Thanks Bob, I see now.
Shorter springs will indeed make the car sit lower and by adjusting the nut upwards, will lift the car on the spring and vice versa.
But this also means the shock will never be fully extended and when the wheel goes in full droop,
(shock fully extended) the spring may come loose.
My theory was based om my units that were made from gas filled shocks and my here was how I went about it.;
I put the chassis on trestles and let the suspension dropped completely and then lifted (bumped)it completely and measured the travel and searched for a shock that have the said travel and will fit fully extended and compressed.
My shocks are gas filled and usually these extent itself fully unlike hydraulic (oil) units that does not extents itself fully.
After I made the adjustable coilovers I calculated the spring length that when fitted with a little pre-tension to tighten the spring in place, so its still 20mm longer than the max droop.
Then I made careful calculations, using correction factors for shock angles etc to have the spring rate that when the car is put on coilovers, it will be at the designed ride height - shock about 38% compressed, so when the spring goes into max bump, the shock still have a little movement left. When full drooped, the shock is about 95% extended.
As said before my car sits exactly where intended - 140mm (with driver) high and the springs sensitive for any input. I hope this will give a good quality ride because the suspension has a lot of travel and the spring rate perfect for car.
I need this because the roads in my area (rural) are very bumpy and in many places, potholes the order of the day - much so for whole of SA..
Here a pic on my self built adjustable coilovers, even done the ally anodising myself in the garage
