Ive never been one to mind having a backpack on while riding, it just needs to be comfortable and I wont notice it. I forget I have this bag on half the time. It has tons of space, fits all my daily necessities and whatever bike accessories like a lock or tools Im carrying. Even has enough room to really max it out and fit a days clothes in it for the ride in. I do 20 miles a few days a week with this pack and its never bothersome. Its super lightweight, the straps are strong and well designed, and the back panel is stiff and doesnt create a giant hotspot on your back. To be honest, I rarely use it for a hydration pack, but that system also works perfectly, Ive had no issues with it, and its easy to removeinstall and clean.