Was just thinking today because we've never tried it. What actually happens when you use a Chorus/ Record BB with a Centaur cranks? With the shorter axles, does the chainrings cut into the chainstays? Or does it depend on the frame geometry? Surely the chainline will be off, but does it matter in the real world?

Good question. Everyone I've talked to says it won't work, but I don't think they've actually mounted a Cent crank on a Chorus/Rec BB and tried it. Since Cent and Chor are so close in weight, etc., I'm sure Campy made them that way to prevent Cent cranks from outselling Chor when mounted on Chor/Rec BB's.

The only options for a lighter Centaur crank / bb setup other than wholesale replacement would be to locate either a Phil Woods bb or an older FSA. Odds are pretty low, however. My suggestion, replace both the crank and bb.

Obviously the chainline would be way off, since the spindle is 9mm shorter, the crankarms should each move 4.5mm closer on both sides, assuming that both BBs are symmetrical. I've never seen any info on the campy website indicating that these BB's are not symmetrical, as El Guapo contends. Only the Record triple BB is listed as being assymetrical as far as I can tell. The new Centaur BB has been improved, so it's really not too bad a choice.

http://www.campagnolo.com/groupsets.php?gid=3&cid=8

http://www.campagnolo.com/groupsets.php?gid=1&cid=8

If the little ring didn't hit the right chainstay, then the chainline would just be off to the left by one cog. The smallest two cogs would not be useable with the little ring and the big ring/smallest cog chainline would be more extreme.

The q-factor (width between the pedal mounting faces) would also be reduced by 9mm, which is a lot.

Good clarification, C-40.