Backpack Pannier: Mount Your Backpack to your Bike Rack.

Follow this instructable to make great bicycle storage from a backpack, without ruining your bag.

Materials:

backpack
webbing, or fabric that you really trust. Webbing is everywhere, though. You could even trim a little off of a strap off your bag. I pulled mine off of a suitcase i found in the tras
bungee cord that isn't too long.
bicycle with rack
needle and high quality thread or floss