Tread for a tyre intended to equip a heavy vehicle, this tread comprising a tread surface intended to come into contact with a roadway and to form a contact patch, this tread comprising - a plurality of grooves (11, 12) of circumferential overall orientation and a plurality of grooves (21, 22) of oblique overall orientation intersecting the grooves of circumferential overall orientation to delimit blocks (31, 32), these circumferential and transverse grooves forming a directional tread pattern, this directional tread pattern imposing a running direction on the tread, - a dividing plane (SS') parallel to the midplane (XX') separating part of the pattern to the left of the said plane and part of the pattern to the right, - the circumferential grooves (11, 12) delimiting at least three intermediate rows formed of a plurality of blocks and two edge rows provided with blocks and situated axially on the outside of the intermediate rows, this tread being such that each block (31, 32) of the rows of blocks comprises a contact face forming part of the tread surface, a front face and a rear face and two lateral faces, - the front face and the rear face intersecting the contact face along a leading edge Ai and a trailing edge Fi respectively, the leading edge of a block coming into the contact patch during running before the trailing edge of the same block when the tread is running in the running direction, this tread being characterized in that its pattern is designed so that the leading edges Ai of all the blocks of the rows formed of blocks are offset from one another in the circumferential direction in a suitable way that: - these leading edges successively enter the contact patch during running, - these leading edges enter the contact patch alternately on one side of the dividing plane and then on the other side of the same dividing plane in a kind of back-and-forth arrangement, the succession whereby the leading edges Ai of all the blocks of the intermediate rows enter the contact patch is such that the end of the last leading edge forming part of the contact patch coincides with an end of the leading edge situated on the other side of the dividing plane entering the contact patch. - a plurality of grooves (11, 12) of circumferential overall orientation and a plurality of grooves (21, 22) of oblique overall orientation intersecting the grooves of circumferential overall orientation to delimit blocks (31, 32), these circumferential and transverse grooves forming a directional tread pattern, this directional tread pattern imposing a running direction on the tread, - a dividing plane (SS') parallel to the midplane (XX') separating part of the pattern to the left of the said plane and part of the pattern to the right, - the circumferential grooves (11, 12) delimiting at least three intermediate rows formed of a plurality of blocks and two edge rows provided with blocks and situated axially on the outside of the intermediate rows, this tread being such that each block (31, 32) of the rows of blocks comprises a contact face forming part of the tread surface, a front face and a rear face and two lateral faces, - the front face and the rear face intersecting the contact face along a leading edge Ai and a trailing edge Fi respectively, the leading edge of a block coming into the contact patch during running before the trailing edge of the same block when the tread is running in the running direction, this tread being characterized in that its pattern is designed so that the leading edges Ai of all the blocks of the rows formed of blocks are offset from one another in the circumferential direction in a suitable way that: - these leading edges successively enter the contact patch during running, - these leading edges enter the contact patch alternately on one side of the dividing plane and then on the other side of the same dividing plane in a kind of back-and-forth arrangement, the succession whereby the leading edges Ai of all the blocks of the intermediate rows enter the contact patch is such that the end of the last leading edge forming part of the contact patch coincides with an end of the leading edge situated on the other side of the dividing plane entering the contact patch. - these leading edges successively enter the contact patch during running, - these leading edges enter the contact patch alternately on one side of the dividing plane and then on the other side of the same dividing plane in a kind of back-and-forth arrangement,