Tyre having an axis of rotation and a median plane perpendicular to the axis of rotation, and comprising a crown having: • a crown reinforcement; and • a tread (9, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130) radially on the outside, the tread comprising: ∘ a plurality of tread pattern elements having lateral faces (11.1, 11.3, 12.1, 12.3, 13.1, 13.3, 14.1, 14.3) and a contact face intended to come into contact with the road surface while the tyre is being driven on; ∘ a plurality of circumferential grooves (11, 12, 13, 14), each of which is delimited by outer lateral faces (11.1, 12.1, 13.1, 14.1) and inner lateral faces (11.3, 12.3. 13.3, 14.3) of adjacent tread pattern elements that face one another, and is delimited by a bottom (11.2, 12.2, 13.2, 14.2); ∘ a circumferential reinforcement (20, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132) made up of a rubber mixture with a stiffness greater than the stiffness of the rubber mixture of the rest of the tread; and ∘ an underlayer (15, 95, 115) disposed radially towards the inside and radially on the outside of the crown reinforcement; characterized in that, the tyre having an outer side and an inner side, the circumferential reinforcement has a reinforcing element (22, 34, 36, 44, 46, 54, 56, 64, 66, 74, 76, 84, 86, 94, 96, 104, 106, 114, 116, 124, 126, 134, 136) positioned in the tread pattern elements disposed axially on the outside with respect to one of the first and second circumferential grooves of the tread from the outside to the inside and axially close to said circumferential groove, in that the reinforcing element extends radially from the radially outer surface of said underlayer towards the outside of said tread with an axial width which decreases gradually and over a partial or total height of the thickness of the tread, in that the tread pattern elements disposed axially on the inside with respect to said first circumferential groove do not have reinforcing elements disposed close to the axially inner faces of said groove and in that the stiffness of said underlayer is less than or equal to the stiffness of the rubber mixture of said circumferential reinforcement. • a crown reinforcement; and • a tread (9, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130) radially on the outside, the tread comprising: ∘ a plurality of tread pattern elements having lateral faces (11.1, 11.3, 12.1, 12.3, 13.1, 13.3, 14.1, 14.3) and a contact face intended to come into contact with the road surface while the tyre is being driven on; ∘ a plurality of circumferential grooves (11, 12, 13, 14), each of which is delimited by outer lateral faces (11.1, 12.1, 13.1, 14.1) and inner lateral faces (11.3, 12.3. 13.3, 14.3) of adjacent tread pattern elements that face one another, and is delimited by a bottom (11.2, 12.2, 13.2, 14.2); ∘ a circumferential reinforcement (20, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132) made up of a rubber mixture with a stiffness greater than the stiffness of the rubber mixture of the rest of the tread; and ∘ an underlayer (15, 95, 115) disposed radially towards the inside and radially on the outside of the crown reinforcement; characterized in that, the tyre having an outer side and an inner side, the circumferential reinforcement has a reinforcing element (22, 34, 36, 44, 46, 54, 56, 64, 66, 74, 76, 84, 86, 94, 96, 104, 106, 114, 116, 124, 126, 134, 136) positioned in the tread pattern elements disposed axially on the outside with respect to one of the first and second circumferential grooves of the tread from the outside to the inside and axially close to said circumferential groove, in that the reinforcing element extends radially from the radially outer surface of said underlayer towards the outside of said tread with an axial width which decreases gradually and over a partial or total height of the thickness of the tread, in that the tread pattern elements disposed axially on the inside with respect to said first circumferential groove do not have reinforcing elements disposed close to the axially inner faces of said groove and in that the stiffness of said underlayer is less than or equal to the stiffness of the rubber mixture of said circumferential reinforcement. ∘ a plurality of tread pattern elements having lateral faces (11.1, 11.3, 12.1, 12.3, 13.1, 13.3, 14.1, 14.3) and a contact face intended to come into contact with the road surface while the tyre is being driven on; ∘ a plurality of circumferential grooves (11, 12, 13, 14), each of which is delimited by outer lateral faces (11.1, 12.1, 13.1, 14.1) and inner lateral faces (11.3, 12.3. 13.3, 14.3) of adjacent tread pattern elements that face one another, and is delimited by a bottom (11.2, 12.2, 13.2, 14.2); ∘ a circumferential reinforcement (20, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132) made up of a rubber mixture with a stiffness greater than the stiffness of the rubber mixture of the rest of the tread; and ∘ an underlayer (15, 95, 115) disposed radially towards the inside and radially on the outside of the crown reinforcement;