Mid-mounted motor vs hub motor, do you know the difference between the two?

Mid-mounted motor vs hub motor, do you know the difference between the two?

At present, the popularity of electric bicycles is getting higher and higher. Its travel convenience and low-carbon attributes cannot be replaced by other means of transportation. The motors on electric bicycles can provide additional pedal assistance to riders, so they will More effort-saving. As the core component of electric bicycles, different motors will also have an impact on the performance of electric bicycles. Currently, the motors on the market are mainly divided into two categories: hub motors and mid-mounted motors. In terms of market share ratio, hub motors have an absolute advantage, but In recent years, most of the best-selling high-end models in Europe and the United States are designed with mid-mounted motors. So what is the difference between the two? This article summarizes the differences, advantages and disadvantages between these two types of motors in detail.

In-wheel motor , as the name suggests, is a design that combines a wheel hub with a motor. Its biggest feature is that the power, transmission and braking devices are integrated into the wheel hub. It is widely used in electric two-wheeled vehicles due to its mature design and low price. , the power design of the car.

Advantages of hub motor

• The vehicle has a simple structure and basically requires no maintenance.
  The wheel hub motor has a simple structure, usually consisting of a coil, a rotating shaft, a magnet and a housing. Due to its simple structure, the wheel hub motor has a relatively low failure rate, so it basically requires no maintenance. It is independent of the pedal drive system. Since they are not connected to the main pedal drive system, and hub motors do not add any additional stress to the chain or shifter, causing wear and tear on other components, the chain on a motor-mounted vehicle is likely to last longer than a non-electric bike.
• Low price and high efficiency
  The technical requirements for the production of wheel hub motors are not high, so the manufacturing cost is low. The cost of an ordinary wheel hub motor is only 200 yuan, and motors costing more than 500 yuan have the function of kinetic energy recovery. In terms of performance, the in-wheel motor has the advantages of high electric energy conversion efficiency and more power saving. Since the in-wheel motor is directly driven by the rear wheel, there is no energy loss during the transmission process. The kinetic energy conversion rate is currently around 80%, and the starting acceleration is also faster. Advantages: When the hub motor is running, the current is relatively uniform, and it relies on electromagnetic induction to operate, with low noise and little wear. It is not easy to burn out the motor, it is more convenient to install and disassemble, and it is simple to maintain.

shortcoming

• comfort
  In-wheel motors have a great impact on the control, comfort and suspension reliability of the vehicle. The handling of vibrations is not gentle enough, and the riding comfort will be reduced. It is more suitable for low-speed commuting below 40km/h. When driving at high speed, the vehicle Easy to tilt your head.
• vulnerable
  Precision motors are placed on the wheel hub. Long-term severe up and down vibration and harsh external environment (water, dust) can easily cause malfunction problems. When it comes to wheel components such as rims, tires and flywheels, the wheel hub motor may be more restricted and replacement Tires are also more difficult.
• Heat dissipation
  In-wheel motors perform well at low speeds, but they tend to generate a lot of heat when running at high speeds, and the internal heat dissipation environment is poor, which not only easily leads to a decline in motor performance, but may also burn tires.

Hub motors can also be further classified into geared hub motors and gearless hub motors. Geared hub motors have internal planetary gears that can reduce the speed of higher-speed motors; gearless hub motors have no gear device and directly reduce the speed of lower-speed motors. The shaft of the tach motor stator is connected to the bicycle. The biggest trouble with geared hub motors is the gears. The gears are highly used and therefore wear a lot. Gearless hub motors have no other moving parts except bearings, and there is basically no wear. As long as the bearings are not rusted or worn, they can be used almost all the time, so they are more widely used.

Mid-mounted motor , the motor is located in the bottom bracket between the center pedals of the bike, and the crank is connected directly to the mid-drive motor. The mid-drive motor is integrated into the e-bike’s frame rather than a separate unit like a hub motor. It does not directly power the wheels like a hub motor. Instead, power is provided through the bicycle's transmission system. The motor turns the crank and chain ring and provides power to the rear wheel through the chain.

advantage

• High efficiency and high torque
  The biggest advantage of a mid-mounted motor over a hub motor is its gear ratio. Riders can power the rear wheel through the same chain and gear set as the pedals, so they can choose low gear for power on steep hills or accelerate from a stop with high torque. A low-speed mid-drive motor can climb better and last longer than a hub motor of similar power. Mid-drive e-bikes provide power through the drivetrain and use torque sensors, which also smooth power delivery for a better riding experience.
• Reasonable center of gravity distribution, suitable for sports vehicles
  The center of gravity of the mid-mounted motor is in the middle of the vehicle, and the load-bearing is relatively balanced. Therefore, it can maintain the balance of the electric bicycle to the maximum extent. It will not affect the shock absorption when traveling quickly. The motor will also bear less road impact and has a higher degree of integration. It reduces the exposure of wire pipes and is superior to vehicles equipped with in-wheel motors in terms of off-road handling, stability, and passability.
• Small resistance
  As the power of the wheel hub motor continues to be consumed, the electromagnetic resistance generated by the motor will continue to increase, making riding without power more difficult. There is no reluctance in the mid-mounted motor, and the internally designed clutch ratchet can make riding without power The motor is completely detached from the bottom bracket ratchet, so even if the power is exhausted, you can ride as easily as a mechanical bicycle.

shortcoming

• Complex structure and high price
  The internal structure of the mid-mounted motor is complex. In addition to the motor, it also requires the cooperation of clutches, transmission shafts, transmission chains, transmissions, differentials and other components to output power to the rear wheels. Therefore, compared with hub motors, it is more expensive and the cost of building a car is higher. The price of the vehicle + motor + battery is generally more than 4,000 US dollars. These components not only increase the complexity, require regular maintenance and repair, are also more difficult to modify, are prone to malfunctions, and are more difficult to repair, and replacing the motor will be more expensive. Just replacing the hub motor is more expensive.
• Drivetrains are more susceptible to wear and tear
  Since the driving force needs to be transmitted to the rear wheel through the gear plate and chain, compared with the hub motor, it will increase the wear of the gear plate and chain. Therefore, the chain should be replaced when the wear is large. Otherwise, if the chain breaks, you will have to push the cart back. Home.

Mid-mounted motors are currently the optimal solution for mainstream products in the market because they are lighter, more energy efficient, and have a better riding experience. They are generally used in high-end models of electric bicycles and are more suitable for high-performance such as off-road sports. Demand models; hub motors have price advantages, maintenance costs are not high, they are environmentally friendly and affordable. Some people like the power and reliability of wheel hub motors when going off-road, while others prefer lightweight and stealthy mid-mounted motors when commuting. However, the price of a mid-mounted motor vehicle is generally more than 10,000 yuan, which is difficult for ordinary consumers. , the wheel hub motor can basically meet the needs.