Tire tread having at least two wearing layers, provided with at least one continuous groove having in the as new condition a plurality of external cavities opening onto the tread surface and a plurality of internal cavities placed radially and completely inside the tread surface, such that: the difference between the mean lengths of the internal cavities and of the external cavities is at most equal to 20% of the longest mean length, the difference in the mean cross-sectional areas of the internal and external cavities is at most equal to 20% of the largest mean area, each external cavity of a continuous groove being connected to at least two internal cavities of the same groove and having a plurality of incisions opening onto the tread surface, each connecting two consecutive external cavities of the same groove and at least two connecting channels and at least one internal cavity.