I fought with the same problem with both Pirelli and Bridgestone fronts at MO. No problems at any other tracks with either of them, but at MO, anything quicker than low :40's would chew them up. I tried about everything I could think of as it was getting way too expensive replacing them all the time. Dave Grey suggested trying stiffer front springs. That ended up being the fix for my bike. Going by sag numbers, the springs I have in there are too stiff for my weight, but they work. Not saying that's definitly your problem, but if you rule everything else out, it might be worth a shot.