| 摘要 |
PROBLEM TO BE SOLVED: To significantly improve performance on ice and snow and keep balance of performance with the other performances by achieving an appropriate tread pattern. SOLUTION: Two or more of block group G<SB>B</SB>formed by densely arranging a plurality of independent blocks 3 which are divided by grooves are provided in a tread part 1. Where a reference pitch length of the block 4 in the block group G<SB>Bn</SB>is PL (mm), the width of the block group is W (mm), the quantity of the blocks existing in a reference zone, partitioned by the reference pitch length P and the width W, of the block group G<SB>B</SB>is a (piece), and the negative rate in the reference zone is N(%), a block-quantity density D (quantity/mm<SP>2</SP>) of each block group given by a/(PL×W×(1-N/100)) comprises two or more types of block-quantity density, and within the range of 0.003 to 0.04 (quantity/mm<SP>2</SP>). COPYRIGHT: (C)2011,JPO&INPIT |
