Methodology
How we calculate e-bike range
Range = usable battery energy ÷ energy used per mile. Energy per mile comes from one physics model applied to every bike: the power needed to roll the tires, push through the air and climb, minus what the rider pedals, divided by the drive's efficiency.
1. Power at the wheel
Pwheel = Crr · m · g · v + ½ · ρ · CdA · (v + headwind)² · v + m · g · grade · v
- Mass m: rider + cargo + bike (brand weight with battery; when a brand doesn't publish it, a typical weight for the bike type, labelled as an estimate).
- Rolling resistance Crr: 0.006 for road e-bike tires, 0.0075 for 2.2–2.6", 0.008 for 3" street tires, 0.01 for 4" fat tires (BicycleRollingResistance.com drum tests; Schwalbe Energizer Plus measured 0.006). Gravel ×1.5, dirt ×2.
- Air drag CdA: 0.55 m² for an upright rider, 0.65 m² for cargo bikes and trikes. Air density follows temperature (denser, more drag, in the cold).
- Hills: "rolling" is half the distance at +2% and half at −2%; "hilly" ±4%. Downhill the motor rests; we assume no regenerative braking.
2. What the rider adds
Pedaling power is subtracted from the wheel power: throttle only 0 W, relaxed 35 W, moderate 75 W, hard 120 W. "Relaxed" matches the light, motor-engaging pedaling of independent range testers. Speed is capped at each bike's top assisted speed.
3. Motor and battery
- Drive efficiency: 78% for hub motors, 75% for mid-drives (motor plus chain and gears). On grades above 4% hub motors lose up to 18% more efficiency (bench study, Arango et al. 2018).
- Electronics: 20 W for controller, display and motor no-load losses while riding; ×1.05 for stops, starts and gusts a steady-state model misses.
- Usable capacity: 90% of rated watt-hours, because the battery management system cuts off before the cells are empty.
- Cold: lithium-ion energy cells deliver 94% at 50°F, 85% at 32°F and 75% at 20°F (Battery University BU-501a). The loss is temporary.
- Battery age: set battery health in the simulator; about 80% after ~800 full charge cycles is typical.
4. Checked against real tests
We calibrated the constants once, against independent run-to-empty tests (Electric Bike Report: lowest and highest assist on paved trails; OutdoorGearLab: maximum power on a hilly course), and apply them unchanged to every bike. Testers don't publish rider weight, so we assume 180 lb.
The model reproduces all 12 calibration tests (750 W hub commuters, Lectric XP 3.0, XPeak, RadRover 6 Plus, Velotric Discover 1, Lectric XP4, Aventon Level 4) within ±20%, with a mean error under 12%.
Out of sample, it is less accurate. Of the 10 independent tests on bikes currently in our catalog, 6 fall inside the band. The misses are mostly highest-assist runs on cadence-sensor bikes, where the motor pulls near full power regardless of how hard the rider pedals; there the model is 28–55% optimistic. One very efficient lowest-assist run (Velotric Fold 1, 78 miles) beat the model by 37%. Every bike page shows its own tests next to our number, and flags the ones outside the band.
That's why results are a band, not a single number: the same bike can vary by 20% between riders, tire pressures and days.
5. Standard scenarios on bike pages
- Easy cruise: 12 mph, relaxed pedaling, flat
- Everyday: 16 mph, relaxed pedaling, rolling hills
- Fast commute: 20 mph, relaxed pedaling, rolling hills
- Throttle only: 15 mph, no pedaling, hilly
Each is shown for 150, 200, 250 and 300 lb riders, at 70°F on pavement with no wind and a new battery.
6. Hill climbing
We solve for the highest speed at which the motor's peak power (times drive efficiency), plus the rider's pedaling, covers rolling, air and climbing resistance on a grade. Hub motors are also limited by their rated torque at the wheel. Where a brand doesn't publish peak power, we use 1.6× nominal and label it. Peak power is meant for short hills; on long climbs motors and controllers heat up and fall back toward nominal power.
7. Charging time and cost
Time to full = (85% of capacity) ÷ (full-charge voltage × charger amps) + about 1 hour of constant-voltage top-off (Battery University BU-409). Cost uses the US average residential electricity price, 18.31¢/kWh (EIA Electric Power Monthly, July 2026), and 85% charger efficiency.
8. Where the specs come from
Battery, motor, weight, load and price come from each brand's US product page, checked on the date shown. A value we couldn't confirm there is marked est. with a source note. We never use retailer listings for specs. If you find an error, tell us and we'll fix it.
9. Limits
- Cadence-sensor bikes in high assist can use more than the model predicts, because the motor runs near full power regardless of how hard you pedal.
- Stop-and-go city riding, very steep terrain and strong gusty wind are outside what a steady average can capture.
- We don't test bikes ourselves. Independent test results are linked to their source.