A rubber-metal adhesion promoter characterized by including a compound (1) represented by the following general formula (A): (in the formula, Z represents a structure selected from the following formulae (z-1) to (z-4); M represents titanium or zirconium; and (RCOO) represents a residue of an aliphatic carboxylic acid having 2 to 25 carbon atoms)

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A tire includes a circular tire frame member formed from a frame-resin material and a covered cord member. The covered cord member includes a reinforcing cord provided in the tire frame member and extending along a tire circumferential direction, a covering-resin layer formed from a covering-resin material, covering the reinforcing cord, and bonded to the tire frame member, and a bonding-resin layer. The bonding-resin layer is formed from a bonding-resin material having an elastic modulus higher than that of the covering-resin material, is interposed between the reinforcing cord and the covering-resin layer, bonds the reinforcing cord and the covering-resin layer together, and has a layer thickness thinner than a layer thickness of the covering-resin layer.

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 rubber-metal adhesion promoter characterized by including: a metal salt (1) of a carboxylic acid which is a metal salt of an aliphatic carboxylic acid having 2 to 25 carbon atoms and in which the metal is bismuth, copper, antimony, silver or niobium; or a compound (2) represented by the following general formula (A): [wherein Z represents a structure selected from the following formulae (z-1) to (z-4); M represents bismuth, copper, antimony, silver or niobium; (RCOO) represents a residue of an aliphatic carboxylic acid having 2 to 25 carbon atoms; and x represents the valence of M minus 1].

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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.

In a pneumatic tire, a bead filler is on an outer circumference of a bead core, a carcass turned up end is inward of an outer diameter side end of the bead filler, the carcass end is spaced from a carcass body, a steel reinforcement is in each bead, a sidewall rubber extends from the sidewall to the bead, and a support layer is between the bead filler and the sidewall rubber to cover the carcass end and an end of the steel reinforcement, the support layer extending toward an outer diameter side and contacting the carcass body on an outer diameter side of the bead filler outer diameter side end, and a 100% modulus of the support layer is at least 1.5 times that of the bead filler, and the sidewall rubber, the bead filler and the sidewall rubber being adjacent to the support layer.

Provided is an elastomer reinforcement cord with improved rust inhibition. An elastomer reinforcement cord (10) includes metal filaments and a polymer material. The elastomer reinforcement cord (10) has a multi-strand structure which includes: at least one core strand (21) formed by twisting plural metal filaments (1a) and (1b) together; and two or more sheath strands (22) each formed by twisting plural metal filaments (11a) and (11b) together, and in which the sheath strands are twisted together around the core strand. In a region surrounded by a line connecting the centers of the metal filaments constituting the outermost sheath layer of the core strand at a cross-section in a direction orthogonal to an axial direction after vulcanization of the core strand, when a region occupied by other than the metal filaments is defined as a gap region, a filling rate, which is a ratio of the area of the polymer material with respect to the gap region, is 52% to 120%.

Provided is an elastomer reinforcement cord in which the problem of stress concentration at an interface between an elastomer and a metal cord is solved and the durability is thereby improved. The elastomer reinforcement cord includes metal filaments (1a) and (1b), and a polymer material (3) having a melting point or softening point of 80° C. to 160° C. The elastomer reinforcement cord has a core (11) and at least one sheath layer (12). In a region surrounded by a line connecting the centers of the metal filaments constituting the outermost sheath layer at a cross-section in a direction orthogonal to an axial direction after vulcanization, when a region occupied by other than the metal filaments is defined as a gap region, the polymer material is contained in this gap region, and a filling rate, which is a ratio of the area of the polymer material, is higher than 120%, taking the area of the gap region as 100%.

In a pneumatic tire, a bead filler is radially outward of a bead core, a carcass turned up end is radially inward of an outer side end of the bead filler, the turned up end is spaced from a carcass body, a reinforcement layer is laterally outward of the bead filler, a sidewall rubber extends from a sidewall to the bead, an inner rubber reinforcing layer is between the bead filler and the reinforcement layer and adjacent to the turned up end, a crack suppression layer is between the reinforcement layer and the sidewall rubber, the crack suppression layer extends 5 mm or more from where the crack suppression layer overlaps, the reinforcement layer contacts the carcass body radially outwardly of the bead filler, and a 100% modulus Kc.sub.M100 of the crack suppression layer is at least 1.5 times that of the sidewall rubber.