It really depends on the design of the rims especially the spokes. I have +33 at the front and it didn't clear the calipers. Had to put in a real thin spacer. 2-3mm to clear them. The rears are usually not a problem.
Guys,
On monday I am going to buy two new rear tires to put on stock wheels. The front tires are the Bridgestone Potenza so I guess the sensible thing to do is use the same tires for the rear............but is that...