This is a heavy duty clutch replacement for standard live axle karts using up to 18 tall tires. 40/41/420 chain sprocket, this fits on a 1 crankshaft and the other end is 3/8. The 1 inch bore centrifugal clutch is ideal for larger horsepower engines, up to 13 horsepower and flat riding; for bigger tire application and extreme riding you will need a torque converter. The crankshaft must be threaded to accept a bolt to hold clutch onto shaft. Please verify whether this part meets your needs before buying. Heavy Duty Centrifugal Clutch Replacement for Go KartDescription:The 10t 1 inch bore clutch 40 chain sprocket allows you to achieve a desired gear ratio for good pulling power, recommend using at least a 60t drive sprocket.The heavy duty centrifugal clutch is designed to be able to move a certain amount of weight, once the weight limit is exceeded, then the life of the clutch will be shortened, please make sure the total weight of the kart and driver will not exceed aver