Calculator
How It Works
RC Tips
Top Speed
0.0
mph / 0.0 kph

Detailed Results

Gear Ratio: -
Motor RPM: -
Wheel RPM: -
Speed (mph): -
Speed (kph): -

How the RC Car Speed Calculator Works

The calculator uses the following formula to determine your RC car's theoretical top speed:

Speed (kph) = (Motor KV × Voltage × 60 × ? × Tire Diameter) / (Gear Ratio × 1,000,000 × Efficiency)

Where:

  • Motor KV: The RPM per volt of your motor (e.g., 3500KV motor spins at 3500 RPM per volt)
  • Voltage: Your battery's voltage (e.g., 11.1V for a 3S LiPo)
  • Gear Ratio: Spur gear teeth ÷ Pinion gear teeth
  • Tire Diameter: The diameter of your tires in millimeters
  • Efficiency: Drive system efficiency (typically 85-95% for brushless systems)

The result is then converted to mph by multiplying by 0.621371.

RC Car Tuning Tips

Gearing Tips

  • Increasing pinion size or decreasing spur size will increase speed but generate more heat
  • Monitor motor and ESC temperatures after gearing changes
  • Start with manufacturer recommendations and adjust gradually

Battery Tips

  • Higher voltage batteries (more cells) will increase speed
  • Higher C-rating batteries provide better voltage under load
  • Always use a properly rated ESC for your battery configuration

General Performance Tips

  • Keep your drivetrain well-maintained and lubricated
  • Reduce weight where possible for better acceleration
  • Use quality tires appropriate for your surface
  • Ensure your suspension is properly tuned for your driving style

Note on Calculations

This calculator provides theoretical speed. Actual speed may vary due to factors like surface conditions, air resistance, motor efficiency, and battery condition.

Drive efficiency accounts for power transmission losses. For brushed motors, use 75-85%. For brushless motors, use 85-95%.