Originally Posted by
teachme
I'm tieing the top handle of the pack to the seatpost and the bungee cords in a criscross pattern over the bulk of the pack. Its ok, but I'm definitely going to a bag and panniers.
I have the same Topeak Explorer on both of my bikes. FWIW, I have the MTX EXP bag. Easily carries my laptop on one side, a change of clothes and my lunch on the other. Plus, there's a ton of space on top for wallet, first-aid kit, glasses, and all the little stuff. It slides right on and snaps secure. Nice shoulder strap too.
It isn't waterproof, so you'll have to spray it with something. I used the Kiwi stuff. Works great.