Electric Bike Motors Explained: Mid-Drive vs Hub-drive

mid-drive motor on the left and hub-drive motor on the right

Motors are a few of the primary components of an electric bike. Ideally, they are a source of power providing enough torque to propel the vehicle’s wheels and conserve the rider’s energy when climbing steep inclines. Motors are also available in different sizes, designs, and power outputs, depending on the rider’s needs.

There are three common types of electric bike motors – hub/direct drive, mid-drive, and friction-drive motor. But each is mounted in different locations on the bike.

The hub and mid-drive are the two most common e-bike motors used today. Hub motors are located on the wheels and are common in cheaper e-bikes, while mid-drive motors are integrated along the center of the bike between the pedals and are more common in expensive electric bikes.

Remember that large e-bikes require more motor power and have more powerful motors than smaller e-bikes. Correspondingly, the drive experience is different in all of them.

We will look at the different types of e-bike motors and explain how they work. Continue reading to know more.

How Electric Bike Motor Works?

electric motor

An electric bike motor has many crucial components working concurrently to convert electrical energy into mechanical energy. Later, this energy will be used to power the bicycle on steep inclines or rigorous terrain.

Related: What is an E-Bike and How Does it Work?

The most basic components, however, include the battery, controller, sensors, motor, and throttle. But there are two ways how the motor can give you power: the pedal assistance and the throttle.

Here is an overview of how e-bikes motor work.

Pedal Assistance vs Throttle

Note that all e-bikes have a pedal-assist feature. Additionally, some e-bikes have a throttle too.

Pedal-assist e-bikes provide electrical assistance and power from the motor to propel the bike forward as you push the pedals. Even so, you must choose your assistance level from low-mid-high acceleration, depending on the terrain. Most pedal-assistance e-bikes provide a natural riding experience with an energy-efficient boost of power from the motor.

The throttle, on the contrary, is a small input device fixed on the handlebars to control the bike speed when pressed. Occasionally, when you engage the throttle, the bike increases or reduces its power output to the motor. You do not have to peddle or add any assistance to the e-bike.

the location of a throttle on e-bike

Assistant Levels

Most e-bikes have different power modes. No matter if the bike has only pedal assistance or it has a throttle, you can choose how much motor assistance you want.

For example, if the battery is getting low, you can choose a low assistance level. Then you have to pedal harder to maintain the desired speed or the bike goes slower. On the other hand, if you are tired and the battery has enough energy, you can choose a high assistance level. Then the bike goes fast even though you provide no or minimal effort.

Most e-bike brands have between one and eight assistant levels. However, some desired brands have between three and five electrical assistant levels. The electrical system in most e-bikes includes OFF > ECO > TOUR > SPORT > TURBO.

What are the Different Types of Motors in Electric Bike?

There are three different types of e-bike motors; the hub-drive, Mid-drive, and friction-drive motor. Nonetheless, hub-drive and mid-drive motors are two popular eco-friendly, efficient, and durable types today.

Here is the difference between the mid-drive and hub motors.

Mid-Drive Motor

electric bike with a bosch mid-drive motor

Mid-drive e-bike motors are installed along the mid-frame bottom bracket of the electric bike. Ideally, they are in this position to provide better weight distribution on the bike. Also, the motor is close to the pedals to drive the chain or belt drive.

These motors are efficient, quiet, and the best choice for hilly terrain because they provide more power and use the bike’s gears.

Hub-Drive Motor

himiway electric bike with a rear hub motor
Himiway e-bike with a rear-hub motor.

Hub-drive motors are quiet and easy-to-install motors mounted on the e-bike’s front or rear wheel. Hub motors provide good balance, control, and stability for the rider. Compared to mid-drive motors, hub-drive motors are less complex and easier to maintain.

Hub motors are available in two different variations – the direct-drive and geared hub motors.

Direct-Drive Hub Motors

Direct-drive motors are low-maintenance motors mounted at the front or rear wheel of the electric bike. These motors do not use gears to propel the wheels for acceleration or deceleration. Instead, they turn at a low rate per minute (RPM) to provide the necessary torque to carry heavy loads or climb a hill.

Overall, direct-drive motors provide a quiet and pleasant riding experience.

Geared Hub Motors

Slightly similar to direct-drive motors, geared hub motors are mounted either at the front or rear wheel of the electric bike. They use gears to reduce the motor’s RPMs and increase the torque output.

Geared hub motors are efficient, lightweight, and the best choices for riders who want to optimize more power to carry heavy loads or climb steeper hills. Overall, these motors are easier to maintain than the other available options.

Direct-Drive vs Geared Hub Motor: Which is Better?

