This invention relates to a tire-rim assembly which is easily produced at low cost, excellent in durability and capable of notably reducing road noise, and more particularly to a tire-rim assembly comprising a pneumatic tire (1), a rim (2) and a sponge member (4) disposed in a tire internal cavity (3) defined by the pneumatic tire (1) and the rim (2), characterized in that the sponge member (4) has a specific gravity of higher than 0.06 but not higher than 0.25 and/or an air permeability of not higher than 5 cc/cm2/sec.