| 摘要 |
PURPOSE: To improve the pressure distribution pattern of a footprint and obtain uniform inter-tread wearing characteristic by specifying the outside diameter of a tire, and setting two types of circular arcs having the respective specified radii on a tread portion. CONSTITUTION: A tread portion 17 is disposed on the outside in the radial direction of a belt structure 14, and at least two grooves 18-21 extending in the circumferential direction about it are provided. The outside radius SR of the tire in each axial edge of the tread portion 1 is in a range smaller than the height SH of the section of the tire by 8%-9.5%. The tread portion 17 has a first radius R1 on the main circular arc in the range of 59% to 63% of the tread width B on both sides of the equatorial plane EP, and the center is taken to be EP. Further, a second circular-arc having a second radius R2 is extended from both ends of the first circular arc to the nearest lateral edge of the tread portion 17, the second radius R2 is within a range of 35% to 40% of the first radius R1 , and it is terminated at least by 90% of the distance from the equatorial plane EP to the axial edges TE1 , TE2 of the tread. |
