Hyperpro has put years of extensive Research & Development on front forks, shocks, springs and suspension systems. As most of the time a linear spring is either too hard or too soft at the beginning and/or at the end, a so called one-step progressive spring is an improvement but still a compromise between comfort and safety. The sudden change from soft to hard is often felt as a disadvantage and can lead to "speed wobbles". Hyperpro came up with the non-compromising solution: the "Link-System Curve Design" for springs. With this construction a spring can be designed to satisfy all the demands of modern motorcycle technology. Hyperpro gives you a sensitive initial part of the stroke with a smoothly increasing spring rate for safety and anti-dive at the end of the stroke. Together with the use of the highest quality materials and precision machining this results in the best springs that money can buy. The shock springs provide superior road holding & handling under all conditions and are thoroughly tested on a computerized dyno and on the bike in question. Springs are designed for use on the OEM Harley-Davidson shock absorbers. Matching front fork spring kits can be found in chapter 17 of the Zodiac Bikers Book.