| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire excellent in assembly uniformity by reducing bead extending force without damaging rim assembling performance in mounting a bead part to a rim. SOLUTION: The pneumatic tire has a pair of bead parts each of which has a bead core formed by winding a bead wire composed of one or a plurality of wires coated with rubber in a ring shape. In a cross section of the tire-width direction, the bead core has an accumulated structure, in which a plurality of cores composed of the wires are aligned and a plurality of lines of the cores are layered in a plurality of steps. The number of the cores composing the radially innermost step of the bead core is less than the numbers of the cores composing other steps. A rubber layer, having a 100% extension modulus of 1.0-5.0 MPa, is placed radially inside the bead core. COPYRIGHT: (C)2009,JPO&INPIT
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