Purpose and benefit Designed for upgrading and converting remote-controlled (RC) vehicles. Use these gears to change gear ratios, improve drivability, or replace worn components without replacing the entire gearbox. Key features Multiple gear options: available in several types with different tooth counts so you can choose the exact gear ratio you need for speed or torque adjustments. Coupling for pinion adaptation: includes a coupling that converts three pinion openings from 5 mm (0.196 in) to 3.175 mm (0.125 in), making it easier to fit different motor pinions or shaft sizes. All-metal internal gears: full-metal internal gears provide high strength and long service life for demanding RC applications. Clear compatibility focus: intended for use in RC vehicle gearboxes and drivetrains where pinion bore size and gear ratio flexibility are required. Why you need it Fast, affordable upgrades: change gear ratios or adapt pinion sizes without buying new motors or housings. Better performance control: select a tooth count that matches your needs—more teeth for higher speed or fewer teeth for increased torque. Durable replacement parts: all-metal construction resists wear and extends maintenance intervals compared with plastic gears. Practical applications Crawlers and rock racers: switch to a lower gear ratio for increased torque when navigating technical terrain, using the appropriate tooth count and the coupling to fit smaller motor pinions. On-road and touring cars: tune for higher top speed by selecting a higher-tooth-count gear and adapt the pinion bore to a larger or smaller motor shaft as required. Repairs and retrofits: replace damaged internal gears in existing gearboxes and use the included coupling to adapt pinion size when fitting a different motor or aftermarket pinion. Compatibility and sizing Pinion bore conversion: 5.00 mm (0.196 in) to 3.175 mm (0.125 in) via the supplied coupling for three pinion openings. Multiple tooth-count options: select from available gear types to obtain the desired translation/gear ratio for your vehicle. Performance and longevity All-metal design increases resistance to wear and impact compared with plastic gears. Suitable for regular use and higher-load situations common in RC upgrades and conversions. Installation tips Confirm pinion bore and shaft diameter before installation to ensure correct coupling orientation. Choose tooth count based on whether you need more torque (fewer teeth) or more speed (more teeth). This product provides a practical, durable solution for adapting pinion sizes and optimizing gear ratios in remote-controlled vehicles, giving you flexibility and long-term reliability without replacing major drivetrain components.