Tread comprising at least one groove delimited by two walls facing one another, joined together by a groove bottom, this groove having a plurality of closure devices, each made up of at least one flexible blade (of thickness E suited to allowing flexing under the effect of a circulation of liquid in the groove, and secured to a wall delimiting the groove, each flexible blade bounded by a bottom wall facing the bottom of the groove, an end wall facing the other wall of the groove and a contact wall to come into contact with the roadway and lateral walls spaced apart from one another by a distance equal to the thickness E of the blade, the bottom wall of each flexible blade having a notch in the vicinity of the wall to which the blade is attached, wherein each flexible blade is connected to one of the walls delimiting the groove inside a housing (formed on the wall bearing the blade, each housing having a depth suited to containing in its entirety a notch.