Coilovers - Spring Rates

[Go2ZZZ]

Hello all!
I have zero knowledge on coilovers and spring rates.

I am currently on swift springs. Considering coilovers as I’m getting bigger tires and if it improve handling even more then the springs, I’ll do it.

I want to see if it’s worth it for more spirited driving and roll racing and some drag racing for fun.

I was looking at FA with swift springs and their default rate is 4KG rear and 11KG front.

BC with swift springs is 9KG rear and 12KG rear.

Wondering why it’s so much different between the two.

 

[Evolution]

The difference in the rear is because one is a divorced setup and the other is a true coilover.

 

[Go2ZZZ]

The difference in the rear is because one is a divorced setup and the other is a true coilover.

BC advertised it as “true” though.

 

[Evolution]

BC advertised it as “true” though.

Someone has a typo then. Divorced rears are typically around double the rate of a true coilover. I dont know the motion ratio F/R or what frequency they target so I cant tell you who is wrong.

Also, please dont get the BC coilovers. They are junk. Go with FA at a minimum.

 

[Go2ZZZ]

Someone has a typo then. Divorced rears are typically around double the rate of a true coilover. I dont know the motion ratio F/R or what frequency they target so I cant tell you who is wrong.

Also, please dont get the BC coilovers. They are junk. Go with FA at a minimum.

I was Leaning to them but I just wanted to understand spring rates for what I want to do

 

[Evolution]

I was Leaning to them but I just wanted to understand spring rates for what I want to do

Start with figuring out what frequency you want to target (based on what kind of driving you are going to do). Then figure out the motion ratio front and rear. After that, you can calculate the spring rates pretty easy.

I would do that over getting the off the shelf rates because most companies dont put in the effort to figure out the correct rates.

 

[VR30Infection]

I wish I had the correct info on our cars for motion ratio and frequency. I am trying to figure out what spring rates I want and do not want off the shelf rates. I find it so curious how big of a discrepancy there is from company to company that all claim to be targeting the same goal. I am wanting to choose the spring rate by targeting the natural frequency I am after and am not sure what company I can trust to have the proper equations for our chassis. If I was enough of a nerd I would create an excel spreadsheet calculator with all of the Z's chassis info already plugged in so you could either plug in desired Hz and have it spit out the spring rate or plug in the spring rate and have it tell you what the natural frequency would be. It would have check boxes for Kg/mm, Lb/in or Nm/mm as well as Divorced rear or True coilover.