JPH05247860

PURPOSE:To provide the subject steel cord to form the strips or reinforcing plies of tire skeletal structure such as carcass, belt plies and filler, intended to improve tire durability and decrease tire weight through enhancing rubber penetrability thereinto and reducing cord diameter. CONSTITUTION:The objective steel cord to form the plies of tire skeletal structure is made up of a core C consisting of three steel elemental wires and a sheath B consisting of seven steel elemental wires surrounding the core, and having the following characteristics: (1) the respective diameters db and dc of each of the core steel elemental wires FC and sheath steel ones FB: 0.15 to 0.28mm, and dc>db; (2) spacings between the sheath steel elemental wires adjacent to each other: >=0.03mm on average; and (3) twisting directions are the same but twisting pitch lengths mutually different for both kinds of wires.