 Both of these systems claim to offer greater rigidity and better feel, with lighter weight.Others such as Proflex (Girvin), Whyte and BMW, have made suspension forks that employ four-bar linkage systems instead of relying upon telescopic fork legs, much like BMW's Duolever.The Suntour Swing Shock fork is based on a coil cantilevered swing set-up, and suspension is given by a coil spring which is located within the steerer tube and can be accessed from the top, technology which was originally used for suspension on early motorcycles.