Patent attributes
A custom valve stem is adapted to fit in a conventional valve stem opening in a tire rim. The valve stem has a primary air channel for a conventional Schrader-type valve. The valve stem also has a secondary air channel extending within the valve stem between a base of the valve stem and an outlet through the material of the valve stem to atmosphere outside of the valve stem. The outlet can have a screen as a debris air filter. An optional tire pressure monitoring system TPMS sensor couples to the primary air channel independent of the secondary air channel. The secondary air channel comprises an atmospheric hose coupled to an electric air compressor and rechargeable battery disposed within a pressure cavity of the tire for maintaining tire pressure. A motion activated power generator disposed within the pressure cavity recharges the rechargeable electric storage.