My experience with grocery panniers is that they work a whole lot better if they have a strap that goes over the top of the pannier to stabilize the side away from the bike. Mine did not have such a strap, and my groceries spilled out all over the street because the weight shifted to the outside when I went around a corner (centrifugal force). A bungie cord would work well. I got rid of mine after that because I was so disappointed with them, and my food coop was only three blocks away, so I walked.