A steel cord for rubber reinforcement comprises a first group of core filaments (105) having a number of m and a second group of sheath filaments (110) having a number of n, m is three or four, the core filaments (105) are forming a helix, the core filaments (105) are not twisted together and being substantially parallel or the core filaments (105) have a twist pitch being more than 300 mm; the second group and the first group are twisted with each other, and the sheath filaments (110) are forming a flattened helix in the same direction of the helix of the core filaments (105), and the sheath filaments (110) have a cord twist pitch, at any cross-section of the steel cord, at least one interstice between two adjacent core filaments (105) is present. The steel cord has improved abrasion resistance and can contribute to the reduction of the weight of the tire.

Provided is a tire including a tread portion. The tread portion includes two circumferential grooves and three land portions. The three land portions include a crown land portion disposed on a tire equator, and two shoulder land portions including tread contact ends. At least one of the shoulder land portions includes a plurality of main inclined grooves and a plurality of subsidiary inclined grooves. The main inclined grooves have tire-axially inner ends ending in the shoulder land portions and tire-axially outer ends disposed outwardly of the tread contact ends Te in the tire axial direction. The subsidiary inclined grooves have tire-axially inner ends ending in the shoulder land portions and tire-axially outer ends ending in the shoulder land portions.

A tire includes a tread and a crown reinforcement arranged radially internal to the tread. The crown reinforcement includes a protective reinforcement and a working reinforcement. The protective reinforcement includes a protective ply that exhibits a force at break greater than or equal to 1300 daN.Math.cm.sup.1. The protective ply includes protective reinforcing elements, each of which exhibits a force at break greater than or equal to 3000 N. The working reinforcement is arranged radially internal to the protective reinforcement and includes a working ply. The working ply includes working reinforcing elements, each of which includes a working cord formed of at least a strand that includes an external layer of unsaturated threads.

A rubber composition is based on at least one elastomer and at least one phenolic compound, the aromatic nucleus of said phenolic compound being substituted with at least one substituent comprising an oxygen atom, the molar mass of said phenolic compound being at most equal to 1000 g/mol, and said composition being free of molecular sulfur or comprising less than 1 phr thereof.

A hooping reinforcement of a tire for a heavy duty civil engineering type vehicle is disclosed. The crown reinforcement (3) of the tire (1), radially on the inside of a tread (2), comprises a protective reinforcement (6), a working reinforcement (5) and a hooping reinforcement (7). Said hooping reinforcement (7) has an axial width at most equal to the smallest axial width (L61, L62) of the two working layers (61, 62), and comprises at least two hooping layers (71, 72) that are formed from strips each made up of elastic metal reinforcers. Each hooping layer (71, 72) is made up of an axial juxtaposition of contiguous turns of the strip (8), which are circumferentially wound around the working layer (51). Each strip (8) is at least 35 mm and at most 250 mm thick, and its distributed breaking tension is at least equal to 100 daN/mm.

There is provided a steel cord including a steel wire and a plating layer that covers the steel wire and has Cu, Zn, and Co, wherein Cu and Zn are alloyed and a region covered with Co and a region not covered with Co are mixed on the outermost surface of the plating layer.

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95MC175, where MC=(JMI+LME)/(J+L); MI=200cos.sup.4()[Q(D1/2).sup.2cos.sup.4()+P(D2/2).sup.2cos.sup.4()+N(D3/2).sup.2cos.sup.4()]/[Q(D1/2).sup.2+P(D2/2).sup.2+N(D3/2).sup.2]; and ME=200cos.sup.4()[Q(D1/2).sup.2cos.sup.4()+N(D2/2).sup.2cos.sup.4()]/[Q(D1/2).sup.2+N(D2/2).sup.2], where D1, D1, D2, D2, and D3 are in mm, and are the helix angle of each internal and external strand (TI), and are the helix angle of each internal thread (F1, F1), is the helix angle of each intermediate thread (F2) and and are the helix angle of each external thread (F3, F2).

Provided is a pneumatic tire having excellent durability by defining a viscosity and a softening point of a coumarone resin within predetermined ranges. The pneumatic tire uses a reinforcing material having a coumarone resin film formed on a surface thereof. The coumarone resin film includes a coumarone resin having a viscosity from 350 to 2200 Pa.Math.sec at a temperature of 160 C. and a softening point from 75 to 130 C., and the reinforcing material is at least one of a bead wire or a steel cord. The coumarone resin film preferably has a thickness from 0.05 to 0.40 m. The reinforcing material is preferably the bead wire or the steel cord.

Provided is a pneumatic tire using a reinforcing material having a coumarone resin film formed on a surface thereof. The coumarone resin film includes a coumarone resin having a viscosity from 350 to 2200 Pa.Math.sec at a temperature of 160 C. and a softening point from 75 to 130 C., and the reinforcing material is at least one of abead wire or a steel cord.

Provided is an elastomer reinforcement cord which takes advantage of characteristics of a composite cord using steel filaments and a resin filament and in which a diameter (a geometrically calculated value) of the cord including only the steel filaments without resin, as calculated from a wire diameter of the steel filaments used, is substantially the same as an actual cord diameter after vulcanization. In an elastomer reinforcement cord 10 including a core and at least one sheath layer, in which metal filaments 2 and 3 and a resin filament 1 are twisted together, gaps between the metal filaments are filled with resin. The diameter of the cord is from 98 to 100.5% of the geometrically calculated value of the diameter of the cord including only the metal filaments, and a total length of gaps between the metal filaments forming an outermost sheath layer before vulcanization is 85% or less of the geometrically calculated value. In a region surrounded by connecting the center of each metal filament forming the outermost sheath layer on a cross section in a direction orthogonal to an axial direction of the cord, the ratio of a polymer material to a region other than the region occupied by the metal filaments is from 52 to 120%.

Provided is a heavy-duty pneumatic tire in which not only occurrence of a damage of CBU but also occurrence of pulling-out of a carcass ply can be inhibited, and which has excellent durability. In the tire, beads each include a cover enclosing at least a part of a core. The cover is located, between the core and the carcass ply, in a portion at which the carcass ply encloses the core. The cover is composed of one cover ply including a large number of aligned cover cords and a cover topping rubber covering the cover cords. A ratio of a distance between the cover cords to an outer diameter of a carcass cord is not lower than 0.35 and not higher than 0.85. A difference between a hardness of the cover topping rubber and a hardness of a carcass topping rubber is not less than 5 and not greater than 5.