Cyclocross - Chainrings...?

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patepluma
08-22-08, 05:55 PM
Why do cross bikes usually have 36/46 or 38/46 up front and 12-25 cass.? As oppossed to a road bikes 34/50 and 11-28 for example? My Fuji has 36/46, 12-25 and I fail to see any disadvantage whatsoever if it were to have 34/48, 11-28. What's the deal?

flargle
08-22-08, 06:09 PM
Why do cross bikes usually have 36/46 or 38/46 up front and 12-25 cass.? As oppossed to a road bikes 34/50 and 11-28 for example? My Fuji has 36/46, 12-25 and I fail to see any disadvantage whatsoever if it were to have 34/48, 11-28. What's the deal?Standard road gearing is 39/53 in front and 11-21 in back.

Typical cyclocross setups have smaller chainrings and a bigger sprocket in the cassette, because you need lower gears for off-road riding.
justinb
08-22-08, 06:33 PM
Why do cross bikes usually have 36/46 or 38/46 up front and 12-25 cass.? As oppossed to a road bikes 34/50 and 11-28 for example? My Fuji has 36/46, 12-25 and I fail to see any disadvantage whatsoever if it were to have 34/48, 11-28. What's the deal?


The 34/48, 11-28 combo you mention is a fantastic one if you're using your cross bike as an all rounder. For racing however, I think you'd find the 34 too small for the fast sections, the 48 too big for quick accelerations and climbs, and wish you had something in between. Thus, the 36/46 which is just about perfect (I'm running 36/44 this year).