18 x 7 steel cored wire-rope is quite tough and multi rowed (or multilayer) strands oppositely lay around its core and can hardly be bended on its rope drum, so tends to be slack and skip to other grooves especially when no load on the hook. 18 x 7 wire rope though do not loosen nor deform in its groove under load nor turn to make windings  one on another even at higher lifting heights. 18 x 7 wire rope thus can be used at smaller rope drum diameters respectively. These ropes generally last longer because of their constructional design and thicker wire sizes.