| 摘要 |
PROBLEM TO BE SOLVED: To improve the CF characteristic while keeping the superior low noise and the wet performance, by forming at least rows of blocks partitioned by longitudinal grooves and lateral grooves, at both sides of an equatorial plane more than one row, under the conditions that each block has specific block length under specific arrangement pitches, and the specific numbers of long blocks and short blocks are alternately arranged. SOLUTION: At least one row of a number of blocks is respectively partitioned at both sides gripping an equatorial plane (central periphera line E), by the lateral grooves 3, 4 and the longitudinal grooves 5, 6. The rows of blocks 7, 8 are positioned near the central peripheral line E, and the rows of blocks 9, 10 are positioned near the edges TE. Each block comprises two kinds of arrangement pitches, that is, the pitches PL of larger arrangement pitch and the pitches PS of smaller arrangement pitch. The arrangement of the block is formed by alternately arranging up to two long blocks 9 and up to two short blocks 8, and the rows of the blocks 9, 10 at the both sides, are similarly formed. The wet performance and the low noise, can be kept, and the CF characteristic (grip performance) can be remarkably improved by the alternate arrangements of the large and small blocks on the basis of the large and small pitches. |
