GET THE BEST OF BOTH WORLDS, SWIFT ASSIST SPRINGS PROVIDE A DYNAMIC STEP LINEAR RATE.
Like Swift's helper springs, the assist springs are designed to be fully compressed at static height. Every one of Swifts assist springs compress to the exact same height. This allows drivers to change assist springs without resetting the perch on the coilovers so the ride height isn't affected. Heavier rates of assist springs over helper springs are used to fine tune the rebound travel of the shock. These springs can also help preventing loss of traction due to inside wheel lift during hard cornering.
HELPER SPRINGS PREVENT DISMOUNTING OF SPRINGS FROM PERCH ON COILOVER WITHOUT CHANGING SPRING RATE.
Unlike assist springs, helper springs are specifically designed to have a minimal effect on the spring rate of the main coilover spring. Helper springs allow the spring to stay on mounted on the coilover perch when the shock is under negative or zero load, also known as droop travel. It is ideal to run helper springs on setups where you cannot preload the main spring due to height issues or when experiencing springs coming loose from the coilover perch.