Cyclocross - Gearing Question

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
btasquared
09-21-08, 08:26 PM
I just built up my first cyclocross bike for riding dirt roads and commuting. I don't have plans to race, but I'm curious about typical gearing on this type of rig.
I used an Ultegra gruppo which has a 53/39 crank/chainring set, which seems pretty big to me. Do 'cross bike usually have smaller rings?
Thanks for any guidance.
darksiderising
09-21-08, 09:17 PM
A cross crankset uses a 46/36 combo. You need a 110 bcd crank to accomplish this.
My ideal setup for a 'cross double would be a 38 x 46 double with a 12-25 or 12-27, just because I feel the 38 is a little more usable throughout the race Not sure if there are 110 BCD 38 rings or 130 BCD 46t rings though.
But that's racing. For an all-rounder I think I'd go with a compact crank (50 x 34, maybe) and a widish range cassette, depending on how much off road you're doing.
c_m_shooter
09-22-08, 12:28 AM
Compact 34/50 cranks and a cassette in the 11-28 or so range would be perfect I think.
jbpence
09-22-08, 10:20 AM
i use 46/36 on the front, 12-27 on the rear. lets me climb 500 feet/mile, for at least a while.
cachehiker
09-22-08, 03:43 PM
I put a pair of 38-48 rings on my Ultegra Crank and sold the original RFE 39-53 pair for almost as much as I paid for the 38-48's. I run an 11-28 cassette for all around commuting and cross but a 12-27 with 36-46 or 38-46 might offer better spacing for racing. I think I'd spin a 46-12 gear out too easily when rolling down the hills on my commute to work though. The RD is an XT mid-cage so I can throw a 11-32 cassette on there in the early spring and ride some easy mountain trails on it too.
btasquared
09-23-08, 07:33 PM
Thanks for the input, everybody. I think I'll look into a compact crankset - further down the line probably, as I don't really want to spend a lot of money on it right now.
Best,
BTA2