Abstract: An adjustable seat suspension for a vehicle seat that includes a linkage arrangement disposed between a seat frame and seat base whose collapse is opposed by a spring lever arm linkage arrangement 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 whose pressure is adjustable and which is powered by an air compressor to tailor suspension characteristics and provide a desired preload. The base includes an upright to which the spring lever arm linkage arrangement is pivotally mounted with its spring lever arms supported by a saddle carried by the air spring at a location disposed between the upright and where the spring lever arms couple with the seat suspension.