A pneumatic radial tire includes a pair of opposing bead areas, in which each bead area includes a bead core and a bead apex. At least one carcass reinforcing ply includes a turn up at each bead core, and each turn up includes a radially outward end. A pair of chippers is disposed axially inwardly of each turn up outward end, in which the pair of chippers includes a first chipper and a second chipper. The first chipper is disposed axially inwardly of the bead apex, and the second chipper is disposed axially outwardly of the first chipper and axially inwardly of the bead apex. Forces due to deflection of the tire are limited by the pair of chippers to reduce stresses along each turn up.

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.

A pneumatic tire for heavy loads comprising a bead core, a bead filler arranged on the outside in a tire radial direction of the lead core, a steel cord-containing carcass ply wound up on the outside from the inside in a fire axis direction around the bead core, a steel cord-containing chafer provided so as to cover the carcass ply from the inside in the tire radial direction, and a reinforcing sheet comprising a rubber and a cotton kneaded therein and interposed between the bead core and the carcass ply. The tire can improve durability of a bead part.

A tire for a motor vehicle comprising: two beads (20); two sidewalls (30) meeting at a crown (25); at least one carcass reinforcement (160) extending from the beads (20) through the sidewalls (30) as far as the crown (25), the carcass reinforcement (160) having a plurality of carcass reinforcing elements and anchored in the two beads (20) by a turn-up around the annular reinforcing structure (70), so as to form in each bead a main strand (162) and a turn-up strand (163); and a stiffening reinforcement (140) arranged in at least one sidewall of the tire, said stiffening reinforcement (140) having a radially inner end (141) and a radially outer end (142), the stiffening reinforcement being formed of a plurality of stiffening elements oriented at an angle less than or equal to 10? relative to a circumferential direction of the tire.

A pneumatic tire mountable on a 15 tapered specified rim includes a bead core, a carcass, a steel cord reinforcing layer, a bead rubber layer, and a first reinforcing rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 12 mm, a complex modulus of the first reinforcing rubber layer is from 6 MPa to 10 MPa, an elongation at break of the first reinforcing rubber layer is from 300% to 450%, a complex modulus of the second reinforcing rubber layer is from 10 MPa to 15 MPa, and a complex modulus of a shock absorbing rubber layer is from 2 MPa to 6 MPa.

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.

A pneumatic tire mountable on a 15 tapered specified rim includes a bead core, a carcass, a steel cord reinforcing layer, a bead rubber layer, and a first reinforcing rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 8 mm; a side of an outer portion and a side of an inner portion of a bead base portion bend at an inflection point located in a range from 8 mm to 18 mm from the first intersection point; and an angle formed by an extension line drawn from the side of the outer portion inward in the tire radial direction and the side of the inner portion is from 4.5 to 14.5.

A pneumatic tire mountable on a 15 tapered specified rim includes a bead core, a carcass, a steel cord reinforcing layer, a bead rubber layer, an organic fiber reinforced layer, and a first reinforcing rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 12 mm, a complex modulus of the first reinforcing rubber layer is from 6 MPa to 10 MPa, an elongation at break of the first reinforcing rubber layer is from 300% to 450%, and a difference between a first height and a second height is from 3 mm to 15 mm.

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 random copolymer (C) and/or an olefin-based homopolymer or olefin-based copolymer (D) (excluding (C)); and a styrene-based elastomer (E) containing a monomolecular chain in which mainly styrene monomers are arranged in series.

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) contains an olefin-based polymer (X) and a vulcanization accelerator (F).