i dont think you could possibly preload a spring too much. theres really no reason to preload it excessively. also, you dont even need any preload. omnipower will tell you that their coilovers require some preload. they also blindly copy other ppls designs and offer free replacements when they mess up. so what do they know?

one misconception about preload is that it changes the spring rate, or makes the spring stiffer. absolutely not. if the spring is linear, the spring rate SHOULD remain the same, no matter the amount it is initially compressed. (not all springs are equal, some of the crappy taiwanese springs have exhibited non-linear behavior when they clearly were not designed to)

the truth is, your cars weight determines the amount of static preload. by that i mean, when all 4 wheels are rested on the ground. on a 2400lb car, say weight is equally distributed at all 4 corners, 600lbs over one wheel. theres not much you can ever do to change this, youd have to physically move stuff (battery, add ballasts) to change the weight distribution, so lets call that constant.

say you used an adjustable spring kit like ground control and had set the spring perch to just a BIT of preload, just so that the lower collar is touching the spring and no more. and say its a 300lbs/inch spring rate on that spring. jack the car up in the air and slowly let it drop, the car will drop 2" from the point the wheel touches the ground. lets say the bottom of the car is 5" from the ground.

now raise that spring perch from the point of nearly zero preload to 1" higher. you put 300lbs of pressure on that spring already. the wheel is probably going to be a bit more than 1" higher now, relative to the chassis because the spring to ride (wheel) height ratio is more like 1:1.5, but lets assume 1:1 here. drop the car onto the ground, and measure. the weight of the car is STILL going to push down on the spring the extra inch, until it reaches 600lbs of weight. the spring is still going to compress 2" and the car is now going to be 6" from the ground. youve raise the car 1" with one other change...

what has changed is whats called droop or sag. the distance the wheel can extend has been limited. now instead of having to raise the car 2" off the ground until the wheel is fully in the air, its just 1". what i do know from motorcycle backgrounds, motorcycles are VERY sensitive to sag distances. but i never really hear it talked about it for cars, so im just gonna figure its not really important and chalk it up as the difference between riding on 2 wheels instead of 4. quite frankly, i dont think you can even put enough pressure on that collar to provide any more than 300lbs anyway. so its quite moot to wonder what happens if you preloaded it 2", which would be 600lbs. then things get really funky. you basically at that point have no droop even though the ride height has NOT CHANGED. but like i said, the point is moot because youll never get there.

now, lets go the OPPOSITE direction. from the point of almost zero preload, lower the collar 1". there is now NO preload and the spring can even move around once the side is jacked up. drop the car again and youll find the ride height has finally changed, and its now lowered 1" with 4" from the bottom of the car to the ground. lower the perch 2", the ride height lowers 2". spring rate has since remained the same as well.

so basically, PRELOAD IS POINTLESS. let me remind you, this goes for adjustable spring kits, sleeve type, like ground controls. the spring should be free and rattling in order to adjust ride height. its very normal. the down side to lowering the spring perch is directly reducing the amount of shock travel. say you lower it 2", youve lost 2" of shock travel, with only perhaps a total of 5" until you hit the bumpstop. you can do other things like extend the top shock mounting point (like GC extended top hats, or just custom shortening your shock which only really koni does for a good price)

on the subject of threaded body shocks with adjustable lower cups, yes, those types of coilovers can (should) independently change ride height to shock travel. id have to say thats a nice thing about the full threaded body coilover setup. but in the case of poorly designed full coilovers, like omnipowers kit for the CRX and EF, the lower cup doesnt even allow any adjustment before it bottoms out. so basically to lower it any decent amount, you have to rely on the spring perch, basically removing any preload and again directly taking away from shock travel. the one benefit of that setup is completely wasted. yeah yeah, tehy got a "fix" for that, "contact your omnipower supplier" or "its coming out next month". when arent they fixing their crap....


in summary, dont worry about preload. it really doesnt mean anything relevent or affect much. you couldnt possibly have TOO much preload, and its fine or even proper to have none.