A pneumatic tire and wheel rim assembly is disclosed in which the rim bead seats are provided with retaining means for retaining the associated tire bead therein. Preferably the bead seats comprise grooves the side portions of which are provided with the retaining means comprising projections such as teeth which engage and retain the associated tire bead in the groove. Alternatively the retaining means comprises retaining members each of which extends across the width of the associated groove through the tire bead to retain the bead in the groove. Preferably the rim is multi-component to facilitate assembly.