An apparatus for pivotally fixing a non-driven wheel assembly to a vehicle frame is disclosed. The apparatus provides a trough through which non-driven wheel assembly components can be passed and protected. In one embodiment, the trough is circular in shape and is fully enclosed by the apparatus. In other embodiments, the trough has various shapes and comprises retaining members to secure and protect non-driven wheel assembly components. A suspension system interface is provided that allows the apparatus to suspend the non-driven wheel assembly. Openings used to pivotally and rigidly fix a mounting plate, suspension system, pivotal axes, and fender assemblies are also disclosed and claimed herein.