I believe that the 68/73 ID is a width measurement of the frame at the bottom bracket. This indicates that you can use a BB for widths between 68-73 with or without spacers.The shell is 92mm wide. These are press fit. I measured mine the last time I had the cranks out. The spindle is about 114mm long (4.5"). I have zero idea where the 68/73 comes into play. Bottom bracket standards confuse the crap outta me. I posted earlier that my XTR 9120 cranks are too long to work in this bike, so I'm not sure what Shimano cranks would, or how to search for them. Obviously the BB needs to be changed for the 24mm spindle, but I'm not sure how to address spindle length. Hope this helps a bit!