I have full coilovers on my car and I am pretty sure I have set the preload too low. The car lifts off the ground at times when hitting hard bumps, so I was wondering; What is the proper way to set up preload on a full coilover suspension?

 

WTF is a "full coilover"? A coil spring over a shock is the definition of a coilover, there is no full or partial...

Preload is simply to keep the spring seated at full droop. There is no "proper way", other than "don't add an absurd amount".

 

Thanks for the information. What I ment by full coilover was a one piece coilover system from top hat, spring, spring adjuster, shock, and preload, with damper adjustment, compaired to something like like ground controls on koni shocks. Thanks for clarifying that for me though. Appreciate the help.

 

Imagining the shock and coilover were removed from the car, or sitting with no weight on them, the "preload" is the amount of pressure on the spring as it is sandwiched between the upper and lower perch. the amount of preload is adjusted by simply tightening the perch, which compresses the spring a bit. I'm not sure how much you should preload the spring, but the minimal amount would be 0, so the spring perches are just touching the spring so it cant move around freely, but not tight enough to actually compress it. Some coilovers just slide on over the shock and the upper perch is not connected to the shock, in which case there is no way to preload the spring.

Anyway, you could just try having little to no preload, or adding a bunch and see if one or the other helps. Its kind of a tuning thing, and there isnt a definite single correct answer. If the car feels like its bouncing off the ground over bumps, you might just have too high of a spring rate, and the bumps arent being absorbed, so the whole car moves upward instead of just the suspension compressing.

 

"Full coilover" is a fine term. I started it :p. Better than "true" coilover.....

Having a wheel come up in a turn is not a problem really. You probably just have a stiff swaybar. Its typical.

If its bouncing up uncontrollably, then your shock is just not doing its job and blown.

 

At full droop the spring should be in contact with the upper and lower perch, if just so.

Now, some race set ups do not actually follow this line of thinking since they assume the wheels will always be in contact with a smooth racing surface. The compromise here is weight...using a smaller lighter spring of the same rate as a heavier spring saves unsprung weight. You simply have to make sure the smaller spring has enough block height for given travel.

Anyway, jack your car up and adjust the spring so that it cannot flop around between the perches...this will also influence ride height so you have to look at both...keep your brain awake and think about how a car actually has to work. I don't like springs flopping around...

 

Keep in mind if preload is not set to 0, and the spring has play within the perches, say for example 1" of up and down movement, you will be losing 1" of valuable shock travel.

 

Great point!!!