Bicycle Mechanics - Frankenbike just needs crank, have BB

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jzsoup
07-31-09, 11:17 AM
I'm looking at an Alivio crank for my Frankenbike. It's the last piece I need to finish this little project which has blended a mountain frame with 700c wheels and cross style tires.

The crank calls for a 113mm BB, but I just happen to have a 118mm BB. Is there any reason I couldn't run these together? I'm thinking I'll just have to adjust the FD stops out further to compensate. Am I right?

Thanks all.

DMF
07-31-09, 11:42 AM
Yeah, you could do it, although the chain line will be off. Is this a geared bike?

You should do a complete reset on the FD every time you change cranksets.
jzsoup
07-31-09, 11:46 AM
Yeah, you could do it, although the chain line will be off. Is this a geared bike?

You should do a complete reset on the FD every time you change cranksets.


Yes, it will be a geared bike. Though I had considered dropping the small ring from the crank and making it a double. I don't think I'll need that ring very often.

DMF
07-31-09, 12:08 PM
I'd recommend keeping the ring on. When you need it you really need it.

Try mounting the crank and measure the chain line (see Sheldon for how). Then compare to rear chain line - they should be the same. (also check chainstay clearance)

Chain line mismatch can result in degraded shifting and increased chain wear.