Description CSI’s progressive bump spring kit has all the same benefits as the progressive bump rubber kit, but in a shorter package. The installed height of this kit is on 2 3/4″, a full 1″ shorter than the progressive bump rubber kit. Each kit comes with (2) Eibach Bump Springs, (4) Spring Retainers, (4) Bump Rubbers, and (6) Packers, all of this is packaged in a nice hard plastic locking carrying case. This is a complete kit with everything you need for your application including detailed instructions. Why a progressive kit? A progressive spring rate gives you a larger target to shoot at when you are setting bump gaps, and trying to use the spring to load the tire for increased drive In short it is much more user friendly than a traditional linear bump.
