Abstract: A rubber composition that is capable of providing vulcanized rubber excellent in the abrasion resistance without the deterioration of the crack resistance and the low heat generation property is provided. The rubber composition contains: (A) a rubber component; (B) carbon black having a CTAB specific surface area of 110 to 160 m2/g, a half value width ?D50 of a peak including a Stokes equivalent diameter Dst obtained by a centrifugal sedimentation method of 60 nm or less, and ?D50/Dst of 0.95 or less; and (C) silica having a CTAB specific surface area of 200 m2/g or more, has a total amount of a content (b) of the carbon black (B) and a content (c) of the silica (C) of 30 to 80 parts by mass per 100 parts by mass of the rubber component (A), and has (b)/(c) of (60 to 85)/(40 to 15).

Abstract: An object of the present disclosure is to provide a rubber composition having satisfactorily low hysteresis loss, while maintaining high wear resistance. In order to achieve the object, a rubber composition contains: a rubber component having diene-based rubber therein; and a tetrazine compound.

Abstract: A rubber composition that is capable of providing vulcanized rubber excellent in the abrasion resistance without the deterioration of the crack resistance and the low heat generation property is provided. The rubber composition contains: (A) a rubber component; (B) carbon black having a CTAB specific surface area of 110 to 160 m2/g, a half value width ?D50 of a peak including a Stokes equivalent diameter Dst obtained by a centrifugal sedimentation method of 60 nm or less, and ?D50/Dst of 0.95 or less; and (C) silica having a CTAB specific surface area of 200 m2/g or more, has a total amount of a content (b) of the carbon black (B) and a content (c) of the silica (C) of 30 to 80 parts by mass per 100 parts by mass of the rubber component (A), and has (b)/(c) of (60 to 85)/(40 to 15).

Abstract: A pneumatic radial tire for a passenger car having a pair of bead portions and a carcass having at least one carcass ply toroidally extending between a pair of bead cores embedded in the respective bead portions and containing organic fiber cords. The organic fiber cord is a polyketone fiber cord satisfying the following equation: ???0.01E+1.2 and ??0.02, where ? is a thermal shrinkage stress at 177° C. (cN/dtex) and E is an elastic modulus at 25° C. under a load of 49N (cN/dtex). The cord has a ply-twisting coefficient N1 of 0.35-0.70 and a cable-twisting coefficient N2 of 0.50-0.95, where N1=n1×(0.125×D1/?)1/2×10?3, N2=n2×(0.125×D2/?)1/2×10?3, n1 is a ply twisting number (turns/10 cm), n2 is a cable twisting number (turns/10 cm), D1 is dtext of ply-twisted yarn, D2 is a total dtex, and ? is a specific gravity of the cord (g/cm3).

Abstract: This invention relates to a tire having an improved durability in the run-flat running without damaging the ride comfort in the usual running, and more particularly to a run-flat tire comprising a sidewall portion provided with a side reinforcing rubber layer having a crescent shape at section wherein a cord layer including a polyketone fiber cord satisfying the following conditions of the following equations (I) and (II): ???0.01×E+1.2??(I) ??0.02??(II) [wherein ? is a thermal shrinkage stress at 177° C. (cN/dtex) and E is an elastic modulus at 25° C. under a load of 49 N (cN/dtex)] is disposed in at least a part of a region A ranging from a belt end to a maximum width part of a tire side portion and a region B ranging from a neighborhood of a bead core to a bead filler.

Abstract: A pneumatic tire for a motorcycle, wherein the tire is optimized in the ground contact shape and the ground contact pressure distribution during high-speed running to achieve excellent driving stability, is provided. Furthermore, a pneumatic tire for a motorcycle, wherein the tire is optimized in the ground contact shape and the ground contact pressure distribution during high-speed running to realize excellent gripping force to stabilize the behavior of the tire near its cornering limit and excellent cornering ability, is provided. Provided is a pneumatic tire for a motorcycle, which employs a multifilament-twist polyketone fiber cord, as a reinforcing material, having a total dtex value of 1000 to 20000 dtex per cord and satisfying the relationships represented by the following Expressions (I) and (II): ???0.01E+1.2??(I) ??0.02??(II) (wherein, E is an elastic modulus (cN/dtex) at 25° C. under a load of 49 N, and ? is a heat shrinkage stress (cN/dtex) at 177° C.).

Abstract: This invention relates to a tire having an improved durability in the run-flat running without damaging the ride comfort in the usual running, and more particularly to a run-flat tire comprising a sidewall portion provided with a side reinforcing rubber layer having a crescent shape at section wherein a cord layer including a polyketone fiber cord satisfying the following conditions of the following equations (I) and (II): ???0.01×E+1.2 ??(I) ??0.02 ??(II) [wherein ? is a thermal shrinkage stress at 177° C. (cN/dtex) and E is an elastic modulus at 25° C. under a load of 49 N (cN/dtex)] is disposed in at least a part of a region A ranging from a belt end to a maximum width part of a tire side portion and a region B ranging from a neighborhood of a bead core to a bead filler.

Abstract: This invention relates to a pneumatic radial tire for a passenger car comprising a pair of bead portions and a carcass comprised of at least one carcass ply toroidally extending between a pair of bead cores embedded in the respective bead portions and containing organic fiber cords, characterized in that the organic fiber cord constituting the carcass ply is a polyketone fiber cord satisfying the following equation (I): ???0.01E+1.2 and ??0.02??(I) [wherein ? is a thermal shrinkage stress at 177° C. (cN/dtex) and E is an elastic modulus at 25° C. under a load of 49N (cN/dtex)] and the polyketone fiber cord has a ply-twisting coefficient N1 defined by the following equation (II) of 0.35-0.70 and a cable-twisting coefficient N2 defined by the following equation (III) of 0.50-0.95: N1=n1×(0.125×D1/?)1/2×10?3??(II) N2=n2×(0.