Ironman 4x4 produce a wide range of coil springs to suit a range of load ratings, all designed to maintain optimum ride height. Coils springs produced by Ironman 4x4 undergo class leading manufacturing processes to ensure the highest possible quality, including: CNC COLD COILED - All Ironman 4x4 coil springs are CNC Cold coiled to ensure perfect consistency and accuracy. The result of cold coiling means that springs are subjected to less heat during the manufacturing process to help maintain the materials properties and resulting in longer life. BAR PEELED – Bar peeling is the process of forming the material to an exact size before coiling. This ensures the diameter remains constant and free of flaws along its entire length. SHOT PEENED – Manipulates material surface tension to reduce stress, greatly enhances spring life. TRIPLE SCRAGGED – Each coil is fully compressed to a solid state 3 times to minimise coil settling. PROGRESSIVE AND LINEAR RATE – Used in accordance to original vehicle manufacturers preference, progressive springs increase rate as the spring compresses, linear springs maintain a consistent rate throughout its range.