| 摘要 |
A heavy duty pneumatic radial tire including a pair of bead portions, a carcass consisting of one steel cord layer and extending between the bead portions, and a tread portion arranged radially outward of a crown portion of the carcass. A normal rim on which the tire is mounted has a bead base at an angle of approximately 5 DEG relative to a rotating axis of the tire and engaging the bead portions of the tire. During filling the tire with inner pressure from 7% to 100% of a determined maximum inner pressure of the tire, a ratio A/B of an enlargement amount A of a shoulder in radial and outward directions to an enlargement amount B of the bead portion in axial and outward directions is within 0.35-0.8, preferably 0.4-0.65, where a radial and outward displacement of a shoulder positions J on the shoulder spaced by 10 mm from each end of said tread toward an equatorial plane of the tire is taken as the enlargement amount A of the shoulder in the radial and outward directions, and an axial outward displacement of a bead position K on the bead portion at a height of 27% of a tire sectional height H from a bead heel is taken as the enlargement amount B of the bead portion in axial outward directions. |
