I have my bike fairly loaded with front,rear,handle bar bag plus the back rack loaded. When I did my first Oregan Coast tour I had lots of shmmying problems until I got the wieght distribution issue settled. I try and do about 35% in the front panniers and 65% in the back ones plus rack. It is also important to keep the wieght balanced in each of the panniers ecspecially the front ones. Nothing worse than flying down a hill with a cliff on your right and the the bike feeling like it`s about to come a part. Also, make sure all scews ect.. are tight. If you are experiencing some shimmying then they have probably looosened up.