Riding bike is an obsession with me, like it is for many of you reading this. But I am very bad with hands-on stuff, tools, even understanding how things work. Fortunately my riding comrades are knowledgeable where I am not (and possessors of many tools). But they don't know the intricacies of wheels, and that's what I'm curious about. What is wheel 'building?' (I told you I didn't know anything) and what is inside the hub that makes them so important (and expensive)? Why are CKs so revered? And what is this Rohloff system? Thanks for everyone's help.