One of the most common questions about electric bikes is, 'How fast do electrical bikes go?The answer, however, isn't straightforward, as several factors influence an electric bicycle's top speed.
From motor power and battery capacity to the bike's weight and external conditions like terrain, these elements all play a role in determining how fast an electric bicycle can travel.
Elecric bike typically range from 20 to 30 mph (32 to 48 km/h) depending on their specifications.
Whether you're commuting, tackling steep hills, or cruising on flat roads, the combination of motor wattage, battery voltage, bike weight, and even wind resistance can impact your ride’s pace.
Motor Power
Typically measured in watts (W), motor power determines the bike’s ability to accelerate, maintain speed, and handle varying gradients or terrains.
E-bikes generally come with motors ranging from 250W to 750W, though some high-performance models can go beyond this range.
250W Motors: These are the most common in urban commuter bike. With a maximum speed of about 20 mph (32 km/h), they offer enough power for flat roads and gentle inclines. In some countries, 250W motors are the legal limit for powered bicycles that qualify for certain classifications.
500W Motors: These motors are often found in more powerful e-bikes designed for mountain biking or faster commuting. With a higher wattage, they can achieve speeds of 28-30 mph (45-48 km/h) on flat terrain and handle steeper inclines more effectively.
750W Motors: These motors provide significant power and are commonly used in high-performance electrical bikes intended for off-road use, heavy-duty commuting, or those requiring high acceleration. With these motors, top speeds can exceed 30 mph (48 km/h). Just like Rictor K1 fat electric bike with 750W Bafang ebike motor.
In general, the higher the wattage of the motor, the better the e-bike can accelerate and maintain high speeds.
The motor's power needs to be balanced with other factors like battery capacity, terrain, and legal restrictions.
SEE ALSO How Fast Can E-Bikes with Different Voltages Go?
Battery Voltage and Capacity
Battery voltage, measured in volts (V), affects the motor's ability to deliver power, while the capacity (measured in amp-hours, Ah) determines how long that power lasts.
Battery Voltage
Most e-bikes use 36V or 48V systems, though higher voltage systems are becoming more common.
A 36V system is standard in lower-end e-bikes, providing sufficient power for average-speed commutes and relatively flat terrain.
However, a 48V system delivers more power, enabling faster speeds and better performance on steeper hills. Some high-performance motorized bicycles use even higher voltages, such as 52V, to maximize motor output.
A higher voltage system ensures the motor has more headroom to perform under load (e.g., when climbing hills or carrying heavy riders), which can prevent the motor from bogging down and losing speed.
A 48V system can improve an powered bicycle’s top speed and acceleration over a 36V system by providing additional power to the motor.
Battery Capacity (Ah)
A battery’s amp-hour rating determines how much energy the battery can store, which impacts how long the bike can maintain high speeds.
A 36V 10Ah battery stores 360Wh (watt-hours) of energy, while a 48V 10Ah battery stores 480Wh. While the 48V battery does not necessarily improve top speed, it allows the bike to sustain higher speeds for longer periods, increasing range.
A higher voltage increases power output and speed, while a larger battery capacity enhances range but does not directly affect the maximum speed.
Wheel Size and Tire Type
Wheel size and tire type are often overlooked when discussing e-bike speed, but they play a significant role in overall performance. Larger wheels generally reduce rolling resistance and improve efficiency, while tire choice directly impacts how smoothly the bike can ride on different surfaces.
Wheel Size
Common electric bike wheel sizes range from 20 inches to 29 inches. Smaller wheels, such as those on folding bikes or compact city bikes, offer better maneuverability but lower top speeds due to higher rotational resistance. Larger wheels, like 27.5 inches or 29 inches, are more efficient for higher speeds, especially on paved roads. The larger circumference reduces rolling resistance, which means less energy is lost, enabling the bike to maintain speed more easily.
Tire Type
Slick tires for smooth pavement or knobby tires for off-road riding. Slick tires, with lower rolling resistance, are ideal for faster speeds on flat surfaces. In contrast, wider or knobby tires designed for off-road conditions generate more rolling resistance, which can slightly reduce speed but provide better traction on rough surfaces.
