Abstract: A tread band having at least one longitudinal groove bounded by a bottom wall, and by two sidewalls; each sidewall of the longitudinal groove has a continuous sequence of alternating projections and recesses, which extend crosswise so that, in plan view, the first longitudinal groove is zigzag shaped; each projection of one sidewall of the longitudinal groove always faces a recess in the other sidewall of the longitudinal groove; and, at all the projections, an outer portion of each sidewall slopes at a first obtuse angle to the bottom wall, and, at all the recesses, an outer portion of each sidewall slopes at a second obtuse angle, different from the first obtuse angle, to the bottom wall.

Abstract: A tread band having at least one longitudinal groove bounded by a bottom wall, and by two sidewalls; each sidewall of the longitudinal groove has a continuous sequence of alternating projections and recesses, which extend crosswise so that, in plan view, the first longitudinal groove is zigzag shaped; each projection of one sidewall of the longitudinal groove always faces a recess in the other sidewall of the longitudinal groove; and, at all the projections, an outer portion of each sidewall slopes at a first obtuse angle to the bottom wall, and, at all the recesses, an outer portion of each sidewall slopes at a second obtuse angle, different from the first obtuse angle, to the bottom wall.