Tein SKM74-AUB00 S.Tech Lowering Spring for Mazda MX-5 Front spring rate: 2.5 kilogram per millimeter (140 pounds per inch) Rear spring rate: 2 kilogram per millimeter (145 pounds per inch) Front ride height: -42 millimeter (-1.7 inch) Rear ride height: -34 millimeter (-1.3 inch) Progressive spring rate design