I needed to know how things work prior to bringing in my bike to the LBS, Mr. Kapaun. Since the '60s I've been doing my own automobile repair and since the '90s my own gunsmithing. How old am I?!?!?!?!?!? I no longer have the time and energy to learn new certain complex mechanisms but desired to know what goes into BB replacement so noone will bee esss me. Again thanks much for all of your time and energy. 8)