Radial tire having a lightweight belt structure

A radial tire, defined in three main directions, circumferential X, axial Y and radial Z, comprising:

• a crown surmounted by a tread;
• two sidewalls;
• two beads, each sidewall connecting a respective bead to the crown;
• a carcass reinforcement that is anchored in each of the beads and extends in the sidewalls as far as the crown;
• a belt that extends in the crown in the circumferential direction X and is situated radially between the carcass reinforcement and the tread, said belt comprising a multilayer composite laminate comprising at least three superposed layers of reinforcers, said reinforcers being unidirectional within each layer and embedded in a corresponding thickness of rubber C1, C2, and C3, respectively;
• wherein, on the tread side, a first layer of rubber C1 comprises a first row of reinforcers defined as first reinforcers, which are oriented at an angle alpha of −5 to +5 degrees with respect to the circumferential direction X and which are made of a heat-shrinkable textile material;
• wherein, in contact with the first layer of rubber C1 and disposed beneath the latter, a second layer of rubber C2 comprises a second row of reinforcers defined as second reinforcers, which are oriented at a given angle beta, positive or negative, of between 10 and 30 degrees with respect to the circumferential direction X and which are metal reinforcers;
• wherein, in contact with the second layer of rubber C2 and disposed beneath the latter, a third layer of rubber C3 comprises a third row of reinforcers defined as third reinforcers, which are oriented at an angle gamma the opposite of the angle beta, said angle gamma itself being between 10 and 30 degrees with respect to the circumferential direction X and which are metal reinforcers;
• wherein the first reinforcers made of heat-shrinkable textile material are heat-shrinkable monofilaments with a diameter φ greater than 0.10 mm or assemblies of such monofilaments;
• wherein an envelope diameter denoted D1 of the first reinforcers is between 0.20 mm and 1.20 mm;
• wherein a density d1 of the first reinforcers in the first layer of rubber C1, measured in the axial direction Y, is between 70 and 130 threads/dm;
• wherein the second and third reinforcers are steel monofilaments of which a diameter, denoted D2 and D3, respectively, is between 0.20 mm and 0.50 mm;
• wherein a density, d2 and d3, respectively, of the second reinforcers and the third reinforcers in the second layer of rubber C2 and third layer of rubber C3, respectively, measured in the axial direction Y, is between 100 and 180 threads/dm;
• and
• wherein, measured in the central part of the belt of the tire in the vulcanized state, on each side of the median plane M over a total axial width of 10 cm:
• the mean thickness Ez1 of rubber separating a first reinforcer from a second reinforcer closest to it, measured in the radial direction Z, is between 0.20 and 0.40 mm,
• the mean thickness Ez2 of rubber separating a second reinforcer from a third reinforcer closest to it, measured in the radial direction Z, is between 0.35 and 0.60 mm, and
• Ez1<Ez2.