| 摘要 |
<p>A radial ply pneumatic tire (10) for trucks or trailers has a tread (12) with at least three longitudinal grooves (20, 22) extending circumferentially to divide the tread (12) into at least four parts and lateral grooves (30, 31, 32, 33, 34) extending across the at least four parts of the tread to form at least four rows (1, 2, 3, 4 and 5) of circumferentially separated blocks (40). The longitudinal grooves (30, 31, 33, 34) have average widths of W1 for a depth extending between the radially outer surface (42) of the blocks (40) to less than 60 % of the tread depth (D) thereafter the average width of the longitudinal groove narrows to less than 50 % of W1. The lateral grooves (22) in each shoulder row (15) extend to a depth of less than 60 % of the tread depth (D). The lateral grooves in the central rows (2, 3 and 4) have an average length of L1 between the radially outer surface (42) of the tread blocks (40) to a depth of less than 60 % of the total depth (D), thereafter the average length increases from L1 between the radially outer surface (42) of the tread blocks (40) to a depth of a less than 60 % of the total depth (D), thereafter the average length increases from L1 to greater than L1, preferably to L1, plus at least 50 % W1. Most preferably, the lateral groove in the central region (2, 3 and 4) also narrows to less than 80 % of averaged width W2 of the lateral grooves. The tire (10) when new provides a tread (12) for the drive axle position, and when less than 60 % worn the tread pattern changes to one ideally suited for the trailer wheel position.</p> |
