What backspacing are the wheels? The backspacing has as much effect on clearance as the diameter. The further out the wheels stick the greater the arc they travel. 15x7 is a good size for a 9.5 tyre. I am running 15x7s with 9.5 tyres (albeit 33"), I run 95mm backspacing, that seems to give the maximum clearance all round and brings the edge of the tread right out to the edge of the arch which means its just legal for road use over here.