Abstract: A device for maintaining a desired inflation pressure within the tire utilizes a motor and air compressor disposed upon the rotating wheel to eliminate the requirement for a rotary pneumatic joint. The air compressor provides a source of air for maintaining inflation pressure and is driven by a DC motor. The motor is, in turn, driven by a generator which is partially disposed upon the rotating wheel and partially disposed upon a non-rotating portion of the vehicle. A stationary magnet attached to a non-rotating portion of the vehicle defines the generator's stator. Windings which define the generator's armature are formed upon a substrate which is applied to the rotating wheel such that the windings pass within close proximity to the stationary magnet. The air compressor may alternatively be mechanically driven directly by the rotation of the wheel.