| 摘要 |
PURPOSE:To heighten the partial wear and pebble sticking prevention effect of a tire having a central and lateral circumferential main grooves on the tread, by providing the main grooves with prescribed cross-sectional shapes whose inclination angles are different from each other. CONSTITUTION:A tire has a central circumferential main groove 1 and lateral circumferential main grooves 2 which divide the outermost ribs 4 of the tread Tr. The cross section of the main groove 1 is shaped symmetrically as to right and left so that the inclination angle alpha1 of the groove wall 1' which is acute with regard to the normal on the outside suface of the tread Tr is relatively large in a region 1'-I of height h1 not less than a half of the groove depth D1. The cross section of the other main groove 2 is shaped asymmetrically as to right and left so that the inclination angle alpha3 of the groove wall 2'-4 at the side of the outermost rib 4 is relatively large and the inclination angle alpha2 of the other groove wall 2'-3 at the side of another rib 3 is smaller than the angle alpha3, in a region 2'-30 of depth d2 not less than 10% of the groove depth D2. |
