| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pneumatic radial tire, which does not degrade rigidity, has superior durability and is lightweight, and is improved in rolling resistance. <P>SOLUTION: The pneumatic radial tire includes a belt 5 constituted of two belt layers, and a belt reinforcing layer 6 made of rubber cloth of the organic fiber cord at the outside in the tire radial direction of the belt 5. The reinforcement material of the belt layer is a bundle of two cords arranged without twisting, and when diameters of all filaments constituting the cord are defined as a (mm), an interval between adjacent bundles is increased by ≥a/6(mm), as an expected value, compared with an interval expressed by using the circumscribing circle of the cord, an initial tensile resistance degree per one organic fiber cord of the belt reinforcing layer 6 is ≤20 GPa, and an apparent treat initial tensile resistance degree in all regions of the belt reinforcing layer 6 is ≤400 GPa/cm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
