How Fast Can Electric Bikes Go?

If you’ve ever wondered how fast electric bicycles can go or questioned the difference between an E-bike and, say, a motorcycle… Well, you’re not alone. These are some of the most asked questions about electric bikes and, to give a proper answer, it’s important to understand more about what E-bikes are in the first place.

When it comes to electric bikes, they are not only powered through the amount of energy put into pedalling, they also have capable motor support and pedal assist that requires less energy whilst riding, so you can climb hills with far less pedal power. However, when it comes to speed, even if the motor has a limit for how fast it can go, there’s no limit for the speed you can achieve on top of the motor’s assistance using your legs or a good old downhill slope.

That’s where it’s a bit easier to answer the question of how fast E-bikes can go. Normally, E-bikes have restrictions on the maximum speed provided by the motor’s electric assistance. The legal speed limit tends to differ based on your country or region’s specific regulations, in this instance, it's 25 km/h in the United Kingdom. Other factors may affect the speed you can reach on your electric bike, such as the motor’s power, your weight, your bike’s weight, and your riding terrain.

If you want to learn how to satisfy your need for speed on your E-bike, keep reading to find out more.

What determines speed?

In general, speed is a product of many factors such as power, and an electric bike is no different. What do we mean when we talk about power? When it comes to an E-bike motor, pay attention to the number of Watts (W). A higher W power rating means the e-bike can pull weight more easily, which, depending on other factors such as torque and pedal assist, can help you accelerate quicker. An E-bike's torque measures the rotary power of the motor. The higher the torque, the less pedalling power is required from your legs in order to accelerate (torque is what gives the oomph to the bike especially when pulling off after stopping). All Momentum E-bikes have a 60Nm torque and 250W motor, that's plenty of power to beat the morning traffic on your daily commute.

Your and your E-bike’s weight

This discussion takes us back to some of the equations from physics class, but let’s use a real-life example instead. Just like a person pulling a sled, the overall weight of the load can determine how difficult it is to tow the sled and get up to speed. For your E-bike’s case, both the weight of the E-bike and the weight of the rider matter. Let’s think back to that same 250W motor again. It’s going to be easier for the motor to accelerate to its maximum speed quickly if it’s moving 50 kg of weight versus 100 kg.

Where you choose to ride

As you would expect, the terrain is another factor that affects acceleration and speed. If you’re riding on a smooth paved road without any obstacles, you can probably let loose and accelerate to your top speed as quickly as possible. Now imagine doing that on a loose gravel surface, a rocky path, or a rough mountain trail. Your momentum will be interrupted by every small bump along the way. Not to mention the issues of safety and the need to maintain control. An inclined or declined surface can have a similar effect. Gravity will work against your E-bike’s motor when climbing a hill and in favour of it when descending, just like it would for your legs pedalling a traditional bike.

The laws where you live

Because an E-bike motor allows you to go faster than a traditional bike, laws in most countries regulate their speed by saying the E-bike can provide an added speed boost up to a certain point. In the UK, the E-bike must have pedal assistance that stops once the bike reaches a speed of 15.5 mph (about 25 km/h).

Once the E-bike reaches a specific speed, the motor stops providing electrical assistance, and any additional speed on top of that is powered by your internal engine (your heart, lungs, and muscles). This means your bike’s top speed depends partially on how fast and hard you can pedal.

How does electrical assistance from the motor affect speed?

As mentioned in the section above, all of Momentum UK's E-bike models use pedal assist, rather than throttle assistance.

Most pedal assist E-bikes offer different levels of assistance from the motor. For the lowest assistance setting, the power comes mostly from your legs. This setting is typically suitable for comfortable, flat terrains or if you want more of a workout from your ride. Higher assistance settings can help you get to your destination faster and with less effort. If you’ve got a large hill coming up or you don’t want to sweat too much under the sun, use a higher assistance setting for a more comfortable ride!

But keep in mind the more assistance you get from the E-bike’s motor, the more quickly the battery will run low. Weight and terrain also affect how much juice the motor needs from the battery to run. But don’t worry! Even if the battery runs out, you can always pedal the rest of your way until the next charge.

A fun fact

The land speed on a non-motorised bicycle was set in 2018 by Denise Mueller-Korenek when she rode over 183 mph! That goes to show your legs can take you a lot faster than the point when an E-bike’s motor stops running.