The variably rated coil spring is manufactured from 12 mm oil-tempered Class 2 wire measuring 2 3/16ths inches in diameter by 9¼ inches in length. There are 20 coils per spring, 16 of these coils are active coils and 4 coils are non-active. The spring has a threaded plug located in each end. This plug is designed so that once it's in place, it cannot be removed. The spring is designed with an initial tension of 400 lbs. This is the poundage required to open the windings of the spring under tension just 1/1000th of an inch.

The kit is installed on the rear section of the leaf spring. It is connected by an eye bracket, which fits around the rear eye of the spring. The opposite end of the unit has an axle-connecting bracket, which is secured to the axle by the U-bolts. Once the kit is installed, it's held in place by the tension of the coil spring. The installation takes approximately one hour and requires no further adjustment or maintenance once fitted.

Once installed and the spring is adjusted with a 2mm gap between the active coils (with the rear axle hanging free) the tension of the spring is now increased to 2,000 lbs. When the vehicle is lowered to the ground and the full weight of the vehicle is on the leaf spring, this gap increases to 2.3 mm increasing the tension to 2,350 lbs. Under all road conditions, with the flexing of the leaf spring, the tension of the coil spring can vary between 1,700 lbs. and 2,600 lbs.

All components are manufactured to the highest standards in the Automotive Industry. All brackets are manufactured from high-grade alloy spring steel, and these components together with the coil springs are fully electro coated in black to withstand 800 hours salt spray testing. The fasteners on the kits are metric 12 mm in diameter. The cap screws have a hardness of 12.9 and a tensile strength of 18,400 lbs. The threaded rods have a hardness of 8.8 and a tensile strength of 12,800 lbs. As the maximum working tension of the coil springs will never exceed 2,800 lbs., both of these fasteners and all components comprising our kits, are designed to withstand considerably more than they could ever be subjected to.