Pneumatic tire having directional tread pattern

A pneumatic tire in which a plurality of inclined main grooves are disposed in a tire circumferential direction from positions spaced apart from one another at both sides of a tire equatorial plane toward tread end sides so as to extend in opposite directions at either side of the tire equatorial plane and so as to be inclined with respect to the tire circumferential direction, wherein

• from a tire equatorial plane side to a vicinity of a tread end side, each of said inclined main grooves extends at an angle of inclination of 15 to 45° with respect to the tire circumferential direction,
• at a vicinity of a tread end side final end, each of said inclined main grooves extends at an angle of inclination of 75 to 105° with respect to the tire circumferential direction, and opens with a narrow width at a tread end,
• at a vicinity of a tire equatorial plane side final end, each of said inclined main grooves extends, in a circular-arc-shape convex toward a tire equatorial plane side, toward an intermediate portion of an inclined main groove which is adjacent in the tire circumferential direction, so as to open at the adjacent inclined main groove,
• at a tread side region, said inclined main grooves which are aligned in the tire circumferential direction are communicated by auxiliary grooves which are more narrow than said inclined main grooves,
• a rib which is continuous along the tire circumferential direction is defined on a tire equatorial plane, and a plurality of blocks which are aligned in the tire circumferential direction are defined at both sides of the rib, and
• at each of said blocks which are disposed from a tread center to said auxiliary grooves, a rigidity of a step-in end of said block is set to be lower than a rigidity of a kick-out end of said block, and at each of said blocks which are disposed from said auxiliary grooves to tread ends, a rigidity of a kick-out end of said block is set to be lower than a rigidity of a step-in end of said block.

A pneumatic tire in which a plurality of inclined main grooves are disposed in a tire circumferential direction from positions spaced apart from one another at both sides of a tire equatorial plane toward tread end sides so as to extend in opposite directions at either side of the tire equatorial plane and so as to be inclined with respect to the tire circumferential direction, wherein

• from a tire equatorial plane side to a vicinity of a tread end side, each of said inclined main grooves extends at an angle of inclination of 15 to 45° with respect to the tire circumferential direction,
• at a vicinity of a tread end side final end, each of said inclined main grooves extends at an angle of inclination of 75 to 105° with respect to the tire circumferential direction, and opens with a narrow width at a tread end,
• at a vicinity of a tire equatorial plane side final end, each of said inclined main grooves extends, in a circular-arc-shape convex toward a tire equatorial plane side, toward an intermediate portion of an inclined main groove which is adjacent in the tire circumferential direction, so as to open at the adjacent inclined main groove,
• at a tread side region, said inclined main grooves which are aligned in the tire circumferential direction are communicated by auxiliary grooves which are more narrow than said inclined main grooves,
• a rib which is continuous along the tire circumferential direction is defined on a tire equatorial plane, and a plurality of blocks which are aligned in the tire circumferential direction are defined at both sides of the rib, and
• given that an angle of inclination of a groove wall surface of said inclined main groove at a block step-in end side with respect to a normal line which passes through an opening end of said inclined main groove and is perpendicular to a tread stepping surface is θ1 and an angle of inclination of a groove wall surface of said inclined main groove at a block kick-out end side with respect to a normal line which passes through an opening end of said inclined main groove and is perpendicular to the tread stepping surface is θ2, θ1<θ2 from a tread center to said auxiliary groove and θ1>θ2 from said auxiliary groove to the tread end.