Electric bikes are becoming increasingly popular due to their environmental friendliness, cost-effectiveness, and convenience. One of the most frequently asked questions by potential buyers is how fast electric bikes can go. We get it: the faster you can go means you can cover more distance in less time, plus sometimes it’s just plain fun to go fast. Unfortunately, pinpointing the potential top speed for each rider is no easy task. In this blog post, we will explore the factors that go into calculating the top speed of an electric bike, and why it’s so gosh-darned difficult for us to give you a clear answer to a simple question!

Factors that Affect Top Speed of an Electric Bike

Motor Power

The motor is the heart of an eBike. It’s the largest factor in determining the speed, acceleration, and torque of the bike. This part is pretty easy: the more powerful the motor, the faster the bike can go (makes sense, right?). The motors on our eBikes have nominal power ratings anywhere between 250W and 2300W. So the 250 Watts of power on the entry-level Kutty FS wouldn’t come close to the same output and speed potential as the Juggernaut XD's 2300 Watt motor, or even the 1000 Watts of power found in the Juggernaut Ultra line. However, keep in mind that the motor power alone does not determine the top speed. Other factors such as battery size, payload, and terrain also play a crucial role.

The 2300 Watt XD motor (left) has nearly 10x the power of the 250W motor found on the Kutty FS (right).

Battery Charge

An eBike's battery is another component that affects not only the top speed, but also the range of travel. When an eBike's battery charge gets low, it can't sustain top speeds for long distances, so it's important to keep your battery charged and look for larger batteries that don't require charging as often.
The Watt hours of our individual eBike batteries vary between 374Wh to 1200Wh, with some of our dual-battery eBikes offering a combined rating of 1898Wh. It's important to note that the battery range will decrease as the speed increases. Therefore, riders should be mindful of their battery usage and plan accordingly.

Rider Weight & Payload

The weight of the rider and cargo also affects an eBike's top speed. The more weight, the more power the motor needs to use to propel the bike forward. Therefore, heavier riders will experience slower top speeds than lighter riders. Our light-duty eBikes are rated for weights up to 265 pounds, while our medium and heavy-duty models can accommodate anywhere between 330 to 380 pounds plus. Larger riders or those who plan to haul cargo or a bike trailer cargo should consider purchasing a bike with a more powerful motor. You know what they say… resistance is a drag.

An eBike's speed and agility is directly affected by how much weight the bike is carrying/towing (image credit: Tim Carpenter, Two-Wheel Tim on YouTube).

Terrain

It’s not just about what you’re riding, but also what you’re riding on. Terrain is a major factor that affects an eBike's top speed - and since bikes aren’t restricted to roads the way other vehicles are, it’s important to consider how a bike performs on more than just pavement . Riding on different types of terrain can affect nearly every aspect of the bike's performance, including speed. Here are some examples:

Sand: Riding on sand can slow down an eBike because of the added resistance.

Snow: Riding on snow can also decrease the bike's speed due to the added resistance and reduced traction.

Dirt: Riding on dirt may slow down an eBike, depending on how loose or compact the soil is.

Gravel: Riding on gravel can decrease an eBike's speed due to the added resistance and uneven surface.

Pavement: Riding on pavement is the easiest terrain for eBikes and allows for the highest potential top speeds.

Keep in mind that travelling at extreme high speeds on loose, uneven surfaces is something we wouldn’t recommend to even the most experienced of riders (unless they really want to put that helmet to a real-world test).

Elevation

Gravity is your friend… until it’s working against you. The steepness of your route is another critical factor that affects an eBike's top speed. Riding uphill requires more power from the motor, which can decrease the bike's speed. When the grade (or slope) of a hill increases, the motor needs to trade speed for torque in order to accomplish steeper climbs. On the other hand, riding downhill can increase the bike's speed, but riders need to be careful to maintain control of the bike (instead of asking “how fast can an eBike go”, a better question might be, “how fast can an eBike fall”).

Travelling on flat, even terrain allows the motor of an eBike to focus on speed, rather than torque.

