It is important to have the correct gear ratio for the tire size for proper operation of your clutch or torque converter. An improper gear ratio can cause the clutch or belt to slip and may result in damage to the unit. To determine the gear ratio necessary for your go kart or mini bike, you must know the maximum top speed. When using a clutch to drive your go kart, the top speed on flat terrain should not exceed 35 mph; if the terrain is hilly or the driver weight is high, the top speed should be limited to 25 mph. Mini bikes perform best with a top speed of 25 mph when using a clutch. When using a torque converter with a go kart, the top speed can reach up to 45 mph on flat terrain and 35 mph on hilly terrain. For mini bikes, 35 mph is the recommended top speed when using a torque converter. Fitment Type: Direct Replacement. Fitment: for Primarily Mini Bikes Go Kart Parts (for reference only). Color: As Shown. Material: Metal. Package Contents: 1 x Centrifugal Clutch. Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.