A pneumatic radial tire includes belt layers disposed on an outer circumferential side of a carcass layer in a tread portion. The belt layers are formed of steel cords in a N+M structure in which the number of wire strands N of an inner layer is 2 to 4 and the number of wire strands M of an outer layer is 2 to 7. A twist direction of the inner layer is different from a twist direction of the outer layer. The steel cords are inclined with respect to a tire circumferential direction to intersect each other in layers of the belt layers. A belt cover layer disposed on an outer circumferential side of the belt layers is formed of organic fiber cords having elongation of 2.0% to 4.0% under 2.0 cN/dtex load. The organic fiber cords are wound spirally along the tire circumferential direction.

Improve endurance of tire for heavy-duty vehicle of construction plant type. A hoop reinforcement has an axially continuous first hooping layer and axially discontinuous second hooping layer, first layer has an axial width LF1 at least equal to 25% and at most 75% of axial width LT of working reinforcement, the discontinuous second hooping layer consists of two hooping strips symmetrical with respect to equatorial plane (XZ) of tire, each extends axially from axially interior end as far as axially exterior end over an axial width LF2 which is at least equal to 10% and at most 35% of axial width LF1 of the first hooping layer, and the distributed tension at break TR of each hooping strip defined as the product of number D of reinforcers per mm times the force at break FR of each reinforcer expressed in daN, is at least equal to 100 daN/mm.

A pneumatic tire comprises a carcass layer, a belt layer radially outward of the carcass layer, and a tread rubber radially outward of the belt layer. The belt layer includes an angle belt having a belt angle ≥45° and ≤70° in absolute values, a pair of cross belts having belt angles of ≥10° and ≤45° in absolute values and having belt angles of mutually opposite signs, and a reinforcing layer having a belt angle within ±5° relative to a circumferential direction. A width Ws of the reinforcing layer and a cross-sectional width Wca of the carcass layer satisfy 0.60≤Ws/Wca≤0.70. The cross belts are radially outward of the large angle belt. The reinforcing layer is radially inward of the pair of cross belts. A width Wb2 of a wider cross belt of the pair and Wca satisfy 0.79≤Wb2/Wca≤0.89.

Provided is a pneumatic tire that includes a belt reinforcing layer formed of an organic fiber cord. A belt layer disposed on an outer circumferential side of a carcass layer in a tread portion is formed of monofilament wires having a wire diameter of 0.30 mm or more and 0.45 mm or less. The belt reinforcing layer is disposed on an outer circumferential side of the belt layer, is formed of an organic fiber cord that is made of a polyethylene terephthalate fiber and has an intermediate elongation under 2.0 cN/dtex load of from 2.0% to 4.0%.

A radial tire (1) for a heavy-duty vehicle of construction plant type, and to reduce the risk of tire tread separation when running over sharp stones, while at the same time ensuring that the crown reinforcement exhibits good resistance to cracking. The tire (1) has a protective reinforcement (50) having three protective layers (51, 52, 53), comprising metal reinforcers that respectively have a diameter (D1, D2, D3) and are distributed at an axial spacing (P1, P2, P3). According to the invention, with Alpha1, Alpha2 and Alpha3 being the angles of the reinforcers of the respective layers (51, 52, 53) with the circumferential direction, the following relationships are satisfied:

15°≤|Alpha1|≤40°

15°≤|Alpha2|≤40°

Alpha1*Alpha2≤0

35°≤|Alpha3|≤75°

As regards the differences between the angles of the reinforcers of the protective layers, the following relationship in terms of absolute values applies:

|(Alpha1−Alpha3)|≥10°

|(Alpha2−Alpha3)|≥10°

The pneumatic tire includes a carcass layer, a belt layer disposed on an outer side of the carcass layer in a radial direction, and a tread rubber disposed on an outer side of the belt layer in the radial direction. Additionally, the carcass layer has a cord angle of 80° or more and 100° or less. Additionally, the belt layer is formed by layering a first reinforcing belt, a second reinforcing belt that is narrower than the first reinforcing belt, and an auxiliary belt that is spaced apart from a tire equatorial plane and disposed between the carcass layer and the first reinforcing belt. Additionally, the first reinforcing belt and the second reinforcing belt have cord angles of 11° or more and 30° or less, and the auxiliary belt has a cord angle of 55° or more and 70° or less.

A rubberized reinforcing ply (1) for articles consisting of an elastomeric material, preferably for vehicle tires, wherein the reinforcing ply (1) has a multiplicity of textile strengthening members (2) which are arranged parallel to and spaced apart from one another, wherein each textile strengthening member (2) is composed of at least one twisted multifilament yarn, and wherein the textile strengthening member (2) is not composed of the material rayon. The reinforcing ply (1) satisfies the following condition: (D.sup.2/E.sub.0) in mm corresponds to a value in a range from 0.22 mm to 0.38 mm, and the reinforcing ply (1) has a strength of >10 kN/dm, where D is the diameter of the textile strengthening member (2) in mm and lies in a range from 0.38 mm to 0.52 mm, and where E.sub.0=100/epdm.

A passenger vehicle tire having rolling resistance without negatively affecting the grip and behaviour. The tread (2) has a radial height H.sub.S between 5 mm and 8 mm, a volumetric void ratio T.sub.EV between 22% and 30%, a total volume V.sub.CP of the main voids (241) at least equal to 80% of the total volume V.sub.C of the voids (24), and comprises an elastomeric compound having a glass transition temperature T.sub.g between 22° C. and 5° C., a Shore A hardness between 45 and 65, and a dynamic loss tgδ at 23° C. at least equal to 0.13 and at most equal to 0.39. The metal reinforcers of the working layers (41, 42) are steel monofilaments having a cross section S with a smallest dimension Dmin between 0.20 mm and 0.50 mm. The monofilaments distributed at a density d.sub.T between 100 threads/dm 200 threads/dm, each working layer (41, 42) having a mean radial thickness E.sub.T between D+0.1 mm and D+0.6 mm.

A pneumatic radial tire is provided that includes belt layers disposed on an outer circumferential side of a carcass layer in a tread portion, and a belt cover layer disposed on an outer circumferential side of the belt layers, the belt cover layer including organic fiber cords helically wound along a tire circumferential direction, the belt layers including steel cords arranged at an incline with respect to the tire circumferential direction in such a manner as to intersect one another between the layers, each of the belt layers having a bending rigidity of 16500 N.Math.mm.sup.2/.sub.50 mm or less per 50 mm width in a direction orthogonal to a longitudinal direction of the steel cords, and the belt cover layer including organic fiber cords having an elongation of 2.0% to 4.0% under a load of 2.0 cN/dtex, the organic fiber cords being helically wound along the tire circumferential direction.

A tire set for a tricycle having one first wheel and two second wheels includes one first tire to be mounted on the first wheel and two second tires to be mounted on the second wheels. Each of the second tires has a cornering power of 50% or more and less than 100% of a cornering power of the first tire.