SPRINDEX ALLOWS FOR TOOL-FREE, EASY ADJUSTMENT OF YOUR COIL'S SPRING RATE.
Adjusting your shock's spring rate can profoundly improve your bike's handling and suspension. In fact, you may find yourself using different spring rates for different trails, depending on the conditions and type of trail. Or you may increase your spring rate for long climbs and decrease it for down hills.
No expense was spared on the materials or manufacturing processed used. The coil itself is made of super high tensile spring steel similar to "lightweight" springs (which is why Sprindex is lighter than regular springs) in order to handle the stress of the system when adjusted to its highest spring rate setting, as well as reduce coil mass. The Sprindex assembly is made of glass reinforced polymer. The 5 included adapters are made of slippery Delrin.
Spring rate is the force required to move a spring a given distance and independent of preload. For example, a "400 lb/in" spring requires 400 pounds to move the spring 1 inch and 800 pounds to move a spring 2 inches. Preload is how much force is required to start moving the spring. Sprindex is patent pending in many countries.
Follow your shock manufacturer's instructions for preload amount and sag and other shock adjustments. Do not preload your Sprindex more than 3 turns and 1 to 2 turns is preferred.
Your Sprindex coil behaves like a regular coil that has a spring rate the same as your adjusted Sprindex spring rate. Adjusting your Sprindex does not change the length of the coil and so does not change your preload. Preload is adjusted normally and with the threaded ring that came with your shock.
SPRINDEX VERSUS "PROGRESSIVE" COILS
Firstly, all coil shocks are already progressive because of the rubber bumper that is contacted at the end of the stroke. The rubber bumper is itself a spring that is active between about 10 and 20% of the end of the stroke, depending on bumper thickness and stroke travel. All by itself, the rubber bumper can add over 200 pounds of force to help prevent a hard bottom out. The rubber bumper will more than double your spring rate for the last 5 to 10mm's of stroke. Ideally, you should only use your full shock travel on the very hardest hits of your ride and your spring rate should be adjusted high enough to never fully bottom out.
SHOCK WITHOUT COIL
BUMPER JUST BEFORE BEING COMPRESSED TOWARDS END OF STROKE.
SHOCK WITHOUT COIL
BUMPER COMPRESSED AT END OF STROKE.
So called "progressive" coils have 1 or 2 coils that are spaced closer together such that they bottom out and become inactive part way through the stroke. This suddenly increases the spring rate at some point in the stroke, but this is not similar at all to Sprindex. Available progressive springs are not adjustable which causes the same problem as regular springs in that they cannot be tuned for you and your riding style.