A grain cart includes front wheels steerable about respective upright and rearwardly inclined steering axes arranged in a trailing self-steering configuration and rear wheel assemblies which are fixed in a forward working direction. The front wheel assemblies are fixed to the main frame of the cart except for the pivotal movement about the steering axes. The rear wheel assemblies are supported on a rear axle support member coupled by a rear suspension to the main frame so as to be arranged for rocking movement about a forward longitudinal axis. The grain cart optionally incorporates a load scale integrally into the main frame, as well as a hitch arm actuator to transfer of some of the load from the grain cart wheels to the towing vehicle by actuating the hitch arm to pivot the hitch arm downward relative to the main frame.