| 摘要 |
PURPOSE:To improve high speed durability, rolling resistance and driving stability, by using a steel cord, which comprises a specified number of strand wires in a specified diameter setting break strength force and bending rigidity, when the cord is formed into a predetermined rubber/cord compounded structure, to a predetermined value, for a carcass cord. CONSTITUTION:Two-four strand wires of 0.15-0.21mm diameter are used forming one cord, and a steel cord, which sets break strength force F (kgf) of the one cord satisfying a specific relation formula I relating to a quantity (n) of the strand wire and its diameter (mm) (d) while bending rigidity EI (kgf.mm<2>) per ten carcass cords cut into 1.0mm thickness to 15 or more and 30 or less, is formed. And this steel cord forms a carcass. By this constitution, high speed durability, rolling resistance and driving stability can be improved preventing the comfortableness of riding from deteriorating.
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