A rotary union for a tire inflation system may comprise a stator and a rotor assembly, and may be contained entirely within the space formed by a hubcap and wheel end. The rotor assembly may be mounted to the interior of a hubcap. The rotor assembly may comprise a tube that extends into the stator. The tube may be sealed in the rotor assembly by a first annular seal, and may be sealed in the stator by a second annular seal.