Tech Tips - Spur Gear Maintenance

The spur gear is considered a consumable item and will require replacement from time to time to ensure maximum performance from your model.

Visually inspect the spur gear after every run for signs of wear or small debris lodged between the spur gear's tooth profile. Small stones can be removed from the gear with a hobby knife, but if the spur gear show signs of excessive wear replace the gear before continuing to run the model. It is also important that you periodically check the engine mounting screws and gear mesh.

For electric vehicles such as the Rustler, Stampede, or Bandit, spur gear replacement is quite easy. Simply remove the gear cover on the transmission and replace the spur gear by removing the three 3mm CS screws that hold the spur gear onto the slipper hub.

Keep stripping or melting spur gears?

Loose or stripped bolts and screws
Inspect the motor/engine mount bolts and screws, make sure they remain tight. If they are stripped or if the motor mount is broken, the gear mesh will move and the spur gear will strip.

Gear mesh not correct
Re-adjust the vehicle's gear mesh properly for best performance. Also consider adding Fixed Gear Adapters to make setting gear mesh simple and painless.

Slipper clutch is too tight
The slipper clutch is intended to slip a slight amount under a heavy or sudden load to prevent stress to the spur gear. If it is too tight, it may result in stripped spur gears. Having the slipper too loose can melt the center of the spur gear. Here's how to adjust the slipper clutch.

Incorrect spur gear
Be sure you are using the spur gear intended for your vehicle as shown in the manual's exploded view drawings.

Stripped spur gear
Replace damaged spur gear.

Bind in drivetrain
Verify that the drivetrain can rotate freely with no serious resistance. If you feel grinding or heavy resistance, inspect the driveline or transmission for damage and repair.