Abstract: A differential mechanism is provided for a dual wheel assembly including a spindle having a drive axle defining a first rotational axis. First and second wheels are supported on the spindle adjacent to one another. The wheels are driven by the drive axle and are rotatable relative to one another about the first rotational axis. A gear assembly having a second rotational axis transverse to the first rotational axis mechanically couples the wheels. A biasing assembly engages the gear assembly thereby preventing relative rotation between the wheels when a torque is applied to one of the wheels below a desired amount from a road input. That is, the biasing assembly and gear assembly cooperate with one another to lock the first and second wheels together so that they are driven together about the first rotational axis by the drive axle. This is desirable when the vehicle is traveling a straight path to provide maximum traction.