| 摘要 |
PROBLEM TO BE SOLVED: To enhance rolling resistance performance while ensuring excellent bead durability. SOLUTION: A bead core 5 comprises a core body 10 wound with a bead wire 5s; and a lapping rubber layer 11 for surrounding its periphery. A bead apex rubber 8 standing up from the bead core 5 comprises a hard lower apex part 12 and a soft upper apex part 13, the lower apex part 12 forms an L shape cross section comprising a bottom piece part 12B along an outer surface SU in a tire radial direction of the bead core 5 and a standing piece part 12A along a ply body part 6a of a carcass 6. Respective rubber hardness Hs1, Hs2 of the lapping rubber layer 11 and the lower apex part 12 are made to 76-88°. Height h1 in a radial direction of the standing piece part 12A is 15 mm or more and thickness t of the standing piece part 12A at 10 mm height position P0 is made to a range of 0.5-2.5 mm. COPYRIGHT: (C)2007,JPO&INPIT
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