A pneumatic tire is disclosed and comprises a tread, a belt package located radially beneath the tread, a pair of bead cores, a pair of sidewalls, with each sidewall extending between the tread and each bead core, a carcass comprising a first carcass ply extending under the tread and being anchored to each bead core, wherein the first carcass ply has a reinforced stiffener applied thereto, wherein the carcass further comprising a second carcass ply, wherein the second carcass ply extends under the tread and is anchored to each bead core.

A tire design for a heavy-duty vehicle of construction plant type has a crown reinforcement (40) radially on the inside of a tread (10) and radially on the outside of a carcass reinforcement (70). The carcass reinforcement (70) has at least two carcass layers (50, 60) having metal reinforcers coated in an elastomer compound. The carcass layers (50, 60) have respective stiffnesses per unit width R1, R2. Metal reinforcers of a first carcass layer (50) form, with the circumferential direction (XX′), an angle A1, and those of the second carcass layer form an angle A2, such that the angles A1 and A2, and the stiffnesses R1 and R2, simultaneously satisfy the following three relationships: R1*sin 2(2*A1)+R2*sin 2(2*A2)≥(R1+R2)*) sin 2(30°), and ∥A1|-|A2∥<10°, and 0.7≤R1/R2≤1.3. The metal reinforcers have a critical compression buckling deformation DF at least equal to 2.5% and a compression elastic modulus MC at least equal to 10 GPa.

The pneumatic tire has an annular carcass formed by using a carcass treat in which a carcass cord arranged along the tire width direction is covered with a rubber material, and a belt layer formed by arranging a resin covered cord outside the tire radial direction of the carcass and covered with a resin material along the tire circumferential direction. The treat strength of the carcass treat along the tire width direction is 10 kN/25 mm or more.

Provided is a pneumatic tire enabling improvement of side cut resistance and suppression of increase in mass. A pneumatic tire 1 includes: a tread portion 2; a pair of sidewall portions 3; a pair of bead portions 4 having respective bead cores 5 embedded therein; and a toroidal carcass 6 disposed between the pair of bead portions 4. The carcass 6 includes a first ply 11 extending on and between the pair of bead portions 4, and a second ply 12 disposed, in the tread portion 2, outward of the first ply 11 in a tire radial direction and extending on and between the pair of bead portions 4. The first ply 11 is formed as a layer of first cords. The second ply 12 is formed as a layer of second cords. A thickness of each second cord is 1.1 to 2.0 times a thickness of each first cord.

In a pneumatic tire, at least one carcass layer mounted between a pair of bead portions is formed from a carcass cord formed of an organic fiber cord having filament bundles of organic fibers intertwined together, a fineness based on corrected mass of the carcass cord is from 4000 dtex to 8000 dtex, an intermediate elongation of the carcass cord at a sidewall portion under 1.0 cN/dtex load is from 3.3% to 4.2%, and a ratio G/R of an interlayer rubber gauge G between a body portion and a folded back portion to a cord diameter R of the carcass cord, at a contact region where the body portion and the folded back portion are in contact in the carcass layer, is from 0.50 to 0.60.

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.

In a pneumatic tire, at least one carcass layer mounted between a pair of bead portions is formed from a carcass cord formed of an organic fiber cord having filament bundles of organic fibers intertwined together, a fineness based on corrected mass of the carcass cord is from 4000 dtex to 8000 dtex, an intermediate elongation of the carcass cord at the sidewall portion under 1.0 cN/dtex load is from 3.3% to 4.2%, and an elongation at breakage of the carcass cord is 20% or more, and a ratio G/R of an interval between adjacent carcass cords within the carcass layer at a tire maximum width position to a cord diameter of the carcass cord is from 0.35 to 0.60.

Provided is a tire in which a steel cord applied to a carcass ply has improved corrosion resistance to water penetration, fretting resistance, and cord untwisting resistance. Provided is a tire including a carcass ply (1) as a skeleton. The carcass ply is reinforced by a steel cord including no wrapping filament. The steel cord is composed of a plurality of steel filaments having 3 or more core filaments, at least a part of the surface of each of the plurality of steel filaments is coated with a resin material containing at least an ionomer, and when a resin component contained in the resin material is composed of a single resin, the melting point of the resin material is 150° C. or less, and when the resin component is composed of a composition containing two or more resins, the softening point of the resin material is 150° C. or less.

In a pneumatic tire, at least one carcass layer mounted between a pair of bead portions is formed from a carcass cord formed of an organic fiber cord having filament bundles of organic fibers intertwined together, a fineness based on corrected mass of the carcass cord is from 4000 dtex to 8000 dtex, an intermediate elongation of the carcass cord at a sidewall portion under 1.0 cN/dtex load is from 3.3% to 4.2%, and a ratio G/R of an interlayer rubber gauge G between a body portion and a folded back portion to a cord diameter R of the carcass cord, at a contact region where the body portion and the folded back portion are in contact in the carcass layer, is from 0.50 to 0.60.

The present invention relates to a tire including an aramid cord in the carcass layer, the tire including a carcass layer including a multi-filament aramid cord. The tire of the present invention can maintain the performance of existing performance of tires for trucks and buses by ameliorating weak fatigue resistance while enhancing the fuel efficiency through weight reduction of the carcass cord.