| 摘要 |
PURPOSE: To reduce partial wear of a tread by making the pinch angle between the outer surface and the side facing to an upper lug groove larger than the pinch angle between the outer surface and the side facing to a lower lug groove in a block adjacent to a shoulder land part row facing to one end of a tread, and making reverse the relationship in the block adjacent to a shoulder land part row facing the other end of the tread. CONSTITUTION: In a block 3 in a 2na land part row 42 adjacent to a shoulder land part row 41 facing to one end E1 of a tread 5, the pinch angleαbetween the outer surface and the side 6u facing to an upper lug groove 2 is made larger than the pinch angleβbetween the outer surface and the side 6d facing to a lower lug groove 2. Meanwhile, in a block 3 in a 2na land part row 42 adjacent to a shoulder land part row 41 facing to the other end E2 of the tread 5, the pinch angleηbetween the outer surface and the side 6v facing to an upper Jug groove 2 is made smaller than the pinch angleδbetween the outer surface and the side 6e facing to a lower lug groove 2. Hereby, in the block 3 in the 2na land part row 4 greatly influenced in appearance of wear, tread-in and kick-out against the grounding surface are always delayed to the shoulder block.
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