Is there an easy way to tell the maximum width of tires a bike can take just by looking at the specs? I'm considering a number of SS/FG bikes right now and have no way to judge this short of visually inspecting them in person at each LBS, and even then I don't trust my eyeballs.
For example, I'm looking at an Origin 8 Uno and its specs list a 1 1/8" fork, 700x32 wheels, and 700x26 tires. Does this mean that I can only fit tires less than 1 1/8" thick, or can I at least go up to a 32 since the factory rims are already that size?
In addition, what about the brakes? Other BF posts favor cantilever brakes over calipers for tire clearance. How can I tell what fits certain brakes?
the stock tires are 26c, not 32 (there are 32 spokes in each wheel). Without knowing the width of the fork and spacing of the seatstays, or the manufacturer sayuing the max width of the tires, it is tough to tell. One indication that wider tires are possible would be cantilever brakes (usually found on MT bikes, cross bikes or touring bikes), or long reach calipers (like is required for the surly steamroller as wider tires are generally taller as well and require more clearance. I would guess you could not fit 32's on the Uno, maybe up to 28's
When I put big tires on, I often get surprised at the places it rubs that I dont' expect.
My solution: have the LBS take a larger tire off another bike and see where it hits.
some areas to look for:
I have clearance in my fork, but have had to dremmel brake calipers to get tires to clear them also.
Front derailer may have contact as it moves - obviously not a problem for a SS/FG
Rear clearance is going to be determined by your gearing, chain, and how far back wheel is in the dropout. I typically can put a pretty big tire on there with the right gearing & chain length.
Really, trial and error is the only way. Besides, a 32mm tire isn't always a 32mm tire. The written size of a tire is only a guideline...