This disclosure aims to provide a tire having excellent braking performance on dry road surface and on wet road surface, and having excellent steering stability. This disclosure is a tire comprising a tread 10, wherein: the tread 10 has a plurality of circumferential grooves extending continuously in a tire circumferential direction C, the circumferential grooves including circumferential main grooves 21a, 21b, 22 with a cross-sectional area in a tire width direction W of 10 mm.sup.2 or more, and a groove width Lb at a 95% groove depth position with a groove depth of a groove bottom as 100% of at least the circumferential groove 21a located on an outermost side when mounted to a vehicle among the circumferential main grooves 21a, 21b, 22 being 25% to 60% with respect to a groove width Lt on a tread surface.

A modified conjugated diene-based polymer containing: having a weight average molecular weight of 20×10.sup.4 or more and 300×10.sup.4 or less, having a star-branched structure with a conjugated diene-based polymer chain bonded to a modifier residue, wherein the modifier residue has at least 4 silicon atoms, and alkoxy groups and/or hydroxyl groups and the conjugated diene-based polymer chain is bonded to the silicon atom, wherein the number of alkoxy groups and/or hydroxyl groups in the modifier residue is larger than the number of the silicon atoms on average.

A rubber composition based on at least: from 50 to 100 phr of one or more diene elastomers, referred to as very low glass transition temperature (Tg) diene elastomers, having a Tg within a range of from −110° C. to −70° C., selected from butadiene homopolymers, copolymers of butadiene and of a vinylaromatic monomer, having a content of vinylaromatic units of between 0 and 5% by weight, and mixtures thereof a reinforcing filler a crosslinking system; and from 50 to 150 phr of at least one hydrocarbon resin predominantly composed of units derived from terpene and phenol monomers, the resin having a content of aromatic protons of greater than 15%.

A polymer composition characterized by containing a diene-based polymer (A) and a filler (B), the diene-based polymer (A) containing the polymer (A1) and the polymer (A2) described below. Polymer (A1): A diene-based polymer that is a polymer of a conjugate diene compound or a copolymer of the conjugate diene compound and an aromatic vinyl compound, the diene-based polymer being modified with a polar group having affinity for the filler (B), wherein the aromatic vinyl content is 25 mass % or less, and the modification rate is 30-100%. Polymer (A2): A diene-based polymer that is a copolymer of an aromatic vinyl compound and a conjugate diene compound including 1,3-butadiene, wherein the aromatic vinyl content is 30-50 mass %, the vinyl content is 5-30 mass %, and the peak molecular weight in terms of polystyrene measured using gel permeation chromatography is 400,000 to 2,000,000.

The present invention provides a rubber composition for tires which provides a balanced improvement in ice performance, fuel economy, and abrasion resistance, and a pneumatic tire containing the rubber composition. The present invention relates to a rubber composition for tires containing a rubber component including at least 80% by mass in total of at least one of an isoprene-based rubber, a polybutadiene rubber, or a styrene-butadiene rubber, the rubber composition containing, per 100 parts by mass of the rubber component, 10 to 120 parts by mass of silica, 0.2 to 10 parts by mass of a tetrazine compound of formula (1), and 1 to 50 parts by mass of a low-molecular-weight diene polymer having a weight average molecular weight of 200,000 or less.

This invention is based upon the discovery that benzoxazine resins can be incorporated into certain rubber compositions to increase the stiffness thereof without increasing hysteresis or reducing tear strength. Such benzoxazine resin reinforced rubber formulations can accordingly be used beneficially in components of rubber products where high stiffness is desirable. Since these benzoxazine resin reinforced rubbers do not increase levels of hysteresis, they can be used in tires components, such as apexes, chaffers, and high stiffness tread blocks without compromising fuel efficiency. This invention more specifically reveals a radial tire having an apex, a chaffer, or a hard tread block segment which is comprised of a rubbery polymer and a benzoxazine resin.

A rubber composition for tires according to an embodiment is produced by kneading a diene rubber, silica, and a granular carbon nanotube prepared as a binder-coated, granulated carbon nanotube. A tire according to an embodiment comprises the rubber composition.

A tire has a sub-layer (7) made up substantially of a first base layer (71) disposed radially on the crown reinforcement (5) and axially between the median plane (CP) and a transition edge (711), the transition edge (711) being situated axially between the median plane (CP) and a shoulder (60), said first base layer (71) being made up of a rubber compound of given stiffness A, a second base layer (72) disposed radially on the crown reinforcement (5) and axially between the transition edge (711) and a shoulder end (721), said second base layer (72) being made up of a rubber compound of given stiffness B, a covering layer (73) disposed radially on the first base layer (71) and on the second base layer (72) and radially on the inside of the tread (6) and axially at least in sections situated between the median plane (CP) and the shoulder end (721), said covering layer (73) being made up of a rubber compound of given stiffness C, the stiffness B being less than the stiffness A, which is less than the stiffness C, and the stiffness C being greater than the stiffness M.

A pneumatic tire includes a surface and is rotatable about a center axis. The surface of the pneumatic tire includes a ground colored region including a surface of rubber, and an image recognition belt region including a colored region provided in a circumferential direction of the center axis.

A rubber composition which contains (A) an organosilicon compound represented by formula (1) and gives a cured object satisfying desired fuel (or power)-saving tire properties.

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(R.sup.1 represents an alkyl or aryl group, R.sup.2 represents an alkyl or aryl group, e, f, and g each indicate a number larger than 0 and satisfy g/(e+f+g)<0.05, and m is an integer of 1-3.)