Still pretty new to gearing and what not, but after riding my friends bike for about 30 miles, I like the gearing of 44/17 compared to 48/16 which is what I'm running. It feels way easier on my knees since I'm still recovering from a torn meniscus. 48/16 is pretty tough on my knees since I ride through a lot of hills in my area. As far as replacing the chain ring/cog, do I need to change out my crank and bottom bracket as well? Thanks for the help.