Patent ID: 7607464

Claim:
A pneumatic tire wherein a tread surface comprises: a pair of circumferential grooves continuously extending in a tire circumferential direction in both sides of a tire equator; a plurality of oblique grooves having a steep decline portion extending to an outer side in a tire axial direction while being inclined at an angle between 15 and 45 degrees with respect to the tire circumferential direction from a position apart from a circumferential groove of said pair of circumferential grooves at a small distance, and provided away from each other in the tire circumferential direction; and a land portion surrounded by said circumferential groove and two of said steep decline portions adjacent thereto in the tire circumferential direction, wherein said land portion has an acute corner portion between said circumferential groove and one of said steep decline portions, and an obtuse corner portion between said circumferential groove and another of said steep decline portions, wherein an outer groove wall surface in an outer side in a tire axial direction of said circumferential groove comprises: a gentle decline wall extending from a nodal line in which the outer groove wall surface and said tread surface intersect, toward an inner side in a tire radial direction so as to be inclined to an inner side in the tire axial direction; and a steep decline wall extending from an inner end in the tire radial direction of said gentle decline wall to a groove bottom side, wherein said inner end of said gentle decline wall is formed in a wavy shape in which an inclined surface width corresponding to a distance in the tire axial direction from the inner end to said nodal line repeats increasing and decreasing in the tire circumferential direction, and wherein each innermost point of the inner end at which said inclined surface width of said gentle decline wall becomes maximum is positioned in a region between a middle position between a leading end of said acute corner portion and a leading end of the obtuse corner portion, and the leading end of said acute corner portion.