34 seems very low for a cross bike, I race mine on 39-48 with a 12-25 on the back, rarely using the 48. A properly designed cross course should have run ups on any hill steep enough to make you want a lower gear than a 39 on the front.
Regarding racing on the road, I'm not much of a road racer, but am pretty quick on an mountain bike or cross course and don't have a road bike. I've been racing my cross bike with the local road club for the past couple of years without any problems. I put on 23mm slicks on semi aero wheels (FSA RD200), flip the stem down and rock a 11-21 on the back which is doable as I can grind on our massive 3 minute climbs we have in Saskatchewan! I'm sure the 2-3 lb weight reduction of a real road bike would be nice on the climbs, but I'm just out for the fun/training anyways. I'm sure my bikes handling is slower than the road machines out there, but I seem to survive. This year I plan on doing some Provincial level road races in Cat4, applied for Cat3, but they wouldn't give it to me due to no road racing experience. So I'm hoping to win, or at least be in the top 3 on my crosser, hopefully it offends some OCP roadies!
