A pneumatic tire assembly comprising a rim, a pneumatic tire that has a double structure including an outer tire and an inner tire inserted thereinto, and is assembled with the rim, and air chambers formed inside and outside the inner tire, wherein the rim includes a pair of bead seats on which bead portions of the outer tire and the inner tire are placed, a first rim flange protruding outward in a diameter direction of the tire from a side end of the bead seat, a second rim flange disposed inside the first rim flange in a rim width direction and formed on at least one of the bead seats while protruding therefrom, and an air valve provided to the second rim flange, the outer tire is held by the first rim flange and the second rim flange with the bead portion thereof being nipped therebetween, the inner tire is mounted with the bead portion thereof being in internal contact with the second rim flange, and in an outer wall surface area of the inner tire extending outward from a position of a maximum height of the second rim flange in a diameter direction of the tire, a groove portion for feeding air supplied via the air valve into the air chamber formed outside the inner tire is formed into a concave shape.