guide not working. Would 275/40/18 rub fender w/ stock rear suspension and 42 offset wheel? i had 30 series tires and already blow up 2 so i kinda wanna go up to 40 so it wont happen again. Besides, 285/30/18 leaves a 2 inch gap between wheel and fender on my car. I dont get it, i have stock suspension. Would 275/40/18 w/ 245/40/18 give me wrong speedo reading and understeering?