How much lower with '0' preload?

[Datcamber]

Currently my fronts are preloaded a good 5-10mm or more. I'm currently threaded down all the way and have no body to spin down beyond messing with my preload. I have a 12kg rate spring in the front. How much will my car drop if I set the preload to '0'? Basically just setting the spring snug enough so it won't move.

[Datcamber]

Anyone?

[Oh Damn, it's Sam]

It depends on whether you've got your preload set up so that the force the springs are exerting is greater than the force necessary to keep the car off the ground. Put another way, in any suspension system, at rest the springs will compress until the force exerted by gravity and the opposite force exerted by the springs (multiplied by your suspension's motion ratio) are in equilibrium. If the amount of preload is less than or equal to the amount the springs would compress ordinarily under the car's weight, you're not going to see any drop from removing the preload. If the amount of preload is greater than the amount the springs would compress under the car's weight, you might actually see lift were you to remove the preload.

[KyleAnderson]

With 12kg springs (672lb), your preload of 10mm isn't exceeding the amount of compression needed to support the corner weight (~840lb). Assuming this is for a front strut with a motion ratio of 1:1, however much preload you remove will lower the car by the same amount.

[Oh Damn, it's Sam]

If the top spring mount is fixed, won't the spring settle to the same height regardless of whether there's preload or not? Seems like as soon as the car's weight has put enough weight on the spring that it is greater than or equal to the force exerted by the lower mount when it's wound up into preload, the preload would become irrelevant for determining the height of the spring.

[Datcamber]

The part that confuses me is that in order to lose the preload, I'd have to raise the top perch up 10mm to get the load off of the spring. What about if I were to droop the spring a half inch or so?

[Oh Damn, it's Sam]

If you're moving the top perch, you'll lose approximately the same amount in ride height as you remove in preload. I had it in my head that you were adjusting the bottom perch, my mistake.

[Datcamber]

If you're moving the top perch, you'll lose approximately the same amount in ride height as you remove in preload. I had it in my head that you were adjusting the bottom perch, my mistake.

So in order to lose my preload I'd have to move the top perch up 10mm. So if I droop .5 inches I'd lose half an inch of ride height ?

[KyleAnderson]

Let's clear up any confusion...

Are we talking about your front coilovers or rear? If rear, are you adjusters on the top perch or bottom?

[Datcamber]

Let's clear up any confusion...

Are we talking about your front coilovers or rear? If rear, are you adjusters on the top perch or bottom?

Front, I just drooped the spring about 1", so I could move the spring up and down by hand an inch and it was not lower at all! I'm so confused!


EDIT: I think I might have figured out why, I'm retarded. I didn't even roll/drive the car for the spring to settle with droop. Haha. Would that affect the ride height after losing the preload?