A tire comprises at least first and second working plies (16, 18) respectively comprising first and second reinforcing elements (50, 52) in which at least one of the following relationships is satisfied:

3324E1+3650(D1.sup.4d11000)/E13998E1+4547(I)

3324E2+3650(D2.sup.4d21000)/E23998E2+4547(II)

where D1, D2 are the diameter of each reinforcing element (50, 52) made up of a metallic monofilament (66, 68), with D1 and/or D2 ranging from 0.25 to 0.38 mm, d1, d2 are the density of the reinforcing elements (50, 52), expressed in monofilaments per decimetre, and E1, E2 are the mean thickness of the working ply (16, 18), expressed in mm.

The tire comprises a carcass ply connecting two beads via two sidewalls, the carcass ply being surmounted radially towards the outside of the tire by a crown reinforcing zone which is itself surmounted radially towards the outside of the tire by a tread, the crown reinforcing zone comprising a plurality of reinforcing strips arranged over at least one ply of strips. The strips are arranged so that they are juxtaposed and at an angle less than or equal to 15 with respect to the circumferential direction. Each reinforcing strip is made up of a laminate of at least 3 composite layers, each composite layer containing oriented fibers having a tensile modulus greater than or equal to 55 GPa, which are parallel to one another and coated in a polymer matrix.

A ply (16, 18) comprises metallic monofilaments (46, 46). Each monofilament (46) of a first group has a positive torsional elastic deformation in a first direction about its main axis (G). Each monofilament (46) of a second group has a negative torsional elastic deformation in a second direction about its main axis (G). The absolute value of the torsional elastic deformation C of each monofilament (46, 46) is such that |C|6 turns per ten metres. The mean S of the torsional elastic deformations of the monofilaments (46, 46) of the ply (16, 18) is such that 0.25 turn per ten metresS+0.25 turn per ten metres. The monofilaments (46, 46) are arranged next to one another so as to alternate one or more monofilaments (46) of the first group with one or more monofilaments (46) of the second group.

The tire comprises a carcass ply connecting two beads via two sidewalls, the carcass ply being surmounted radially towards the outside of the tire by a crown reinforcing zone which is itself surmounted radially towards the outside of the tire by a tread, the crown reinforcing zone comprising a plurality of reinforcing strips arranged over at least one ply of strips. The strips are arranged so that they are juxtaposed and at an angle less than or equal to 15 with respect to the circumferential direction. Each reinforcing strip is made up of a laminate of at least 3 composite layers, each composite layer containing oriented fibers having a tensile modulus less than or equal to 30 GPa, which are parallel to one another and coated in a polymer matrix.

Technique to increase the endurance of tires comprising two crossed working layers (41, 42), comprising mutually parallel reinforcing elements (411, 421) forming, with the circumferential direction (XX) of the tire, an angle at least equal to 20 and at most equal to 50, the reinforcing elements being made up of individual metal threads or monofilaments having a cross section at least equal to 0.20 mm and at most equal to 0.6 mm. The end of the monofilaments comprises flats such that they reduce the shear forces in the rubber compounds of the tire under compressive loading.

A radial tire comprises a multilayer composite laminate (10) comprising at least three superposed layers of reinforcers (110, 120, 130), the reinforcers being unidirectional within each layer and embedded in a thickness of rubber (C1, C2, C3, respectively), with a first layer of rubber (C1) comprising at least one row of heat-shrinkable circumferential textile reinforcers (110), for example made of nylon or polyester. The first layer radially (in the direction Z) surmounts two other layers (C2, C3) comprising metal reinforcers (120, 130) which are crossed from one layer to the next, in the form of steel monofilaments of a diameter between 0.20 mm and 0.50 mm. The reinforcers (110) made of heat-shrinkable textile material are tapes of thickness denoted T between 0.1 mm and 1 mm, and of thickness denoted W between 2 and 50 mm.

A tire comprises at least first and second working plies (16, 18) respectively comprising first and second reinforcing elements (50, 52) in which at least one of the following relationships is satisfied:

4053E1+4720(D1.sup.4d11000)/E1 (I)

4053E2+4720(D2.sup.4d21000)/E2 (II)

where D1, D2 are the diameter of each reinforcing element (50, 52) made up of a metallic monofilament (66, 68), and D1 and/or D2 ranges from 0.34 to 0.38 mm, d1, d2 are the density of the reinforcing elements (50, 52), expressed in monofilaments per decimetre, and E1, E2 are the mean thickness of the working ply (16, 18), expressed in mm.

Breaking energy test performance of lightweight tyres that have a good performance in terms of rolling resistance and having a nominal width at least equal to 135 mm and at most equal to 235 mm is increased. These tyres comprise two thin and lightened working layers (41, 42) comprising metal reinforcing elements (411, 421) made up of monofilaments having a linear breaking strength Rct at least equal to 300 daN/cm and at most equal to 400 daN/cm, and a single carcass layer (6) radially on the inside of the working layers. In order to improve performance in the breaking energy test, this carcass layer comprises textile reinforcing elements and has surface breaking energy at least equal to 1.75 J/cm.sup.2.

Tires comprising a hoop reinforcement (5) and 2 crossed working layers (41, 42) in which the breaking strength R.sub.C of each working layer (41, 42) is at least equal to 30 000 N/dm have improved endurance. The working layers comprise reinforcing elements made up of individual metal threads or monofilaments having a cross section at least equal to 0.20 mm and at most equal to 0.5 mm. The density of reinforcing elements in each working layer is at least equal to 100 threads per dm and at most equal to 200 threads per dm. The tire also comprises axially exterior cuts (25). At least one of the two axially exterior portions of the tread comprises a rubbery material having a Shore hardness at least equal to 48 and at most equal to 60.

Breaking energy test performance of lightweight tyres that have a good performance in terms of rolling resistance is increased. These tyres comprise two thin and lightened working layers (41, 42) comprising metal reinforcing elements (411, 421) having a linear breaking strength Rct at most equal to 400 daN/cm, and a single carcass layer (6) radially on the inside of the working layers. In order to successfully undergo the breaking energy test, this carcass layer comprises textile reinforcing elements that have an elongation at break Acc at least equal to 15%, the carcass layer having a linear breaking strength Rcc at least equal to 0.55 times the linear breaking strength of the working layers.