Use the leveling kit to raise the front of the RAM, and eliminate the factory nose down rake, to make room for tires 1 inch to 2 inch taller than stock. Also order the 2 inch rear block kit if you desire to retain the factory rake for load hauling/towing. Rear kit includes two U-bolt sets to applicate both rear axle types found in these pickups, plus brackets to prevent suspension over-compression. The 2 inch lift products also fit RAM 1500 mega Cab. RAM 2500/3500 rear block kit (P5155452) includes two U-bolt sets to applicate both axle types found in these pickups, plus brackets to prevent suspension over-compression. Tire Diameter: For 2 inch Lift - 33 inch or For 4 inch lift - 35 inch. Maximum tire width: 12.5 inch. Wheel diameter: No less than 17 inch. You can run factory wheels. Wheel width: 8 inch - 9 inch. Do not use less than an 8.5 inch wide wheel with a 12.5 inch wide tire. Wheel back spacing: 4 inch minimum - 5 inch maximum.