| 摘要 |
PURPOSE:To surely check the progress of should part abrasion and to prevent the occurrence of stone biting in a fine groove by forming grooves continuously in the peripheral direction of a tire on both ends of the tread portion of a tire, and specifying the depth of the groove and the width of the opening portion, respectively. CONSTITUTION:A tire has a slant face portion 3 formed between a tread portion 1 and buttress portion 2. In this case, a little flat portion 4 is left behind on the slant portion 3 side, and and an opening linear fine groove 5 is continuously formed in the peripheral direction of a tire on the tread portion 1. The depth (h) of the fine groove 5 is set 30-120% of the depth H of an adjacent main groove 8, and the groove width Wg of an opening portion 6 is set 1.2% of the width Wr of the tread portion 1. The distance between the opening edge 7 and the center line CL in the peripheral direction of the tire on the slant face portion 4 side of the fine groove 5 is set 1/2.6 with respect to the rim width WR. Further, the width Wa of the flat portion 4 is set 0.25-2.5% of the width Wr of the tread portion 1. |
