An air retaining and bead-seat-lock device for pneumatic tire wheels is provided having air retaining engagement with an aperture in a tire rim adjacent the seated tire bead, and having two positions of operative engagement with the rim, one position disposing the inner end of the device substantially flush with the inner rim surface facilitating air-pressure seating of the tire bead against the rim flange, and the other position disposing an end to protrude beyond the inner rim surface adjacent the tire bead to support the same in seating engagement with the rim flange. In its simplest form the device comprises an elongated threaded shank closely fitting a threaded aperture in the rim and having an enlarged head externally of the rim adapted for clamping an air sealing gasket against the rim, and being movable between the first and second positions by rotating the threaded shank to appropriately position its inner end. In another adaptation of the invention the device is intended for reversible positioning with respect to the rim and is provided with a central wrench engaging enlargement with threaded studs at each side thereof of a length to extend through a sealing gasket and the rim wall, with the stud at one side having an unthreaded extension adapted to protrude at least 1/2" beyond the inner rim surface. In a preferred adaptation of the invention, the device comprises an axially movable cylindrical shank passing through an externally threaded stud secured outwardly of the tire rim in alignment with the aperture therein, said stud carrying clamping means for a packing element circumferentially of said shank for air sealing and axial positioning of said shank.The device is used in pairs, axially aligned on the rim adjacent the opposed rim flanges with two or more pairs being employed at uniformly spaced intervals circumferentially of the rim.