Custom tune the spring rate and ride height of your 4-inch lifted 2005-2025 diesel Ford F-250 or F-350 Super Duty 4WD by swapping coil springs. A critical part of your vehicle's suspension, BDS coil springs support the weight of your truck's body and chassis while your suspension, wheels and tires follow changes in road surface.Manufactured from high tensile steel, our direct OE replacement coil springs are engineered with properly sized wire diameter. This results in maximum reliability without premature coil bind.