Bike Weight
The total weight of the electrical bike, including the frame, motor, battery, and other components, directly impacts its speed and acceleration. Heavier bikes require more effort from the motor to reach the same speeds, reducing overall performance, particularly on inclines.
A typical e-bike weighs between 40 to 70 pounds (18 to 32 kg), with lighter models, such as urban commuters, weighing closer to 40 pounds. Heavier e-bikes, especially those designed for off-road or long-range travel, can weigh upwards of 60 pounds. The added weight means the motor has to work harder to accelerate
While a lightweight electric ride accelerates faster and can maintain higher speeds, a heavier bike with a powerful motor can still achieve good speed on flat terrain, especially if the motor is sufficiently powerful and the battery capacity is high.
Grade and Road Conditions
The gradient of the road and the type of terrain significantly affect an e-bike's speed. While an electrical bike can achieve high speeds on flat terrain, hills and rough conditions will slow it down and require more power from the motor.
Flat Terrain: On a flat road, the bike’s motor can operate at full efficiency, and its top speed is primarily determined by the motor power, battery voltage, and aerodynamics.
Hills: When climbing a hill, the motor needs to work harder to overcome gravity, and speed can decrease, especially if the motor is not sufficiently powerful. For instance, a 250W motor on a steep incline will struggle to maintain the same speed it would on flat ground. A 500W or 750W motor, however, can maintain a higher speed on inclines without significant loss of power.
Rough Terrain: Off-road riding, with its combination of uneven surfaces, rocks, and obstacles, results in higher energy consumption and lower speeds. Fat tires, often used in off-road powered bicycles, are great for traction but generate more rolling resistance, reducing speed on rough terrain.
Electronic Control System Limitations
Finally, the electronic control system plays a crucial role in limiting the speed of the e-bike. Most e-bikes are equipped with a controller that regulates the motor's power output to ensure smooth operation and prevent overheating.
Speed Limitations: In many countries, electric bicycles are legally restricted to certain maximum speeds. For instance, in the European Union, electrical bikes are limited to 25 km/h (15.5 mph) under the pedal-assist mode. In the U.S., the limit is typically set at 20 mph (32 km/h) for bikes that operate solely under motor power. These speed limits are often enforced through software or firmware settings that prevent the motor from exceeding legal thresholds.
Throttle Limiting: E-bikes with throttle control may also have speed limits imposed by the manufacturer to prevent excessive speeds or to comply with regulations. The throttle might cut off or reduce power as the bike approaches its maximum legal speed.
Wind Resistance
At higher speeds, the force required to overcome wind resistance grows exponentially.
Rider Position: The rider's position on the bike, such as whether they are sitting upright or leaning forward, affects how much air resistance the bike faces. A more aerodynamic riding posture reduces wind resistance, allowing the bike to maintain higher speeds.
Weather Conditions: Headwinds can significantly slow down a electric ride. A 15 mph headwind could reduce a rider’s speed by several miles per hour, depending on the bike's power and speed capabilities. Conversely, tailwinds can increase speed, allowing the rider to go faster with less effort.
Conclusion
The speed of an electric bike is influenced by several interdependent factors, including motor power, battery voltage, wheel size, weight, road conditions, wind resistance, and the electronic control system.
Each of these elements can be optimized based on the rider's needs—whether for urban commuting, off-road adventures, or high-speed cycling.
FAQs
Are electric bikes heavy?
Yes, electric bikes are generally heavier than traditional bikes due to the motor and battery, with most e-bikes weighing between 40-70 pounds (18-32 kg).
Can electric bikes be used for long-distance travel?
Yes, many e-bikes are designed for long-distance travel, especially those with larger batteries and higher power motors.
How do I ensure the battery lasts longer?
To preserve battery life, avoid extreme temperatures, don’t overcharge, and recharge when the battery is about 20-30% drained.
