| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire having greatly reduced rolling resistance while maintaining good ride comfort performance and control stability. SOLUTION: The pneumatic radial tire comprises a carcass layer 4 mounted between bead portions 3, 3, a belt layer 7 arranged on a tread portion 1, and sectionally triangular bead fillers 6 arranged on outer end portions of circular bead cores 6. A rubber composition constituting the bead filler 6 has a JIS-A hardness of 80 or more. The bead filler 6 has a height of 35 mm or lower and a cross section area X satisfied with a relationship, 1.1×H×W/2<X <1.6×H×W/2, where W is the width of the bottom of the bead filler 6, H is the height from the bottom up to a peak and X is the cross section area. A rubber composition constituting a sidewall rubber layer 2a outside at least the carcass layer 4, out of a rubber member existing in a buttress region B ranging from an edge 7e of the belt layer 7 to a tire maximum width position m has a JIS-A hardness of 50 or less. COPYRIGHT: (C)2003,JPO
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