A combine harvester (10) has a suspension axle assembly (34) supporting the rear end of the chassis (12) of the harvester. Side frames (56) of the chassis direct loading down to a transverse axle (36) through a pair of suspension devices (76) interposed between the side frames and the axle. The suspension devices are resilient and expandable to cushion the chassis and to provide changes in the fore-and-aft attitude of the combine. The suspension devices may be independently operated to tilt the axle relative to the chassis, and provision is made for shifting the axle longitudinally, side-to-side of the chassis to facilitate turning of the steerable rear ground wheels.