The present invention provides an assembly of a tire and a rim, which assembly has on the tire inner cavity side thereof a sound absorbing member capable of effectively suppressing cavity resonance and reducing road noise, while suppressing increase in weight of the tire and increase in volume of the sound absorbing member. In this assembly of a tire and a rim, the sound absorbing member is mounted on the inner cavity side of the tire as a sound absorbing layer for suppressing cavity resonance inside the tire. The sound absorbing member is unwoven cloth made of plural fibers, and the average distance d between fibers constituting the unwoven cloth is within the range of 0.50δ to 4.00δ.