what is the most compressed condition of a spring in a spring suspension system?
That is known as the solid height of a spring; when all the wires are stacked on top of eachother. You can calculate it by just multiplying the number of turns of the spring by the diameter of the wire.
It is when the spring becomes solid - the coils all touching each other. In automobile suspensions, there are usually stops that prevent the spring from compressing this much in use. In this case the most compressed condition depends on the details of the suspension.
