Patent ID: 8205651

Claim:
A pneumatic tire comprising: a tread surface; a first main groove extending in a circumferential direction of the tire and being provided in the tread surface; first lateral grooves extending from the first main groove outward in a widthwise direction of the tire beyond one ground contact end of the tire and being disposed at prescribed intervals in the circumferential direction of the tire; blocks being defined by the first main groove and the first lateral grooves; wherein the first lateral grooves include inner groove portions and outer groove portions, with boundary positions therebetween, the inner groove portions having widths, the inner groove portions extending with the widths gradually increasing from the first main groove outward in the widthwise direction of the tire to the boundary positions of the first lateral grooves in an inclined manner toward one side of the circumferential direction of the tire, the outer groove portions having widths, the outer groove portions extending with the widths gradually decreasing from the boundary positions outward in the widthwise direction of the tire, the outer groove portions also extending beyond the one ground contact end of the tire in an inclined manner toward the other side of the circumferential direction of the tire; and wherein a circumferential narrow groove, which extends in the circumferential direction of the tire and is less in width than the first main groove, is disposed at the boundary positions between the inner groove portions and the outer groove portions, wherein the pneumatic tire has a specified vehicle-mounting direction, the tread surface having a vehicle inner side region located on a vehicle inner side of an equatorial plane of the tire when the tire is mounted on a vehicle, and a vehicle outer side region located on a vehicle outer side of the equatorial plane of the tire is mounted on the vehicle, the first main groove and the first lateral grooves being disposed in the vehicle outer side region of the tread surface.