Skyjacker Leaf Spring 2008-2010 Ford F-350 Super DutySoftride(R) springs use only American steel and the individual leafs of each spring are shot peened with hard steel pellets at very high velocities. This shot peening compresses the surface of the steel thereby increasing the tensile strength of the spring. Without this shot peening procedure, the maximum wheel travel and ride quality could not be achieved without sacrificing the life of the spring. Softride(R) springs use bolt style spring clips,