How much power does an electric bike need? Here is a helpful guide

Electric bikes are available in a wide range of power levels. From adorable little 250W e-bikes to massively overpowered 10kW+ motorcycle level e-bikes. But which power is best for you? Keep reading to find out more!

Just a quick note before we get to power level comparisons: not all motor horsepower ratings are created equal.

Due to different standards for measuring the power ratings of electric motors, a pair of 500W motors from different companies can have quite different power ratings. Additionally, power output limiting laws in Europe and other restricted areas have caused many manufacturers to often underestimate their power levels.

For example, Bosch mid-drive systems are often listed as 250W motors, although the actual power output is often over 500W peak.

So when discussing motor ratings, we will largely take e-bike manufacturers at their word. But keep in mind that just because two motors are labeled the same doesn’t mean they’ll necessarily have the same horsepower.

Finally, if you’re the kind of person who likes to watch and listen, check out my video on the topic of e-bike power. So read on for all the details below!

250W Electric Bikes

The lowest power class for e-bikes is usually the 250W class. There are a few 200W e-bikes, but these are often smaller scooter-type bikes.

With 250W of power, you’re basically looking for a flat-land cruising e-bike. Most 250W e-bikes will struggle to climb hills without any user-added pedaling, although mid-drive e-bikes provide better climbing performance than hub motors at these low power levels in because of their ability to get higher torque by downshifting the bike’s gears.

If you’re a heavier rider, you can still use a 250W e-bike as long as you’re on flat ground. Acceleration will be quite slow, but the bike will move you. Keep in mind that 250W continuous is more power than most people create while pedaling.

I weigh 70 kg (154 lbs) and find that 250 W can still move me comfortably. But as soon as I hit the hills, the performance quickly drops and the bike slows down considerably. Heavier riders shouldn’t really try to climb long hills on 250W hub motors without risking motor damage from repeated high heat cycles. Heavier riders can sometimes still find 250W mid-drives sufficient for small hills, especially if they want to add some pedal input, but big hills will still seriously degrade the performance of an e-bike from 250W with a heavy rider. There just isn’t enough power or torque in a 250W system to propel heavy riders up medium-sized hills while maintaining reasonable speed.

As for speed, 250W motors are also generally limited to between 25 and 32 km/h (15 and 20 mph). Above such speeds it becomes difficult to overcome wind resistance without adding more power.

Electric bikes 350 W – 500 W

The next increase in power results in an increase in acceleration. While 250W e-bikes are slow to accelerate, bikes that reach closer to 500W will roll off the line much quicker.

For lighter riders like me, that will seem like a pretty big difference. Heavier riders probably won’t feel too much of a difference on flat ground, depending on the motor.

Roadster Ghost 500W Electric Bike (Check my review here!)

On the hills, 500W will do a much better job of propelling light riders to the top. Small hills can become conquerable for heavier riders. Again though, these riders won’t see a huge difference to the lower powered 250W motors when it comes to a decent grade.

It should also be noted that 500W is usually the minimum power necessary for an e-bike to exceed 32 km/h (20 mph) in speed.

Electric bikes 750 W – 1000 W

We are talking now! Once you hit 750W, you’re dealing with real power. For light riders like me, 750W will give much more exciting acceleration off the line. This level will also start to offer good hill performance.

For heavier riders, 750W is when flat-land performance starts to get more enjoyable and hills actually still become possible. With 1000W of power, most heavy riders will be happier with the performance.

Speeds of 45 km/h (28 mph) are increasingly common with 750W e-bikes. You will still see Bosch-powered mid-drive bikes capable of 45 km/h (28 mph) while still claiming a “250 W” motor. But again, these are underrated motors and not really fair comparisons to the real 250W motors.

Cafe Moto Go 45kph (28mph) e-bike with a ‘250W motor’

Electric bikes over 1500 W

At 1500W you start to leave typical bicycle territory and encroach on the light levels of electric motorcycles. I built a 60 km/h (37 mph) e-bike using a 1.5 kW hub motor, and the performance is amazing. It doesn’t matter if you put me or a 250 lb (110 kg) rider on this bike – the thing just pulls freaking!

I recently rode the Rungu all-terrain three-wheel electric bike with a Bafang BBSHD 1.5kW mid-drive motor. It was another great example of extreme power that can carry both light and heavy riders up the highest hills. In fact, the only time it failed to carry me up the hills was when they got so steep the bike just couldn’t get traction in the loose dirt.

Keep in mind, however, that mid-drive motors at such high horsepower levels require special chains and sprockets to avoid completely destroying themselves.

Choose the right power level for you

Hopefully the take home message for you will be that e-bikes come in many flavors and power levels and the right power for you is a very personal decision.

While I’m perfectly happy commuting on a 250W e-bike in my flat city, I would never take less than 750W off-road. Others might say it’s 1kW of power or nothing to them. The key is to find what works for you and the power that will allow you to achieve your goals.

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