Just a quick question, i am looking to fit an open cup bottom bracket, i have the bracket size of 68mm, and the threading of 1.37x24tpi...What i need to know is, i have heard that the length of the spindle is the criticle measurement, i am assuming down to whether you have single double or triple chainset.......I plan to run a 6 speed with single chain ring, hubs are 120, but i have no idea what length spindle i will need or how to obtain the info........many thanks