Wind

Few things ruin a bike ride the way pedaling into the wind does. Luckily, increasing the pedal-assist level on electric bikes can make it feel like you’re always going with the wind instead of against it. Still, while an eBike might be capable of carrying you through strong winds at the same speeds you’d be travelling on a non-windy day, the performance will likely suffer because of the additional drain on the battery. Wind resistance significantly impacts an eBike's top speed: headwinds can slow down the bike, while tailwinds help increase its speed. The impact of wind depends on the strength and direction of the breeze on that particular day (or the sake of this article, we’re going to assume you aren’t attaching a sail to your eBike.. Though you might reach some pretty impressive speeds during hurricane season!). Riders should keep in mind the wind conditions and adjust their speed accordingly.

Rider Ability

Sometimes, the biggest limitations are the ones we set on ourselves. Truly, an eBike can go as fast as a rider is able to pedal it. So, to reach maximum speed, riders will need to work in addition to the power from the motor. While the motor not only provides an additional boost to the rider's own pedaling power, a rider’s ability and awareness on how their eBike performs can help improve the performance. The motor's assistance can make pedaling less tiring, allowing riders to maintain a higher speed for longer. Pedaling in conjunction with the motor can also help conserve battery life, allowing riders to travel further distances at higher speeds. When pedaling, riders should try to maintain a steady cadence to optimize their efficiency and speed. 

A rider’s fitness ability also needs to be considered: if a bike is to get up to maximum speed, the rider needs to sustain a higher tempo in higher gears at a higher effort, which requires a certain level cardiovascular strength. 

By combining pedaling with the power of the motor, riders can achieve their desired top speed while getting a workout and enjoying the ride. Muscle and machine working together for full efficiency! 

Experienced riders are more likely to maximize the performance of their electric bicycle.

Tire Size & Pressure

The width of your tires has a slight effect on an eBike’s top speed; a 4” fat tire has more surface area and weight than a 3” tire, and requires more power from the motor to get moving. As you reduce tire width, the potential top speed increases at the expense of traction and stability. We generally recommend fat tires for most riders because of the all-terrain capabilities they provide, and electric motor power takes reduces the effort on the rider. However, if speed is your primary goal, skinnier tires will help you go faster.

Tire pressure is another often-overlooked factor that also goes into an eBike's speed capabilities. Overinflated tires can make the bike bouncy and unstable, while underinflated tires can cause drag and reduce the bike's speed. Refer to our Tire Pressure & Inflation Guide for the recommended tire pressure for your eBike, and remember to use a pressure gauge to ensure your tires are properly inflated. Keep in mind that different terrains may require different tire pressures; for example, lower tire pressure may be necessary for riding on sand or gravel to improve traction.

Local Laws

Just because you’re able to, doesn’t mean you’re allowed to. Most jurisdictions in Canada and the United States have specific rules for eBike riders and limits on the allowable power output. By default, our eBikes are programmed to be “street-legal”, where the motor will not give provide any more power once the bicycle reaches 20 miles / 32 kilometers per hour. This is a satisfying and realistic speed for the majority of customers who ride our eBikes. However, as mentioned above, riders might still able to pedal above and beyond that speed if they have the experience, ability, and desire to do so. If an eBike will be operated on private land, customers can order their bikes “unlocked”, without the speed limiter in place. In many cases, this is a setting that riders can change themselves using the display panel and controller on the bike.

It’s on you, as a rider, to be responsible for following the regulations in your area. Our eBikes may be fast, but they aren’t designed to outrun the law.

With electric motor power at your fingertips, city commuters can ride without worrying about holding up traffic.

Conclusion

With so many factors to consider when calculating top speed, it’s nearly impossible to have a clear answer on how fast eBikes are capable of travelling. Even riding the same eBike, different riders might experience different top speeds depending on the total weight they’re carrying, the route they’re travelling and the weather conditions that particular day. Instead of giving a generic “one-speed-fits-all” estimate that may be inaccurate and risk disappointing you, we aim to be as transparent and upfront as possible when it comes to the top speed of our eBikes and the factors that affect how fast they can travel. If you’re still looking for a more specific answer, we suggest you make a post on the Biktrix Owners' Group Facebook page and hear from our riders personally on their own individual experiences. You may be surprised by what you learn!