- The ‘Original’ Progressive Rate Fork Springs soak up the small road bumps, yet are firm enough to absorb the molar-rattling ones. Spring rates have been chosen to reduce front end “dive” during braking, yet still provide excellent ride comfort. Better yet, we warranty our fork springs for life! Progressive Rate Fork Springs have several advantages over straight rate springs. A Progressive Rate Spring has the advantage of a rising rate resistance to compression. The benefit of this is that the spring can be soft enough at the start of the travel to offer a “plush” ride, yet be firm enough at the end of the travel to soak up the big bumps.