Moteur central vs moteur roue arrière, quelle solution choisir ?

Central motor vs rear wheel motor, which solution to choose?

Mid-engine and rear-engine have significant differences in driving feel, cost and performance. Mid-mounted motors provide proportional assistance based on rider effort, improved stability through their low, central positioning in the frame, and ease of repair with the use of a standard rear wheel. On the other hand, rear motors offer a more pronounced feeling of thrust but require more maintenance and can compromise the stability of the bike. The choice between the two often comes down to considerations of price, comfort and performance for bike manufacturers, with brands like Decathlon opting for the rear motor for economic reasons. Libbri favors mid-mounted motors for the increased safety they offer riders and passengers in their cargo bikes.

How is a mid engine different from a rear engine?

The motor in the rear wheel gives a feeling of significant thrust, similar to having the wind at your back. However, it requires more maintenance and can make the bike a little less stable due to a higher center of gravity. Additionally, shifting while stationary is not possible due to the derailleur.
Mid-engine is the most popular solution for several reasons. Thanks to its location at the bottom bracket, this motor provides gentle assistance as soon as you start pedaling. In addition, it allows for better weight distribution for increased stability. Ideal for long distances and daily commutes, this versatile engine is suitable for all terrains.

For some cargo bike manufacturers, like the Decathlon R500 model, opting for a rear motor is primarily a decision based on price rather than comfort and performance.

Mid-engine costs more due to several factors. First of all, mid-engines are more complex to design and produce. Their internal components are often more sophisticated and require more careful manufacturing. Additionally, integrating these motors into the bicycle frame is more demanding, as the frame must be specifically designed to accommodate the motor and its mountings. Unlike rear wheel motors, which can be installed in conventional bicycle frames without requiring major modifications. This design around the central engine results in additional manufacturing costs for the frames. In contrast, the frames of rear-wheel motor bicycles are often similar to those of traditional bicycles, reducing manufacturing costs.

Mid-engines offer several significant advantages. First of all, their positioning in the center of the frame improves the dynamic balance of the bike by placing the center of gravity lower between the wheels. This promotes better stability while preserving the maneuverability of the bike. Additionally, mid-mounted motors are often more powerful and provide more natural assistance thanks to an integrated torque sensor that adjusts the energy delivered based on the force the rider exerts on the pedals. This feature is particularly useful in mountainous regions such as Switzerland where increased assistance is required. Another major advantage is that mid-mounted motors allow the use of a standard rear wheel, making repairs such as changing tires in the event of a puncture easier 🤜 🤛

Libbri has chosen to equip its cargo bikes with a central motor mainly to guarantee the safety of the cyclist and passengers.

The disadvantages of the rear wheel motor are numerous. First of all, being located in the rear wheel, its weight affects a moving part, resulting in inertia when starting when the motor is not in action. Additionally, this positioning can make the assist less responsive to accommodate the rider's pedaling, which can lead to a less natural assist feel. Additionally, by concentrating some of the weight on the rear of the bike, the bike's balance is compromised, making the bike less agile in certain situations.

Mid-mounted motors represent the most sophisticated and widespread type of assistance in electrically assisted bicycles (VAE). This system offers proportional assistance, which means that the power of the motor is directly linked to the effort exerted by the cyclist on the pedals. Mid-mounted motors are equipped with multiple sensors that measure torque, speed and pedaling cadence, allowing the electrical system to precisely regulate the assistance provided by the motor. By positioning the mass in the center of the frame and down, bikes with mid-mounted motors maintain similar handling and stability to conventional bikes. For the user, this results in a riding experience very close to that of a traditional bicycle, which contributes to a feeling of familiarity and comfort when using the eBike.

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