1. Lower Rolling Resistance And Higher Energy Conversion Rate
The hub-drive motor is generally a brushless motor that has a really simple structure. It is driven by electromagnetic induction: it affects the motor speed by controlling the magnitude of the current. However, limited by its traditional structure, rotating friction, motor heat accumulation, etc., the hub-drive motor has a lower conversion rate of electric energy to kinetic energy which is only between 70-80%. In addition, hub-drive motors have always had a “Magnetic Leakage” phenomenon, which means the electromagnetic resistance generated by the motor will gradually increase as the battery power is consumed. The electric bike will be more and more difficult to continue riding without electricity.
The mid-drive motor collects the power signal acting on the pedals and then cooperates with the clutch, driveshaft, differential, and other components to apply the output kinetic energy to the crankset to assist the rider in pedaling. In the case of no battery power, the mid-drive motor is completely separated from the bottom bracket axle, and there is no magnetic resistance. Therefore, when the battery is exhausted, you can still ride unimpeded.
2. More Torque
Even with the addition of a torque sensor, the hub-drive motor can still only control the speed through the magnitude of the current, simply increasing the motor’s rotating speed to increase the torque. This will result in greater power consumption, more energy waste, and lower overall efficiency.
The more technologically advanced mid-drive motor is a combination mechanism of internal transmission gears. Multiple clutch gears form a variable-speed ratchet inside the motor, which will increase the output torque and has a higher load and climbing ability. And its torque sensor is more sensitive, sensing changes in the pedaling force of the crank, which will directly act on the bottom bracket axle and accelerate faster.
3. A More Reasonable Center Of Gravity
Due to the high weight of the hub-drive motor, whether it is placed on the front wheel or the rear wheel, the center of gravity of the bicycle will not be balanced. Moreover, when the motor is assisting, it will cause a strong sense of frustration, which is not suitable for controlling the bicycle and seriously affects the riding experience. In addition, the rotating inertia generated by the motor’s own weight will increase the load of the braking system.
The mid-drive motor has a better gravity balance, it will not affect the balance of the bicycle under fast driving, and does not need additional batteries for counterweight. Therefore, most newly released electric bikes integrate the battery in the down tube. It will also reduce the burden on the braking system, improve braking performance and extend the life of the braking system.
4. Less Wiring And A Higher Degree Of Integration
Many components are integrated into the mid-drive motor, with only a few wires extending out to connect to the handlebar controller. This simplified and integrated design makes the bicycle has a more concise appearance and convenient maintenance.
5.Extended battery distance
The additional sensors and more sophisticated management system can give the rider options on how the motor and rider interact. The rider can often choose the ride distance and pedaling effort to ensure that the battery does not fade early.
Mid-Drive Vs. Hub-Drive e-bike Motors
- Where electric hub motors are fine for commuting and use or tarmac roads, mid-drive motors offer a better balanced bike which is important for many sports. Mid-drive motors allow improved suspension and reduced strain on the spokes of the drive wheel.
- Sensors on hub motors can only provide information about the pedal speed. Mid-drive motors can provide detail of the pedal force that the rider is exerting. The advantage here is that management software can micro-adjust the power of the motor creating synergy between rider and machine.
- Rear wheel electric hub motors take up a lot of space around the rear axle. Gear clusters have to be narrower and often limit the rider to between 3 and 5 gears.
- Hub motors become less efficient as they approach their designed top speed. Gear selection on mid-drive motors keeps the motor closer to its most efficient speed. There is, therefore, a small efficiency in battery usage which can help extend travel distance.
- Front wheel hub motors lose traction off road as there is little weight over the drive wheel. Rock hopping becomes impossible as front end weight damps the bike’s agility. A front end hub motor provides no assistance when the weight is on the rear wheel.
- Rear wheel hub motors bog in mud and slide out on slippery corners. Poor weight distribution affects the way the bike lands after jumps making them more difficult to control. Extra weight at the back can make the bike awkward, and slower to respond to rider input.
- Extra weight of hub motors hamper the ability of the suspension to absorb bumps. If the tire has less time in contact with the ground this equates to less traction for the rider.
Mid-drive electric motor place the electric engine in the middle of the bicycle. The engine position improves the control the rider has on the bike, while the distributed weight enhances suspension and damping making the bike more planted.
Mid-drive electric motors are a ‘must have’ on sport bikes. Mid-drive electric bikes are more capable in fast off-road terrain and can maneuver well when rock hopping.
There are no speed advantages to a mid-drive electric bike, however, larger gear clusters can be fitted. Greater selection of gears allows the rider to keep the motor in the power curve for greater efficiency.