Many electric bikes in the U.S. are limited to 20 mph because that speed is tied to how low-speed electric bicycles are classified and regulated. But a 20 mph limit does not necessarily mean the bike’s motor, battery, and controller are physically incapable of going faster.
On some e-bikes, the higher speed is restricted electronically by a speed limiter. If that limiter is removed, bypassed, or reprogrammed, the motor may continue providing power beyond the original cutoff.
Are E-Bikes Really Limited to 20 MPH?
Not all of them.
In the U.S., 20 mph is an important threshold for both federal definitions and the commonly used three-class electric bike system.
The Consumer Product Safety Commission defines a low-speed electric bicycle as a two- or three-wheeled vehicle with fully operable pedals, an electric motor of less than 750W, and a maximum motor-only speed of less than 20 mph under specified test conditions.
At the state level, many jurisdictions use a three-class system:
| E-Bike Class | How the Motor Works | Assisted Speed |
|---|---|---|
| Class 1 | Pedal assist | 20 mph |
| Class 2 | Motor can propel the bike without pedaling | 20 mph |
| Class 3 | Pedal assist | 28 mph |
Under these definitions, Class 1 assistance stops at 20 mph, Class 2 motor assistance also stops at 20 mph, and Class 3 pedal assistance can continue up to 28 mph.
So when you see an electric bike described as being “limited to 20 mph,” it often refers to the point where its electrical assistance is programmed to stop rather than a mechanical limit that prevents the wheels from turning any faster.
Why Are Many E-Bikes Limited to 20 MPH?
The 20 mph threshold is mainly about keeping lower-speed electric bikes within a bicycle-style regulatory category.
Without some limit on motor speed and power, it becomes much harder to distinguish an electric bicycle from a moped, motorcycle, or other motor-driven vehicle.
Legal Classification
Speed is one of the main factors used to classify an electric bike.
A Class 1 or Class 2 electric bike generally stops providing motor assistance at 20 mph, while Class 3 allows pedal assistance up to 28 mph.
Once a bike exceeds the requirements of the applicable electric bike category, different state or local rules may apply.
That distinction can affect:
- where the bike can be ridden
- helmet requirements
- rider age
- registration or licensing requirements
- access to bike lanes and trails
The rules are not identical across every state. New Jersey, for example, changed its electric bike framework in 2026 and now treats Class 2 and Class 3 bikes differently from the three-class approach used in many other states.
Rider Safety
Higher speed gives riders less time to react to traffic, pedestrians, road debris, intersections, and other cyclists.
It also increases braking distance and places greater demands on the brakes, tires, suspension, and rider control.
An electric motor makes it possible to reach higher speeds with much less physical effort than would normally be required on a conventional bike. Limiting assistance helps keep many everyday e-bikes closer to speeds expected on bicycle-oriented roads and paths.
Bike Lanes and Shared Paths
Electric bikes often share infrastructure with conventional bicycles and pedestrians.
On a multi-use path, a bike traveling under motor power at 30 or 35 mph would create a much larger speed difference than a typical Class 1 or Class 2 e-bike.
Speed classifications give states, cities, parks, and land managers a practical way to determine which types of electric bikes are suitable for different riding environments.
What Is the Difference Between 20 MPH and 28 MPH E-Bikes?
For U.S. riders, 20 mph and 28 mph are much more relevant than the 15 mph figure commonly seen in overseas electric bike regulations.
A Class 1 electric bike provides pedal assistance up to 20 mph. A Class 2 e-bike can use motor propulsion without pedaling but also stops providing assistance at 20 mph. A Class 3 bike provides pedal assistance up to 28 mph.
That extra 8 mph can matter on longer road commutes where riders want to maintain a higher cruising speed.
However, a higher assisted speed can also affect where the bike is permitted. Some states and local jurisdictions place additional restrictions on Class 3 bikes, particularly on trails and shared-use paths.
That means the fastest option is not always the most practical one.
