| 摘要 |
PROBLEM TO BE SOLVED: To improve the wear resistance and wettability of a heavy loading tire. SOLUTION: A tread surface 2 is provided with a lug groove 3 extending to a tire equatorial side from a tread edge E, a longitudinal main groove 4 extending in the tire circumferential direction in succession to the lug groove 3 at the both side positions of a tire equator C and further its groove depth is 10 to 12% of tread width TW, and both inner and outer longitudinal sub- grooves 5i and 5o in the tire axial direction being arranged both sides of each longitudinal main groove and smaller in depth than the longitudinal groove 4, in succession to the lug groove 3, respectively. Then this tread surface 2 is partitioned to a ribbed part 6 extending on the tire equator, first block B1, a second block B2 and a third block B3, respectively. In addition, the ribbed part 6 is formed with a fine groove 7 having its depth being 0.2 to 0.3 times over the depth of the longitudinal main groove 4 and extending in a direction succeeding both inner longitudinal sub-grooves 5i and 5i. |
