vintage look.
__________________
1959 Bottecchia Milano-Sanremo(frame), 1966 Bottecchia Professional (frame), 1971 Bottecchia Professional (frame),
1973 Bottecchia Gran Turismo, 1974 Bottecchia Special, 1977 Bottecchia Special (frame),
1974 Peugeot UO-8, 1988 Panasonic PT-3500, 2002 Bianchi Veloce, 2004 Bianchi Pista