| 摘要 |
PURPOSE:To reduce pattern noise by arranging at least three types of pitches in specified order, which are composed of two blocks, namely larger and small ones in the circumferential direction of a tire, and thereby specifying a ratio of a maximum pitch length to a minimum pitch length. CONSTITUTION:The tread pattern of a tire is composed of longitudinal grooves 1 extending in the circumferential direction E through E of the tire, lateral grooves 2 crossing the circumferential direction of the tire, and of blocks 3 partitioned by these respective grooves 1 and 2. In this case, at least three types of pitches A through C are arranged in the tire. And each of pitched A through A is composed of two blocks 3 which are large and small having specified lengths a1, a1, b1 through b3, and b3 respectively in the circumferential direction. In addition, each pitch A through C is arranged in the circumferential direction in order of the magnitude of a ratio a1/b1 through a3/b3 of the large block 3 to the small block 3 in the circumferential length. Furthermore, a ratio of a maximum pitch length a1 to a minimum pitch length b3 is set to be 1.2 to 1.6. |
