Vehicle suspension system

A vehicle suspension system (15) couples an axle (20) to a vehicle frame (24) so that the axle (20) pivots about a first location (25) with respect to the frame (24) when the axle (20) has a first range of articulation. The axle (20) pivots about a second location (32a,32b) with respect to the frame (24) extending laterally out from the first location (25) when the axle (20) has a second range of articulation greater than the first range of articulation. When the axle (20) exceeds the second range of articulation, the suspension system retains the axle (20) in a substantially rigid contact with the vehicle frame (24).