A radial ply pneumatic tire 10 for trucks or trailers has a tread 12 with at least three circumferential 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 circumferential grooves 20,22 have average groove widths of W1 for a depth between the radially outer surface of the adjacent blocks and a groove depth that is less than 60% of the non-skid depth D, the circumferential grooves having a second average groove width W2 at the groove depth less than 60% of the non-skid depth D, the second average groove width W2 being less than 50% of W1. The lateral grooves 30,34 in each shoulder row 15 have a first average groove width W3 and a groove depth that is less than 60% of the non-skid depth D. The lateral grooves 31,32,33 in the central rows 2,3 and 4 have a first average length L1 for a depth between a radially outer surface of the adjacent blocks and a groove depth that is less than 60% of the non-skid depth D, the lateral grooves in the central rows having a second average length L2 at the groove depth that is less than 60% of the non-skid depth D, the second average length L2 being greater than the first average length L1. The tie 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.