Hub Motor VS Mid Drive Motor – Which One to Pick?

By Ibrahim Mawri


How an electric bike performs is highly dependent on the type of motor that powers it. When it comes to hub motor vs mid drive, most people only pay attention to  nominal — and peak — power an e-bike's motor is able to generate when reading through the bike's specifications. To most of us, the more the power; the better the performance.

While this statement holds true, it's worth noting that motor type — whether it's a hub or mid-drive — determines how an electric bike performs under certain conditions.

To better explain this concept, let's find out how each motor-type's special features affect an electric bike's overall performance.

What is a hub motor

A hub motor is an electric motor integrated within the wheel(s) of a vehicle. In the case of electric bicycles, they are located in the middle of the hub (could be the front or rear wheel, sometimes even both).

Hub Motor VS Mid Drive Motor – Which One to Pick? 1

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How does a hub motor work

In a hub-drive system, the controller sends power to the hub motor which causes the motor to spin. As the motor begins to spin, the wheel's spokes — which are connected to the motor — then stimulate the entire wheel to rotate, propelling the bike forward.

What is a Mid-drive motor

This is an electric motor that drives an e-bike forward using its chain drive. As the name — and application — suggests, it is located in the middle of the bike in-between the pedals.

Hub Motor VS Mid Drive Motor – Which One to Pick? 2

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How does a Mid-drive motor work

A mid-drive motor uses electric power to engage the bike's chain drive. An electric motor inside the mid-drive system engages the chainring by spinning a shaft connected to it.


Hub motor VS Mid-drive efficiency

Hub motors

1) Hub motors are flexible

And that's why most DIY conversion kits are equipped with hub motors – because they're easy and affordable to install. Even e-bike manufacturers prefer to use hub motors because they are cheaper and faster to install, unlike mid-drive motors that, in most cases, require the e-bike's frame to be built around them.

2) Hub motors don't even require a chain-drive to work

Since a hub-drive system has a motor integrated into its wheel, it doesn't require external assistance to push it forward. There's the exception of pedal-assist cheap ebike conversion kits like Swytch that come with smart control systems that act as connectors between the cadence – or torque – sensors and the hub motor.

However, if your e-bike is equipped with a throttle-assist feature you can enjoy this functionality.

Mid-drive motors

1) Mid-drive electric bikes are better for off-road riding.

 In a mid-drive electric bike, the motor is located in the center of the bike. This facilitates better weight distribution than with hub-drive bicycles. Uneven weight distribution affects an e-bike's performance when climbing up steep hills or cruising through trails.

For example, imagine you're riding an e-bike with a rear hub motor up a steep hill. You're probably going to face more resistance climbing up that hill because of the e-bike's weight imbalance (since the motor is located in the rear wheel, that half of the e-bike will weigh more than the front half).

2) Maintaining a mid-drive e-bike is easy and cost-efficient

With mid-drive electric bikes, the one component that'll require a lot of maintenance — and probably a few replacements — is the chain. This is because a mid-drive motor places a lot of stress on the e-bike's chain just like a hub motor works the bike's spokes loose (more on this in a bit)

Replacing a bicycle's chain isn't exactly complicated nor is it expensive, respoking, on the other hand, is not just a complicated process, it requires professional assistance.

Which is better; mid-drive or hub-drive

This depends on your needs as a rider. There is no one-size-fits-all approach to resolving this dilemma. Each drive system has its perks and flaws. For example, mid-drive systems are perfect for off-road riding because of their gear ratio and balanced weight distribution. 

Hub motors on the other hand offer riders a wider selection of riding options to choose from. Need a workout, pedal; Need to beat traffic and get to work without getting completely drenched in sweat, use your bike's throttle-assist feature; chain cut? No need to panic, keep riding with your independently-propelled hub motors.

As you might have already guessed, replacing flats on a hub motor isn't as straightforward as it is with a mid-drive motor.

If you're thinking about converting a traditional bike to an electric bike, you can easily get a hub motor DIY kit. However, converting to a mid-drive electric bike isn't going to be that easy.

Eventually, It all just boils down to your perspective of a perfect electric bike. 

Are hub motors reliable

This depends on the caliber of the hub motor in question. Higher-end hub motors aren't just more powerful than standard hub motors, they can be ridden under harsher conditions and not deteriorate as quickly as basic models.

In instances where the wheel faces considerable rolling resistance, engaging the controller to release more power to a low-powered hub motor will cause it to spin faster than normal which might cause it to overheat and then burn. 

You might want to consider going for a higher-powered hub motor if you're in the market for one that won't disappoint and leave you stranded after it gets fried.

How long do mid-drive motors last

That depends on how well you maintain your e-bike. Mid-drive motors are more complicated – with multiple moving parts — than hub motors and should be treated as such.

Avoid pressure washing your e-bike. Just because the manufacturer says the e-bike is water-resistant doesn't mean you should shoot water from a pressure valve at it or immerse it in water to clean it.

As I mentioned earlier, one component of a mid-drive system that might require frequent replacing is the chain (you can always opt for a mid-drive e-bike with a belt drive – they can withstand more stress than chains)

How long do Hub motors last

Long enough! As long as you don't upgrade your battery to a higher-volt pack without replacing your e-bike's controller.

As with mid-drive motors, how long your hub motor lasts is largely dependent on how you maintain it. Replacing your battery pack with a higher-volt pack without upgrading your controller will burn the bike's motor.

Also, always remember to inflate your e-bike's tire every time the pressure drops. Do not ride on a flat tire, especially when it's the wheel housing the motor.

 

About the author 

Ibrahim Mawri

Electric Engineer by profession. Throughout my career, I have been driven by my curiosity to find better answers to big questions. This curiosity makes me a lifelong learner. I am passionate about leveraging technology and automation to continuously improve human life. if you ever want to bounce some ideas, feel free to reach out.