| 摘要 |
PURPOSE:To improve the acoustic tone-quality of pattern noise by providing linear or zigzag main grooves in the circumferential direction, forming plural number of ribs conforming to specified conditions in a tread ground contact area under a JIS standard internal pressure, load, and making the types of arrangements of pitch elements plural. CONSTITUTION:Linear main grooves 2 are provided on the tread surface T in the circumferential direction EE', and ribs 3, 4, 5 whose maximum depth are formed in a tread ground contact area W1 under a JIS standard internal pressure, load. Further, sub-grooves 6, 6' are provided across the tire width on the ribs 3, 4 at uneven intervals along the circumferential direction. Thus, blocks 7 partitioned by the sub-grooves are arranged as pitch elements in a specified order, and at least two types of arrangements are obtained. As a result, the acoustic tone-quality of patter noise can be improved. |
