Coil springs
These are spiral wound springs using 4- 8 pieces per set made from heat treated high carbon steel and come in various shapes and sizes delivering differing spring tensions depending on the size of the bike and the horsepower of your engine. It is important to note that you cannot change the basic shape of these springs to gain any performance advantage but what you CAN do is buy a EBC Brakes CSK kit which have slightly thicker winding material and deliver 10-15% more clamp pressure.
All EBC Brakes™ clutch spring kits are made in the UK and are individually load tested by hand to guarantee that spring pressure is above that of stock springs.