Disclosed is a tire wheel assembly allowed to enhance working efficiency in rim assembling without destabilizing mounting of a run-flat support member, and furthermore, allowed to realize noise reduction by improving a vibration characteristic during normal traveling. The tire wheel assembly is one where, while a pneumatic tire is fitted to a rim of a wheel, inserted into a cavity portion of the pneumatic tire is a run-flat support member formed of a pair of elastic rings fitted to the rim; and an annular shell straddling between the elastic rings. In the tire wheel assembly, inner diameters of the pair of elastic rings are made different from each other to make an inner diameter of one elastic ring fitted to the rim in a back side of the wheel smaller than an inner diameter of the other elastic ring fitted to the rim in a front side of the wheel.