Magnus...what the boys above said is true you can go wider. I don't know if you do much off roading but if you do BF Goodrich is coming out with a 285/55/20 All-Terain KO that I am definately going to consider. Should be out late winter. Of course the big thing to watch out for when changing wheels is off-set / back spacing. You could put your stock tire on a wheel with improper back spacing and experience rubbing.