| 摘要 |
PROBLEM TO BE SOLVED: To improve various performance by gradually decreasing the inclina tion in relation to the tread periphery of a curved line connecting the width centers of a first main groove and a second main groove at the specified posi tion in the specified range, making the block edge and the sipe edge into the length in the specified range, and setting the negative ratio of the tread and the specified % modulus of the tread rubber into the specified range. SOLUTION: The inclinationsθ1 ,θ2 in relation to the tread circumference, of curved lines connecting respective width centers of first main grooves 2 and second main grooves 3 are gradually decreased from respective ends to the tread width center in the range of 90 to 40 deg., and they are gradually decreased from the tread width center to the vicinities of respective edges in the range of 50 to 10 deg.. The edges of blocks B1 , B2 and the edges of sipes S are formed into the length three to ten times on the equatorial plane and five to fifteen times on the meridian section by the magnification corresponding to the block arrangement pitch length of the total length projected to the tire equatorial plane and the tire meridian section. The negative ratio of a tread 1 is in the range of 35 to 45%, and the 300% modulus of the tread rubber is in the range of 40 to 110kgf/cm<2> . |
