Abstract: A steerable axle assembly for a grain cart or manure tank unit designed to be pulled in a forward direction over and agricultural field by a farm tractor is disclosed. The invention involves a steering axle assembly that is easily guided to improve the maneuverability and safety of the unit and reduce field compaction. The steering system design features angled kingpins that transfers some of the unit weight to assist in turns. Thus, the steering system reduces the resistance of the unit steering system to turning and minimizes ground compaction during turns. The steering system is particularly designed for rear-steering grain carts and manure tank units and larger versions of such units with multiple alternating steering and non-steering axles.