For riders primarily using bike paths or recreational routes, 20 mph may be sufficient. Riders covering longer road distances may place more value on Class 3 assistance.
Why Are Some E-Bikes Limited to 15 or 15.5 MPH?
The 15 or 15.5 mph figure generally comes from regulations outside the United States.
For example, in the UK, an Electrically Assisted Pedal Cycle, or EAPC, must have a motor with a maximum continuous rated output of no more than 250W and must stop providing electrical assistance above 15.5 mph. You can find the current requirements in the UK government electric bike rules.
That is why you may see both 15 mph and 20 mph when researching electric bike speed limits online.
For U.S. riders, however, the more useful comparison is usually:
- 20 mph — Class 1
- 20 mph — Class 2
- 28 mph — Class 3
The 15.5 mph figure is not another U.S. electric bike class. It comes from a different regulatory system.
Can an E-Bike Go Faster Than 20 MPH?
Yes. Some e-bikes are capable of much higher speeds even when their factory settings restrict motor assistance at 20 mph.
The most important factor is the speed limiter.
An electric bike speed limiter is usually electronic rather than mechanical. Depending on the bike, the speed restriction may be managed through the controller, display settings, wheel-speed sensor, firmware, or communication between different parts of the electrical system.
Once the bike reaches its programmed threshold, the controller reduces or stops motor output.
This means the bike's hardware may still have more performance available.
For example, an electric bike may have a powerful motor, high-voltage battery, and controller capable of supporting greater speed, but its factory settings prevent the motor from continuing to assist beyond 20 mph.
If the speed limiter is removed, bypassed, or reprogrammed, the motor may continue providing power beyond that original cutoff, allowing the bike to reach a higher powered speed.
That is fundamentally different from simply rolling downhill or pedaling above the assistance threshold. In those situations, the motor remains limited. When the limiter itself is changed, the electric drive system can continue contributing power beyond the original factory setting.
This is also why some high-output electric bikes have substantially more performance headroom than a typical low-power commuter bike. A stronger motor, larger battery, higher system voltage, and more capable controller can provide additional acceleration and higher-speed performance once the electronic restriction is no longer the limiting factor.
However, removing or changing a limiter can affect the vehicle's legal classification. A product that exceeds the requirements for an electric bicycle may instead fall under other motor-vehicle rules. PeopleForBikes also notes that products capable of being easily unlocked beyond electric bike power or speed definitions may not qualify as electric bicycles under applicable rules.
Limiter changes can also increase electrical and mechanical load on components such as the motor, controller, battery, brakes, tires, and drivetrain.
For that reason, higher unlocked speed should not be treated as simply a free performance upgrade.
Does a More Powerful Motor Mean a Higher Speed Limit?
No.
Motor power and speed limiting are two different things.
A more powerful electric bike may have stronger acceleration, better hill-climbing ability, and more capacity to carry heavier loads without necessarily having a higher programmed speed limit.
Motor output can be especially useful when:
- climbing steep hills
- carrying cargo
- riding on loose terrain
- accelerating from low speed
- maintaining performance under heavier loads
The limiter determines when motor assistance is reduced or stopped. Motor power determines how much performance the drive system can deliver before reaching that restriction.
This distinction is especially important when comparing high-performance electric bikes.
The Tesway X7 AWD, for example, uses a dual motor system producing up to 3,600W peak output and 200Nm of torque. Its 52V 60Ah battery provides up to 200 miles of pedal-assist range, giving it substantial power reserve for steep climbs, heavier loads, and long-distance riding.
The Tesway X9 Ultra increases peak output to 4,000W and 240Nm of torque, paired with a 60V 30Ah Samsung battery and up to 120 miles of pedal-assist range.
Those specifications describe the bikes' performance capability. They should not be confused with a universal legal speed classification or permission to use the bike's full output on every public road or trail.
What Actually Happens When an E-Bike Reaches Its Speed Limit?
An electronic speed limit does not normally make the bicycle suddenly brake.
