| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in run flat durability without impairing riding comfort in the normal internal pressure travelling. SOLUTION: In the pneumatic tire provided with at least one belt reinforcing layer 8 arranged in a belt 7 outside in the tire radial direction to cover the whole of the belt 7, a cord structuring the belt reinforcing layer 8 is a polyketone fiber cord formed by twisting several bundles of filament made of polyketone. The polyketone fiber cord satisfies following formulas I and II. The formula I is expressed withσ≥-0.01E+1.2, and the formula II is expressed withσ≥0.02 (in the formulas,σmeans heat-shrinking stress (cN/dtex) at 177°C, and E means elasticity (cN/dtex) when 49 N load is applied at 25°C). COPYRIGHT: (C)2007,JPO&INPIT
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