Electric Bicycle Motors: Everything You Need to Know

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The electric bicycle motor is the heart of any e-bike. Does the mid-drive motor, front or rear wheel make a difference when you ride an electric bike? Spoiler alert: yes, it does.

Motorization is an essential criterion to consider when choosing your electric bike. This electronic part influences both your experience and the power of your e-bike. Now, what are the advantages of the front wheel motor? How does the mid-drive motor work? Which motor to choose for a more natural pedaling assistance? Why are e-bikes with mid-drive motors more expensive? Let’s explain. 

Read also: Front, mid-drive, or rear e-bike motor. Which one to choose? And, What is the difference between e-bike motors?

How does an electric bike motor work?

To simplify, three elements make up the system of an electric bike: the battery, the motor, and the steering console.

On an e-bike, the motor is located at the level of the front or rear wheel or in the crankset. It is the motor that activates the pedaling assistance.

Sensors measure or limit the level of assistance you need so that the motor distributes the appropriate power. There are several sensors: torque, rotation, power, and speed sensors. 

Understanding the power of an e-bike motor

The motor helps the cyclist on an e-bike but does not replace pedaling. The assistance stops when the bike reaches 25 km/h (15.5 mph), or the cyclist stops pedaling. That is called “assisted pedaling.” 

Above 250 Watts, we talk about speed electric bikes (assistance authorized up to 45 km/h or 28 mph). The term “electric bike” is commonly used to refer to e-bikes.

The word torque refers to the actual mechanical power of the motor, not its power rating. That is expressed in Newton meters (Nm). The torque indicates the performance and responsiveness of your e-bike when climbing, a time when you usually need a little help.

With an e-bike with a nominal power regulated at 250 Watts, several torques are possible depending on the motor. The higher the number, the better your engine will perform when faced with difficulties on the road. 

Read also: What is the difference between e-bike motors? What are the differences between rotation and torque sensors?

What are the different types of motors found on electric bikes?

Mid-drive motors

Without surprise, they are located at the level of the axle of the crankset. Currently, these motors are the most advanced and efficient on the market. Moreover, they have better technologies than hub motors. That’s why they are found on middle and high-end bikes (from 1 800 $/€ to 5 000 $/€ and above).

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In terms of user experience, this motor accompanies pedaling naturally and smoothly; the assistance is proportional to the force you put on your pedals. 

You get the same pedaling sensations as on a muscle bike. The motor’s position in the center of the frame favors the bike’s balance, thanks to better weight distribution. 

To summarize: because of its reliability, its comfort, and its technology, it is generally the motorization that is recommended for widespread use, even daily.

Front-wheel hub motors

This motor is positioned at the hub of the front wheel. It is the most common motorization on entry-level bikes (between 500 $/€ and 1 500 $/€).

With this system, the cyclist is driven by the front wheel. The sensor (of rotation or pressure) located on the crankset triggers the assistance. The force you put in the pedaling does not enter into calculating the intensity of assistance. 

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Also, driving is less natural and requires a time of adaptation. Moreover, contrary to the crank motor, which does not disturb the center of gravity, this motorization can destabilize the cyclist.

Finally, this type of motor is criticized for its lack of grip on certain surfaces, especially wet ones. 

In short: the front wheel motor does not enjoy an excellent press anymore; that’s why many reference brands stop equipping their bikes with this system.

Read also: Front, mid-drive, or rear e-bike motor. Which one to choose? And, What are the differences between rotation and torque sensors?

Rear-wheel hub motors

This motor is positioned on the hub of the rear wheel of your electric bicycle. It is mainly found on mid-range and high-end bikes.

In terms of user experience, this motor is more responsive than the central motor, which explains why it is used on some sports bikes such as road, mountain bikes, and gravel.

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If its brother installed on the front wheel can give you the impression of being pulled, the rear wheel motor gives the feeling of being propelled. Whether you like it or not, it’s still devilishly efficient when climbing! 

In case of a puncture, the inner tube change is nevertheless more constraining because of the presence of the transmission, the braking, and the engine harness.  

Finally, its position at the rear can reduce riding comfort and handling, especially if the engine is not lightweight. 

Comparative table of the advantages and disadvantages of e-bike motors

Mid-drive motorRear-wheel hub motorFront-wheel hub motor
Price €€€€€ – €€€
Rider experiencenatural pedaling sensationresponsiveness, propulsion sensation, rear weighttraction sensation, front weight, slippage
Advantagesreliability, technologies, comfort, maintenancereliability, design, power, technologiesprice, aesthetics
Disadvantageshigh price, faster wear of the transmissionless choice of transmission, more complex repair of a puncture, weight at the rearlack of grip on certain surfaces, imbalance because of weight at the front, and quality of materials

What are the major brands of e-bike motors on the market?

Bosch, the leader in the field of e-bike motors

It is THE reference of the market. The German equipment manufacturer Bosch offers a wide range of pedal motors for all cycling disciplines, including

  • Bosch Active Line and Active Line Plus motors
  • Bosch Performance Line, Line CX, Line Speed motors
  • the Bosch Cargo Line motor for electric cargo bikes

Like its competitors, the brand regularly updates its historical models (engine, software, features).

Yamaha is a safe bet

Yamaha has been riding electric bikes since 1993, when it introduced the first electrically-assisted bikes (PAS system). Since then, the brand has designed new robust and reliable motors and developed innovative technologies for “smooth” assistance. 

We are considering the Triple Sensor System embedded in the PWseries motors and the Quad Sensor System with its four sensors. Last argument in favor of the Japanese brand? It equips the bikes of renowned brands such as Giant, Lapierre, Gitane, Ghost, etc. 

Shimano, the historical giant

Shimano has developed its own motorization system: the Shimano Steps system. The mechanical parts giant and historical equipment manufacturer offers several crankset motors for e-bikes and mountain electric bikes: Shimano Step E5000, E6000, E6100, E7000, and E8000… 

Several innovations are part of the brand’s track record, such as smart walking assistance – a feature highly appreciated by mountain bikers in case of too steep a trail – or AUTO SHIFT that shifts gears for you. They also offer electronic transmissions coupled to the engine, like the Nexus system for the city.

The other reference brands

This triumvirate does not have a monopoly on electric motorization. There are, of course, other reference brands, such as Panasonic, Bafang, Brose, Impulse, Mahle, and Tranz’X. 

The e-bike market continued to grow, and new brands are regularly appearing. Also added are proprietary motors (VanMoof) and collaborations (Specialized and Mahle).

How to choose the motor for your electric bike?

It is impossible to give a ready-made answer to this question. The best way is to answer the question with other questions: these five questions will allow you to sort out and specify your choice.

  1. What kind of riding (mountain biking, city riding, trekking, bike touring, road riding, carrying children)?
  2. What is the trip’s profile (flat, with differences in altitude, surfaces, and duration)? 
  3. Which frequency (weekend, daily, from time to time)?
  4. What budget do you plan to spend? 
  5. What level of comfort do you prefer?

On this basis, you can already sort out the different models.

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