Abstract: The radial-ply tire for use on trucks and constructed according to the invention possesses a tread profile which comprises an equatorial line, a tread-profile width and a plurality of rows of blocks separated from one another by circumferential grooves. Each block comprises two substantially parallelogram-shaped blocks parts separated from each other by a fine cross slit substantially centrally extending through the respective block. Two of four block edges of each substantially parallelogram-shaped block part extend substantially parallel to the equatorial line of the tread profile. The other two block edges inclinedly extend relative to the equatorial line at angles which are not 90.degree., whereby all inclinedly extending block edges in a row of blocks form with the equatorial line at least substantially equal angles of inclination.

Abstract: The tire comprises a tread with central grooves between exterior grooves. Both types of grooves extend in a zig-zag shape in the circumferential direction and define ribs between them. Each one of the central grooves is bounded by sidewalls which define two opposite sidewall sections between angled regions of the central grooves. The two sidewall sections alternate from one angled region to the other in the circumferential direction of the tread. A first sidewall section of the two opposite sidewall sections extends at least approximately normally to the tread and a second sidewall section of the two sidewall sections comprises two sidewall portions extending substantially normally to the tread and an interconnecting flank portion therebetween which extends at an inclination in the range of 20.degree. to 60.degree. with respect to a line perpendicular to the tread.