Used Firestone 520/85R42 R1 Combine Dual Set, 50% Tread, Includes 16" Axle & Drive Shaft Extensions, Truss Rod, Dual Ladder Landing for S Series, In-Between Dual Spacer with 20 Wheel Bolts, off an S660, 10-Bolt Pattern. Before driving to see this item, please call or email to confirm availability.