| 摘要 |
PURPOSE:To reduce the extent of wear in the center of a tread, by constituting it in setting up each thin nick, whose both ends are connected to main grooves, in each land part of a tread center part sandwiched between main grooves at the outermost side at the specified pitch, in case of the tread provided with more than two main grooves. CONSTITUTION:A tread 2 is divided into tread shoulders 5 and a tread center part 6 by plural numbers, for example, four main grooves 3. And, three land parts 6a-6c are formed in this tread part 6. Each nick 7 of about 0.3mm-1.5mm in thickness U, tilted at a tilt angle X of about 0-+ or -45 deg. to a tire turning axis O and of a circumferential pitch P of 5-15% in tread width is formed in these land parts 6a-6c so as connect three main grooves. With this constitution, wear in the tread center is prevented from occurring and, what is more, tire life against abrasion is improvable. |
