Abstract: 1. A rubber composition for a tire tread containing: (i) 100 parts by weight of a diene rubber, and (ii) 1 to 20 parts by weight of an elastic gas-encapsulated thermoplastic resin hollow particle having a particle size of 5-300 .mu.m, which is obtained by expanding, upon heating during vulcanization, a thermally expansible thermoplastic resin containing an encapsulated liquid or solid substance capable of generating a gas by vaporization, decomposition or chemical reaction upon heating to form the hollow-type expanded particle and, optionally containing (iii) 1 to 20 parts by weight of a short fiber or (iv) 1 to 20 parts by weight of a hard particle.

Abstract: Rubber compositions are disclosed for automobile tire treads. One or more SBR rubbers of higher than -40.degree. C. in Tg are combined with carbon black of specified N.sub.2 SA, DBP, .DELTA.DBP and .DELTA.Dst qualities. The resulting composition has enhanced tan .delta. at 0.degree. C. and 60.degree. C., breaking strength, breaking energy and abrasion resistance characteristics.

Abstract: A rubber composition for use in steel-belted automobile tires containing specified amounts of a partial condensate of hexaethylolmelamine pentamethylether, a cresol resin, sulfur and a cobalt resin of an organic acid, thereby exhibiting improved adhesion to metal in warm water after vulcanization and increased extension on break after aging.

Abstract: A rubber composition for the manufacture of automotive vehicle tires suitably as a bead filler therefor. The composition comprises specified proportions of carbonblack, a modified novolak phenolic resin, hexamethylenetetramine and a polymeric cardanol based on a starting rubber component such that the resulting rubber composition has a relatively low rigidity prior to vulcanization and a relatively high dynamic modulus after vulcanization.

Abstract: A rubber composition for steel-belted automobile tires containing selected amounts of partial condensates of hexamethylolmelamine pentamethylether, cresol resin, sulfur and cobalt salts of organic acid, to improve its warm water to steel cords in the tire and increased tensile strength.

Abstract: A rubber composition for tire treads which comprises 100 parts by weight of a rubber component comprising 10 to 100 parts by weight of a styrene-butadiene copolymer rubber produced by a solution polymerization and 90 to 0 parts by weight of at least one of other diene rubbers having a glass transition temperature (Tg) of -60.degree. C. at lowest, and at least 70 parts by weight of a carbon black mixed in the rubber component, the styrene-butadiene copolymer rubber having a styrene content of 45 to 65% by weight, a content of butadiene derived vinyl groups of 20 to 70 parts by weight and a content of a styrene sequence consisting of not less than 8 bonded styrene monomer units of at largest 10% by weight of the above styrene content.