This Recommended Practice provides uniform laboratory procedures for fatigue testing of hubs intended for highway use on trucks, buses, truck-trailers, and multi-purpose passenger vehicles having bolt circles from 6.5 - 13-3/16 in (165.1-335 mm) diameters. The tests described in this Recommended Practice are not to be construed as the only tests required or permitted to assure that a hub will perform satisfactorily for its intended use.