I have a few questions and concerns about spring rates…is there like a formula or some kind of calculation you can determine to choose the right spring rates for your particular application…I am in the market for new springs for my car and i really cant afford coilovers…i was thinking of getting ground controls and i know u can custom rate them i just dont know to determine this…i was considering just gettign Eibach Pro-kit
Miata.net has a spring rate calculator, but I’m not sure if it is universal for all cars. To really choose the correct rates, you should know the corner weights of your car, for starters, and what the ratio of the spring rates currently is from front to rear. Keep in mind that sway bars will also play a role in your spring rate selection. A stiffer bar will mean less spring is needed to control body roll.
currently there is no bar on the rear…but i am hoping Santa Claus changes that
instead of starting my own thread… i’ll just use yours
I have dropzone d1 coilovers on my car. its the spring and strut together
these come with the spring rates of 450front/350rear
these are way too high of a rate for a daily driven car. the bounce is crazy.
and adjusting the dampening doesnt really seem to do to much, except if it on full stiff, there is a little less bounce than on full soft
stock springs have a rate of 150front/120rear
the mopar hi rate springs i had were 225/185
and the mopar extra hi rates are 310/230
i would like something a little stiffer than the mopar hi rates i had
so i was thinking 250/200 would be good. any thoughts?
the bounce should stop then right?
custom rated ground controls…or even Eibach pro-kit…they are usually on the stiffer side but still driveable…they are progressive so they are nice when drviing but in the corners get stiff…to give an example the ones for my car are
Front 166~257 Rear 166~343
well i was just going to get these for the front
and these for the rear
GOTO swiftsprings.com…they do all kinds of custom rates and stuff…also eibach does have “unviversal” springs u know where if u know ur diamters u can choose different springs…but check out that swiftsprings.com…but hey for 35 bux a spring…choose the heigh u want…and the rate the ones form summit dont look to bad…i would do a little more comapring to make sure they are right for u beuse the length may be the same but the actual ride height will differ depending on rates
Keep an eye on the shocks/struts you use with the springs. I have ground controls with 380/300, because the KYB AGX’s will not perform worth a damn beyond those rates. If you are getting alot of bouncing, then your spring rate may be too high for your shocks.
If you call up Ground Control and tell them your setup, they are VERY helpful in selecting the proper spring rates. They have alot of experience with these things.
I know ground control has different setups for diff struts…i emailed them and they told me that their rates for AGXs which i have are different for koni, tokico and so on…so maybe they fixed that issue
these are what i’m currently running… maybe i’ll email ground control and see if they recommend anything
Here is the conversion formula for spring rates:
You can convert that into lb/in with this formula:
Kg(55.68 ) = lbs/in
That converts into lbs/in from Kg/m.
IMHO if you are driving the car year round, just get the Eibach Prokit, the progressive springs wil lbe stiff enough to improve handling without making your ride extremely rough. I wouldn’t go with Ground Controls unless you are trying to do something more specific/dedicated with the car. Ground Controls still cost $$$$ and you will probably have to change your shocks when you get them as well.
Prokits would be the most economical.
On a side note, good luck getting Ground Control to help. There customer support is shoddy at best. If you can find a vendor that stocks the particular spring rate you are looking for, I’d go with them, but even they will have problems depending on their stock. There are plenty of horror stories with GCs around (fairladyz, myself, others)