Hi
I'm building up a bike for bad roads and for riding in the woods.
Coming from road bikes I'm somewhat scared about mounting wider tires (32mm or 1,25") on those narrow road rims.
I already have a wheelset lying around that I want to use for this bike, its inner rim width is 13mm. Is that wide enough? Mavic's Open Pro (often used in cyclocross) has 15mm.

Second question:
The tire will be a touring/trekking tire which is as i have experienced very puncture resistant and long lasting.
Is there a difference between touring tires and real cross tires (maybe a different shape of the tire hooks) that makes the use of touring tires on road rims unsafe?

I had an interesting conversation with a well-known and respected fit technician who owns a pro shop in the Philly area. I basically wanted to "convert" a Merckx road frame to a 'cross setup using side pull brakes (not cantis)...

He commented that the widest tire I could expect to fit on a road frame would probably be around 28c and even tires with aggresive knobs in that size may not fit. He voiced a larger concern that dirt, mud, etc...kicked up by the tires would overwhelm traditional road brake calipers. That's why cantis or disc brakes are used.

I'm sure there are riders on this board have ridden off-road with side pull calipers, hopefully they'll chime in.