Swift Progressive Helper Springs 65mm ID, 4 in length 5.3-11.6kg/mm Pair Bump Springs Sold as a pair

Sold as a pair

Round Wire Linear Rate Bump Springs 700 lbs/in

Professional installation is required

65mm ID All Kits come with 4 thrust sheets & 4 metal washer sheets (1 kit for 2 springs)

200/500 lbs/in Progressive

Swift Progressive Helper Springs 65mm ID, 4 in length 5.3-11.6kg/mm Pair Bump Springs Sold as a pair65mm ID, 4 in length 5. 3 11. 6 kg mm Progressive Swift helper Springs are made from a proprietary material. 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. The same springs are used in Super GT, Formula Nippon, F3, F3000, Super Taikyu, IMSA, Pirelli World Challenge, Rally America, VLN, Le Mans Series, Formula Drift, and many other professional racing