| 摘要 |
PURPOSE:To enable the radial tyre in the caption to be prevented from wear of tread while still holding its wet resistance, by arranging, a zigzag angle of grooves in the peripheral direction on the surface of tread in relation the equator of the tyre, to increase as the wear of tread increase. CONSTITUTION:A radial tyre comprises a tread 1. Carcass 2 and a belt 3 disposed between former portions and the tread 1 is sectional laterally into several ribs 5 by means of rather wide grooves 4 in circumferential direction. In relation to the above statement, the ridge L serving as a border line between the groove 4 in the circumferential direction and the surface of tread is designed to be substantially parallel to the equator C of a new tyre but to be deformed in a zigzag groove of a constant pitch P as the wear of tread progresses. Namely, although the point height PH of the groove is set in a range from 0% to 1.5% of the tread width TW when the tyre is new, but allowed to increase, as the wear of tread progresses, to its maximum allowable value, in a range from 1% to 4% of the tread width TW. |
