Steel cord for rubber reinforcement

A steel cord, said steel cord having a construction comprising an outer layer and an inner strand surrounded by and adjacent to said outer layer, said inner strand comprising at least one steel filament with a number of N1, said at least one steel filament of said inner strand having an average diameter of d1 expressed in mm, said outer layer comprising steel filaments with a number of N2, said steel filaments of said outter layer having an average diameter of d2 expressed in mm, wherein said inner strand has a torque T1, said outer layer has a torque T2, T1 and T2 satisfy the following formulas:

• T1=G×RT1×π2×D12×d12×N1/16000,
• T2=G×RT2×π2×(D12+D22)×d22×N2/16000,
• |T1+T2|<60,
• wherein,
• D1 is the theoretical diameter of the inner strand while D2 is the theoretical diameter of the steel cord, D1 and D2 are expressed in mm,
• RT1 is the residual torsion of the inner strand while RT2 is the residual torsion of the outer layer expressed in the number of turns per meter in “+” if in clockwise direction or “−” if in anticlockwise direction,
• G is 80000 N/mm2,
• and the absolute value of RT2 is less than 2 turns per meter and no less than 0.05 turns per meter, and the absolute value of RT1 is no less than 0.05 turns per meter.