In a tire 2 according to the present invention, belt cords 42 included in a belt 22 each include a twisted string obtained by twisting together four filaments 46. Each belt cord 42 has an elliptical cross-section. On the cross-section, the ratio of the length of the minor axis to the length of the major axis is greater than or equal to 0.67 and not greater than 0.94. A first filament 46a and a third filament 46c are disposed along the minor axis. The first filament 46a and the third filament 46c are each in contact with a second filament 46b and a fourth filament 46d, or the first filament 46a is in contact with the third filament 46c.

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.

A tire includes a carcass structure including at least one carcass ply, a belt structure applied in a radially outer position with respect to the carcass structure and a tread band applied in a radially outer position with respect to the belt structure. The belt structure includes at least one reinforcing strip incorporating a plurality of reinforcing elements arranged substantially in the circumferential direction. The reinforcing elements include at least one high-elongation metal cord. The metal cord includes a plurality of intertwined strands and each strand includes a plurality of filaments. Advantageously all the filaments of each strand have a diameter not greater than 0.175 mm.

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.

Provided is a pneumatic tire. A belt cover layer made of an organic fiber cord spirally wound along the tire circumferential direction is provided on the outer circumferential side of a belt layer in a tread portion, and a polyethylene terephthalate fiber cord of which the elastic modulus under a load of 2.0 cN/dtex at 100° C. is in the range of 3.5 cN/(tex.Math.%) to 5.5 cN/(tex.Math.%) is used as the organic fiber cord. The coating rubber covering the organic fiber cord contains one or more of natural rubber, styrene-butadiene rubber, or butadiene rubber as a rubber component. The coating rubber is formed of a rubber composition in which the content of natural rubber in the rubber component is 50 mass % or more, and 5.0 parts by mass to 9.0 parts by mass of zinc oxide is blended per 100 parts by mass of the rubber component.

In a pneumatic tire, a belt cover layer is provided on an outer circumferential side of a belt layer in a tread portion and includes organic fiber cords helically wound along a tire circumferential direction. As the organic fiber cord, a polyethylene terephthalate fiber cord is used which has a single yarn size fineness of 700 dtex or less and in which the number of twists is 30 twists or more/100 mm. A layer thickness of the belt cover layer is 1.6 times or more as large as a cord diameter of the organic fiber cord.

A radial tire (1) for a heavy-duty vehicle of construction plant type, and aims to increase the rupture strength of the hoop reinforcement thereof having circumferential layers, ensuring satisfactory endurance of the crown reinforcement thereof. According to the invention, the at least one circumferential hooping layer (71, 72) comprises a median portion (711, 721) having a median width (L11, L21) and a median tensile elastic modulus (E11, E21), and two lateral portions (712, 722) that axially extend the median portion (711, 721) on either side and each have a lateral width (L12, L22) and a lateral tensile elastic modulus (E12, E22), the lateral width (L12, L22) is at least equal to 0.05 times the median width (L11, L21), and the lateral tensile elastic modulus (E12, E22) is at most equal to 0.9 times the median tensile elastic modulus (E11, E21).

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°

A pneumatic tire including a belt constituted by at least one belt layer on a tire radial-direction inner side of a tread portion. The belt layer includes a reinforcing element containing plural metal filaments aligned in a single row without being twisted together is embedded in an elastomer. The tread portion includes: two or more circumferential main grooves arranged within a width of a ground-contact surface; and land portions, and widthwise sipes are arranged in at least one of center land portion. The widthwise sipes each include: a linear portion linearly extending from the surface of the tread portion toward the tire radial-direction inner side; and a bent portion extending from the linear portion toward the tire radial-direction inner side, and the length of the linear portion increases from an extending length center portion of each widthwise sipe toward at least one of tread widthwise end portions.