| 主权项 |
1. A pneumatic tire comprising:
one first main groove that extends in a circumferential direction of the tire on each side of a tire equatorial plane on a tread surface, one second main groove that extends in the tire circumferential direction formed on the outward side of each first main groove, and five land portions that are formed by the four main grooves, wherein these five land portions are formed from: a center land portion positioned between the first main grooves, two middle land portions located between the first main grooves and the second main grooves, and two shoulder land portions located to the outside in the tire width direction from the second main grooves, each of the land portions having sub-grooves and sipes formed therein, wherein a combined groove surface area ratio of the sub-grooves and the sipes in each of the land portions is different in the center land portion and the shoulder land portions, as compared to the middle land portions; the groove surface area ratio of the center land portion and the shoulder land portions being lower, and the groove surface area ratio of the middle land portions being higher, the sub-grooves of the middle land portions comprise:
third sub-grooves that extend from the first main groove to the second main groove in the tire width direction, wherein the third sub-grooves are located at a prescribed interval in the tire circumferential direction,fourth sub-grooves that extend from the second main groove to a halfway region of the middle land portion in the tire width direction,the middle land portion is formed into blocks demarcated by the first main groove, the second main groove, and the third sub-grooves, and one of the fourth sub-grooves is formed in each block, and sipes in the middle land portion include third sipes that extend from the inner edge of the fourth sub grooves to the first main groove in the tire width direction and a fourth sipe that transects each block in the tire circumferential direction. |
