To provide a steel cord especially useful for reinforcement application to tire crowns, able to be efficiently produced with stable quality without causing for any trouble in production as in conventional production, a rubber-steel cord composite and a tire.

The steel cord has a multiple strand structure in which N (N=2-8) strands 2 prepared by twisting two or more element wires 1 are twisted. In the steel cord, εcis defined by the following formula, wherein d(mm) expresses the diameter of the strand, D(mm) expresses the diameter of a circumscribed circle of the cord and P(mm) expresses a twisting pitch: εc=√(-b/2+√(b2/4-c))-1 [wherein b expresses -1+π2(-4R2+d2)/P2; c expresses π2d2k(4π2R2+P2)/P4; R expresses (D-d)/2; k expresses tan2(π/2-π/N)] and satisfies εc≥0.005. The tire has a reinforcing layer using the rubber-steel cord composite as a reinforcing material.

COPYRIGHT: (C)2007,JPO&INPIT