Did you know that you can use the spur gear and pinion size for setup tuning? And I'm not referring to the gear ratio. The examples below achieve the exact same FDR (6.9) but with either more or less teeth on both ends. In this case, the motor shifts forward or rearward by 2-3mm, which is definitely noticeable, not only for the weight bias of the car, but because of the torque of the motor under acceleration- and braking.

Using a smaller spur and pinion:
  • Moves the motor forward
  • Shifts weight bias to the front
  • Makes the car easier to drive
  • Less precise braking feel
    •

    		Using a bigger spur and pinion:
  • Moves the motor rearward
  • Shifts weight bias to the rear
  • Improves rotation
  • More precise braking feel
    •


    For modified TC outdoors I've preferred a smaller spur and pinion as of late, to improve drivability!

    Source:

    A. Hagberg