A tire (1) for a heavy construction plant vehicle with satisfactory compromise between the breaking strength of its circumferential hoop reinforcement (7), having an axial width LF and having a circumferential hooping layer (71, 72) with elastic metallic reinforcers having a structural elongation AS and a force at break FR, and forming an angle at most equal to 5° with the circumferential direction (XX), and the endurance of its working reinforcement (6), formed by two working layers (61, 62) with inextensible metallic reinforcers, the mean angle AM of which with the circumferential direction (XX′) is at least equal to 15° and at most equal to 45°. The axial width LF, the structural elongation As, the force at break Fr and the mean angle AM satisfy the relationship:

Zn/Z0*(T0+(a1+a2*As)/AM+b*LF*(AM−A0)/A0+c*AM)<Fr/CS, where Zn is the nominal load, Z0=100 t, T0=7000 N, a1=−230,000 N*°, a2=−160,000 N*°/%, b=−34,000 N/m, A0=29°, c=550 N/°, CS>=1.

A tire for a heavy-duty vehicle of construction plant type comprises a crown reinforcement (35) radially on the inside of a tread (10) and radially on the outside of a carcass reinforcement (50). The crown reinforcement (35) comprises: at least one “low-modulus” layer (20) formed of elastic metal reinforcers having a structural elongation at least equal to 0.4%, and a total elongation at break at least equal to 3%, and a tensile elastic modulus of between 40 GPa and 130 GPa; at least one “rigid” layer (30) formed of rigid metal reinforcers, the structural elongation of which is less than or equal to 0.2% and the tensile elastic modulus of which is between 140 GPa and 200 GPa. The ratio of the breaking tension of the rigid layer to that of the low-modulus layer is greater than or equal to 1.2.

The invention relates to a metallic reinforcing cord (10) for tyres for vehicle wheels, comprising: —a) a plurality of metallic wires (11) twisted to one another with a single twisting pitch (P), or—b) a single metallic wire twisted with at least one second metallic wire with a single twisting pitch, or—c) a plurality of first metallic wires twisted to one another with a first twisting pitch to define a first strand of metallic wires and at least one second metallic wire twisted with said first strand of metallic wires with a second twisting pitch equal to or different from the first twisting pitch. The metallic reinforcing cord (10) has a part load elongation greater than or equal to 1%.

Provided is a steel cord for rubber article reinforcement, which has both the tensile strength in the cord axial direction and the strength in the shear direction at higher levels. A steel cord (10) for rubber article reinforcement includes: a single core strand (11) having a layer-twisted structure; and plural sheath strands (12) each having a layer-twisted structure, and the sheath strands (12) are twisted around the core strand (11). In the sheath strands (12), a ratio between the diameter of a core filament (12a) and the diameter of a sheath filament (12b) is 0.75 to 0.85, and a ratio between the strength of the core filament (12a) and the strength of the sheath filament (12b) is 0.55 to 0.7.

A cord for reinforcing elastomers excellent in adhesion to elastomers such as rubber is provided. The cord is a cord for reinforcing elastomers (10) that includes metallic filaments (1) and a resin filament (2) twisted together, the resin filament (2) being made from a polymeric material having a melting point or softening point of 80 to 160° C. The cord for reinforcing elastomers includes a core and at least one sheath layer, wherein, after vulcanization, a distance w between metallic filaments (1b) forming an outermost sheath layer is 100 μm or less, and, on a cross section of the cord taken along a direction orthogonal to an axial direction, a filling ratio, which is a ratio of an area of a polymeric material (3) derived from the resin filament (2) to a gap region is 52 to 120%, where the gap region is defined as a portion occupied by a material other than the metallic filaments (1) within a region formed by connecting the centers of the individual metallic filaments (1b) constituting the outermost sheath layer.

Provided is an organic fiber doubled-and-twisted yarn cord the twist structure of which is uniform and with which it is possible to reduce weight. A doubled-and-twisted yarn cord comprising an organic fiber characterized in that a total fineness is 5000-15000 dtex inclusive, a coefficient of twisted yarn length difference between untwisting yarns constituting the doubled-and-twisted yarn cord that is obtained by an expression: coefficient of twisted yarn length difference (%)=(maximum value of yarn length difference between untwisting yarns)/(average value of yarn length of untwisting yarns)×100 is 1.5% or less, and breaking strength is 7.0 cN/dtex or greater.

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 metres≤S≤+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.

In a pneumatic tire including a carcass layer mounted between a pair of bead portions and a belt reinforcing layer disposed on an outer circumferential side of the carcass layer, the carcass layer is formed of a carcass cord made of an organic fiber cord, an elongation at break of the carcass cord is set to 20% or more, an elongation under a load of 1.5 cN/dtex of the carcass cord on the inner circumferential side of the belt layers is set to from 5.5% to 8.5%, the belt reinforcing layer is formed of a cover cord made of an organic fiber cord, and a tensile strength of the cover cord per width of 50 mm at a 3.0% elongation is set to from 2.8 kN to 4.0 kN.

A tire includes a carcass, a tread disposed radially outward of the carcass, a sidewall including a shoulder extends toward the tread, and a reinforcing structure positioned radially between the carcass and the tread. The reinforcing structure includes a plurality of belts extending axially toward the shoulder and an overlapping spiral wound strip positioned at a radially outermost portion of the reinforcing structure. The overlapping spiral wound strip includes a uniform width having groups of four first cords with a single second cord therebetween. The first cords include a hybrid construction and the second cords include a single material construction.

A pneumatic tire includes a ply having a plurality of cords each having an average cord diameter D, and a sidewall rubber having a loss tangent tan δ The plurality of cords each includes a plurality of filaments twisted together, the plurality of filaments each having an outer diameter d. The plurality of cords each has a ratio D/d of the average cord diameter D to the outer diameter d being equal to or more than 28. The ratio D/d and the loss tangent tan δ of the sidewall rubber satisfy the following formula;

(tan δ)/(D/d)*1000≤5.5.