Question: What [bottom bracket] thread would a late-1950's to mid-1960's Bottecchia be likely to have used?
The answer is apparently "NOT Italian thread", either.
The bb cups are Ofmega ...a cottered axle, crank setup (not otherwise marked).
The bb width is 70mm. The shell diameter appears to be a tad under 36mm (my caliper isn't very precise).
I have Campy NR cups (clearly marked 36x24 F), and a set of Sugino similarly marked. They both start to thread in, but stop after a turn or so. The Campy lockring threads loosely onto the Ofmega cup, but the Ofmega lockring won't thread onto the Campy cup.
I don't have any French thread cups to try ...but Bottecchia wouldn't have used a French threaded bb, would they?
...any suggestions appreciated.
PS: I finally figured out what y'all were saying about the stem on the BSA being backwards ...took me several tries to visualize it. Doh! - I agree ...backwards.
--- brandon davis ---
-- sacramento, ca --