Patent ID: 9259971
Filing Date: 2016-02-16
CPC Classification: B60C,Y10T

Claim Text:
1. A pneumatic tire having a carcass layer, a belt layer disposed on an outer side in a tire radial direction of the carcass layer, a tread rubber disposed on an outer side in the tire radial direction of the belt layer, at least three circumferential main grooves extending in a tire circumferential direction, and a plurality of land portions defined by the circumferential main grooves, wherein the belt layer includes: an inner-side cross belt and outer-side cross belt having belt angles of not less than 46° and not more than 80° as absolute values with respect to the tire circumferential direction, the belt angles having mutually opposite signs; a circumferential reinforcing layer having a belt angle satisfying a range of ±5° with respect to the tire circumferential direction and disposed between the inner-side cross belt and outer-side cross belt; and a supplemental belt having a belt angle of not less than 10° and not more than 45° as an absolute value with respect to the tire circumferential direction and disposed on an outer side in the tire radial direction of the outer-side cross belt, the supplemental belt and the outer-side cross belt having belt angles of mutually opposite signs; wherein a difference Dr=R1−R2 between a radius R1 of the circumferential reinforcing layer at a tire equatorial plane and a radius R2 at an outer end portion in a tire width direction of the circumferential reinforcing layer, and the width Ws of the circumferential reinforcing layer have a relationship such that −0.010≦Dr/Ws≦0.010.