| 摘要 |
PURPOSE: To secure grip and wet grip performances in the initial abrasion so as to suppress deviated abrasion of heel and toe by forming narrow grooves provided in side ribs into prescribed arc shapes and the groove depth shallower than the main grooves. CONSTITUTION: A linear center rib 24 is formed in the center of a tread part 20, and side ribs 27, 28 and shoulder ribs 31, 32 are formed in both side of the center rib via center main grooves and via their outside side main grooves 29, 30 respectively. First and second shallow grooves 33, 34 which cross the rib longitudinal direction and have such forms as being broadened and tapered toward their mouth in the circumferencial direction respectively, are spacedly formed on the side ribs 27, 28 in the circumferencial direction and have arc shapes whose radius centers are set in the rib width deviated from the rib centers of the side ribs 27, 28 toward the center line side and groove depth is shallower than that of the main grooves 25, 26. This constitution can thus prevent deviated abrasion of heel and toe, rib punch, etc. while securing the initial grip performance. |
