A main tire body, mounted to the rim (3) of a wheel, includes in one embodiment, an annular tire material (6) and a fiat wound spring ring (8) disposed within the annular tire material (6). The annular tire material (6) is a material with a cross section that can form in a semi-circular annular space (7) between the rim (3). The flat wound spring ring (8) a is annularly arranged within the annular space (7). In another embodiment, the main tire body includes an annular first tire material (10), a second tire material (11), and a plurality of airtight chambers (15) which help to absorb impacts. The first tire material (10) is mounted to the rim (3). The second tire material (11) is an annular material with an elastic body attached to the outer peripheral side of the first tire material. The airtight chambers portion (15) are formed in the second tire material between the first tire material. In another embodiment, the main tire body includes an annular first tire material (20), and a second tire material (21). The second tire material (21) is an annular material with an elastic body attached to the outer peripheral side of the first tire material. An airtight annular chamber (22) is formed between the first tire material (20) and second tire material (21). A flat spring ring (24) disposed within the annular chamber (22) to absorb impacts.