New from HPI Racing is a Heavy-Duty Final Gear Set for Nitro RS4 3 touring cars. These are standard replacement parts for the high performance Nitro RS4 3 18SS cars, and can be installed on the standard Nitro RS4 3 for increased drivetrain strength, extended maintenance intervals, and a taller gear ratio for higher top speed. These heavy-duty gears are heat treated, making them a great upgrade for Nitro RS4 3 owners who are using powerful engines. The set includes one 36 tooth ring gear and one 14 tooth bevel gear, two sets are required for a complete upgrade to the Nitro RS4 3 cars. Not recommended for Nitro MT off-road trucks due to the taller gear ratio.