Patent ID: 6026874
Filing Date: 2000-02-22
Classification: B60C

Abstract:
A pneumatic tire comprising:a tread portion with a ground contacting area, the ground contacting area having a sea/land ratio in the range of 0.30 to 0.50,said tread portion provided with a single circumferential groove having a pair of sidewalls defining two lateral portions on each side of the circumferential groove,said circumferential groove being disposed within the ground contacting width of the tread portion in the axial direction of the tire,the ground contacting width being the maximum axial width of the ground contacting area of the tread portion under a standard loaded state where said 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 thatthe axial width of said circumferential groove is in the range of from 0.2 to 0.35 times the ground contacting width,said circumferential groove having edges and being the only groove which extends continuously in the tire circumferential direction, andeach said sidewalls has a plurality of inwardly protruding parts so thatthe width of the circumferential groove is periodically decreased in the longitudinal direction thereof so as to form narrow width portions having a first positive circumferential length, wide width portions with a second positive circumferential length and intermediate portions respectively connecting each of the wide and narrow width portions, along said longitudinal direction,the width at each said narrow width portion is more than 0 but not more than 0.8 times the maximum width of the circumferential groove, andthe maximum width of the circumferential groove is in the range of from 30 to 70 mm, andthe protruding parts provided on one of the sidewalls are circumferentially shifted from the protruding parts provided on the other sidewall, whereby the configuration of the circumferential groove is not symmetrical about the center line thereof wherein the edges of the circumferential groove in each of said narrow width portions and said wide width portions are substantially parallel to the circumferential direction, each narrow width portion is defined by only one of said protruding parts, and the second positive circumferential length of each of the wide width portions is greater than the first positive circumferential length of each of the narrow width portions.