Instead, the controller changes how much power is delivered to the motor.
A simplified example looks like this:
- The rider accelerates with motor assistance.
- The bike approaches its programmed speed threshold.
- The controller detects the speed through the bike's sensor system.
- Motor output is reduced or cut off.
- The bike can continue moving, but the motor no longer provides the same assistance above the threshold.
This is why riders sometimes feel a noticeable drop in assistance when they reach the programmed limit.
The motor has not necessarily run out of power. The control system is simply preventing it from continuing to deliver that power at higher speed.
If the limiter is removed or altered, that cutoff behavior may change.
Are U.S. E-Bike Speed Limits the Same in Every State?
No.
Federal consumer-product rules provide one definition of a low-speed electric bicycle, while actual road and trail use is largely regulated by states and local jurisdictions.
Many states use the Class 1, Class 2, and Class 3 framework, but details can vary.
Depending on where you ride, local rules may determine:
- which classes can use bike lanes
- whether Class 3 bikes can enter multi-use paths
- throttle restrictions
- helmet requirements
- minimum rider age
- trail access
- registration or licensing requirements for vehicles outside e-bike definitions
That means a bike that is legal to own is not automatically legal to use everywhere.
This becomes particularly important with high-output or unlocked electric bikes. If a bike no longer fits the electric bicycle definition used in your state, it may be regulated differently.
Before riding on public roads or trails, check the current state and local rules for the specific vehicle you are using.
15 MPH vs 20 MPH vs 28 MPH: What Do These Numbers Mean?
The easiest way to understand these speeds is to look at the regulatory system behind them.
| Speed | Commonly Associated With | Meaning |
|---|---|---|
| 15.5 mph | UK EAPC | Motor assistance cutoff under UK EAPC rules |
| 20 mph | U.S. Class 1 | Pedal assistance stops |
| 20 mph | U.S. Class 2 | Motor assistance stops |
| 28 mph | U.S. Class 3 | Pedal assistance stops |
For a U.S. rider, 20 mph vs 28 mph is normally the more meaningful comparison.
The 15.5 mph figure appears frequently in search results because electric bike regulations differ internationally, but it is not part of the standard U.S. three-class framework.
More importantly, none of these numbers tells you the complete performance capability of every electric bike.
A factory speed limiter, motor output, battery voltage, controller capability, and legal classification all describe different parts of the bike.
Final Thoughts
A 20 mph limit does not always represent an e-bike’s full performance capability. On some models, an electronic speed limiter is what prevents the motor from continuing to assist at higher speeds.
Removing or changing that limiter may allow higher powered speeds, but it can also affect the bike’s legal classification. Always check state and local rules before riding on public roads or trails.
FAQs
Why are most electric bikes limited to 20 mph?
The 20 mph threshold is widely used for Class 1 and Class 2 electric bikes in the U.S. It helps distinguish lower-speed electric bikes from faster motorized vehicles and influences how they are regulated and where they can be ridden.
Can an electric bike motor go faster than 20 mph?
Some motors and electrical systems are capable of supporting speeds above 20 mph. Whether the motor continues providing power depends partly on the controller and programmed speed limiter.
What happens if you remove the speed limiter on an electric bike?
Removing, bypassing, or reprogramming the limiter may allow the motor to continue providing assistance beyond its original cutoff speed. It can also affect the bike's legal classification and increase stress on electrical and mechanical components.
Is a 28 mph electric bike legal in the U.S.?
Class 3 e-bikes are commonly defined as providing pedal assistance up to 28 mph, but rules covering their use vary by state and locality.
Why do some electric bikes have a 15 mph limit?
The 15 or 15.5 mph figure is mainly associated with UK and other overseas e-bike regulations. In the U.S., 20 mph and 28 mph are more commonly tied to e-bike classifications.
Does higher wattage make an electric bike faster?
Not automatically. Higher motor output can improve acceleration, climbing, and performance under load, but the programmed speed limiter and controller settings can still restrict how fast the motor continues assisting.
