i keep my saddlebag in my backpack. it has emergency tools in it, what if i leave it on the bike, come back its not there and i get a flat on the way home. i also carry a few bucks expired id in my saddle bag too. the only time i attachet my saddlebag to my bike is on recration rides on my "little bit fast" road bike. my "little bit old steelie" never gets a bag mounted, cept for the backpack in the rear basket.