| 摘要 |
PURPOSE:To improve the blowout of a tire, in the transversal contours of the outer surfaces of the blocks situated in the central region of the tire at the time when a normal rim is fitted with the internal pressure zero, by positioning the centers of the radii of curvature forming the same contours outward in the radial direction of the tire. CONSTITUTION:A tire whose flatness is set to be 0.6 or less is provided with a narrow groove I0 extending in the circumferential direction at the central part of the tread part and a plurality of wide-breadth circumferential main grooves 1, and a plurality of blocks 3 through 3'' are formed by these grooves and a plurality of transverse grooves 2. In this constitution, the transversal contours of the outer surfaces of respective blocks 3, 3' on the circumference of at least one row situated in the central region S0 of the tread part, at the time when the internal pressure is zero, and a normal rim is fitted, are so contrived that the centers of the radii R1, R2 of curvature forming the same contours are positioned outward in the radial direction of the tire. Thus, the blowout of blocks contributary to high-speed durability can be improved. |
