Patent ID: 8720506

Claim:
A pneumatic tire having, in at least a part of a tread portion, a block group formed by arranging blocks close to each other, the blocks being defined by grooves and being independent of each other, wherein, when a symbol P (mm) stands for a reference pitch length of the blocks in the block group, a symbol W (mm) stands for a width of the block group, a symbol a (pieces) stands for the number of the blocks existing in a reference zone of the block group, the reference zone being comparted by the reference pitch length P and the width W, and a symbol N (%) stands for a negative ratio in the reference zone, a block number density S, which is the number of the blocks per unit of an actual ground contact area of the block group and given by a formula of S=a/{P×W×(1−N/100)}, is set within a range of not less than 0.003 (pieces/mm 2 ) but not more than 0.04 (pieces/mm 2 ), the distance (BGL) between the blocks adjacent to each other in the tread circumferential direction is larger than the distance (BGO) between the blocks adjacent to each other in a direction diagonal to the tread circumferential direction, the distance (BGW) between the blocks adjacent to each other in the tread width direction across the groove between the blocks adjacent to each other in the tread circumferential direction is smaller than the length (BW) of each of the blocks in the tread width direction.