How an Electric Motor For Bicycle Works

An electric motor provides power to your wheels in four ways. Cytronex of Britain manufactures an innovative yet lightweight and high tech kit utilizing a geared front hub motor (though this makes your bike quite front heavy).

Direct drive motors can offer regenerative braking and assist with hill climbs.


Hub motors are built into wheel hubs on electric bicycles and are most often found either front or rear wheels. Hub motors are popularly described as feeling natural and lighter and smaller than mid-drive motors, offering greater versatility without needing to adjust torque curves accordingly. They can also be removed quickly for repairs or swap-out, making maintenance or upgrades simpler and allowing repairs or swaps without much fuss.

Hub motors can be highly efficient at higher speeds where they make full use of their available power, yet may feel weak at lower speeds due to being tailored more toward pedaling speed than to using its full potential. They’ve also been known to break spokes more frequently than other drive systems and may require slightly different frame designs in order to integrate seamlessly.

Hub motors can help distribute weight more evenly front-to-back on an electric bicycle, which improves handling and ride quality. Furthermore, these hub motors may allow riders to utilize all available gears – although this depends on your motor design – while offering redundancy since each motor works independently from its chain and will still function even if this component fails.

There are a variety of reputable manufacturers of hub motors. Bafang’s home base in Suzhou near Shanghai and ZEHUS are two large suppliers, though smaller and medium-sized companies produce quality motors as well. Globe, Electra, VanMoof Hummingbird Neomouv Velotric are some popular e-bike brands that utilize hub motors.

Bimotal offers a removable hub motor system, which is easily attached and removed from your frame of your bicycle, which makes for an excellent solution when riding trails, hill climbing and other challenging terrain conditions. Furthermore, you can upgrade to stronger motor without altering your frame structure.


Mid-drive systems differ from hub motors by being integrated directly into the crankset and battery box to deliver powerful yet balanced and efficient pedaling assistance. Mid-drive systems work by passing current through electromagnets in the stator’s electromagnets which activate rotors to spin at high speed to generate torque that provides pedaling assistance through small chainrings on your bike.

The efficiency of the motor lies in its ability to only have to turn part of your wheel at any one time, meaning its rotor can be smaller than traditional cranksets while still producing comparable power to larger-wheeled bikes with similar power ratings.

Once installed in the crankset, a motor evenly disperses its weight between front and rear wheel for optimal balance and reduced center of gravity, making pedaling simpler while decreasing stress on frame (particularly if using throttle). This also makes use of throttle easier!

Mid-drive motors can also make riding hills more efficient, enabling you to travel faster and further on a single charge by matching your cadence with its internal gearing. They are often found on mountain bikes like the Tern GSD S10, as well as more performance oriented e-bikes such as Kalkhoff Entice 3b Move.

Mid-drive systems do require more maintenance than hub motors due to being directly linked with chain and cogs that move directly with the motor. Routine cleaning and lubrication will help to keep this type of system operating at peak condition for years to come.

Mid-drive motors may wear down faster due to the extra force applied when using the throttle, making mid-drives unsuitable for frequent commutes or rides over challenging terrain, so it is essential that these considerations are taken into account when selecting an electric motor suitable for your bike.

Mid-drive motors tend to be larger in size than hub motors, which may increase your bike’s overall weight. Some riders opt for hub motor systems instead as these can easily fit onto most existing frames without altering them; additionally, hub motors can often be less costly due to not requiring special wheels with integrated motor hardware.

Friction Drive

Friction drive electric bike motors utilize a roller to contact the tire of a bicycle to provide power. They’re usually mounted to the rear wheel and controlled using either throttle or pedal-assist systems – perfect for adding some muscle without spending a ton. This type of motor offers great value to those looking to add some extra horsepower without spending an arm and leg!

An attractive feature of friction drive electric bike motors is their adaptability; they can fit virtually any bicycle. Attaching to the frame and typically featuring spring tensioned rollers that come into contact with either front or rear tires, they make mounting to different bikes easy while can also be easily removed once not needed.

This type of motor may not provide as much power as hub or mid-drive motors, but it provides an easy and lightweight solution for adding electric bike power. Furthermore, its cost is typically much more reasonable.

Friction drive electric bike motors are typically intended for use with light road or city bikes, and attach directly to the seat tube of the bicycle. Most standard frames can accommodate these motors, and their simple mounting setup makes them an excellent option for people wanting to convert their existing ride into commuter or city biking options.

Friction drive electric bike motors can be an excellent solution for many riders; however, there are some drawbacks associated with using such systems. Perhaps most noticeable of all is that the motor may cause significant wear on drivetrain components when used to assist climbing hills or covering long distances. Furthermore, this form of system often produces noise and vibration during use – factors which should be carefully considered before purchasing one of these motors.


Rubbee offers an affordable kit that turns any regular bike into an electric one by mounting a small motor on its rear wheel. Claimed to weigh less than both tyre and tube combined, it fits frames ranging in diameter between 16in and 29in with ease, has its own battery, can be charged via dynamo when off, and prices begin at EUR579.

Pendix offers all-in-one kits that integrate their motor directly with the frame itself, like this model from German brand Pendix. This system replaces bottom brackets on folding bikes as well as conventional bikes; claimed to be 30 per cent lighter than Bafang mid-drive systems and equipped with torque sensor compliance to meet European ebike regulations; starting from EUR999 with an estimated range of up to 28km, its price may start as little as EUR999.

Front-wheel motors tend to provide a smoother riding experience, but their added weight may make steering feel less responsive and handling less balanced. Furthermore, a throttle-controlled motor could put riders at greater risk during jumps or steps; Belgian cyclocross champion Femke Van den Driessche used one such front-wheel-motor device known as Vivax Assist during 2016 to win her home championship title, only for later race authorities to discover this fact and ban them for six years!

An effective way of estimating how much power will come from any given motor is to look at its wattage rating, which manufacturers typically list in terms of torque applied and speed at which it spins. You can then multiply these two figures and determine its total rated power, although you’ll likely do the calculation while riding.

Some ebike systems lack gears altogether and therefore qualify as direct drives; these are less commonly seen on new bikes. Others like this Zipforce one feature a conventional gear system but incorporate an electric motor within the hub which can be switched on/off for extra power, with which you can select your desired amount using either an onboard display/hand throttle, pedal cadence sensor and torque sensor to control.

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