What have you managed to fit? I had some issues running a Specialized 25c on my 23mm rims and the tire rubbing on the brake spring. Trying to run as big as possible on my training wheels.

What brakes are you running? I have 303FC clinchers with Maxxis 25mm tires on and still have 5mm of clearance front and rear with Red 2012 brakes.

7900

101 with gp4000 25mm, but only on the rear. by choice, never tried the 25 on the front.

most importantly, what brakes?

A friend of mine is running a set of 25c pro 2 race's which on the 404 firecrests he has them on measure out to just over 29mm wide on a 58cm Caad10 4 no problem... However we had another person try and put a set of 25c set of lithions and it has clearance issues with the fork (vertically not horizontally)

I was running Specialized Roubaix Armadillo 25s on both the front and rear with 7900 brakes. 0 issues on the front, but the rear would rub on the spring on the brake when the bike had my bodyweight on it.