| 摘要 |
<p>Sipes are formed on blocks on a tread surface. Each sipe has a zig-zag shape in which protruding portions which protrude in a direction A1 and protruding portions which protrude in a direction A2 are alternatingly formed at the sides of an imaginary central plane V. The sipe has a wavelength (a peak distance between two adjacent protruding portions in the same direction along the imaginary central plane) that gradually decreases from a tread surface toward a bottom portion. Therefore, the length of the sipe exposed at the tread surface gradually increases with the process of abrasion, thereby increasing the edge effect. As a result, a decrease in gripping ability on wet surfaces due to rubber degradation or the like, which accompanies the process of abrasion, can be suppressed. <IMAGE></p> |
