INSIDE DIAMETER = 50.0, LENGTH = 90mm, 30% STIFFER THAN STOCK. Variator springs. An underestimated part of optimal variator adjustment is the variator back pressure spring. (Torque Spring) This spring puts back pressure on the back converter (“Speed Drive/Torque Drive”). This in turn influences the “behavior” of the variator. When the drive belt starts to slip, or the torque changes when accelerating or when the motor, despite variator adjustment with rolls, doesn’t reach optimal RPM’s; then it’s time for variator springs. After being installed, variator rolls and clutch springs should be re-adjusted. This is the only way to adjust the whole system for proper operation. TESTED and it works. Allows greater take off without sacrificing Top Speed. Clutch will need to be disassembled to install Spring.