| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire which has improved driveability in a high-speed running or safety and run flat durability at a drop in internal pressure while maintaining ride quality and rolling resistance in a low-speed running or a usual running. SOLUTION: A reinforcing cord layer containing a polyketone fiber cord which satisfies the condition of formula (I):σ≥-0.01×E+1.2 and formula (II):σ≥0.02 (wherein,σis thermal contraction stress (cN/dtex) at 177°C ; E is an elastic modulus at a load of 49 N at 25°C) is applied to a side wall part 2. Two side rubber layers 5A, 5B are applied to the side wall part 2, and tanδof the side rubber layer at 80°C of the inside in the tire width direction among the side rubber layers is made larger than tanδof the side rubber layer at 80°C of the outside in the tire width direction. COPYRIGHT: (C)2007,JPO&INPIT
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