Usually, it depends on your preference or needs when choosing the best hub-drive motor. But here are the most crucial factors to consider for the best choice.

  • Power and Torque: A geared hub is the best motor for carrying heavy loads or climbing steep inclines. Direct-drive motors, on the contrary, provide more power and torque than geared-hub motors.
  • Efficiency: A geared-hub motor is the best option to optimize power output for efficient rides. This motor uses a gear system to boost its performance and maintain the battery life.
  • Maintenance: Geared-hub motors require slightly more maintenance than direct-drive hub motors. Ordinarily, you must lubricate and replace worn-out gear parts for improved performance.
  • Weight and noise: Geared hub motors are ideal for agile rides because they are lighter than direct-drive hub motors. On the contrary, the direct-drive hub motors are quieter and the best for gentle rides.

In conclusion, direct-drive hub motors are the best choice for riders who want more power and torque, whereas geared hub motors are ideal for riders who wish for efficiency and a lightweight riding experience.

Hub Motor Placement: Rear-Mounted vs Front-Mounted

The motor placement on an e-bike differs expressively between the front and the rear end. However, the back end is the most common position for a hub motor.

Note that the hub motor position should match the weight distribution on the bike. For example, smaller bikes have weaker hub motors mounted on the front wheel, while more powerful e-bikes have hub motors mounted on the rear wheels.

But again, which position is better?

Here are a few factors that determine the hub motor’s position.

  • Weight distribution: The rear-mounted hub motors provide better weight distribution than front-mounted hub motors and a rider can control or handle the bike more easily.
  • Traction: Rear-mounted hub motors provide better traction, grip, and stability than front-mounted hub motors because more weight is distributed uniformly on the bike’s rear end.
  • Maintenance: It is faster to maintain a rear-mounted hub motor than a front-mounted hub motor because of its straightforward accessibility.
  • Performance: Rear-mounted hub motors are more powerful and guarantee better performance than front-mounted motors. These motors are also the best alternatives for agile riders who want more torque and power. Nevertheless, rear-hub motors are more costly than rear-mounted hub motors.

As you can see, there are hardly any pros to having the motor mounted in the front hub. Therefore, most hub-motor e-bikes come with a rear-hub motor.

Mid-Drive vs Hub Motor: Which Type of Motor is Best for Electric Bike?

The type of motor often depends on a rider’s preference and specific needs. However, the motor type defines the riding experience, efficiency, cost, power, and maintenance.

Since mid-drive motors often use a torque sensor instead of a cadence sensor, riding with mid-drive motor e-bikes feels much more natural. Also, mid-drives are usually better at hill-climbing. Additionally, changing a rear tire on a mid-drive e-bike is much easier because there are no wires between the wheel and the frame.

However, mid-drive motors are much more expensive because of the more complex build. Additionally, mid-drive e-bikes require more maintenance. Especially the chain, which needs more frequent replacement.

The most important advantage of a hub motor is its relatively cheap price tag. It’s because hub motors are produced in much larger quantities and e-bike brands can easily purchase this component.

Usually, hub motors (especially direct-drive) are less efficient in climbing hills. However, powerful geared hub motors (750W+) are actually as efficient hill climbers as mid-drive e-bikes.

This in turn leads to the fact that a high-powered motor needs a bigger battery. And a bigger battery adds quite a lot of weight to the bike.

Mid-Drive Motor Pros and Cons

Today, mid-drive motors have become a popular motor choice among agile riders. But here are their advantages and disadvantages.

They provide efficient and more powerful rides.
They are the best motors for hilly terrain or transporting heavy loads because they provide more torque.
They help to distribute weight on the bike uniformly.
They provide better bike handling due to their “mid-bike” position.
They are more complex and have extra components than other motors.
They require regular maintenance because of the additional mechanisms.
They are more costly than other motors.

Hub-Drive Motor Pros and Cons

Some riders prefer e-bikes with hub-drive motors for smooth commuting. Here are their advantages and disadvantages.

Have a simple design with few moving parts. So, installing them is easier.
They are quiet and require less maintenance.
They are cheaper than other types of motors.
Some hub-drive motors have regenerative braking systems.
Hub-drive motors are less efficient because they use more power and produce limited torque.
Hub-drive motors do not guarantee efficient performance on hilly terrain or transporting heavy loads.
They add extra weight to the wheels affecting the overall weight distribution on the bike, acceleration, and handling.
They can be difficult to service because of their integration into the wheels.

E-Bike DIY Systems: E-Bike Conversion Kits

An e-bike’s conversion kit is a Do it yourself (DIY) system that allows you to convert any regular bicycle into an electric bike despite its size and type. Typically, the conversion kit includes a battery, motor, controller, and display unit.

