of an inch. overall if you end up with 290mm rotor surface without getting into the vent hole area of rotor surface, your good to go. I only have pictures to go by, and can't really tell if you have the 10mm of stock you'll
need. A buddy of mine (racer) says even if you get into the vent hole area, you'll be fine, no different than the wave style rotors.
just trying to help