this is the KEY problem im dealing with when it comes to cutting fenders, which will not solve anything because the tires are hitting on the mounting points of the bumper (which is just mocked up)
with wheel turned showing contact point
with wheel turned away to show the point where the bumper attaches to the fender
edit:
I was thinking of adjusting the caster, but i only have about 1/4 inch - 1/2 inch of space back there when the wheels are turned so i don't think it would get me very far