Eleven things you need to know about electric bicycles

What is an E-BIKE electric assist bicycle?

The E-Bike we usually refer to in China refers to electric-assisted bicycles, which originated in Japan and then developed in Europe. According to EU regulations, the relevant products are generally divided into three categories: electric assist bicycles (Pedelec), high-speed electric assist bicycles (S-Pedelec) and electric bicycles (E-Bike).

Electric assist bicycle (Pedelec)

Pedelec is the abbreviation of Pedal Electric Cycle in English. Usually, the motor will provide assistance to the rider only when actively pedaling. Therefore, it is also called a semi-pedal electric bicycle, which is the E in the usual sense of our domestic riders. -Bike.

Using different assist modes, the pedaling assist of electric-assisted bicycles (Pedelec) can meet the special requirements of different users. Usually, the gears are divided according to the strength of the assist. Some brands also distinguish the gears according to the application scenarios, such as flat roads. , off-road, climbing, downhill. Of course, the degree of power assistance will affect the cruising range of the electric motor and the energy consumption of the battery.

Power ratings and speed limits for pedelecs vary from country to country. According to EU standards, the rated power of the electric motor for pedelecs must not exceed 250 W. The power assist is automatically switched off after reaching a speed of 25 km/h, and is automatically switched on again below this speed. Some electric-assisted bicycles (Pedelec) also have a push assist system. When the rider is pushing, the push assist system can be activated by pressing a button. At this time, the bicycle will move forward according to the walking speed, making the push easier and less labor-intensive.

High Speed Electric Bicycle (S-Pedelec)

S-Pedelec is a high-speed version of an electric power-assisted bicycle (Pedelec), also known as a high-speed electric power-assisted bicycle. It works in the same way as a normal electric assist bicycle (Pedelec). It also requires manpower to pedal, and the motor will provide assistance. The difference is that the rated power and power-off speed threshold of the high-speed electric power-assisted bicycle (S-Pedelec) are higher. Also according to the EU standard, the high-speed electric power-assisted bicycle (S- The upper limit of the rated power of Pedelec is increased to 500W, and the motor will only disconnect the power assist when the speed exceeds 45km/h. Therefore, in Germany, the high-speed electric power-assisted bicycle (S-Pedelec) has been classified as a light motorcycle according to the traffic law, so this model requires compulsory insurance and a license to use it. And you need to wear a "suitable" protective helmet when riding, you must install reflectors, and you must not occupy the bicycle lane.

Electric Bike

The third category of electric bicycles is the electric bicycle (E-Bike) model. E-Bike is the abbreviation of ElectricL Bike. The biggest difference between it and the power-assisted bicycle is that the vehicle will be driven by the motor even if the pedal is not stepped on. Some Electric bicycles (E-Bikes) that are started by throttle handles or buttons can reach a speed of up to 45 km/h. Therefore, in Europe, electric bicycles (E-Bikes) belong to the category of light motorcycles and require insurance and registration.

In fact, "E-Bike" can also generally refer to Pedelec and S-Pedelec models in the daily language environment. This usage is especially common in the field of sports bicycles. Few brands subdivide products into Pedelec and S-Pedelec , everyone agrees to use E-Bike to refer to their own electric bicycle products. Over time, the original attributes of ElectricL Bike gradually faded away, and gradually became what we now call E-Bike, that is, electric-assisted bicycles.

How the electric power assist system works

No matter what brand of electric power assist system, its essence is to convert electric energy into kinetic energy and apply it to the transmission system of the bicycle to make riding easier and less labor-intensive. The electric power assist system we often say actually consists of three parts: sensors, controllers, and motors.

Electric bicycle with variable speed travel

When the electric power assist system is working, the sensor transmits the detected speed, cadence, torque and other data to the controller, and the controller sends commands to control the motor through calculation. It is worth mentioning that most motors do not directly act on the transmission system. The motor outputs power at high speed and low torque. It needs to amplify the torque through the deceleration system, and at the same time make the output speed close to the cadence of human legs (the middle motor ) or the rotational speed of the wheel set (hub motor).

coaxial motor, parallel shaft motor

As mentioned above, after the motor converts electrical energy into kinetic energy, it is not directly applied to the transmission system, but through a series of speed reduction devices to amplify the torque and reduce the speed. Therefore, for a mid-mounted electric power-assisted bicycle, the power output shaft of the motor and the crankshaft shaft of the bicycle are structurally two shafts, which are linked by a deceleration mechanism in the middle. According to the difference in the relative positions of the two shafts, the mid-mounted motor can be divided into a coaxial motor (also called a concentric shaft motor) and a parallel shaft motor.

The picture shows the transmission structure of the Shimano central motor. The white pinion on the right is connected to the power output shaft of the motor, and the leftmost is connected to the crankshaft. The two shafts are in parallel position, one left and one right. The transmission gears are connected one after another, so the motor with this structure is called a parallel shaft motor.

The picture shows the internal structure of the BOSCH (Bosch) motor, the output shaft of the motor is at the rear, and the chain shaft is at the front, which is also a parallel shaft structure.

Due to the long internal cavity space required by the parallel axis motor, it is bulky and has a wax gourd shape.

The coaxial mid-mounted motor used on Electric bicycle with variable speed travel

Coaxial motor, as the name implies, means that the crankshaft and the power output shaft of the motor are on the same axis. Most of these motors are outer rotor motors, which use the inner ring of the motor stator and the space on both sides to install the deceleration system, so the coaxial motor The exterior looks smaller and the internal structure is more compact.

However, in a limited space, it is not easy to achieve multi-stage deceleration while taking into account torque, heat dissipation and ensuring the concentricity of the transmission shaft. The TTIUM motor used in the double-speed electric bicycle we introduced earlier is a typical coaxial mid-mounted motor. As a rising national brand, it is really admirable to break a new road in the environment of many technical barriers, and has three world patent technologies, 21 national patent technologies and a unique lifetime number.

