Hey guys, quick question. What is the point of preloading? Say with gc/konis, you preload the spring using the gc height adjuster before dropping the car on it.

A preloaded spring has more tension, so I am assuming a preloaded spring compresses less when the car's weight is put on it... Am i right?

Oh yeah one last thing... is preloading a spring bad for the shock? Since the spring is basically trying to pull the rod out of the shock shaft.

 

Preload only affects the spring during initial loading. The final weight on the spring still yields the same loaded spring height, regardless of how much preload you put on it.

Say you have an 8" long 400 lb/in linear spring, and you load it with 800 lbs. That will compress the spring 2" to a final height of 6". Now say you put 100 lbs. of preload on it, to compress the spring 1/4", for a preloaded height of 7-3/4". When you start to put your load on it, the spring doesn't compress any more until after you put over 100 lbs on it. Now this time the spring will only compress another 1-3/4" because you already had compressed it 1/4", but the final weight of 800 lbs. will still compress the spring the same 2" with respect to the unloaded spring's length, and the loaded spring will still be 6" long.

With regard to Ground Controls, there is no separate preload adjustment, so if you preload your spring, your car will sit very high. A Ground Control setup set to a normal "lowered" ride height will not have preload like stock springs do, and they will be loose on the shock when the shock is at full droop. This is not a big deal in most cases while driving, especially if you have sway bars, in which case the inside wheels going around a corner do not droop much at all.

On coilover setups with preload adjustment, you should only put a small amount of preload on the spring, really only enough to keep the spring in place when the damper is fully extended. Any more than that would be pointless.