PURPOSE: To have compatibility between a grip property and an abrasion resistance property by specifying respectively a ratio between effective ground areas in the left and right of a tread part, and a difference in respective outer diameter dimensions of the tread part and shoulder part when a prescribed maximum load is eliminated from a tire.

CONSTITUTION: In a tire 10, there is a tread pattern including a plurality of grooves 12 extending in a tire circumferential direction and a plurality of grooves extending in the direction crossing therewith. And in the tread pattern, left and right parts 20, 22 in relation to a tread center 18 are formed in respective shapes different from each other. In this occasion, the ratio RT between respective effective ground areas RL and RR of left and right parts 20, 22 in the condition when a prescribed maximum load is applied on the tire 10, is set so as to satisfy 0.85<RT<0.98. In addition, a difference Dc-Ds between respective outer diameter dimensions Dc and Ds of a tread part and a shoulder part, is set so as to satisfy 4.0mm<Dc-Ds<12.0mm.