Adjusting on scales is the "correct" way, but not everyone has them, and for those that don't have them, or don't have access to them, then it's a lot of mickie mouse from here on. It works though, in my experience to say the least.

With car on jacks, wheels off, suspension should be fully unloaded. Sometimes a pull on the control arm, downwards, will get it "fully" unloaded. Inspect, if the springs have free play, there is no preload on them. If there isn't free play, then there is some, to no preload on the springs themselves. It's not a good thing, but not really a horrible thing, to have the spring with free play. I use this to have my Miata to obtain a certain ride height, w/o any bad habits, but will be in the near future looking into helper springs. The idea is that you don't want the spring to be moving around in a corner when one side is unloaded, and then comes slamming down on the "loose" spring, when you turn the other way. Solution: helper springs of course. Their duty is to remove that free play during the time the suspension is fully unloaded, without compromising the ride height. Not to be confused with tender springs, which look the exact same, but have a spring rate designated on them.

Simple? Just keeping adjusting, and keep record of how you measure your adjustments, via the coilover. Toy around with it, as ride height makes a difference, and affects camber as well.

Have fun, hope it helps you, well at least not confuse you any more

Good read: http://e30m3performance.com/tech_articles/...rings/index.htm

 

16k = 896 lb/in so roughly 900

Let's say your car is on jackstands and you turn the spring perch so that the spring is now compressed 0.1 of an inch even when the suspension is at full droop.

You just added 90 pounds of preload to that corner. That's all there's to it.

BTW, when you add preload to the springs, you reduce the amount of droop travel available from static ride height. This means the ride height would've rose, which means the ride height have to be re-adjusted, and corner weight will also have to be readjusted.

edit: The easiest way to count how much preload you added in, is to count the number of turns you made on the perch. First however, you need to determine the amount the spring compresses on one turn of the perch. You then multiply that number by the # of turns on the perch, multiply THAT product by the spring rate and you get your preload amount. Use a caliper please, we're talking tenths to hundredths of an inch per turn on the perch here A measuring tape just isn't going to cut it.

 

Thank you but I was looking for a rule of thumb on how to initially set preload.
I'm guessing it should have something to do with the length of the shock and the amount it compresses.