Tyre (100) for vehicle wheels comprises a belt structure (106) comprising at least one reinforcing layer having a plurality of reinforcing cords (10), wherein each reinforcing cord (10) comprises a first metallic wire (11) having a first diameter and a second metallic wire (12) having a second diameter greater than the first diameter, wherein the first wire (11) is substantially straight and the second wire (12) is helically wound around the first wire (11) with a predetermined winding pitch (P).
