The 50-tooth spur gear and 20-tooth pinion gear combo (1.0 metric pitch) is machined from hardened steel with extra-wide steel teeth for ultimate power handling and durability. Traxxas spur gears let you fine-tune the performance of your Traxxas model. Changing gear ratios can help balance acceleration and top speed for different running conditions. Please consult your owner’s manual for more information on recommended gearing options for your specific model.