Abstract: An improved inflation pressure regulator is disclosed of the type which automatically releases pressure above a predetermined maximum during inflation of a vehicular tire. The regulator, which is particularly suitable for use with low capacity tires and for use with high capacity air pumps, comprises a generally tubular housing adapted to be coupled between a vehicular tire and a source of compressed air. A substantially friction-free flexing seal arrangement within the housing couples the air source to an exhaust aperture and bypasses the tire when the pressure within the tire reaches a predetermined level. The use of a flexing seal substantially reduces seal wear and thus reduces seal leaks and minimizes variations in the regulator rating over the life of the regulator.