i am building a car that will be setup for roadracing and am going to order Eibach ERS springs and set up a custom spring rate. I currently have ground control coilovers and they are far too soft. I will be mating these ERS's to koni yellows, ore than likely with a modified shorter shockrod and will e lowered from stock ride heigth approximately 1.8-2.0". I am curious as to how I should calculate what spring rate to use. This car will see the streets here and there, but is in no way a daily driver and loss in comfort is ok if gain in performance is created. If anyone has experience with calculating spring rates or knows someone who could help, please lemme know Thanks!!

 

anyone?