Heavy-duty pneumatic tire tread

Abstract From the Canadian patent

A heavy duty pneumatic tire tread includes a tread portion formed of five ribs separated by four circumferential zig-zag grooves, wherein each groove is made up of successive circumferentially and obliquely alternating one-half pitches having two different lateral widths, each of which remains substantially constant throughout its circumferential extent and wherein within, each one-half groove pitch, when viewed in the lateral direction, the lateral widths of the center grooves are of a first width whereas the lateral widths of the shoulder grooves are in the second width. The oblique angulation of the zig-zag grooves, relative to the circumferential direction of the tire changes every …