Cups can be either 3 or 5mm thick. For a 68mm wide bottom bracket shell, the thicker cups require a spindle whose bearing races are 4mm closer together. One can play various games, such as replacing thick (typically Japanese) cups with thin (typically European) ones and simultaneously swapping in an Italian spindle designed for a 70mm BB shell and thin cups. Under this scenario, the adjustable cup has to be advanced another 2mm, but this generally leaves enough exposed threads for the lockring.