Fabtech's Radius Arm system for the Ford Super Duty is built to handle the on and offroad demands of the truck enthusiast. This system is a complete upgrade to the factory suspension and will provide additional strength for use with oversized tires. The heart of this quality system is Fabtech's tubular Radius Arms. The design of these arms comes from Fabtech race components built with a tubular structure reinforced by a dimple die side plate and heavy gusseting for rugged offroad use. They are a superior upgrade to the stock stamped arms. Included in this system is the massive Dirt Logic 4.0 Coilover Conversion for outstanding damping capacity offroad with a quality on road ride. The Coilover bolts in place of the factory coil spring without removal of the coil spring bucket. The giant 4?? diameter aluminum remote reservoir mounts horizontally above the Coilover to allow for full compression travel with oversized tires. The Dirt Logic 4.0 Coilover is the biggest and baddest on the market for the Ford Super Duty. High quality components with properly designed suspension geometry is what sets this system apart from all other Radius Arm suspensions. System includes a free 5 year 60,000 mile powertrain warranty. Each Fabtech component has been designed with specific features and benefits that create this quality suspension system.