An apparatus and method for filling a tire and wheel assembly cavity, that can be a large tire and wheel, with a flexible closed cell polyurethane foam that is passed as a mixture of reacting constituents through a fill hose whose end is fitted between the tire bead and wheel rim, and after filling and removal of the fill hose end, providing for lifting and maintaining the tire bead in engagement with the wheel rim as the reacting materials complete their reaction, uniformly filling the tire and wheel cavity with the flexible closed cell polyurethane foam that has expanded and urges the tire bead into sealing engagement with the wheel rim.