Cyclocross - Tire/Rim Issues, Please Help...

I recently bought a Crosscheck to be my do everything bike. So far I've only used it for touring and commuting. Anyway, this weekend I'm going north to camp and I wanted to bring it with me to ride some of the single track. I ordered two Panracer Fire Cross tires 700 x 45 to mount up and figured I was in business. Then it occured to me that they might not fit on my Mavic CXP 33 rims. I looked at the Mavic website and just as I thought CXP 33 rims have a maximum "recommended" tire width of 28mm. This really sucks because I built these rims based on reviews and suggestions I read on this site. I know that people ride CXP 33 rims on cyclocross bikes. What sort of tires should I get? Do I have to shell out for a secondary wheelset just for offroading?

Thanks in advance. I appreciate the help. I'll be really depressed if I can't ride this weekend.

I've run 44c Mutanoraptors on my CXP33's. They feel squirmy at low pressures, but I never thought the tire was about to come off. Getting a wider rim will improve the tire profile and make it a bit rounder. Put them on and find a grass field, do a few hard corners at speed, and see how they feel. If you can't get enough traction there to pull the tire off, you probably won't find it on the dirt either. Plus, the penalty for failure is minimized on nice soft grass.

I've run 44c Mutanoraptors on my CXP33's. They feel squirmy at low pressures, but I never thought the tire was about to come off. Getting a wider rim will improve the tire profile and make it a bit rounder. Put them on and find a grass field, do a few hard corners at speed, and see how they feel. If you can't get enough traction there to pull the tire off, you probably won't find it on the dirt either. Plus, the penalty for failure is minimized on nice soft grass.

Thanks!

I just talked to a guy at a LBS and he told me that there shouldn't be an issue fitting the tire into my rim. The distance between the beads on the rim is 15c and he said that I could mount up to 45c tires on without too much trouble.

Anybody else have input?

I sure wouldn't run out and buy a new set of wheels.

Should be fine.

Thanks to everyone. I ordered some Panaracer Cinder Cross tires 32mm. But, for the information of anyone who finds this tread in the future I could have mounted the 45mm Panaracer Fire Cross tires on my Mavic CXP 33 rims no problem according to numerous sources. But, the 45mm tires probably would have had a small clearance problem in my Surly Cross Check. I've read that knobby 45mm tires would probably require that I clip the knobs on the edge of the tire to clear in the back. For that reason I opted for the still relatively aggressive 32mm knobby Cinder Cross tires instead.