On a tire inner surface “is” facing a tire cavity “i” surrounded by a rim 2 and a pneumatic tire 3, the tire is provided with a noise damper 4 made of a spongy material and extending in the circumferential direction of the tire. Noise dampers 4 having the same cross sectional shape are used in a size group of tires which include a minimum volume tire that the cross sectional area S of the tire cavity on the meridian cross section has a minimum value Smin and a maximum volume tire that the cavity cross section area S has a maximum value Smax, and which have sizes such that the cavity sectional area ratio Smax/Smin falls within the range of 1.00 to 1.95.