13 X 5 , I run that on the front of my super stock , Steel white wheels replace the cheap bearings with the snap ring bearings , Besides did'nt you say 4 1/2 wide how you going to put a 6 wide tire on there without it having tons of sidewall flex , You will be suprised just how much the 5 will bite . Mark , Correction Big Chuck runs the 4 1/2 But anyways thats what I run to