| 摘要 |
PURPOSE:To make improvements in durability of bead part, by dividing a bead core into plural bead wire groups in a radial direction of a tire, while constituting each sectional area of bead wires in the outside group to be smaller than that in the inside group, in case of a radial tire for heavy vehicles. CONSTITUTION:A bead core 1 is constituted of two bead wire groups 2a and 2b divided in a tire radial direction. And, each sectional area of bead wires 5 of the bead wire group 2a situated in an inner side of the tire radial direction is set to be larger than that f bead wires 6 of the bead wire group 2b. With these bead wires formed in a suchlike way, stress acting on these bead wires is almost uniformized so that powerful strength in each bead wire is available so effectively, thus durability in the bead part is improvable.
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