Abstract: Land transportation vehicles using pneumatic tires loose air over time, including tractor trailers, private vehicles, race cars and other vehicle classifications. Tire pressure is important, but only a small number of attendants are concerned. Our invention is an automatic device which supplies air to tractor trailer tires using an onboard air supply. This air, supplied to the rotary air chamber system can be adjusted to a desired tire air pressure by the individual driver to suitable levels of load weights, climates, travel speed and terrain. Rotating tires at high speeds build up friction raising tire pressure to dangerous levels. This will be corrected by built in relief valves. To maintain and verify tire pressures each tire is protected by check valves and visible pressure gauges. The rotary air chamber automates, corrects continuously the neglect of proper tire maintenance, adds road safety for users and public alike.