I now have 215/70/15 if i increased my rear tire size to 255/70/15,with 3.55 Ring Pinion on my 1948 1/2 ton, at normal high way RPM i now go about 50 MPH.I do not have tac or working speedomiter. If increase my tire size to the 255/70/15 how much will my MPH. increase? And will the tires fit my wheelwell ? I saw that tire size on truck like mine, but i never talked to the ouner.Thanks

Last edited by oldchevyguy; 10/05/2013 3:54 PM.