Originally Posted by
HillRider
I thought the recommended bb for the Ultegra 8-speed double crank (6400) was 115 mm. I remember a BB-UN72 in 115 mm as the matching bb. In any event, a mm here or there isn't that critical.
Yeah, that's what my 8-sp Ultegra bike came with. But it is has a fat seat tube and needs the crank a little more outboard to allow for shifting to the small ring. I think a skinny seat-tubed bike would be better with a 113mm but would still work fine with a 115mm or 116mm.