RC calculators

Speed estimator

Motor KV Battery voltage Gear ratio (FDR) Tire diameter Speed
KV V : 1 mm 68 km/hr, 42.3 mi/hr
Typical tire diameters:
  • 1/12 pan car: 45mm
  • 1/10 mini touring car: 60mm
  • 1/10 touring car, pan car, F1: 65mm
  • 1/10 buggy and stadium truck: 90mm
  • 1/10 short course truck: 110mm
  • 1/8 buggy: 115mm

Single gear size conversion

Changing a value will calculate conversions for other values.
64dp 48dp
teeth teeth
0.4mod 0.6mod 0.8mod / 32dp 1.0mod
teeth teeth teeth teeth
Pitch Diameter

Gear spacing

Gear pitch Gear 1 teeth Gear 2 teeth Gear 1 pitch diam. Gear 2 pitch diam. Distance (center-to-center)
teeth teeth 39.7 mm 13.2 mm 26.5 mm

Motor power estimator

No load speed Stall torque Power estimate
RPM g·cm 101 W
Electric motors generally lose torque linearly as speed linearly increases.
Since power is speed multiplied by torque, the highest power output will roughly be at 50% of the maximum RPM.
Actual motors do not exactly behave this way, so this calulator is a rough guess-timate.
Formula: Power = ((MaxRPM / 2) * (StallTorque / 2)) / 97667;