Progressive Suspension Progressive Rate Fork Springs - Harley Davidson Sportster (04 to current)

Our Progressive Rate Fork Springs soak up small road bumps yet can absorb the larger ones. The Progressively Wound design gives you the best of both worlds. When you install these fork springs you'll be amazed at the improvement you'll feel in the handling and ride of your cruiser. The rates and lengths of these Progressively Wound Springs have been carefully designed to fit most cruiser models. Spring rates have been chosen to reduce front end "dive" under braking yet still provide excellent ride comfort. Plus, we warranty our fork springs for life! Progressive Rate Springs have many advantages over straight rate springs. A straight rate spring only offers linear resistance to compression and is a compromise. For example, if you have a 20lb. straight rate spring it will take 20lbs. of force to compress the spring one inch. Then it will take 20 more lbs. of force to compress it the next inch, and so on, until the end of the travel.

A Progressive Rate Spring has the advantage of a rising rate resistance to compression. For example, a 15lb. to 25lb. Progressive Rate Spring will take 15lbs. to compress it the first inch, then 17lbs. the next inch, and so on, until the end of the travel; it will take 25lbs. to compress it the last inch. 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 stiff enough at the end of the travel to soak up the big bumps.