Does your back hurt when riding?
Any ideas on what you can do to remedy that? I ride a hardtail, but I took a 25 mile ride on a rails-to-trails path the other day, and even then my back was killing me by the end. I'm not sure if it's the camelbak that's getting to me but, I sort of need my pack for water (obviously) and it's where I stash a spare tube and some fold up tools in case I need to make adjustments.