ICON's 4.5" Stage 4 System is comprised of 4.5” lift coil springs optimized for trucks equipped with gasoline engines with a dual rate design that allows for a softer initial rate for superb on-road comfort and a firmer secondary rate that increases during compression for excellent bottoming resistance and off-road performance. Fabricated radius arms offer significantly more strength over the OE units and feature built in caster cams for on-vehicle caster adjustment, maintenance free bushings, and improved tire clearance at full steering lock, all while eliminating the need for drop brackets and thus raising ground clearance under the chassis. The fabricated track bar drop bracket allows the axle to be properly centered under the frame and reduces road feedback throughout the steering system with improved on- and off-road manners thanks to the elimination of bump steer. An adjustable track bar allows for on-vehicle adjustment to fine tune track alignment as well as eliminating the deflective OE track bar bushings for an overall more rigid unit to improve the vehicles handling characteristics.