Marketing sheets quote peak numbers; physics quotes RPM × wheel circumference. This theoretical e-scooter speed estimator models unloaded top speed from your electrical and mechanical inputs—so you know the ceiling before rider mass, sag, and firmware limits apply.
Benefits
- Frames speed as a theoretical estimate—not a road guarantee—matching how KV and voltage math is used in build planning.
- Combines motor RPM, wheel diameter, and a practical derating factor in one km/h output.
- Useful for comparing decks, motor swaps, and 36 / 48 / 52 V tiers before buying parts.
How it works
- Gather nominal battery voltage, motor KV (RPM/V), and measured wheel diameter in mm.
- Estimate motor RPM with voltage × KV × ~0.88, then convert RPM to km/h via wheel circumference.
- Treat the result as theoretical no-load speed—subtract margin for rider weight, wind, and controller caps.
FAQ
What does a theoretical e-scooter speed estimator calculate?
It estimates unloaded maximum ground speed from electrical constants (voltage, KV) and wheel size. The number is a physics ceiling for planning—not the speed you should expect on a loaded commute or downhill run.
Why call it theoretical instead of actual top speed?
Actual speed includes aerodynamic drag, tyre loss, voltage sag under load, and software limits. Theoretical speed isolates motor RPM potential so you can compare hardware—then apply real-world discounts separately.
How far below theoretical speed will I ride?
Many commuters see several km/h less on flat ground with a rider onboard. Hills, low SOC, and conservative controllers widen the gap. Use hill-climb and peak-amps calculators after the estimate to see where torque—not RPM—becomes the limit.
Can I use this for regulatory or warranty claims?
No. It is a free planning estimator. Always follow local speed limits, OEM firmware settings, and manufacturer specifications for legal and warranty compliance.
Technical specifications
- Theoretical RPM ≈ battery voltage (V) × motor KV (RPM/V) × 0.88.
- Theoretical km/h = (RPM ÷ 60) × π × wheel diameter (m) × 3.6.
- Example: 52 V, 14 KV, 255 mm (10″) → ~641 RPM, ~30.7 km/h theoretical.
- Loaded cruise, firmware caps, and terrain reduce real-world speed below this estimate.
- Related: e-scooter-top-speed-calculator, calculate-max-speed-from-motor-kv-and-voltage.