Use these high strength steel alloy shims (sold in a box of 6) to adjust caster and pinion angles 1° on your most rigorous applications. Designed for 4" wide leaf springs, this steel shim will adjust steer or drive axles on everything from cement and garbage trucks to OTR. Using "Z blocks" on your axle? Take a look at our axle spacers, PN 10798 to spread the load and tweak your ride height