I am purchasing BFG AT 285 70 17, and I want them to stick out from the fenders a little bit. I was thinking about a 17"X9" rim with a backspace of 5". Does anyone know what number on the rim size tells me what will protrude these tires? I want the tires to look flat on the side walls so I am going with a wider rim than the stock. The stock rims I have are only 7.5" wide. Another question, is there a certain size to get around the 4 wheel disc brakes? Do I have to stay at 17" rims? Any help would be appreciated.