The "E-Bike," a popular term in recent years, is derived from "Electric-Bicycle," signifying bicycles with electric assistance, commonly known as electric-assist bikes. Different countries have varying regulations regarding the rated power and speed limits for electric-assist bikes. According to EU standards, the motor's rated power should not exceed 250 W, and assistance should automatically cease once the bike reaches a speed of 25 km/h.
The E-Bike wave has swiftly surged across developed countries like Europe, America, Japan, and South Korea, becoming one of the fastest-growing consumer products in the bike industry, maintaining a substantial market share with annual sales growth exceeding 30%.
Major international players such as Shimano have introduced dedicated E-Bike transmission and brake kits and even ventured into comprehensive motor product lines. Other renowned brands like NECO have also delved into E-Bike motor development. In this emerging market category, the core technology of electric assist lies in motor technology and its associated components like sensors and transmission. Mastery of this core technology dictates the direction of market development. Traditionally, the power of "electric" bikes is located in the hub of the wheel, known as the hub motor, a common sight in recent exemplary electric-assist bike models. However, the recent trend showcases elegantly hidden batteries placed within the frame's downtube and motors concealed within the bottom bracket. This motor, situated within the bottom bracket, with a gearbox structure, has come to be commonly termed as the "mid-drive motor."
The mid-drive motor stands as the current optimal solution among mainstream products. In the top-selling high-end bike models in Europe and America, a majority are designed with mid-drive motors. Why is it considered the best electric assist solution currently? The mid-drive motor offers numerous advantages compared to hub motors or various older products: it's lighter, more energy-efficient, and hence, most manufacturers adopt it.
To delve into its advantages comprehensively might take days, but simplifying, the benefits of using a mid-drive motor in E-Bikes can be summarized as follows:
1. Lower resistance and reduced rolling friction: Hub motors, driven by brushless technology and magnetic induction, tend to suffer from lower energy efficiency, with a conversion rate between electrical energy and kinetic energy ranging only between 70-80%. Additionally, they experience 'magnetic seepage' where the motor's electromagnetic resistance increases as the battery depletes, making riding without power exceedingly challenging. On the other hand, the mid-drive motor directly acts on the central axis, involving a clutch, transmission shaft, differential, etc., which aids the rider's pedaling effort. Its efficiency generally exceeds 80%, and its design allows for disengagement from the central axis when not in use, ensuring a smoother ride even when the battery is depleted.
2. Versatile speed conditions and increased torque: Unlike hub motors, which primarily control speed through current regulation, mid-drive motors use an internal gear system for variable speed conditions, increasing torque and power for uphill climbs without significant energy consumption. Their torque sensors are more responsive, directly impacting the central axis and enabling faster acceleration.
3. Balanced weight distribution and suitability for sport bikes: The mid-drive motor's positioning in the bike's frame ensures balanced weight distribution, enhancing the bike's balance during high-speed rides without the need for additional weight redistribution via the battery.
4. Streamlined connections and high integration: Mid-drive motors exhibit high integration with all sensors housed within a single unit, simplifying wiring and maintenance, leading to a sleeker design and more user-friendly experience.
5. Enhanced dust and water resistance, leading to lower failure rates: Advanced mid-drive motor solutions, such as NECO's MM18, boast high levels of integration and robustness, resisting external elements and potential water ingress, significantly reducing the probability of malfunctions compared to systems with multiple external components.
E-Bikes are leading the way in the evolution of bicycles, lightening the rider's load and enhancing the joy of cycling. As manufacturers compete to produce superior products, innovation in the electric bike industry continues to flourish. In this wave of technological advancement, the hope is not just for advancements in mid-drive motor technology but for even greater innovations in the future. The real convenience and experiences are right at our fingertips. Given the chance, experiencing the new sensations and pleasures that E-Bikes bring is worth exploring.