Torque is a key term for both mid-drive and gear hub motors (explained further in the following section). Essentially, when such a motor operates, it produces torque, which is the force responsible for moving the motor's shaft.
In a gear hub motor, this rotating shaft powers the wheel axle. In a mid-drive motor, it powers the crank arms or “cranks” (the levers to which the pedals are connected). The motion generated in both cases is what drives the bicycle forward.
Torque, the rotational force that initiates this motion by spinning the motor shaft continuously, is measured in Newton meters (Nm).
RPM, an acronym for revolutions per minute, denotes the motor's velocity. The higher the RPM, the more swiftly the motor functions. The combination of RPM and torque provides an indication of the motor's overall power. More details on this will follow.
Power is calculated based on the motor's torque and speed, as per the formula: W = Nm x RPM. Power essentially describes the rate at which torque and RPM occur.
Therefore, a higher torque (Nm) and a higher number of revolutions per minute (RPM) result in a more potent motor. This is analogous to the concept of horsepower in automobiles.
Throttle vs. Pedal Assist (PAS)
During your search for e-bikes, you'll often come across terms like "throttle assist" and "pedal assist," or the pedal assist system (PAS). What do these terms signify?
Throttle is a mechanism for activating the motor. Engaging the throttle propels the bicycle forward. This throttle is managed through either a grip-shift or a trigger-style control located on the handlebars. When throttle assist is activated, it allows the rider to either pedal or simply relax and enjoy the journey.
Conversely, pedal assist is engaged by the physical action of pedaling, which in turn activates the motor. A pedal assist system (PAS) typically offers multiple levels. The degree of assistance it provides depends on the amount of effort applied by the rider's pedaling.
For instance, the Movin Pulse and Tempo models of e-bikes feature both five-level pedal assist and throttle assist. This implies that their motors can be activated either through pedal assist or without pedaling by using throttle assist.
Varieties of Electric Bicycle Motors
Having acquainted yourself with basic e-bike motor terminology, it's time to delve deeper. E-bike motors vary in RPM, W, and Nm, but they also differ in their fundamental mechanisms. Below are the primary varieties of e-bike motors.
Central-drive motors are positioned at the heart of the bike's framework, nestled between the crank arms (the levers to which the pedals are fixed). This motor is named for its central placement between the bike's rear and front wheels.
Such motors produce torque via a rotating shaft connected to a chainring. This chainring then engages the cranks and pedals, propelling them forward. Essentially, the rotating shaft generates torque, thereby activating the PAS.
Central-drive motors are known for their efficiency and for providing a balanced ride due to their strategic placement. This position ensures a direct connection between the propulsive force and the motor, leading to smoother acceleration, consistent power delivery, and easier control. The central location of the motor, being the heaviest part, aids in balanced handling.
However, central-drive motors come with drawbacks: they are costlier and more complex to maintain. Furthermore, if the chain snaps, the bike becomes inoperable.
Rear-Hub Direct-Drive Motors
Rear-hub direct-drive motors are situated at the bike's rear, with the motor's shaft doubling as the e-bike's rear axle. In this design, the shaft remains stationary.
Contrary to a moving shaft generating torque, in this model, the motor (the "hub") revolves around the stationary shaft. This rotation generates the torque needed to move the bike forward.
These motors are recognized for their simplicity, longevity, and quiet operation. They also maintain a consistent high power level.
The drawback of these motors is their bulkiness, heaviness, and relative inefficiency. Riders might experience slower acceleration and a noticeable drag while pedaling. The weight distribution, with the motor positioned at the rear, can also affect handling.
Geared Hub Motors
Geared hub motors share similarities with direct-drive motors in having a moving shaft. However, unlike in a central-drive motor where the shaft connects to a chainring and cranks, in a gear hub motor, the shaft powers the wheel axle.
In this design, the internal electric motor spins rapidly, and its shaft links to various gears. These gears, in turn, rotate the hub at a reduced speed. The entire gear hub system is housed within the hub.
This results in higher torque (Nm) but lower speed (RPM). Geared motors are more compact than direct-drive motors and are relatively cost-effective. They are also lightweight and do not cause much resistance when pedaling.
Understanding Power Ratings in Electric Bike Motors
E-bikes might also be marketed based on "rated power." This term essentially denotes the highest power output the e-bike motor can continuously deliver without damaging the motor.
While technically the e-bike motor might exceed its rated or "maximum power," such speeds are not sustainable over time. "Maximum power" is sometimes referred to as “peak power.”
Many e-bike manufacturers provide both the motor's rated power and "peak power" figures. The higher the wattage of an e-bike motor, the more powerful it is. For instance, the Movin Tempo/Pulse has a motor with a rated/peak of 500/900W.
Generally, a higher wattage indicates a stronger motor, but is that always preferable? Not necessarily. It depends on your specific needs from the bike. A stronger motor may be beneficial for carrying heavy loads, ascending hills, or navigating rough terrain.
However, there are scenarios where a less powerful motor might be more suitable. For instance, if extending the range is a priority, a less powerful motor would be advantageous. The Pulse/Tempo e-bikes, with its 500/900W rated/peak motor, offers a long range of 65 miles and 75 miles.
Electric Bicycle Categories
The motor of an electric bicycle significantly influences which "category" the bike is classified under. It's crucial to be aware of these e-bike categories, as different states have specific regulations about which categories are permissible. Understanding these categories is also helpful in determining whether wearing a helmet is necessary while riding an e-bike.
Here is a brief overview of the four primary categories of electric bicycles:
Category 1: E-bikes in Category 1 have a maximum speed limit of 20 mph and lack throttle assist, functioning solely when the rider is actively pedaling. These bicycles are also referred to as pedelecs. Typically, Category 1 e-bikes are permitted on standard bike trails and lanes, although this can vary by local laws.
