| 摘要 |
PURPOSE: To compatibly realize the riding comfort and the braking performance by making the ratio of the modulus in the width direction of a base rubber layer arranged on a carcass side of a cap rubber layer to the modulus in the circumferential direction larger at the equatorial part of the tire than that of the tread shoulder part. CONSTITUTION: A belt layer 18 is provided on the outer side in the radial direction of a crown part of a carcass 14 across beads 12, a tread 20 is provided on the outer side thereof, and the tread is of double-layered structure of a cap rubber 20A on the tread side and a base rubber 20B on the carcass 14 side. The ratioηof the modulus in the circumferential direction to the modulus in the width direction at the base rubber 20B is made larger at the equatorial part of the tire than at the tread shoulder part. Thus, the shearing rigidity in the circumferential direction on the equatorial part side where the contribution to the braking performance is high becomes higher while the bending rigidity on the shoulder part side where the contribution to the riding comfort is high becomes lower, and the braking performance and the riding comfort are compatibly realized.
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