I have 30mm Grand Prix 5000 S TR on 26mm internal hooked rims, they measure as 32.5mm wide and 27.2 high. There's enough side clearance in the fork (around 6.5-7mm), but tire height is the main limitation with only 4mm of free space. The situation is reversed with the frame. Even with the same tires and wheels, there's only about 4.5mm of side clearance and over 8mm of height clearance.