| 摘要 |
PURPOSE:To improve the performance of a heavy load pneumatic tire for a bus or the like on an iced or snow-covered road by applying the constitution wherein a ratio of the widthwise edge component of a block to the peripheral edge component thereof with each sheeting is specified with a center block row and an adjacent block row respectively, and a ratio of each widthwise block projection length to a block surface area is further specified. CONSTITUTION:A center block row 4, an adjacent block row 6 and a shoulder block row 8 are respectively formed with main grooves 2 and sub-grooves 3. Also, sheetings 5, 7 and 9 are formed in the blocks 4a, 6a and 8a of each block row. Furthermore, a ratio alpha/beta of the widthwise edge components alpha of respective blocks 4a, 6a and 8a to the peripheral edge components beta thereof is taken as equal to or larger than 1.5 in the center block row 4. Also, alpha/beta is taken as 0.7 <= alpha/beta <= 1.0 in the block row 6, and as 0.5 <= alpha/beta <= 0.7 in the block row 8. In addition, a ratio gamma of widthwise block projection length to block surface area is taken between 0.05 times and 0.2 times of tread ground plane width (a). According to the aforesaid construction, a tire performance on an iced or snow-covered road can be improved. |
