When you’re looking for a new electric bike (also called e-bike), there are many features to consider and one of those features is the motor. It’s important to choose a motor that fits your riding style and environment. In this post, I describe some aspects of motors you should know before purchasing an e-bike or an e-bike motor.
Three types of e-bike motors
There are three types of e-bike motors you should be aware of when purchasing your bike.
Geared Hub Motor
A geared hub motor is probably the most common motor on e-bikes today. When I say gear, I’m talking about internal gears, inside the case. The gears don’t shift or change speed.
A bafang 750-watt motor I have has a 5-to-1 reduction. That means that for every one rotation of the wheel, the motor has to spin five times. It also means that the motor is spinning at a higher RPM and it’s giving you better torque output to the wheel. It has more torque than a direct-drive motor. They are also physically smaller and lighter than direct-drive hub motors.
Additionally, it has a one-way bearing inside, so when you are pedaling and not using the motor, you’re not getting resistance from the motor, meaning you’re not having to turn the motor over with your pedaling.
It’s a very efficient mode of transportation because you can coast down a long hill and the motor is free-spinning in the back, not giving you any drag. The only downside is that it does eliminate the possibility of regenerative braking. If you live in a hilly area, a geared hub motor is a great option.
Direct Drive Hub Motor
A direct drive hub motor looks like the geared hub motor, but the outer diameter is larger. It is so named because it is a direct drive to the rear wheel. One revolution of the motor means one revolution of the rear wheel.
There are fewer moving parts to a direct drive hub motor, which in theory should mean that they last longer, but I haven’t really seen that to be the case.
A direct drive hub motor is common for high-powered applications, so typically it is used on bikes that are 3000 watts and up. Also, it has to be physically larger to get the torque sufficient to move the bike, and it dissipates heat more easily because of that larger size.
One turn of the motor equals one turn of the bicycle wheel, which makes this type of motor better for higher top speeds, but doesn’t necessarily have as much torque as a geared hub motor. This means you don’t have the free-wheeling bearing inside, so you can use the motor to slow down the bike (so they do have the regenerative braking capability).
You can feed some of the power back into the battery when you are slowing down. The most I’ve ever seen someone gain is 10% on their braking, so it’s not a large amount and makes more sense on bigger, more powerful bikes.
If you live in a flatter area or you want higher cruising speeds, a direct drive hub motor might make sense for you.
A mid-drive motor is one that is found up by the cranks of the bike. It turns the sprocket by the front and the turns the chain. So all the power is running through your chain and through your gears and through the derailleur on your bike, so the downside is that you will see more wear and tear on the drivetrain.
However, the benefit is the range of performance. You can shift through gears like you would in a car or a motorcycle. You can shift into a low gear when you climb a hill and then shift into a high gear when you’re on a flat area or heading downhill and want to hit a higher top speed. So, mid-drive motors feel more performance-oriented. You switch gears using the power of the motor, and this is what gives the wider range of power, anywhere from pulling wheelies on the low end up to very high, 35-mph-or-more top speeds on the high end, assuming it’s unlocked and off-road, of course.
So, I recommend this type of motor if you want a wider range of performance than what another type of motor can provide.
Because you will see more wear and tear on the drivetrain of the bike with this type of motor, I recommend learning how to replace a broken chain or cassette or your freewheel. You will have to do that eventually.
One example of a mid-drive motor is the BBSHD 1000-watt mid-drive motor. The BBSHD can be hidden inside the frame. Personally, I have a mid-drive motor on my bike and I like it, but I made the decision based on my needs.
How will e-bike wattage affect my ride?
Power is probably the first thing people are going to start comparing when they look at different electric bikes. You have 250 watts, 350 watts, 500 watts, 750 watts, and even more combinations in between.
250 watts may not seem like much, but 250-300 watts is the range of power sustained by a professional cyclist. That is similar to a pro athlete hidden in your bike pedals.
500 watts is a small bump in power, but it's common. It's enough power to maintain 20 mph on flat ground, even on a fat bike. At 500 watts, the hills start to melt away and become more gradual. It may struggle to get up the steeper hills and you may have to pedal to help the motor. Most bikes that have a throttle-only option can make up most hills without pedaling at all. If they will do that for sure, of course, depends on the rider weight, the gearing, whether it's a mid-drive hub motor, and other factors.
750 watts is the legal maximum in the United States. With 750 watts, you will be able to fly up most hills on throttle only and get up to top speed very quickly.
But... not all wattage is the same
One small caveat, since I have experienced this, is that most wattage is not equal. Some bikes will claim 750 watts, but use a smaller motor than another bike that also claims to be equal at 750 watts, but one is clearly faster than the other. So, 750 watts doesn't always mean the same thing.
Consider your cycling needs and environment
As you might have noticed, each motor has unique benefits. Some benefits may matter more to you than others. Your choice of motor will depend on how you ride and the environment you’re living in. Are you cycling through a hilly area or generally over flat land? What are you like as a cyclist? As you read through the benefits above, some may appeal to you more than others.
View our motor-related products to get a sense of the product options.