The invention relates to a multi-strand cord (50) comprising an internal layer (CI) of the cord made up of K=1 three-layer (C1, C2, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), the intermediate layer (C2) being made up of M intermediate metallic threads (F2) and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) of the cord made up of L>1 three-layer (C1′, C2′, C3′) external strands (TE) wound around the internal layer (CI) of the cord, with the internal layer (C1′) being made up of Q′ internal metallic threads (F1′), the intermediate layer (C2′) being made up of M′ intermediate metallic threads (F2′) and the external layer (C3′) being made up of N′ external metallic threads (F3′).

The cord (50) has: an endurance criterion SL≤40 000 MPa.Math.mm with

[00001]$SL=\max \left(\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CI}}}{\mathrm{Cp}};\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CE}}}{C_r\times \mathrm{Cp}}\right);$  and a size criterion Ec≥0.46 with Ec=Sc/Se.

The invention relates to a multi-strand cord (50) comprising an internal layer (CI) of the cord made up of K=1 three-layer (C1, C2, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), the intermediate layer (C2) being made up of M intermediate metallic threads (F2) and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) of the cord made up of L>1 three-layer (C1′, C2′, C3′) external strands (TE) wound around the internal layer (CI) of the cord, with the internal layer (C1′) being made up of Q′ internal metallic threads (F1′), the intermediate layer (C2′) being made up of M′ intermediate metallic threads (F2′) and the external layer (C3′) being made up of N′ external metallic threads (F3′).

The cord (50) has: an endurance criterion SL≤40 000 MPa.Math.mm with

[00001]$SL=\max \left(\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CI}}}{\mathrm{Cp}};\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CE}}}{C_r\times \mathrm{Cp}}\right);$  and a size criterion Ec≥0.46 with Ec=Sc/Se.

An apparatus for building tyres for vehicle wheels are described. A substantially cylindrical carcass sleeve, having at least one carcass ply, includes consecutively adjacent strip-like elements laid one after the other around the circumferential extension of a substantially cylindrical deposition surface. Circumferentially consecutive strip-like elements laid one after the other form overlap zones along respective longitudinal edges superimposed on each other. Each overlap zone has, along a longitudinal extension thereof, terminal sections that are laterally opposite with respect to an intermediate section. The intermediate section of each overlap zone has greater width than the width of the terminal sections.

An apparatus for building tyres for vehicle wheels are described. A substantially cylindrical carcass sleeve, having at least one carcass ply, includes consecutively adjacent strip-like elements laid one after the other around the circumferential extension of a substantially cylindrical deposition surface. Circumferentially consecutive strip-like elements laid one after the other form overlap zones along respective longitudinal edges superimposed on each other. Each overlap zone has, along a longitudinal extension thereof, terminal sections that are laterally opposite with respect to an intermediate section. The intermediate section of each overlap zone has greater width than the width of the terminal sections.

In a pneumatic tire including a tread portion, a sidewall portion, a bead portion, a carcass layer mounted between a pair of bead portions, a plurality of main grooves extending in the tire circumferential direction and formed in the tread portion, and a plurality of land portions defined by the main grooves, the carcass layer includes a carcass cord formed of a polyester fiber cord, an elongation at break of the carcass cord is from 20% to 30%, and a groove area ratio SgA in a ground contact region of the tread portion is from 20% to 40%, a groove area ratio SgB in a center region of the tread portion satisfies a relationship 1.1≤SgB/SgA≤1.5, and a depth of the main groove included in the center region is from 5 mm to 8 mm.

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.

A pneumatic radial tire for passenger vehicles of the present disclosure includes a carcass toroidally spanning between a pair of bead portions and including plies of radially arranged cords. A sectional width SW and an outer diameter OD of the tire satisfy a predetermined relational expression. At least one noise reducer is provided on an inner surface of the tire. A ratio L (mm)/S (mm.sup.2) is in a range from 0.02 to 1.5, where L (mm) denotes a circumferential length of the noise reducer and S (mm.sup.2) denotes a cross-sectional area of the noise reducer.

An outer diameter of a pneumatic tire 350 mm or more and 600 mm or less. As RW is defined by a rim width of a rim wheel assembled to the pneumatic tire and SW is defined by a tire width of the pneumatic tire, the relation of 0.78≤RW/SW≤0.99 is satisfied. A carcass has a carcass cord arranged along the tire width direction. The carcass cord is formed of a filament of steel. The outer diameter of the carcass cords is 0.7 mm or less, and a distance between adjacent carcass cords is 4.0 mm or less.

An outermost end of a carcass folded-up portion is located in a tire width direction inside than an end in the tire width direction of the outermost inclined belt layer, in the tire radial direction between a carcass main body portion and the innermost inclined belt layer. A carcass cord in the folded-up portion located on the outermost side of the tire and a belt cord of the outermost inclined belt layer cross each other to be inclined in the same direction in a tire circumferential direction as being from one side toward the other side in the tire width direction, a difference in inclination angle is 30° or less, a width of the outermost inclined belt layer is larger than that of the innermost inclined belt layer, and in-plane rigidity per unit width of the innermost inclined belt layer is higher than that of the outermost inclined belt layer.

An outermost end of a carcass folded-up portion is located in a tire width direction inside than an end in the tire width direction of the outermost inclined belt layer, in the tire radial direction between a carcass main body portion and the innermost inclined belt layer. A carcass cord in the folded-up portion located on the outermost side of the tire and a belt cord of the outermost inclined belt layer cross each other to be inclined in the same direction in a tire circumferential direction as being from one side toward the other side in the tire width direction, a difference in inclination angle is 30° or less, a width of the outermost inclined belt layer is larger than that of the innermost inclined belt layer, and in-plane rigidity per unit width of the innermost inclined belt layer is higher than that of the outermost inclined belt layer.