I've got a CrossCheck with Axiom Streamliner rack (narrow mounting) with Ortlieb front packers or rollers. I'll strap a bungie from the bottom strut of the rack over the pannier to the top to keep it flat when unloaded (otherwise it kind of inflates into full size) and loose items like a lock from bouncing around. Most of the time I ride with just the left pannier. Absolutely solid. The only time it's noticable is if there's a lot of weight, then it's like riding with a lot of weight but it doesn't flail around.

http://www.axiomgear.com/products/ge...reamliner-dlx/

I installed it with flat ss straps common to Blackburn and others because the Axiom mounts stick down to far into the fenders. The narrow rack is very, very stiff.