Quote Originally Posted by Travelor View Post
Actually, no, the spring doesn't control the shock, the shock controls the spring (it restricts the free movement, the natural frequency, of the spring), dampening or restricting the movement but not restricting the distance the spring can move. The adjuster that is provided on the F6b is a spring preload adjuster, not a shock damper adjustment. With the preload set at minimal, the spring is not pre-compressed (it actually is, but for the discussion here we will assume that it isn't) and as soon as someone sits on the bike, the spring sags (compresses). With minimal preload, the spring compresses more - therefore leaving less travel to absorb bumps. In other words, it bottoms out the suspension sooner. If you crank up the preload, the spring now doesn't move as far when initially loaded with the rider, leaving more travel to absorb bumps.

As an example, if we have a total of 4 inches rear suspension travel (not spring travel, the suspension itself as limited by the shock travel), and there is no preload dialed onto the spring, the rear suspension may sag 2 inches with a 200 pound rider. That leaves only 2 inches (like a Harley) of travel left out of the 4 inches total to absorb bumps. Then crank up the preload so the same 200 pound rider only compresses the spring 1 inch, there are now 3 inches of travel left to absorb bumps. This is a very simple example, and assumes that the spring is a straight rate spring as opposed to a progressive rate spring (which it probably is), but the action is similar.
I could not have said it any better and why with my 400 lb carcuss I set mine all the way up and get the softest ride ever with all the travel