In a tire, a tread includes a cap layer, an intermediate layer formed such that a loss tangent of the intermediate layer at 30° C. is less than a loss tangent of the cap layer at 30° C., and a base layer formed such that a loss tangent of the base layer at 30° C. is less than the loss tangent of the intermediate layer at 30° C. The intermediate layer is disposed outwardly of the base layer and the cap layer is disposed outwardly of the intermediate layer, in the radial direction. An outer end of the intermediate layer is disposed outwardly of an outer end of the base layer and an outer end of the cap layer is disposed inwardly of the outer end of the intermediate layer, in the axial direction. A difference between an axial width of the cap layer and an axial width of the base layer is not less than −10 mm and not greater than 10 mm.

In a tire, a shape index of a reference ground contact surface is not less than 1.20 and not greater than 1.50. In the tire, a tread includes a cap layer, an intermediate layer formed such that a loss tangent of the intermediate layer at 30° C. is less than a loss tangent of the cap layer at 30° C. and a base layer formed such that a loss tangent of the base layer at 30° C. is less than the loss tangent of the intermediate layer at 30° C. In the radial direction, the intermediate layer is disposed outwardly of the base layer and the cap layer is disposed outwardly of the intermediate layer. In a shoulder land portion of the tread, a thickness of the cap layer at a center of an axial width is less than a thickness of the cap layer on the shoulder circumferential groove side.

In a tire 2, a tread 4 includes a cap layer 38 forming a part of the outer surface of the tire 2, an intermediate layer 40 disposed inwardly of the cap layer 38 in the radial direction, and a base layer 42 disposed inwardly of the intermediate layer 40 in the radial direction. A loss tangent of the intermediate layer 40 at 30° C. is less than a loss tangent of the cap layer 38 at 30° C., and a loss tangent of the base layer 42 at 30° C. is less than the loss tangent of the intermediate layer 40 at 30° C. An outer end PC of the cap layer 38 is disposed outwardly of an outer end PB of the base layer 42 in the axial direction. In the radial direction, a position of the outer end PC of the cap layer 38 coincides with a position of the outer end PB of the base layer 42, or the outer end PC of the cap layer 38 is disposed inwardly of the outer end PB of the base layer 42.

A heavy vehicle tire tread that contains a rubber component and a reinforcing filler that includes silica and a second filler. A first and second vulcanization accelerator are used together with sulfur and a silane coupling agent in the tire tread, wherein the 300% modulus of the tire tread is 8 MPa or more. The silane coupling agent, sulfur and total reinforcing filler content in the tire tread composition are present in a ratio range of 1:0.4:0.4 to 1:1.4:1.4.

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.

An object of the present disclosure is to provide a tire having improved overall performance of fuel efficiency, breaking resistance, and abrasion resistance. The tire comprises a tread, wherein a cap rubber layer of an outer surface of the tread is formed of a rubber composition comprising a rubber component having a total content of 90% by mass or more of an isoprene-based rubber and a butadiene rubber and silica having a nitrogen adsorption specific surface area (N.sub.2SA) of 180 m.sup.2/g or more, wherein a total cis content in the butadiene rubber is less than 90% by mass, wherein a tan δ at 70° C. of the rubber composition of the cap rubber layer is less than 0.15, wherein the tread has circumferential grooves extending continuously in a tire circumferential direction and lateral grooves extending in a tire width direction, and wherein a ratio of a total area S2 of the lateral grooves to a total area S1 of the circumferential grooves (S2/S1) is less than 0.80.

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 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.

##STR00001##

(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.)

Provided is a tire comprising a tread formed of a rubber composition comprising a rubber component comprising 0 to 50% by mass of an isoprene-based rubber, wherein the tire satisfies the following conditions (1) to (6): (1) when a tan δ at 30° C. (tan δ.sub.30° C.) is A, A≥0.12, (2) when a ratio (EB.sub.80° C./EB.sub.23° C.) of an elongation at break at 80° C. (EB.sub.80° C.) to an elongation at break at 23° C. (EB.sub.23° C.) is B, 0.60≤B≤1.00, and (3) when an abrasion resistance index with a tire of Comparative example 1 being 100 as measured by a LAT tester is C, 110≤C≤140, (4) when a ratio (LAND.sub.Sh/LAND.sub.Cr) of a land ratio of the entire pair of shoulder parts (LAND.sub.Sh) to a land ratio of the crown part (LAND.sub.Cr) is D, 0.80≤D≤2.00, (5) when a maximum groove depth of the circumferential main groove is E (mm), 5≤E≤20, and

[00001]$\begin{array}{cc}25\le \left(B\times C/A\right)\times \left(D/E\right)\le 200.& \left(6\right)\end{array}$

Provided is a rubber composition, from which a pneumatic tire with an excellent balance between rolling resistance performance (fuel efficiency) and wet grip performance can be obtained. The rubber composition contains, per 100 parts by mass of a diene-based rubber, 1 to 100 parts by mass of microparticles formed of a polymer having a glass transition point of −70° C. to 0° C., and the polymer includes a random copolymer composed of three or more kinds of structural units including at least a structural unit A, a structural unit B, and a structural unit C. The structural unit A is derived from an alkyl methacrylate whose homopolymerized polymer has a glass transition point of −50° C. to 0° C., the structural unit B is derived from an alkyl acrylate whose homopolymerized polymer has a glass transition point of −70° C. to −50° C., and the structural unit C is derived from a polyfunctional vinyl monomer.