Tyre with lightened belt structure including steel monofilaments

A radial tyre comprising:

• a crown;
• a tread surmounting the crown;
• two beads;
• two sidewalls, each sidewall connecting a corresponding one of the beads to the crown;
• a carcass reinforcement anchored in each of the beads and extending in the sidewalls and the crown;
• and
• a belt extending in the crown in a circumferential direction (X) and situated radially between the carcass reinforcement and the tread, the belt including a multilayer composite laminate,
• wherein the multilayer composite laminate includes at least three superposed layers of reinforcers such that, for each layer, reinforcers within the layer are unidirectional and are embedded in a thickness of rubber, with:
• on a side towards the tread, a first layer of rubber including a row of first reinforcers, which are oriented at an angle alpha of −5 to +5 degrees with respect to the circumferential direction (X), the first reinforcers are heat-shrinkable textile reinforcers,
• in contact with the first layer of rubber and arranged underneath the first layer of rubber, a second layer of rubber including a row of second reinforcers, which are oriented at an angle beta, the angle beta being positive or negative and having a value between 10 and 30 degrees with respect to the circumferential direction (X), the second reinforcers being metal reinforcers, and
• in contact with the second layer of rubber and arranged underneath the second layer of rubber, a third layer of rubber including a row of third reinforcers, which are oriented at an angle gamma, the angle gamma being opposite in direction to the angle beta and having a value between 10 and 30 degrees with respect to the circumferential direction (X), the third reinforcers being metal reinforcers,
• wherein:
• the second reinforcers are steel monofilaments having a diameter D2 between 0.20 mm and 0.50 mm;
• the third reinforcers are steel monofilaments having a diameter D3 between 0.20 mm and 0.50 mm;
• and
• wherein, measured in a central part of the belt when the tyre is in a vulcanized state, on each side of a median plane (M) over a total axial width of 4 cm:
• a mean envelope of a diameter D1 of the first reinforcers is between 0.40 mm and 0.70 mm,
• a density d1 of the first reinforcers in the first layer of rubber, measured in an axial direction (Y), is between 70 and 130 threads/dm,
• a density d2 of the second reinforcers in the second layer of rubber, measured in the axial direction (Y), is between 120 and 180 threads/dm,
• a density d3 of the third reinforcers in the third layer of rubber, measured in the axial direction (Y), is between 120 and 180 threads/dm,
• a mean thickness Ez1 of rubber separating a first reinforcer from a second reinforcer closest to the first reinforcer, measured in a radial direction (Z), is between 0.25 and 0.40 mm, and
• a mean thickness Ez2 of rubber separating a second reinforcer from a third reinforcer closest to the second reinforcer, measured in the radial direction (Z), is between 0.35 and 0.60 mm, and
• wherein:
• CT<7.5%, (1)
• 0.20<Ez1/(Ez1+D1+D2)<0.30, (2)
• 0.30<Ez2/(Ez2+D2+D3)<0.50, and (3)
• Ez1<Ez2, (4)
• with CT being a thermal contraction of the first reinforcers after 2 minutes at 185° C.