Tyre for a vehicle of the heavy-duty, construction plant or agricultural type, comprising: - a crown reinforcement, radially on the inside of a tread and radially on the outside of a carcass reinforcement, - the crown reinforcement comprising, radially from the outside towards the inside, a protective reinforcement and a working reinforcement, - the protective reinforcement comprising at least one protective layer (311, 312) comprising hyperelastic metal reinforcers, coated in an elastomeric material, parallel to one another and forming, with a circumferential direction (XX') tangential to the circumference of the tyre, an angle at least equal to 10°, each hyperelastic metal reinforcer comprising at least one cord, called hyperelastic cord: characterized in that said hyperelastic cords comprise a single layer consisting of N metal filamentary elements wound in a helix and having an external diameter D, each metal filamentary element of the layer describing, when the cord extends in a substantially rectilinear direction, a trajectory in the form of a helix around a main axis substantially parallel to the substantially rectilinear direction, so that, in a section plane substantially perpendicular to the main axis, the distance between the centre of each metal filamentary element of the layer and the main axis is equal to half the helix diameter Dh and is substantially constant and equal for all the metal filamentary elements of the layer, the metal filamentary elements defining an internal enclosure of the cord of diameter Dv, each metal filamentary element having a diameter Df and a helix radius of curvature Rf defined by Rf=P/(π × Sin(2α)) with P the pitch of each metal filamentary element expressed in millimetres and α the helix angle of each metal filamentary element, characterized in that, with Dh, D, Dv, Df and Rf being expressed in millimetres: 9 ≤ Rf / Df ≤ 30, and 1.30 ≤ Dv / Df ≤ 4.5, - the enclosure diameter Dv being calculated using the relationship Dv=Dh-Df, - said hyperelastic cords being embedded in a rubber compound. - a crown reinforcement, radially on the inside of a tread and radially on the outside of a carcass reinforcement, - the crown reinforcement comprising, radially from the outside towards the inside, a protective reinforcement and a working reinforcement, - the protective reinforcement comprising at least one protective layer (311, 312) comprising hyperelastic metal reinforcers, coated in an elastomeric material, parallel to one another and forming, with a circumferential direction (XX') tangential to the circumference of the tyre, an angle at least equal to 10°, each hyperelastic metal reinforcer comprising at least one cord, called hyperelastic cord: characterized in that said hyperelastic cords comprise a single layer consisting of N metal filamentary elements wound in a helix and having an external diameter D, each metal filamentary element of the layer describing, when the cord extends in a substantially rectilinear direction, a trajectory in the form of a helix around a main axis substantially parallel to the substantially rectilinear direction, so that, in a section plane substantially perpendicular to the main axis, the distance between the centre of each metal filamentary element of the layer and the main axis is equal to half the helix diameter Dh and is substantially constant and equal for all the metal filamentary elements of the layer, the metal filamentary elements defining an internal enclosure of the cord of diameter Dv, each metal filamentary element having a diameter Df and a helix radius of curvature Rf defined by Rf=P/(π × Sin(2α)) with P the pitch of each metal filamentary element expressed in millimetres and α the helix angle of each metal filamentary element, characterized in that, with Dh, D, Dv, Df and Rf being expressed in millimetres: 9 ≤ Rf / Df ≤ 30, and 1.30 ≤ Dv / Df ≤ 4.5, - the enclosure diameter Dv being calculated using the relationship Dv=Dh-Df, - the enclosure diameter Dv being calculated using the relationship Dv=Dh-Df, - said hyperelastic cords being embedded in a rubber compound.