| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire for heavy load capable of preventing occurrence of any separation troubles of a bead part and achieving long service life by suppressing web occurrence in a return carcass ply while preventing any contact of a bead core with the carcass ply. SOLUTION: The carcass ply 2 has a return part to wind the periphery of the bead core 3 from the inner part to the outer part of the tire, and a reinforcing rubber layer 4 having a two-layered face and back structure of a hard rubber layer 4A and a soft rubber layer 4B of different hardness is disposed between the bead core 3 and the carcass ply 2 at the return part. The hard rubber layer 4A side and the soft rubber layer 4B side are disposed on the bead core 3 side and the carcass ply 2 side, respectively, the Shore A hardness of the hard rubber layer 4A is≥68, and the gauge of the hard rubber layer 4A is≥1.0 mm. COPYRIGHT: (C)2003,JPO
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