When it comes to buying an electric bike, you may think that buying the most powerful one is the best option. Although lots of power is advantageous in certain situations, a powerful electric bike may not be the best thing for you.

So how do you decide what electric bike to buy based on the power of its motor?

The Basics Of Power And Torque

When looking at the characteristics of an electric bike's motor, you need to look at its power and torque. The torque figure of an electric bike's motor indicates how the motor delivers power to the wheel.

Electric bike motors usually have torque figures between 75Nm to 90Nm. Motors with higher torque figures make pedaling easier, which is advantageous when climbing hills. But how much torque you get will depend on what assistance level you use.

The lowest assistance level will usually amplify your pedaling effort by 50%. But if you ride with the highest assistance level, the motor can assist you up to 300%.

These figures will vary between electric bike brands and models, but this will give you an idea of what to expect. How you use the assistance level will affect how far you can ride before you need to charge the battery.

Riding at high assistance levels calls for more power from your bike's battery, depleting it faster. Also, your range will be affected by the profile of your journey. Hilly rides will zap your battery power, as will cold temperatures and excessive weight.

Smaller batteries give your electric bike a shorter range. A large motor will use your battery much quicker than lower-powered motors.

To illustrate how long a battery will last with specific motor power, consider a 250W motor powered by a 500wh battery. If you run it at 100%, the battery will be completely flat in 2 hours.

Why Lots Of Power Isn't Always Good

While high-powered motors are great for climbing hills and powering over rough terrain, there are two main drawbacks of all that power:

The Cost

More powerful electric motors cost more money to make, increasing the price of your electric bike. However, motor power isn't the only thing that makes an electric bike expensive, the type of motor, brand, and build quality also plays a part. Still, high power significantly contributes to the price.

If you ride a lower-powered electric bike, say 250W, there is a good chance that it will be powerful enough for you. Therefore, you won't need to pay extra for a more powerful electric bike.

Battery

We touched on the battery earlier, but aside from the range issue, higher-powered motors require larger capacity batteries. This means the battery is heavier and more expensive.

The extra weight of the battery also needs to be compensated for. The motor has to work harder to carry the weight, which in turn draws more energy from the battery.

Stay On The Right Side Of The Law

The most significant factor in owning an electric bike is the local laws. Different parts of the world have their own rules when it comes to electric bike power.

These rules are so governments can determine what an electric bike is. Bikes with a motor exceeding a specific power rating are deemed motor vehicles requiring a license, insurance, taxation, etc. 

Local laws also dictate where you can ride your electric bike. For example, you are not allowed to ride a motor vehicle on public paths or mountain bike trails in some areas.

Most American states currently have a legal limit of 750 watts for electric bikes. However, the rules vary in other countries. In the EU, UK, and Japan, you can only ride electric bikes with a maximum power rating of 250 watts. The limit is 500 watts in Canada and 400 watts in China.

Before you buy an electric bike, make sure it complies with the local laws of where you want to ride it. There is no point in getting into trouble over a too powerful bike for the law.

The Different Electric Bike Powers Available

Here is a rundown of the different power ratings you will find on electric bikes and what they are suitable for:

250 Watt Motor

250W electric bikes are the least powerful ones you can buy. These are more than sufficient for general road use and are great for giving your pedaling a boost when you get to a hill.

Most people who ride 250W electric bikes use them for commuting, as they can get to work without arriving hot and sweaty. But these bikes are also ideal for leisurely rides over the weekend.

250W bikes are excellent for people with mobility issues or rehabilitating from an injury. They can stay active without overdoing it and causing further problems. Alternatively, they can use one of these bikes to keep up with other fitter riders.

350 Watt Motor

A 350W motor isn't a massive leap from a 250W motor, but it gives you extra power if you feel like you need it. The great thing about this power level is that you get more boost without spending lots of money on a high-powered electric bike.

If your local laws permit it, a 350W electric bike is a better option than a 250W. This is especially the case if you carry cargo, are heavier, or ride in a hilly area.

500 Watt Motor

Most people will find 500W enough for their needs, even if you are a medium-weight person riding up hills and carrying cargo. In most situations, anything more than 500W may be excessive.

If you are a heavier rider, you should still find 500W sufficient, but you may want to go for a bike with a mid-mounted motor. Electric bikes with this system are more efficient and give you a more natural feel.

Electric bikes with mid-mounted motors are more expensive than ones with hub-mounted motors. Remember, more powerful motors draw more energy from the battery, requiring larger and more expensive batteries.

So a mid-mounted 500W motor may be a better option than a 750W hub-mounted motor.

750 Watt Motor

If you are permitted to ride a powerful electric bike in your area and are heavier, you may want to go for a bike with a 750W motor. This is especially the case if you're going to ride off-road and in hilly areas.

A mid-mounted motor will maximize the assistance and help slow down the extra drain on your battery, but it will add to the cost of the bike. 

If you are lightweight and only ride on flat and smooth terrain, a 750W electric bike would be overkill. You won't gain anything from the extra power, but you will be paying for it.

But, if you like the idea of lots of power, or your riding is varied, you may benefit from the punchiness of a 750W motor. There is a good chance you won't need all that power most of the time, but it might come in handy on a cycling trip or a pedal through the mountains.

A 750W motor won't give you a significant advantage over lower-powered motors when riding on the flat. You will get faster acceleration from a standing start, but the top-assisted speed is limited, so you won't be able to ride any faster.

Faster acceleration can get you out of dangerous situations, but it can also cause accidents. The acceleration can take you by surprise, and many people new to electric bikes get into accidents because of it.

1000 Watt Motor

An electric bike with a 1000W motor will give you impressive hill-climbing capabilities and allow you to power over all kinds of terrain.

However, most countries don't allow you to ride bikes with this much power on public land. They are often classed as motor vehicles, so riding one would come with strict rules. 

As you would expect, electric bikes with 1000W are pretty expensive, so you would need to be pretty serious if you required one. Most people don't need this kind of power, but those who live in the mountains or carry heavy cargo would benefit from it.

These super high-powered electric bikes require a large battery to provide a decent range. Riding one requires careful monitoring of the battery life to ensure that you don't have to push or pedal a dead bike back home.

Final Thoughts

As you can see, there is more to life than brute force and lots of power. Having extra power is great, but not if you don't need it, especially as it comes at a premium.

The most important thing you should take from this is how important your local rules and regulations are. There is no point in buying an electric bike that is illegal to ride. If you are restricted to 250W, at least your options have been narrowed down, so you can find an electric bike with features that are important to you.