Note that ordinary conversion kits are available in different types. But here are the most common ones.

Front-wheel conversion kits: They come with the front hub motor, controller, battery, and throttle. They are also an essential choice for most traditional bikes.

Rear-wheel conversion kits: They are among the most popular choices in the market because they are easy to install and ideal for casual riders. A rear-wheel conversion kit includes the battery, rear hub motor, throttle, and controller.

e-bike conversion kit
E-bike conversion kit found from Amazon.

Mid-drive conversion kits: They offer improved performance but can be challenging to install. They include the battery, mid-drive motor, controller, and display.

mid-drive e-bike conversion kit
Mid-drive conversion kit found from Amazon.

Electric Bike Motor Power and Torque Explained

Power and torque are two crucial mechanisms in an electric bike’s motor for determining the overall riding experience and the bike’s performance. Also, you must understand their differences before purchasing an e-bike.

E-Bike Motor Power

An e-bike’s motor power, measured in kilowatts (kW) or watts (W), is the energy rate converted from one form to another. Normally, the motor transfers the energy to the bike’s wheels per unit of time. So, the higher the motor power rating, the more powerful and faster the e-bike will be.

The power output also determines the bike’s speed, the amount of weight it can carry, and how effectively it can climb hills. The e-bike’s motor power output depends on the motor’s design, the size and shape of the motor’s stator or rotor, and the number of magnets in the motor.

The Torque of E-Bike Motor

An e-bike’s torque is the twisting force produced by a motor or the motor force applied to the wheels to propel the bike forward. Torque is measured in Newton meters (Nm), and it determines how fast the bike can accelerate and how well it can climb steep hills.

Bikes with higher torque ratings accelerate faster and climb hills better because the motor applies more force to the bike’s drivetrain. For hilly or challenging terrain, e-bike motors with higher torque are the better option. Electric bike motors with lower torque but higher power output are ideal for leisurely rides or commuting.

It is also worth noting that an electric bike’s motor power differs from the battery capacity or range. A higher-powered motor, for instance, might draw more energy from the battery, resulting in a shorter range.

Therefore, you should always check the power, torque rating, and other necessary factors before purchasing an e-bike. Remember that the correct measurements will improve your riding experience and the bike’s performance.

Nominal Power vs Peak Power

Normal power is the average e-bike’s motor power output under normal operating conditions over a specific time. Usually, normal power is taken when commuting or riding leisurely and is measured in watts (W) or kilowatts (kW).

Peak power is the maximum e-bike’s motor power output under ideal operating conditions over a short period. Typically, it is the performance potential of an e-bike when climbing a hill or accelerating. It is also measured in watts (W) or kilowatts (kW).

Note that peak power ratings are higher than nominal power ratings because they are equivalent to the maximum motor’s power output under ideal conditions.

How Many Watts are E-Bike Motors?

An e-bike’s motor watts differ considerably, depending on the model and size of the motor. But generally, most e-bike motors range from around 250 watts (W) to 750 watts (W). Nonetheless, some models can reach up to 1000 W or more. Additionally, the e-bike’s motor watt defines the bike’s performance.

Is 250W Motor Good in an Electric Bike?

Depending on your preference and specific needs, a 250W motor can be ideal. These motors provide enough power for comfortable rides, leisure, flat terrain, or commuting.

Higher-powered motor, on the contrary, is suitable for demanding activities, hilly or challenging terrain, off-road riding, or long-distance touring.

Is 500W E-Bike Motor Enough?

A 500W e-bike is enough for most riding experiences and situations. Also, this motor has enough power and will perform outstandingly on hilly or rough terrain. You can accelerate faster under specific conditions for an improved riding experience.

Is 750-Watt Motor Better Than 500-Watt Motor?

A 750-watt motor provides extra power than a 500-watt motor. So, the bike will have better acceleration, upgraded hill-climbing capability, and superior performance.

Overall, the total wattage in a motor depends on a rider’s intentions of use. So, it would be best to know what you want to do with the e-bike to help you decide on the motor size.

A 750-watt motor is better for dexterous riders who prefer to accelerate fast, enhance the bike’s performance, or ride in rough terrain.

Popular E-Bike Motor Brands

Mid-Drive Motor Brands:

Rear-Hub Motor Brands:

Final Words on E-Bike Motors

Motors are reliable and efficient methods of powering e-bikes. Modern motors provide eco-friendly and quiet service compared to traditional gasoline-powered engines.

As a rider, you must understand that e-bike motors are available in several types. A mid-drive motor provides more power & convenience, while a hub-drive motor is designed for leisure rides. So, choosing between mid-drive, hub motors, pedal assistance, geared hub motors, or throttle will depend on your needs and specific preference.

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