PNEUMATIC TIRE

A pneumatic tire which has improved drainage property on a wet road surface and improved uneven wear resistance and steering stability on a dry road surface while enhancing drainage property on a wet road surface. The tire has at least a pair of circumferential grooves 2 disposed at a tread portion 1. An inner land portion 3 and an outer land portion 4 are defined by outermost circumferential grooves 2a. A plurality of transverse grooves 5 are disposed on at least the outer land portion 4 and the outer land portion 4 is divided and formed into a large number of blocks by these transverse grooves 5. The width W 1 of the groove bottom 6 of the outermost circumferential groove 2a is narrower than the opening width W 2 . The groove bottom extends with inclination with respect to the tire circumferential direction so that it substantially continues to the transverse groove between the adjacent transverse grooves. The groove bottom forms the zigzag shape as a whole. The outermost circumferential groove 2a has chamfered parts 10, 11 on each of the inner and the outer groove walls 7, 8 which is inclined with certain angles ¸ 1 , ¸ 2 from the opening end edge 9a, 9b toward the groove bottom 6, respectively. The chamfered widths C 1 , C 2 of the chamfered parts are gradually increased in the opposite orientations in the circumferential direction.