Actually the difference is in the wheel well opening with the big trucks the 57s opening is 1 inch forward compared to the 55 and 56 this is true with the front springs as well 55 and 56 the axle pin is centered on the spring 57 is one inch to the front centering the wheels in the well. This allows for a larger steer tire to be used on a 57 without hitting the fire wall when turning.
Last edited by HevyHauler; 11/28/2010 10:11 PM.
