How To Measure & Set Coilover Spring Preload
Updated: 12/30/24
Establishing the right coilover spring preload is the crucial initial step for configuring your suspension system. But what exactly is preload? Preload refers to the initial tension (or load) exerted on your springs prior to bearing the vehicle’s weight. The measurement of coilover spring preload is expressed in inches, indicating how much the springs have been compressed before any weight is applied to them.
Setting Initial Preload on New Springs or Coilovers:
Follow this procedure if you have just purchased new springs or coilover shocks from us.
- Start with the springs and shocks installed on the vehicle.
- Springs loose
- Dual rate nuts high on the body, spring slider not touching dual rate nuts
- Tighten the preload nut down while gently rattling the springs, when they stop rattling that is Zero Preload
- Measure and record how many inches of threads are showing above the preload nuts
- Every inch you tighten the preload nut down is another inch of preload
- Every inch you loosen the preload nut is one inch of negative preload
- Tightening the preload nut down one inch will also increase the shaft showing by one inch
- Tighten the preload nut down to give you the target preload
- Contact us if you’re not sure how much preload you are supposed to have
- Adjust the preload up or down to give you the desired amount of shock shaft showing at ride height
If you have negative preload, or your preload is more than +/-1″ from our target we should swap springs.
Read our article How To Calculate New Preload And Springs By Using Existing Springs in order to take measurements for the new springs.
hello ive got a set of king offroad racing shocks 3.0. My truck is on a custom 4 link suspension with 49 inch tires. i need advice on how much preload to set the shocks at. truck is a 2002 f150 4 door
thanks for any help
Sounds like you have a very custom setup. For universal fit coilovers we like to have 1″ of preload front and rear. Assuming the spring rates are correct.
Hi, on a Fox 2.5 12″ coildover resi DSC. I currently have almost 4″ of preload. Would it be correct to run a 14″ lower spring and a 12″ upper?
Thanks!
Hey Robert, 4″ of preload sounds a bit excessive and may require a spring rate change. If you’re interested in going that route, please fill out our spring swap form and email it to our sales team so they can help make suggestions: https://accutuneoffroad.com/wp-content/uploads/FM-1000-0004-Spring-Swap-Form.pdf