Fabtech?s 6" Radius Arm lift kit for the Ford F450 and F550 Super Duty is built to handle the on and offroad demands of the truck enthusiast. This vehicle?s suspension is more robust than the Ford F250 and F350 and therefore demands specialty parts only available from Fabtech. This Radius Arm system is a complete upgrade to the factory suspension and will provide additional strength for use with oversized tires. The design has been proven in over 10 years of service in consumer, commercial and military applications. High quality components with properly designed suspension geometry is what sets this system apart from all other Radius Arm suspensions. Each Fabtech component has been designed with specific features and benefits that create this quality suspension system. For a greater understand of each these components please see below. FEATURES: RADIUS ARM - Tubular construction with dimple die side plate for superior strength. Arms are offset to allow for full turning radius of the Dana Super 60 front axle with wide tires. Fabtech Radius Arms have 1 degree of caster built in for the increased ride height. Adjustable alignment cams on the Arms allow for an additional 1.5-2 degrees of caster adjustment. COIL SPRINGS - American made coil springs have been designed for a very compliant ride quality both on and offroad. Each coil is preset during the manufacturing process to insure no ride height settling over time. Allows for a 2" increase in wheel travel over stock when used with Fabtech shock absorbers. TRACK BAR BRACKET - 1/4" thick steel bracketry repositions the factory track bar to center the axle under the vehicle with the increased lift height. Super stout box style bracket is designed to eliminate deflection when the track bar moves through its full cycle. DROPPED PITMAN ARM - Forged steel construction with high strength material that exceeds the factory specifications. Designed specifically for the F450 and F550 to work in conjunction with the factory