I tried panniers on my commuter bike but they interfered with my pedal stroke. I'm sure I could have found other ones but I don't like having to take them off and on the bike all the time. I eventually got a rear rack and attached a wire basket to it. It works really well because I'm not limited too much by the size of things I can put in there and I don't have to worry about someone steeling it while my bike is parked. I can fit a whole grocery bag in there or use a mesh bungy cord and attach odd shaped things.