A tire and wheel rim assembly includes a tire supporting rim having an outward facing mounting surface; a tire mounted to the rim positioning an internal tire cavity over the rim mounting surface; a passageway extending through the rim for communicating air pressure between the tire cavity and a side of the rim opposite the tire cavity; and means for controllably regulating the flow of air through the passageway. A connecting member such as a bolt may extend through the rim outside mounting surface to affix a tire pressure monitoring housing to the rim and the axial passageway through the rim may be an axial bore through the bolt. Regulation of air flow through the passageway may be effected by setting the diameter of the passageway sufficiently small; or incorporating a needle orifice in the passageway; or incorporating a porous insert body into the passageway. The insert body may be composed of sintered metal and may be fused to the internal sidewalls of the bolt.