I installed my nre coilovers and I wanted to know how to set the preload. My ride height is set by adjusting where the strut attaches to the car. like the JIC coilovers. I do not know how much preload I should set on the springs. I dont want the car rideing on the top of the suspension travel but I dont want it bottoming out. Right now I have more preload in the fronts than in the back. I was thinking of putting mpre preload in the rears to stop my car from squatting when accelerating. But im not sure what to do. anyone here have a suspension with adj preload wanna help?

 

ok, after a lot of pondering, discussing with adam, mityvr6, and some reading, its all cleared up now in my head and i want to clear this up.

while you can effectively PRELOAD a spring, it is NOT relevent to corner weighing. corner weighing is not dependent on spring preload, which usually there is none, but dependent solely on ride height. adjusting ride height does not change preload, until you reach the limit of shock travel, which is not commonly done to my knowledge.

with typical koni/gc suspension combo, you raise the lower spring perch and the ride height raises. weight at that corner changes and is made greater only because like on a 4 legged table, that leg has been made longer and now the weight is less on the other two legs of the perpindicular diagonal. (read this GRM article) if the ride height is adjustable independently, like in the JIC models, then it achieves the same thing. you may also raise the lower spring perch, but thats not ideal, more on that later.

so to talk about preload and corner weighing is irrelevent and not correct. and preload is irrelevent unless you are tuning active spring travel during rebound, which ive not heard of (ok i made up that term), maybe just because at this level its not really possible without threaded shock body and independent lower spring perch and ride height adjustment. the koni/gc combo for example, the amount of sag from the weight of the car is the only active spring travel during rebound.

it seems to me that separating ride height from adjusting the lower spring perch the only advantage is the ability to lower the ride height and not sacrifice shock travel, which is a big plus actually, but any other thoughts?

another thought. if you did effectively preload the spring by jacking up the lower spring perch past the zero length of the main spring and reached the limit of shock travel, what use is the tender/helper spring anyway?


Modified by Tyson at 3:54 AM 9/13/2003

 

Are you guys talking about limiting droop? It's the only way I know to preload a spring other than just putting weight on the car. I've never heard of anybody using them for sedans, because swaybars generally work better.

 

That was fun, Tyson. Not a bad way to spend an hour late on a Friday night.
-Adam

 

"Typically" you use the lower spring perch to do the corner weighting and the threaded shock body to set ride height. The reason being that it is a pain in the *** to unbolt the fork, or lower arm, just to make a 1/2 turn adjustment when corner weighting.

If you are just getting started sorting your set-up, you may not have enough travel in the lower spring perch - example: where you need to raise a corner 5 full turns. In that case, depending on shock design, you may run into travel issues and end up "pre-loading" the spring too much, and you will have to revert to using the threaded lower portion for adjustment.

When just getting started setting up a new package, my reccomendation is to preload the springs evenly on all 4 corners and go through the added time and effort required to set ride height and corner weight using the threaded lower portion. Again, once you get it close then you can start using the lower perch for adjustment.

A benefit to a little pre-load is that the spring stays put and does not "clank" around when the corner is unweighted and at full rebound - inside rear wheel on a Honda

I've been using 1 full turn of pre-load on the Mugen package.

Tyson is correct - by our definition preload assumes you are at the limit of rebound travel.

Anyone wonder what upper shock bushings come with the Mugen dampers?