| 摘要 |
PURPOSE:To reduce pattern noise and improve comfortability, by combining a plurality of main grooves on a tire tread with a plurality of sub grooves, and making a width of the sub grooves near tread side edges smaller than a width of the sub grooves at a tread central portion and near side walls. CONSTITUTION:Main grooves 6-9 are combined with sub grooves 11 and 12, and simultaneously the main grooves 6 and 9 are combined through sub grooves 10 with side walls 5, respectively. An angle theta of the sub grooves 10-12 relative to a circumferential direction of a tire is set to a value not more than 65 deg., and an opening width (a) of the sub grooves 10 and 11 opening to the main grooves 6 and 9 near tread side edges is set to a value smaller than an opening width (b) of the sub grooves 11 and 10 opening to a tread central portion A and the side wall portions 5 side, respectively. Thusly, the sub grooves 10 and 11 are made tapering, and it is possible to improve continuity in rigidity of block portions and sub groove portions in a block pattern. Accordingly, it is possible to reduce pattern noise due to discontinuity in rigidity and improve comfortability. |
