With a pneumatic tire not mounted on a rim, in a meridian cross-section a first line is parallel with an innermost bottom side of a bead core in a radial direction and passes through an outermost projection of the bead core in a lateral direction, a second line is orthogonal with the first line at the outermost projection, a third line is orthogonal with the first line and passes through an intersection of a rim cushion rubber, a distance between the second and third lines is 2.0 to 4.0 mm, a shortest distance between an innermost projection of the bead core in the lateral direction and a cord of a carcass layer is 0.6 to 1.4 mm, and a shortest distance between an innermost end of the bottom side of the bead core in the lateral direction and the cord of the carcass layer is 1.2 to 2.2 mm.

The present invention has an object of providing a pneumatic tire that exhibits better uniformity by improving the wire wound body for constituting the bead core. The pneumatic tire 1 comprises a bead core 5 comprising a wire wound body 10 in which one bead wire 10a is spirally wound in a continuous around a tire rotational axis CL so that a plurality of layers of the bead wire are formed in a radial direction of the tire. The wire wound body 10 comprises a first part 13 and a second part 14. The first part 13 comprises a plurality of layers of the bead wire 10a each circumferentially extending with a constant radius from the tire rotational axis CL. The second part comprises a plurality of layers of the bead wire 10a each circumferentially extending while changing its radius from the tire rotational axis CL.

The bead wire (52) comprises several windings of wire and a basic hexagonal bead wire (56) comprising: two axially and radially external lateral rows (F1, F2) of N2 windings, two axially external and radially internal lateral rows (F3, F4) of N2 windings, where N1=N2+1 or N1=N2, two junctions (J1, J2), each formed by a winding that an axially and radially external lateral row (F1, F2) and an axially external and radially internal lateral row (F3, F4), have in common, each winding in common having no winding of wire axially on the outside of it. The bead wire (52) comprises two axially and radially external additional lateral rows (A1, A2) of N3 windings substantially parallel respectively to each axially and radially external lateral row (F1, F2).

Of layers configuring a bead core of a pneumatic tire, the width W0 of one of the layers including the greatest number of rows, the width W1, W2 of other of the layers located respectively innermost and outermost in the radial direction satisfy W1>W2 and W20.5W0. The position of width W0 is inward in the radial direction of the center of the bead core. A carcass is folded and curved along the bead core and extends toward sidewalls where a folded back portion of the carcass contacts a body of the carcass. A rubber occupancy ratio in a closed region formed by the body and the folded back portion is 0.1% to 15%. The cross-sectional area S2 and hardness H2 of a filler outward of the carcass in the lateral direction, and the cross-sectional area S1 and the hardness H1 of the side reinforcing layer satisfy 0.12(S2H2)/(S1H1)0.50.

A manufacturing method of a bead core of the present disclosure comprises an annular body forming step of winding a strip member formed by coating one or more bead wires with a coating resin to form an annular body, and a resin coating step of coating the annular body formed in the annular body forming step with a resin.

In a pneumatic tire, a turned back portion of a carcass layer contacts a body portion of the carcass layer in a cross-sectional view in a tire meridian direction to form a closed region surrounding bead cores. A rubber occupancy ratio in the closed region is in a range of 15% or less. The bead cores have a predetermined wire arrangement structure formed by arranging wire cross sections of bead wires in the cross-sectional view in the tire meridian direction. Additionally, a self-contact height (CH) of the carcass layer and a circumferential length (L) of the wire arrangement have a relationship 1.0CH/L10.0.

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.

A run-flat tire comprises a tread portion, sidewall portions, bead portions, and a carcass ply extending between the bead portions. The sidewall portions are each provided therein with a sidewall reinforcing rubber layer having a crescent-shaped cross sectional shape and disposed on the axially inside of the carcass ply. The sidewall portions are each provided in the axially outer surface thereof with a rim protector which projects radially outward most on the radially outside of the radially inner edge of the sidewall reinforcing rubber layer. The bead portions are each provided therein with an axially inside core and an axially outside core between which each radially inner edge portion of the carcass ply is secured. When measured along a normal line drawn normally to the carcass ply from an apex of the rim protector, the thickness of the sidewall reinforcing rubber layer is in a range of from 29% to 35% of the thickness of the tire.

A bead for a tire in accordance with the present invention includes a core with at least one yarn of a multifilament textile fiber embedded in an organic matrix having a density between 0.9 g/m.sup.3 and 2.0 g/m.sup.3 and an outer sheath layer including at least one metal wire wound around, and in contact with, the core. The core has a diameter between 5.0 mm and 30.0 mm.