Have you ride an electric scooter or e-bike ? It is considered as an easy way to get around short distance with shorter time and less effort. I remembered the electric bike I had 15 years ago is very bulky and heavy. The electric scooter now is much lighter and have less component. The new electric scooter have the motor inside the wheel and it is called “wheel hub motor”
What is a wheel hub motor, the definition of a hub is a central part of a wheel rotating on or with the axel and from which the spokes radiate, so basically the hub is the part between the wheel and the axle usually houses the bearings and the bearings reduce the friction so the wheel can spin more freely.
Now an electric motor can be built into the hub, combining the wheel and motor together, it’s usually a brushless dc motor, so basically in this kind of motor, you got the stator that stays still and that you attach to your bike. It contains multiple magnet wire coils, and these coils are arranged in a ring surrounding a shaft and that’s all one part, the stator then bearings connect the shaft on the stator or to the face plates. And they spin between both face plates is a ring and beneath that ring is the neodymium magnets. They react with the coils on the state. Finally spokes are attached between the hub face plates to the rim and then the tube and the tire are installed on the rim to make a complete wheel.
To get things moving, electric current is passed through the coils to make a magnetic field that forces the magnets to move the hub. On most basic dc or ac electric motors speed is proportional to voltage and torque is proportional to current or amps, so you get more acceleration or torque, current is increased, which means that your magnet wire is needed, making a bigger and heavier so to get around this, some motors use gears in the hub instead which allows the motor to be smaller and then they can get the desired speed acceleration ratio, using the gears and avoid using heavier wire.
The downside to gears is that they also add mass to the motor and they will also wear out probably before the electronics in the motor wear out.
When looking at hubmotor there’s at least five different factors you have to compare. First off you got wheel size, for example twenty inch or twenty six inch or 300 c fat tire. You have to get the right size of wheel for your bike
Second, you have to consider power, that’s measuring watss and for hub motors is usually for power levels you’ll find online the 250 watts or 500 watss, 750 and 1000.
Third, you got the drive mechanism. You can have a gear drive that may be lighter and give you the speed acceleration ratio you want, or you may want a direct drive motor because they usually last longer
Then you got to choose between a rear hub kit with the cogs in usually free wheel or the more simple front up kit,
Lastly, you have to consider the company and the reputation of the brand for making quality products and do they have a warranty.