Abstract: The present invention is directed to a rotary air coupling that distributes air to tires mounted on a rotating hub of a driven axle. The coupling is positioned adjacent the parking brake of a rear disk brake configuration. In the preferred design, the rotary member is connected to the hub and rotor assembly via rotor mounting bolts and a stationary component is disposed on the axle tube to provide a rotary air coupling that minimizes change to existing wheel assemblies.