Abstract: A 4-spring, tandem axle suspension system comprising a pair of semi-elliptic compound leaf spring assemblies positioned on each side of the vehicle frame in fore-and-aft alignment. The remote ends of each pair of leaf springs are retained by engagement with front and rear brackets extending from the vehicle frame on each side, while the adjacent or proximate ends of the spring assemblies on each side are connected by means of a pair of shackles to opposing ends of an equalizer bar pivotally mounted on a bracket rigidly attached to the vehicle frame between the adjacent spring ends. Each inner or adjacent end of each spring assembly is pivotally attached to its shackles by means of a pivot bolt passing through a bushing and spring eye formed on the uppermost leaf of the spring assembly.