Tread for radial tire the elements in relief of which are provided with incisions having broken line or undulated line traces in the direction of their depth

A tread for tires with radial carcass reinforcement, comprising at least elements in relief or blocks, separated by circumferential grooves and transverse grooves and provided with incisions of a width between about 0.1 mm and 2 mm, the incisions having on the surface of the tread rectilinear traces which form with the axial direction angles at most equal in absolute value to 30.degree. and which are parallel to each other and to the traces of the transverse grooves, two adjacent incisions defining a strip of rubber the axial dimension of which is at least equal to 30% of the corresponding axial width of the element in relief, characterized by the fact that each element in relief comprises an even number of incisions of equal depth and having in cross-section over the entire depth broken line or undulated line traces with mean axes perpendicular to the surface of the tread and formed of segments forming angles

• defining crests, said segments forming angles which are other than zero and at most equal to 40.degree. with the normal to said surface, the trace of an incision being a mirror image of the trace of a circumferentially adjacent incision.