Quote Originally Posted by penright View Post
Are the "stock rear springs" variable rate? Otherwise preload should not change the spring rate. I am not denying the effect (slowing weight transfer to the rear), just not seeing the physic yet. Be patient to the newbie. :-)
I found this web site http://www.zoomsquared.com/technical...#comment-11266 It had a pretty good explantion of what I was trying to ask, but still I did not see it totaly. Here was my question to him....

Something I am missing here. To compress the spring to 400lb/in of preload and the system is static or balanced, then as you said the spring pushing up with 400lb but the ring has to be pushing down with 400lb. Then when you add 938lb to the system is not the total weight now 1328lb? I know my thinking has to be flawed, it just been a while since my physic. And it was physic I at that :-). My only way of seeing this is some sort of potential energy cause by the preload, but my poor mind is not seeing it yet.

I asked the question to author and I am waiting on a reply.
A Spring when at rest has a certain tension and can support X amount of weight before noticeable compression happens.
When you pre-compress it, the weight needed to compress it more is higher. The stock rear springs at rest can barely handle the weight of a lunch box in the trunk without dropping lol.
When compressing them in advance via a pre-load device then the initial rate of the spring is now higher because it starts with tighter coils. But you lose suspension travel.

Right now a 200lbs guy has a hard time even making the rear end drop even a little while jumping in the trunk.