Tyre, comprising: • a tread which is intended to come into contact with the ground via a tread surface comprising grooves, • a groove forming a space opening onto the tread surface and being delimited by two main lateral faces (241, 242) connected by a bottom face, • at least one groove having a width W defined by the mean distance between the two lateral faces (241, 242) and a depth D defined by the maximum radial distance between the tread surface and the bottom face, • at least one groove is referred to as a major groove, having a width W at least equal to 1 mm and a depth D at least equal to 4 mm, • the tyre further comprising a crown structure radially on the inside of the tread, made up of a radial stack of continuous or discontinuous layers of material (3, 4, 5, 6, 7), • the crown structure comprising radially from the outside to the inside a crown reinforcement, a carcass reinforcement and an inner polymeric layer, • the crown reinforcement comprising at least one working reinforcement comprising at least one working layer (41, 42), said at least one working layer (41, 42) comprising a radially outermost working layer • the radially outermost working layer extending radially from a radially outer surface to a radially inner surface, • the radially outermost working layer comprising reinforcing elements at least partially made of metal, which are continuous from one axially outer edge of the working layer to the opposite axially outer edge, coated in an elastomer material, mutually parallel and which with the circumferential direction (XX') of the tyre form an oriented angle the absolute value of which is at least equal to 20° and at most equal to 50°, the radially outermost working layer comprising at least one undulation, the at least one undulation in the radially outermost working layer being such that the working layer portion of the undulation is radially on the outside of the points of the working layer that are in line with the centre of the bottom face of the major groove closest to the said undulation, all the layers of material (3, 6, 7) making up the radial stack of the crown structure having mean surfaces parallel to that of the radially outermost working layer, characterized in that the at least one undulation in the radially outermost working layer is such that, over at least 10% of the radially outer surface of the said radically outermost working layer, the radial distance (do), between the radially outer surface of the radially outermost working layer and the tread surface, is at least 1 mm less than the radial distance (dc) between the radially outer surface of the radially outermost working layer and the tread surface, which is the distance in line with the centre of the bottom face of the major groove closest to the said undulation, and in that the minimum radial distance (du) between the radially outer surface of the radially outermost layer of the crown reinforcement and the tread surface is at most equal to the depth D of the closest major groove, increased by 2 mm. • a tread which is intended to come into contact with the ground via a tread surface comprising grooves, • a groove forming a space opening onto the tread surface and being delimited by two main lateral faces (241, 242) connected by a bottom face, • at least one groove having a width W defined by the mean distance between the two lateral faces (241, 242) and a depth D defined by the maximum radial distance between the tread surface and the bottom face, • at least one groove is referred to as a major groove, having a width W at least equal to 1 mm and a depth D at least equal to 4 mm, • the tyre further comprising a crown structure radially on the inside of the tread, made up of a radial stack of continuous or discontinuous layers of material (3, 4, 5, 6, 7), • the crown structure comprising radially from the outside to the inside a crown reinforcement, a carcass reinforcement and an inner polymeric layer, • the crown reinforcement comprising at least one working reinforcement comprising at least one working layer (41, 42), said at least one working layer (41, 42) comprising a radially outermost working layer • the radially outermost working layer extending radially from a radially outer surface to a radially inner surface, • the radially outermost working layer comprising reinforcing elements at least partially made of metal, which are continuous from one axially outer edge of the working layer to the opposite axially outer edge, coated in an elastomer material, mutually parallel and which with the circumferential direction (XX') of the tyre form an oriented angle the absolute value of which is at least equal to 20° and at most equal to 50°,