courier bag? I've used them when my rack wasn't enough to carry all my stuff. I got smarter though and began storing food, clothes, shoes, etc at work and restocking with my car occasionally. then I got to carry less on my rack on a daily basis except, lunch, snacks daily towel, etc. personally I can't live without my rear rack even if I'm strapping on a small bag for a day ride, it's just so convenient (for me). they do make very light weight racks for road bikes.