Patent ID: 8225831

Claim:
A pneumatic tire having a tread surface comprising: at least two circumferential grooves extending in the tire circumferential direction to define land sections respectively on the outer sides in the tire width direction; lateral grooves extending in the tire width direction to partition the land sections into a plurality of blocks; and a cutout having a plurality of steps in the tire width direction formed in an edge portion of each of the blocks, the edge portion facing a corresponding one of the circumferential grooves, wherein each cutout is formed to have two steps, wherein the ratio N 1 /N of N 1 to N is set in a range from 0.40 to 0.60, while the ratio N 2 /N of N 2 to N is set in a range from 0.30 to 0.50, where N 1 represents the length, in the tire circumferential direction, of a first step, on the groove bottom side of the corresponding circumferential grooves, of each cutout; N 2 represents the length, in the tire circumferential direction, of a second step of each cutout; and N represents the length, in the tire circumferential direction, of each block, and wherein the ratio P 1 /P of P 1 to P is set in a range from 0.60 to 0.80 while the ratio P 2 /P of P 2 to P is set in a range from 0.45 to 0.65, where P 1 represents the depth, from the tread surface, of the first step, on the groove bottom side of the corresponding circumferential grooves, of each cutout; P 2 represents the depth, from the tread surface of the second step of each cutout; and P represents the depth of each of the circumferential grooves.