Adjustable vehicle seat suspension

An adjustable seat suspension for a vehicle seat that includes a linkage arrangement (28) disposed between a seat frame (22) and a seat base (24) whose collapse is opposed by a spring lever arm linkage arrangement (32) supported on a fluid powered spring actuator carried by the base that has a plurality of pivotable spring lever arms that are each coupled to a portion of the frame. In a preferred embodiment, the fluid powered spring actuator is an air spring (30) whose pressure is adjustable and which is powered by an air compressor (76) to tailor suspension characteristics and provide a desired preload. The seat base (24) includes an upright (84) to which the spring lever arm linkage arrangement (32) is pivotally mounted with its spring lever arms (94) supported by a saddle (114) carried by the air spring (30) at a location disposed between the upright and the location where the spring lever arms (94) couple with the seat suspension.