Campagnolo cranks - easy question
 

Hello, I am still learning about all of this, so please bear with me for this question.

I am just starting to build up my first road bike (the first one I'll have built, not owned) and I am trying to do all campagnolo parts for the drive train. Anyway, I have access to a some 9 speed campy record stuff (brake shifters, front+rear hub) at my local bike co-op, so I was going to go that route. But I have a problem, I am unsure of how to pick out a crank for this bike. I am going to get that off eBay since the only one in the shop is $140 and I'm sure I can pick one up cheaper online. I want to get a campy record crank for this bike, but I think I need to get a newer one to work with the 9 speed chain right? Or can I just get chain rings since all campy cranks seem to use 135 BCD? What's my best bet? Is there any way on knowing if a complete crankset will work without having to swap chainrings?

Sorry for the silly question, like I said, I am a newbie when it comes to mechanics.

I'm not the world's greatest Campy expert, but I'll take a shot. I think if you are going for a 9-speed indexing system you need at least 8-speed chainrings in good condition, but 9's will work better. There is a small difference in chainring spacing between the 9 speed and 10 speed. I know this is based on the chainrings, because I've installed a 10-speed compact on a bike that uses 7-speed friction (price was perfect!), and had a bit of chain rub when in the small chainring and teh smaller cogs. The fix, according to the Branford Bikes website, was to install a chainring bolt spacer set. I haven't done it, and on teh road teh rub is not noticable. If it's a problem for you, they have a wide range of spacers available.

Probably more important in crank selection, is matching the crank arms to the bottom bracket. You need to have the correct chainline, involving a matching between the frame alignment, cogset, and the midplane between the chainrings. The midplane between the chainrings is also the midplane of a 9-speed cogset, and it's about 43 mm away from the centerline of the BB. The correct BB is necessary to locate the chainring, once you know the frame and cogset are correct.

if you go with a record crank, make sure your bottom bracket spindle is 102mm in length. I am assuming your bottom bracket is either campy or campy compatible. Chorus uses the same 102mm spindle length. I believe the others use a 111 or 115 depending on whether the crankset is double or triple chainrings. I don't think you have to worry to much about whether your crank is 8speed or 9speed compatible if you are running 9spd for everything else. If you were running 10sp then you might run into some issues if the crankset was designed for an 8speed drivetrain as the teeth may not mesh well with the narrower 10sp chain...but an 8/9 mix should not give you any grief.

-j

Centaur doubles, Veloce doubles, C-record doubles, and Chorus pre-199? doubles use symmetrical 111 mm BBs, same for an early Racing T that I have. The Centaur 111 BB, the AC-H 111, and the AC-S 111 all fit this bill.

Wow guys! Thanks for all the info! I haven't picked out the bottom bracket yet, I was actually going to wait until I got everything else first then take it all in to the the local bike co op and have them show me how to measure it for the proper BB (it's a co-op where they offer tools/knowledge to work on your own bike, my kind of thing).

EDIT: So most likely will a 10 speed crank work then?

based on your first post, the answer to your question "will a 10 speed crank work then?" is it depends.

You can get a 10sp crank to work with 9sp components. You just need to make sure your bottom bracket and crank are compatible with each other.

Cheers,
-j