the spring rate is whatever is needed to just hold the car up
2 things are missing:
1. there's more than one way to get the car to the same ride height (assuming you know what you want already):
A. short stiff spring - stops transferring weight when it tops out
B. long weak spring, the extra length is pre-load - transfers weight up to its full length
2. spring stiffness must be enough to control the weight of the unsprung components (axle etc.). An 8-1/4" and a Dana need different rear springs regardless of the rest of the tuneup.
Not really. In my case, the coil overs are a given length. So because there is less energy loss per inch in the weaker spring , it would top out quicker with the weak spring than the stiff one.
I have never heard of controlling the unsprung components. How would you know when your spring values are too low to handle the unsprung weight. We all know what would happen if you had too low a spring pressure for the sprung weight. And when I lightened my car, I had to change springs several times to get it down from it's 4x4 stance.
