I installed these SumoSprings on my 07 Tundra 4x4 4WD camper before my last hike. I rode 40 miles over very rough terrain. and then 10 miles off-road. They were preformed exactly as advertised. It made the ride very comfortable and took the influence out of corners, and I never felt like the suspension bottomed out of balance. I also have a One Leaf Super Spring on each side of the main spring, but prior to installing the Sumo springs I didn't have a great ride and was not comfortable with the suspension. I am very satisfied and recommend this product. They are rated at 1500 pounds at 50% compression. They make 2 other suits that have different weight classes.