Alright, clearly my googlefu and searchfu is sucking at the moment, so I'm posting here. What is the difference between a road and FG/SS hub? From what I have been able to tell, the SS/FG hubs are not as wide and are clearly not designed to hold a cassette. But are those the only differences? and could I get more specific (like how wide are SS hubs? and things like that) information?

Thanks!