To repair the odometer permanently you will need both the 15 tooth gear and the pod. The ONLY way to determine which tooth count you need is to count the teeth of your old gear.
Odometer Gears (Optional 2)
The ONLY way to determine the correct tooth count needed for the E3 gear is to remove and count the teeth on your old gear. The outside of the gear will have 48 teeth. Remove and count the smaller underside of the gear.
Odometer Gears (Optional 3)
To repair the odometer permanently you will need both the 20 tooth gear and the pod. The ONLY way to determine which tooth count you need is to count the teeth of your old gear.