Choosing Between Hub Motors and Mid-Drive Motors for Electric Bicycles

Currently, electric bicycles can be categorized into two types based on the position of the motor: hub motors and mid-drive motors. Cyclists often wonder what the differences are between hub motors and mid-drive motors.

First of all, it can be confirmed that whether it's a hub motor or a mid-drive motor, they are both highly integrated core driving components that provide timely auxiliary power. They are the most important components of electric bicycles.

Hub Motors

Advantages: Mature technology, low cost, easy maintenance

The hub motor is designed with the motor part on the hub of the wheel, and it mainly uses rear-wheel drive. Currently, hub motors used on electric bicycles are mostly brushless motors with gears. Thanks to the mature design and large-scale application, compared to mid-drive motors, hub motors can significantly reduce the cost of the entire vehicle. Therefore, during the development of electric bikes, hub motors have become popular and dominated the market.

Unlike traditional electric bicycles that use a handlebar to drive the motor, electric assist bicycles only provide assistance after the rider pedals. Therefore, the electric assist system of a bicycle with a hub motor requires careful calibration of the motor, sensor, controller, and the entire system.

From an appearance perspective, if you want to convert a traditional bicycle into an electric assist bicycle, choosing a hub motor can maximize the retention of the frame, transmission system, and overall appearance of the bicycle. You only need to replace the rear wheel hub with a motor hub, and reasonably arrange the controller, sensor, and other parts.

In terms of specifications, the frame's dropout specifications have a significant impact on the hub motor, directly affecting whether the motor can be installed successfully. Additionally, the chainstay length, whether the motor is compatible with disc brakes or caliper brakes, the number of spoke holes, and whether the rim matches the wheelset are all things that need to be considered in advance.

On the other hand, hub motors have a smaller size and lighter weight compared to mid-drive motors and have less impact on the frame.

Therefore, in the pursuit of ultra-lightweight and minimalist design for road electric assist bicycles, most manufacturers' first choice is to use a hub assist system.

Mid-Drive Motors

Advantages: Better balance of the entire vehicle, more efficient energy transmission, high compatibility with traditional bicycle parts, and quick power output

The mid-drive motor integrates the motor, gearbox, controller, sensor, and other systems, with a unified design and integrated solution. Compared to hub motors, mid-drive motors have a more complex structure and higher technical difficulty.

The high technical barriers of mid-drive motors directly lead to their high prices, which is more expensive than hub motors. However, for manufacturers, high value-added products mean a stronger pricing power and higher profit margins. Therefore, many manufacturers are embracing mid-drive motor systems, and more brands will join this battle in the future.

In terms of power assistance, mid-drive motors act directly on the gear, which is closer to the power output characteristics of traditional bicycles, making them the mainstream solution for mid to high-end mountain bikes.

Why do mid to high-end mountain bikes all choose mid-drive motors?

1. The mid-drive motor is located in the middle of the vehicle, which balances the center of gravity and does not affect the balance of the vehicle during fast riding, making it easier to control off-road.
2. The off-road environment changes rapidly, and frequent gear changes are required. Traditional transmission systems are easier to install with mid-drive motors.
3. Mid-drive motors have a more powerful torque output and higher efficiency. The motor power acts directly on the axis, providing faster acceleration, which is a significant advantage in the frequently starting and stopping off-road environment.
4. High integration makes the entire vehicle simpler. Apart from a few brands that have special mid-axles and handlebars for mid-drive motors, other mechanical components of electric assist bicycles with mid-drive motors are completely compatible with traditional bicycles, making it easy to upgrade and replace.

Conclusion

In conclusion, both mid-drive motors and hub motors require the coordinated work of motors, controllers, and sensors to accurately monitor and intervene in time to safely and reliably output power.