Originally Posted by schiavonec
I am only an occasional commuter and would not recommend the performance bike grocery pannier without mods. It tends to 'bounce' around over the rough stuff and isn't securely fastened at the bottom (bottom of bag bounces against rack that is).
I had the same prob when using a set of Trek grocery panniers. If I hit a big bump one of them would usually pop off the rack(fortunately I had an emergency strap from the handles to the rack). I modified the bungee straps,but they're really only so much you can do. Dropped the dosh for a set of REI's with proper latches and no probs since.