| 摘要 |
A heavy duty pneumatic tire comprises a carcass ply of steel cords turned up around a bead core in each bead portion so as to form a pair of turned up portions and a main portion therebetween. The steel cords of the carcass ply are rubberized with a topping rubber having a hardness Ht1 of from 68 to 90 degrees. The bead core is composed of: a bead core main made of windings of a steel wire; a rubber coating penetrating into the bead core main and having a hardness Hb of from 78 to 90 degrees; and a bead core wrapping layer surrounding the bead core main and composed of at least one ply of parallel organic fiber cords rubberized with a topping rubber having a hardness Ht2 of from 70 to 90 degrees. The fineness of each of the organic fiber cords of the bead core wrapping layer is in a range of from 940 to 4200 dtex. The distances between the organic fiber cords of the bead core wrapping layer is in a range of from 0.3 to 1.4 mm. The organic fiber cords of the bead core wrapping layer are inclined at an angleα1 in a range of from 20 to 70 degrees with respect to the tire circumferential direction. A minimum distance between the carcass cords and the axially innermost winding of the steel wire of the bead core main is in a range of from 0.8 to 3.0 mm.
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