Abstract: An air inflation system is provided for a vehicle including an axle that supports a wheel and an air supply structure. The air inflation system includes a rotary coupler having a tubular member for communicating with the air supply, a sleeve member connected to an end portion of the tubular member, a bearing receiving the sleeve member, a housing body having a passageway therethrough, wherein the tubular member is received in the passageway, and a housing cap attached to the housing body, wherein the housing cap is provided for communicating with at least one air connection element in communication with the wheel. A first seal for sealing an area between the tubular member and the housing body, and a second seal for sealing an area between the housing body and the housing cap are included. The rotary coupler is provided for supplying air from the air supply to the wheel.