An object of the present invention is to provide: a rubber-fiber composite obtained by coating a core-sheath fiber with a rubber, in which adhesion between the rubber and the fiber is improved and which is thereby allowed to exhibit an improved durability as compared to conventional rubber-fiber composites when used as a reinforcing material; a rubber-resin composite; and a pneumatic tire using the same. The rubber-fiber composite is obtained by coating a reinforcing material with a rubber, which reinforcing material is composed of a core-sheath type composite fiber whose core portion is constituted by a high-melting-point resin having a melting point of 150 C. or higher and sheath portion is constituted by an olefin-based polymer having a melting point lower than that of the high-melting point resin.

Provided are: a rubber-reinforcing fiber, in which adhesion between a rubber and a fiber is enhanced and which is thereby capable of further improving the durability than before when used as a reinforcing material; a rubber-fiber composite; and a pneumatic tire using the same. The rubber-reinforcing fiber includes a core-sheath type composite fiber whose core portion is composed of a high-melting-point resin (A) having a melting point of 150 C. or higher and sheath portion is composed of a resin material (B) having a melting point lower than that of the high-melting point resin (A). The resin material (B) includes an olefin-based copolymer composition (X) which contains two or more olefin-based polymers selected from a propylene--olefin copolymer (C1), a propylene-nonconjugated diene copolymer (C2), an ionomer (C3) whose degree of neutralization with a metal salt of an olefin-based copolymer containing a monomer of an unsaturated carboxylic acid or anhydride thereof is 20% or higher, and an olefin-based homopolymer or olefin-based copolymer (D) (excluding (C1) and (C2)).

A pneumatic tire 2 includes a buttress reinforcing layer 22. A carcass 12 includes a first ply 38 and a second ply 40. The first ply 38 and the second ply 40 each have a main portion that is extended on and between beads 10 on both sides. The buttress reinforcing layer 22 extends along the first ply 38 and the second ply 40 between the first ply 38 and the second ply 40. An outer end 22a of the buttress reinforcing layer 22 is disposed inward of a shoulder region S of a tread 4 in a radial direction. An inner end 22b of the buttress reinforcing layer 22 is disposed at a maximum width position of the tire or disposed outward of the maximum width position of the tire in the radial direction.

Tire comprising two beads comprising a bead wire and a carcass anchored around the two bead wires by turning back, a squat filler of small height, a sidewall stiffening reinforcement which is metallic, an outer strip of soft rubber compound, placed axially on the outside of the carcass and of the filler, and a protective layer of rubber compound, wherein the assembly formed by the stiffening reinforcement and the outer strip has a thickness EB(R) and the protective layer has a thickness EE(R), R being the distance with respect to the radially innermost point of the bead wire, and wherein the thicknesses EB(R) and EE(R) satisfy a set of geometric conditions.

Tire having two beads having an annular reinforcing structure and a carcass reinforcement anchored in the two beads by a turn-up. Each bead has a bead rubber filler extending a radial distance from the radially innermost point of the annular reinforcing structure of the bead. The radial distance is not more than 10% of the tire's radial height. A sidewall has rigidifying metal reinforcing elements oriented along an angle not more than 10 to the circumferential direction and positioned with the distance between the radially innermost point of the annular reinforcing structure and the radially outer end of the rigidifying reinforcement between 20% and 40%, inclusive, of the tire's radial height and with the distance between the radially innermost point of the annular reinforcing structure and the radially inner end of the rigidifying reinforcement not more than 20% of the tire's radial height.

In an apex 34 of a tire 2, a reinforcing portion 48 is located inward of a main body 46 in an axial direction. When a position on an outer surface of the tire 2 at which position a height from a BBL is 14 mm is defined as a first point P1 and a position on the outer surface of the tire 2 at which position a height from the BBL is 20 mm is defined as a second point P2, the reinforcing portion 48 overlaps the first point P1 and the second point P2 in a radial direction. A loss tangent of the reinforcing portion 48 is equal to a loss tangent of the main body 46 or less than the loss tangent. A hardness of the reinforcing portion 48 is equal to a hardness of the main body 46 or greater than the hardness.

This tire is provided with reinforcing cord layers that reinforce a bead part. The reinforcing cord layers are such that at the bead part at the inner side of vehicle mounting, the number of layers of the reinforcing cord layers with respect to a bead filler is greater at the inner side in the direction of tire width compared to the outer side in the direction of tire width with respect to the bead filler, and at the bead part at the outer side of vehicle mounting, the number of layers of the reinforcing cord layers with respect to the bead filler is greater at the outer side in the direction of tire width compared to the inner side in the direction of tire width with respect to the bead filler.

A tire that comprises a knit (44) comprising: columns (C1, C2, C3, C4) of loops (B), the loops (B) of one and the same column (C1, C2, C3, C4) being arranged one after the other substantially in an overall direction (X1) referred to as the main direction; and rows (R1, R2, R3, R4) of loops, the loops (B) of one and the same row (R1, R2, R3, R4) being arranged one beside the other substantially in an overall direction (Z1) referred to as the transverse direction.

The knit (44) has, in the main overall direction (X1) and/or the transverse overall direction (Z1), a force at 100% elongation greater than or equal to 250 N, the force at 100% elongation being determined from a force-elongation curve obtained by applying standard ISO 13934-1:2013 to the knit (44) embedded in a standard elastomer matrix.