Unstable loads while towing and hauling don’t just make for an uncomfortable ride. Difficult handling, rear sag, and corner sway create dangerous driving conditions — for you, your passengers, and other vehicles. Whether you’re towing your RV across the country or hauling hay down the highway, our Timbren SES kits level your load, making for a safe, controlled ride so smooth, you might forget you’re towing altogether. How? Our Aeon® rubber springs deliver a progressive spring rate. As load increases, our rubber springs push back harder, eliminating squat, sway, and roll . After installation, the rubber spring will be in contact with the vehicle’s frame. This contact won’t affect ride quality — you’ll still enjoy a comfortable unloaded ride , too. What makes Timbren SES kits different from other suspension enhancement systems? Unlike air bags, our kits require no post-installation maintenance . And unlike other systems, you can install and haul in under 30 minutes , right from your driveway.