How fast does an e-bike go?
A legal US e-bike stops helping at 20 mph (Class 1 and 2) or 28 mph (Class 3, pedal assist only). A typical 750 W hub e-bike needs about 415 W from the battery to hold 20 mph on throttle and about 980 W for 28 mph, so speed costs range fast.
Legal speed limits by class
- Class 1: pedal assist only, motor stops helping at 20 mph.
- Class 2: throttle allowed, motor stops at 20 mph.
- Class 3: pedal assist up to 28 mph; most states require a speedometer and set an age minimum.
Federally, a low-speed electric bicycle has a motor under 750 W and a top speed under 20 mph on motor power alone with a 170 lb rider (15 U.S.C. § 2085). You can pedal faster than any limit; the motor just stops helping. 48 of the 76 bikes in our database can be set to 28 mph. See e-bike classes explained.
How much power each speed takes
Battery power needed to hold a steady speed on flat pavement, 180 lb rider, typical 750 W hub commuter (63 lb, upright position), from our physics model:
| Speed | Throttle only | Relaxed pedaling | Throttle range (706 Wh) |
|---|---|---|---|
| 12 mph | 141 W | 96 W | 51 mi |
| 15 mph | 217 W | 172 W | 42 mi |
| 20 mph | 415 W | 370 W | 29 mi |
| 25 mph | 727 W | 682 W | 21 mi |
| 28 mph | 980 W | 935 W | 17 mi |
Air drag power rises with the cube of speed: going from 20 to 28 mph takes roughly twice the power. That's why the same battery that lasts 42 miles at 15 mph is gone in 17 at 28.
Top speeds of popular e-bikes
- Aventon Level 4 REC: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- Aventon Pace 5 REC: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- ENGWE Engine Pro 2.0: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- ENGWE EP-2 3.0: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- ENGWE L20 3.0: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- Gotrax Tundra: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- Gotrax Z4 Pro: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
- Heybike ALPHA: 28 mph pedal assist, throttle limited to 20 mph under Class 2 rules
Common questions
How fast does a 750 W e-bike go?
On flat ground a 180 lb rider needs about 415 W from the battery to hold 20 mph on throttle, so a 750 W motor (which peaks higher) can reach and hold its legal limit. Holding 28 mph takes about 980 W without pedaling, which is why Class 3 speeds are pedal-assist only.
What is the fastest legal e-bike speed in the US?
28 mph with pedal assist (Class 3). Throttle-only riding is limited to 20 mph (Class 2). Anything faster is legally a moped or motorcycle in most states.
Does riding faster reduce range?
Yes, sharply. On throttle, the same 706 Wh bike goes about 51 miles at 12 mph but about 17 miles at 28 mph.
Sources
Last checked 2026-10-20.