Pneumatic tire

A pneumatic tire comprising:

• a tread portion,
• said tread portion provided with a circumferential groove having a pair of sidewalls and a center line located substantially equidistant from and between the two sidewalls,
• said circumferential groove being disposed within the ground contacting width of the tread portion in the axial direction of the tire and defined by a plurality of straight segments with parallel walls that are angled with respect to the tire equator, he straight segments being disposed in series to form a continuous zig-zag shape thereby with a plurality of axially spaced peak points located on the groove center line at each interconnection of the straight segments,
• the ground contacting width being the maximum axial width of the ground contacting area of the tread portion under a standard loaded state where the standard loaded state is such that the tire is mounted on a regular rim, inflated to 70% of its maximum air pressure and then loaded with 88% of its maximum load, characterized in that
• the axial width of said circumferential groove being in the range of from 30 to 70 mm and also in the range of from 0.2 to 0.35 times the ground contacting width, and
• the circumferential groove satisfies the following condition:
• ##EQU4## wherein A is the axial distance between a first and a second circumferentially adjacent peak points on the center line of the circumferential groove,
• p is the circumferential distance between said first and second peak points, and
• W is the width of the circumferential groove measured at a right angle to the center line thereof,
• said circumferential distance (P) being in the range of from 0.8 to 3 times the ground contacting length, and
• the ground contacting length being the maximum circumferential length of said ground contacting area.