Patent ID: 9221303
Filing Date: 2015-12-29
Classification: B60C

Abstract:
1. A pneumatic tire having an intended tire rotational direction and comprising a tread portion provided with a tread pattern defined by tread grooves and having a tread pattern center line positioned at a certain distance from the tire equator of not more than 15% of a tread width, the tread grooves including major oblique grooves and minor oblique grooves disposed on each side of the tread pattern center line, wherein each of the major oblique grooves extends toward the opposite direction CR to the intended tire rotational direction from its axially inner closed end at a first axial position to its axially outer open end opened in a tire shoulder, while increasing its angle θ with respect to the tire circumferential direction, and each of the minor oblique grooves extends toward the opposite direction CR to the intended tire rotational direction from its axially inner closed end at a second axial position axially outside the first axial position to its axially outer open end opened in the tire shoulder, while increasing its angle β with respect to the tire circumferential direction, wherein the major oblique grooves on one side of the tread pattern center line are circumferentially shifted from the major oblique grooves on the other side of the tread pattern center line so that the major oblique grooves are arranged staggeredly on both sides of the tread pattern center line, on each side of the tread pattern center line, a plurality of the minor oblique grooves are disposed between every two of the circumferentially adjacent major oblique grooves, without intersecting the major oblique grooves, on each side of the tread pattern center line, if the axial width between the center line and a zero-camber tread edge is partitioned into five equi-width zones which are 1st to 5th zones in this order from the center line, the angle θ of each of the major oblique grooves satisfies the following equations (1) and (2): wherein θ1 to θ5 are mean values of the angle θ in the 1st to 5th zones, respectively, and the major oblique grooves respectively have largely bent points, at which the angle θ changes at least 30 degrees, and which are positioned in one of the 1st zone and 2nd zone, and wherein the part of the major oblique groove located on the center line side of the largely bent point has a circumferential length Li in a range of from 0.7 to 1.5 times the circumferential pitch length Lp between the circumferentially adjacent major oblique grooves.