Patent ID: 8910682

Claim:
A pneumatic tire comprising: a tread portion provided with a circumferential main groove extending in a circumferential direction of the tire at a location distant from the tire equator toward an axially outer side thereof, said circumferential main groove having a profile shape such that, in a meridian cross section of the tire including the rotation axis of the tire in a standard state that the tire is mounted on a standard rim and inflated to a normal inner pressure and no load is applied to the tire, the profile shape includes an inner wall portion extending radially inwardly from an axially inner edge of the groove on a tire equator side, an inner arc portion continuous with said inner wall portion and having a smaller radius of curvature than that of said inner wall portion, an outer wall portion extending radially inwardly from an axially outer edge of the groove on a tread edge side and having a smaller length than that of said inner wall portion, an outer arc portion continuous with said outer wall portion and having a smaller radius of curvature than that of said outer wall portion, and a groove bottom portion extending straight from said outer arc portion toward said inner arc portion while being inclined in a radially inward direction, wherein said circumferential main groove has a maximum depth portion on a tire equator side of a center position of its width, wherein said inner arc portion has a radius of curvature R 1 and said outer arc portion has a radius of curvature R 2 that satisfy the following relationships: R 1 ≧0.6 mm, and R 2 ≧2×R 1 , and wherein on the tread edge side of said circumferential main groove, a plurality of shoulder blocks are disposed circumferentially of the tire, and with respect to each said shoulder block, the radius of curvature R 2 is gradually decreased from a center portion toward both end portions of the block in the tire circumferential direction.