Patent ID: 8272415

Claim:
A heavy duty tire comprising a tread portion provided in the tread surface with a plurality of circumferential main grooves extending in the circumferential direction to provide rib-like land portions between the adjacent circumferential main grooves and between tread edges and the circumferential main grooves, wherein at least three of the rib-like land portions each has a row of blocks arranged in the circumferential direction formed by lateral grooves crossing each said rib-like land portion, each said lateral groove is provided in its bottom with a sipe-forming region having a sipe which extends along the groove center line of the lateral groove and has a width of 0.5 to 2.0 mm, a depth DY of the lateral groove measured from the tread surface to the sipe-forming region is from 0.5 to 0.75 times a depth H from the tread surface of the circumferential main grooves that intersect with the lateral groove, a depth DS from the tread surface of the sipe is from 0.75 to 1.0 times the depth H of the circumferential main grooves, said at least three rib-like land portions each having a row of the blocks include a center block row rib-like land portion disposed on the tire equator and a side block row rib-like land portion disposed on each side of said center block row rib-like land portion, the lateral grooves disposed in said center block row rib-like land portion have an S shape comprising a first arc portion having its center on one side in the circumferential direction of tire and a second arc portion having its center on the other side in the circumferential direction, the lateral grooves disposed in said side block row rib-like land portion each have a U shape comprising a single arc portion having its center on said one side or said other side in the circumferential direction, and the U-shaped arc portions of said lateral grooves are oriented in the reverse direction to said first arc portion or second arc portion adjacent thereto with the circumferential main groove lying therebetween.