The present invention relates to a tire noise reducing system comprising a pneumatic tire, a wheel rim on which the pneumatic tire is mounted, and a noise damper disposed in a cavity surrounded by an inner surface of the rim and an inner surface of the tire mounted thereon, wherein the noise damper has a volume V2 which is from 0.4 to 20% of the volume V1 of the cavity, and the noise damper is made of a porous material having a hardness of from 10 to 80 N, a tensile strength of not less than 70 kPa and a specific gravity of from 0.014 to 0.026.