In a tire 2 according to the present invention, belt cords 42 included in a belt 22 each include a twisted string obtained by twisting together four filaments 46. Each belt cord 42 has an elliptical cross-section. On the cross-section, the ratio of the length of the minor axis to the length of the major axis is greater than or equal to 0.67 and not greater than 0.94. A first filament 46a and a third filament 46c are disposed along the minor axis. The first filament 46a and the third filament 46c are each in contact with a second filament 46b and a fourth filament 46d, or the first filament 46a is in contact with the third filament 46c.

A steel cord containing a core layer and an sheath layer, the core layer containing a plurality of core wires with a number of n and the sheath layer comprises a plurality of sheath wires with a number of m, and the steel cord has a flat cross-section with a major axis and a minor axis, the flat cross-section has a flat ratio being the ratio of the length of the major axis and the length of the minor axis, the flat ratio is more than 1.2, the steel cord has a breaking load being BL.sub.cord, the core wires and the sheath wires have a sum breaking load being Sum BL.sub.wires when the core wires and the sheath wires are un-twisted from the steel cord, BL.sub.cord and Sum BL.sub.wires satisfies the following formula: BL.sub.cord/Sum BL.sub.wires>96%. The steel cord has higher breaking load.

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.

A steel cord containing a core layer and an sheath layer, the core layer containing a plurality of core wires with a number of n and the sheath layer comprises a plurality of sheath wires with a number of m, and the steel cord has a flat cross-section with a major axis and a minor axis, the flat cross-section has a flat ratio being the ratio of the length of the major axis and the length of the minor axis, the flat ratio is more than 1.2, the steel cord has a breaking load being BL.sub.cord, the core wires and the sheath wires have a sum breaking load being Sum BL.sub.wires when the core wires and the sheath wires are un-twisted from the steel cord, BL.sub.cord and Sum BL.sub.wires satisfies the following formula: BL.sub.cord/Sum BL.sub.wires >96%. The steel cord has higher breaking load.

Provided is a steel cord for reinforcing rubber articles, which can prevent a reduction in the strength of the steel cord caused by twisting steel filaments, and a tire and a crawler using the steel cord. Provided is a steel cord 1 for reinforcing rubber articles formed by twisting a plurality of sheath strands 3 are twisted around a core strand 2, and the core strand 2 comprises: a core composed of two core filaments 2a aligned in parallel without being twisted; and at least one sheath composed of a plurality of sheath filaments 2b twisted around the core, and a diameter dc of the core filament 2a and a diameter ds of the sheath filament 2b satisfy the following expression (1):

dc<ds (1)

and the tensile strength T (MPa) of the core filament 2a satisfies the relationship represented by the following expression (2):

T<365017000(dc0.15).sup.2 (2).

Provided is a steel cord for reinforcing rubber articles, which can prevent a reduction in the strength of the steel cord caused by twisting steel filaments, and a tire and a crawler using the steel cord. Provided is a steel cord 1 for reinforcing rubber articles formed by twisting a plurality of sheath strands 3 are twisted around a core strand 2, and the core strand 2 comprises: a core composed of two core filaments 2a aligned in parallel without being twisted; and at least one sheath composed of a plurality of sheath filaments 2b twisted around the core, and a diameter dc of the core filament 2a and a diameter ds of the sheath filament 2b satisfy the following expression (1):

dc<ds (1)

and the tensile strength T (MPa) of the core filament 2a satisfies the relationship represented by the following expression (2):

T<365017000(dc0.15).sup.2 (2).

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.

A cable bead comprising an annular core and a side wire spirally wrapped up around the annular core, wherein the annular core is made up of a round steel wire made to circle once or made, without being stranded, to circle 2 to 10 times side by side, and wherein the side wire is a round steel wire consecutive from the annular core. This provides a high-strength cable bead that can press a tire main body against a wheel without fail even if a tire is charged with a high load.

Disclosed is a tire-reinforcing steel cord for a radial tire. The tire-reinforcing steel cord has a double layer structure including a first-layer core and a second-layer core provided on the surface of the first-layer core. The first-layer core has an elliptical or rectangular cross section. The tire-reinforcing steel cord can improve processability, fatigue characteristics, and rolling resistance performance of a tire, resulting in improved fuel efficiency. A radial tire using the tire-reinforcing steel cord is also disclosed.