Easily calculate the CSR and FDR. How to use: Choose two or three belt setup at the bottom of the screen. Type in the teeth count of the pulleys into the textboxes below the schematic drivetrain. Start with the front diff pulley on the left and continue along the drivetrain to the right. To calculate the FinalDriveRatio (FDR) also type in the teeth count of the spur gear and pinion. Hit CALCULATE. That s it, the CSC will give you the values for the CS ratio and the FDR.