Why are hub motors the mainstream of two-wheeled e-bikes?

Anyone who has ridden an electric bike knows that the rear hub of an electric bike is actually the motor, unlike a motorcycle where the entire drive system is independent. So the question arises, why can't the middle motor be the mainstream drive system for two-wheeled electric bikes?

The structure of a hub motor is relatively simple, usually consisting of a metal housing, a rotating shaft, a coil, and magnets, and the production cost is between $150-300. Intermediate motors are more complex, with structures such as clutches, differentials (gearing), flywheels, drive chains, etc., in addition to the motor itself. A high-quality intermediate motor costs at least $1,000, while the retail price of a mainstream e-bike is only about $3,000.
Because the hub motor omits the transmission structure, its electrical energy conversion efficiency and drive performance below low speed (60km/h) is superior to that of the intermediate motor. With the same battery and power, the hub motor can run farther.

Due to the complex structure, the intermediate motor is prone to mechanical failure and requires regular maintenance. Whereas hub motors don't, they only need the motor to be sealed and very durable at low speeds.

Why do some e-bikes need a mid-motor?
The core reason is "heat dissipation". When a motor spins at high speed, it releases a lot of heat. When the tire is wrapped around the hub motor, the tire expands with heat and will burst. The middle motor is different, because it is an independent power structure, generally placed on the chassis of the car or hanging in the rear, ventilation and heat dissipation are better than the hub motor. So the middle motor is more suitable for high-speed driving!
But with the development of liquid cooling technology, the motor is filled with coolant (such as the liquid-cooled motor of Green Source). The heat dissipation of hub motors has been greatly improved, changing the structure that relies on air to dissipate heat. Even if the motor rotates at high speed, the temperature can be kept within the normal range, which greatly expands the application scenarios of hub motors.
In the future, hub motors for electric bicycles will still be the mainstream. Mid-mounted motors are favored by many players because of good heat dissipation, good balance and good maneuverability!

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