Stretch a string between the bottom of the tire and the edge of the bumper or whatever hangs down the most. If the tire is above that (accounting for possible suspension deflection, if you want to be all scientific-y about it), you have practically no chance of it hitting stuff as you haven't altered the departure angle.
11" is quite a good bit of clearance. My car (a Honda Fit) has just about exactly half that clearance underneath it, and that's adequate for just about anything that sort of resembles a road. (It's also shorter, which is an advantage, but still...)