I have a 2006 Trek 4500 and it comes with a front alloy hub and a rear Shimano RM60 Rear Hub with Bontrager Camino Rims. I would like to upgrade to disc hubs and I was wondering: what should I buy? I know I need disc hubs (I'm looking into Shimano M495) but should I get new rims? What else should I do? Should I buy new rims? I'm new to this so help is greatly appreciated!