Category 2: Category 2 e-bikes are also capped at a top speed of 20 mph, but they include throttle assist, enabling the bike to move forward even without the rider pedaling. These bikes are generally allowed on regular bike paths and lanes as per most regulations.
Category 3: E-bikes in Category 3 can reach speeds up to 28 mph. They might come with throttle assist, though some regions (like California) restrict this feature on Category 3 bikes. These bikes should also be equipped with a speedometer (such as a small LCD screen).
Typically, Category 3 e-bikes are not permitted on conventional bike paths or lanes, and are instead expected to be ridden in road lanes or designated bike-only shoulder lanes.
Category 4: E-bikes in Category 4 are distinguished by their high-powered motors, ranging from 1,000 to 3,000W. They can operate with PAS or throttle assist and do not have a set speed limit. These bikes are often treated similarly to scooters or mopeds under various legal jurisdictions, requiring the same level of regulation. For instance, you cannot use a Category 4 e-bike in a bike lane but must ride it on the road. Additionally, in many areas, riding a Category 4 e-bike requires a license and registration.
Top Electric Bike Motor Brands
Gaining knowledge of electric bike terminology is key to making a well-informed choice regarding e-bike motors. Moreover, being familiar with various motor system producers is beneficial. Let's explore some of the leading companies in this sector.
Most of the Buffing motors are mid-drive motors (there are some models that have Hub-motors), and this helps them to give much higher performance. What distinguishes Bafang motors is that they have high performance and last for long periods, in addition to the less need for constant maintenance of the motor.
The cost of the Bafang motor is one of the strengths that distinguish this brand, and you can get it from a price ranging from $ 300 to $ 700, depending on the model and capacity of the motor, and this price is considered a small price compared to the rest of the models available in the market.
You can reprogram every part of the bike and access the controller easily and quickly. This is a unique feature that no other manufacturer offers you, at least with such ease. By programming, you can control the motor’s response to the different speeds of the throttle or PAS, for example, you can increase the power of the first gear of the PAS and many other settings that will suit the way you ride your electric bike. As we mentioned earlier, the tool available to program the motors is not complicated at all, and you will only need a USB cable and a computer in order to get a motor that suits you perfectly.
Another advantage of Bafang motors is that they are reliable motors, have few breakdowns, and live for long periods.
5-Availability of spare parts.
Although Bafang motors are motors that do not require much maintenance, even if you need any spare parts, you will get them quickly because they are available all the time and the reason for the proliferation of spare parts is that there are many cyclists using this motor.
Bafang motors are characterized as quiet motors and do not make noise, which is what I personally like. The quiet motor sound does not give you the impression that the motor is of high quality, and on the other hand, it allows you to distinguish any other fault sound in the electric bike.
7- High torque.
The other advantage of most Bafang motors is that they are characterized by great torque and this feature is a very wonderful feature that will make it easier for you to go uphill also you can pull a trailer and load many things on the bike with ease.
If you have purchased a motor from Bafang Motors and need help with its assembly, there is support available 24 hours a day.
Shimano stands as the foremost manufacturer of bicycle components globally. Remarkably, they manufacture 70% of the world's bicycle brakes and gears and are responsible for half of all bicycle parts. Shimano is also a notable name in professional cycling circles. For instance, in the 2015 Tour de France, Shimano components were used by 17 out of 22 teams.
Shimano has successfully extended its reach to the e-bike segment with its Shimano STEPS system, a highly favored choice among bike makers. The STEPS line includes six different motors: E500, E600, and E6100 for city and trekking bikes; and E700, E800, and EP8 for electric mountain bikes (eMTBs).
Bosch is another leading brand in electric bike systems, specializing in mid-drive motors. Their major motor lines are Active Line, Active Line Plus, Cargo Line, Performance Line, and Performance Line CX.
Each line serves a specific purpose. The Active Line is perfect for commuter bicycles, the Performance Line suits sporty adventures, and the Cargo Line is ideal for transporting heavy loads.
Bosch's e-bike motors are renowned for their precision engineering. They are equipped with three sensors that detect cadence, velocity, and pedal force, ensuring a natural and fluid riding experience. These sensors foster a harmonious interaction between the rider and the bike, enabling efficient pedal assistance.
Yamaha, widely recognized for its motorcycles, also excels in the production of e-bike motors. The company has been in this field since 1993 when it launched its first power assist bicycle.
Yamaha's range of mid-drive motors includes the PW Series, PW-X2, and PW-X3. The standard PW series caters to urban and general biking, the PW-X2 is more suited to eMTBs and e-road bikes, and the PW-X3 is typically used for electric mountain bikes.
Selecting the Ideal Motor for an Electric Bike
Deciding on the best motor for your e-bike is not straightforward, as the "ideal" motor varies based on individual objectives. Opting for a reputable brand like Bafang, Shimano, Bosch, or Yamaha is a great starting point.
Once you've chosen a trusted brand, consider the e-bike class you're interested in and the necessary power level. For activities like trekking, off-roading, or carrying heavy loads, a more robust motor (over 750W) might be appropriate. Conversely, for commuting and urban riding, a lower power motor around 500W should suffice.
Ultimately, motor selection is largely a matter of personal preference. Mid-drive motors offer a smooth experience, though they come with a higher price tag.
The information provided here aims to enhance your understanding of motor specifications, assisting you in making the optimal choice for your needs.
If you need more information about top-quality motors, come and visit our store at 654 College street, Toronto. We will help you to find a best motor for your needs!