| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of enhancing its fatigue resistance, in particular, its durability when a vehicle runs at low internal pressure while maintaining a high level of stability in steering. SOLUTION: In the pneumatic tire, a carcass cord 10 is formed by aramid fiber cords 13 having a double twisting structure constituted by intertwining a plurality of primarily twisted filament bundles 10A mutually by final twisting. Fineness of each filament bundle 10A is smaller than 1,100 dtex. Twist coefficient T of the cord expressed by the expression (1) T = n×ä√(D/ρ)}×10<SP>-3</SP>(wherein, n indicates the number of twisting per 10 cm of cord length (unit: number), D indicates gross fineness of the cord (unit: dtex), andρindicates specific gravity of the aramid fiber) is in a scope of 2.6-3.4 when the number of filament bundles 10A is two and in a scope of 1.7-3.4 when the number is three or more. Complex modulus of elasticity E*1 of topping rubber 11 of a carcass 6 is in a scope of 3.7-12.0 Mpa. COPYRIGHT: (C)2009,JPO&INPIT
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