With a 2015 Ford F350 SRW and NorthernLite 9.6, my rated payload was 3,885, and fully loaded camper, truck and people/pets was 4,000 total. Adding 2 of the 3 lower StableLoad bars/wedges was all I needed, and the factory over-leaf bumper just touched. I did just 2 wedges, since that's all that would fit naturally in the spring gaps when the truck was unloaded. Other than the over-leaf bumpers making knocking sounds when on bumpy roads, the support and leveling is excellent. I later added a RoadMaster sway bar, which profoundly reduced sway to near zero! I purposely avoided air-bags, since they have been known to increase porpoising and sway.