At present, the booster motor systems on the market can be roughly divided into two types: center-mounted and hub-mounted. The mid-mounted motor refers to the motor whose drive motor is installed at the bottom bracket of the frame (including the original integrated type and the bottom bracket external type). The motor is connected to the body and is connected to the rear wheel through a chain to transmit power. The hub motor refers to the motor whose driving motor is installed at the hub of the wheel, and the motor directly acts on the wheel set.

For sports models, the integrated mid-motor is undoubtedly the best choice.

• First of all, the motor drive system is located at the bottom bracket of the frame, which will not affect the weight balance of the whole vehicle. For the full-suspension model, the mid-mounted motor reduces the unsprung mass, and the feedback of the rear shock absorber is therefore more natural. There is an inherent advantage in handling.
• Secondly, the replacement of the wheel set is relatively convenient. If it is a hub motor, it is difficult for riders to upgrade the wheel set by themselves, but this situation does not exist with the mid-mounted motor. Players can buy a frame set and DIY it by themselves, which greatly increases the playability. At the same time, an excellent and efficient wheel set can also reduce transmission loss and greatly improve battery life.
• Third, when riding off-road, the mid-mounted motor suffers less impact than the hub motor, so it is more beneficial in terms of protection, thereby reducing the risk of damage to the motor and reducing the failure rate.

For non-sports bikes, the use of rear motors drive system does not require major changes to the traditional frame structure, and the low cost makes it easier for commuters to accept.

What is the size of the chainrings ?

Cyclists who often pay attention to electric power assist products may notice that some E-bikes with a mid-mounted motor have large chainrings and some small chainrings. Why is this?

Take the double-speed PESU MONSTER electric bicycle as an example. Although the motor is equipped with a small chainring, it is not slow to pedal. The secret is that there is a mechanical speed-up device inside the motor. Use speed to make up for torque. That is to say, when the crank is stepped on for one turn, the chainring actually turns two and a half times. Therefore, a dozen-toothed small plate is equivalent to the pedaling effect of a thirty-odd toothed plate.

Using speed to make up for torque, on the one hand, can reduce the tension burden of the chain, which is especially important for E-bikes with violent output. On the other hand, the high rotational speed of the chain shaft reduces the pressure on the motor reduction mechanism in a limited space. The volume of the reduction gear, the operating load, and the overall volume of the motor will all be reduced.

However, everything has two sides. High speed will increase the wear of the small chainring. It is necessary to work hard on the material of the chainring. At the same time, the designer also needs to solve the problem of interference between the chain and the chainstay when the small chain is mounted on the small fly.

Motor rated power:

Usually, the rated power of the motor we refer to refers to the rated output power of the motor, that is, the maximum output power that can operate normally for a long time under ideal conditions, and some people call it "maximum use power". peak power. Many riders are accustomed to using the rated power to measure the performance of the motor. Strictly speaking, it is wrong, because it also involves many factors such as the structural design of the motor, rated voltage, conversion efficiency, output torque, etc. Even two models with the same rated power The motor, too, has a completely different riding experience.

battery capacity:

Many people are used to expressing battery capacity in mA, but strictly speaking, this is a wrong expression. Milliampere is the unit of measurement for current, milliampere-hour (mAh) is the correct battery capacity unit, and some serious brands will also mark watt-hour (wh) at the same time. Take the battery on the PESU MONSTER we are currently evaluating as an example. The battery voltage is 36V and the capacity is 13.6Ah. If it is converted into watt-hours (wh), it is 13.6*36=489.6, that is, 489.6 watt-hours, about Equal to 0.5 kWh is half a degree of electricity.

Tips to improve battery life

Endurance is one of the most important parameters for many riders to buy electric bicycles. In fact, in the case of the same power, using some energy-saving tips can effectively improve battery life.

Reasonably use the boost gear to maintain a stable riding rhythm. Many riders like to increase the power boost gear to the strongest position as soon as they get on the car, and they often pull it when riding a long distance. Such an operation will undoubtedly consume a lot of power. If you want to ride farther, maintaining a uniform pedaling rhythm and just the right power assist is the most energy-efficient mode of operation.

Some countries and regions have mandatory regulations on the rated power of electric power-assisted bicycles. For example, the EU standard is that the rated power should not exceed 250W, while in some parts of the United States, this standard will be relaxed to 750W. In China, the new national standard It is stipulated that the rated power of electric vehicles and electric bicycles shall not exceed 400W.

E bike Frame: 

The frames is the soul of the whole electric bicycle, related to pedaling efficiency, comfort, transmission efficiency, the better the rigidity of the frame (it can be simply understood that pinching the brake lever and stepping on the pedal forcefully pedals the bottom of the frame to shake very little, if it shakes more If there is too much force, the force will be unloaded, and the power of your pedaling will not be well transmitted to the transmission system), the less effort you pedal, the higher the efficiency, the faster the uphill and acceleration, and the thinner the frame The better the road feel, Better shock absorption from the road.

From the terrain of riding, there are Mountain E bike frames,Gravel e bike frame, Road e bike frames.

From the material of frames, there are Carbon e bike frames, aluminum e bike frames, steel e bike frames and titanium e bike frames.

From the functional of the frames, there are full suspension e bike frames, hardtail e bike frames, endurance/endure e bike frames, aero e bike frames...

Xiamen Tour de Cycling Industry&Trade Co.,Ltd.--Our company has 16 years his perfermance and super light carbon frames experience and develop new trend of design frames with Italy designer each year. Welcome to contact us to do your OEM service for your own electric carbon frames.