I have a 2002 Magnum 500 4X4 with a single coil over shock absorber for the rear suspension. It appears that there are "steps" on the lower spring seat that allow for preloading of the spring. I would guess there is a relationship between the weight of the rider and the terrain you ride on that would help determine a setting for this. I have not found anything in any of the manuals that tell me how this should be adjusted or any guidelines for adjusting it. Any help on this would be appreciated.

 

The best way to gauge is to go ride it in the areas you have trails you like. If it keeps bottoming out with your weight on it adjust it up until you're not bottoming out. If it feels to stiff and your suspension isn't really cycling fully in the rough terrain take a notch or two off. It's also best to jack it up in a way that the springs/shocks you want to adjust are at full extension. Makes adjusting much easier. Swing arms like that aren't quite as comfortable a ride as the independent rear suspensions are but are great for towing and sliding flatly around corners.