Originally Posted by
blargman
Aren't messenger bags kinda floppy on a bike? I would hate to have something moving around while I'm biking. My backpack stays pretty well in one place.
As mentioned, some (including my Timbuk2) come with a secondary strap to stabilize the bag. Also, I like to wear mine a bit snugger than I did when I was wearing it around town or on the motorcycle and that helps keep it in place.