Modifying front fenders for tire rub..?

When I put 235/60 X 15s and cop car wheels on the Duster, the tires rubbed on the flat flange at the lowest part of the fender front. Triming the flat part of the flange back at a 45 degree angle and rounding slightly with a file gives 3/16" to 1/4" clearance unless I'm backing up with the wheels cocked just right and then step on the brake, especially when going downhill (like out of my driveway), then they still rub. Noise tread makes against that part of the fender gets your attention in a hurry but leaves no evidence when you get out and inspect, aside from wiping the rust off the cut back edge. Guess I'll have to try autoxcuda's trick of moving the brace to tweek the fender out a little next.