An annular bead core forming former is for manufacturing a bead core including a wire array in which a bead wire is helically wound in a width direction of the bead core. The bead core forming former comprises a main body portion having an outer circumferential surface with a circumferential groove extending in a circumferential direction for winding the bead wire and at least one width adjusting portion which moves relatively to the main body portion to changes a width of the circumferential groove.

A steel filament for twisting into a steel cord for the reinforcement of rubber articles, which contains a steel substrate that is coated with a coating comprising brass. The coating is different in that the amount of iron at the surface is distinctively higher than that prior steel filaments. The coating has an average iron content of 4 or more atomic percent compared to the total of iron, zinc and copper atoms in the layer extending from the surface to a depth of 3 nanometer below the surface. The steel filaments show an improved adhesion retention under hot and humid conditions and in organic cobalt compound containing rubbers as well as rubbers that are substantially free of cobalt. The lifetime of the rubber article is extended.

Disclosed are a cable bead and a tire. The cable bead includes a core wire located at the middle position of the bead and at least one layer of outer winding wires wound around the core wire, each layer of outer winding wires being evenly wounded along the circumferential direction of the core wire, where the cross section of the outer winding wires is a flat surface having a major axis and a minor axis; the major axis is perpendicular to the radial direction of the cross section of the bead, and the minor axis is parallel to the radial direction of the cross section of the bead; the outer winding wires are in surface contact with the core wire; and when there are at least two layers of outer winding wires, a line contact is formed between the layers of outer winding wires.

Provided are a high-strength bead wire and a method of manufacturing the same. The method includes preparing a wire rod containing 0.86% to 1.02% by weight of carbon, applying 5 g/m.sup.2 to 10 g/m.sup.2 of phosphate coating onto the surface of the wire rod, and drawing the wire rod onto which the phosphate coating is applied. In the drawing, the wire rod is drawn by a drawing apparatus including a drawing die capable of drawing the wire rod and a pressure die installed in front of the drawing die and capable of applying pressure to the wire rod. The diameter of the pressure die is 1.05 times to 1.20 times the diameter of the drawing die. The high-strength bead wire includes a wire rod containing 0.86% to 1.02% by weight of carbon and 5 g/m.sup.2 to 10 g/m.sup.2 of the phosphate coating applied onto the surface of the wire rod and is manufactured by the above-described method.

An annular bead core forming former is for manufacturing a bead core including a wire array in which a bead wire is helically wound in a width direction of the bead core. The bead core forming former comprises a main body portion having an outer circumferential surface with a circumferential groove extending in a circumferential direction for winding the bead wire and at least one width adjusting portion which moves relatively to the main body portion to changes a width of the circumferential groove.

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.

A pneumatic tire is provided that can achieve performance that is equivalent to or higher than that of known tires while allowing weight reduction of bead cores by using, for the bead cores, a composite cord. A pneumatic tire includes annular bead cores (5) embedded in bead portions (3), and a carcass layer (4) locked on the bead cores (5). Each of the bead cores (5) includes a cable bead structure in which a composite cord (10) is spirally wound around an annular core body (20), the composite cord including a core wire (11) formed of carbon fibers and a plurality of siding wires (12) formed of glass fibers disposed around the core wire (11).

Disclosed are a cable bead and a tire. The cable bead includes a core wire located at the middle position of the bead and at least one layer of outer winding wires wound around the core wire, each layer of outer winding wires being evenly wounded along the circumferential direction of the core wire, where the cross section of the outer winding wires is a flat surface having a major axis and a minor axis; the major axis is perpendicular to the radial direction of the cross section of the bead, and the minor axis is parallel to the radial direction of the cross section of the bead; the outer winding wires are in surface contact with the core wire; and when there are at least two layers of outer winding wires, a line contact is formed between the layers of outer winding wires.

Provided is an annular bead ring formed from a bead wire that has been subjected to wire drawing, the bead wire having a true strain of 2.80 or greater as calculated by =ln(d.sub.0/d.sub.1).sup.2, a tensile strength of 2000 MPa or greater, and a proof stress of 1700 MPa to 1980 MPa, where do is a wire diameter (mm) of the bead wire before wire drawing and di is a wire diameter (mm) of the bead wire after wire drawing.

Provided are: a cable bead which can realize a weight reduction while maintaining the breaking pressure resistance; and an airplane tire including the same. A cable bead (10) includes: a core (1) composed of an annularly formed steel; and a sheath (3) composed of at least one sheath layer, which is formed by spirally winding a sheath filament (2) composed of a steel around the core (1). The sheath filament (2) has a carbon content of higher than 0.90% by mass but 0.95% by mass or less, and a chromium content of 0.15 to 0.30% by mass.