Mastering the 5 key points to easily choose an electric-assisted bicycle
Get an e-bike? No, it is expensive! Indeed, 2,000-3,500 US dollars is not sweet as the commuting tool for most people. However, if you are a rational consumer who is not blindly loyal to brand names and understands the key points of how to choose a product, you can select an electric-assisted bicycle at a satisfactory price. Below, I will guide you through the five main points to consider when purchasing an electric-assisted bicycle.
- Why get an e-bike over a conventional bike?
Many regular cyclists wonder why they would need an electric-assist bike when they already own a traditional bicycle for exercise. This sentiment is similar to the one expressed by many sport bike brands in the beginning, mocking the idea of electric-assist bikes. However, any brand without a well-planned electric-assist bike series is now facing a serious decline. It wasn't until the COVID-19 pandemic worsened this year that sales of traditional bicycles began to rebound for these brands.
This market evolution tells you, as a cyclist, that you should consider purchasing an electric-assist bike. Not only can it still meet your exercise needs, but it can also provide new challenges and riding fun that you may not have considered before. For those who use bicycles for transportation and leisure, the convenience of electric-assist bikes is definitely worth a try.
- Composition of e-bikes
Before we start discussing how to choose an electric-assisted bicycle, let's first understand that apart from the general components of a regular bicycle, there are other components to consider for an electric-assisted bicycle.
1)Motor + Controller
The motor and controller can generally be divided into front-wheel drive (hub motor), rear-wheel drive (hub motor), or mid-drive motor, with distinctions between cadence sensing and torque sensing for controller programming. From the market trend of the earliest 24V200W motor to the current mainstream 36V250W, and the North American market's preference for high-power such as 48V500W and 750W. The voltage of the motor is related to the load it can withstand. In North America, a weight of over 120 kilograms is common, which explains why there is a demand for high-power motors.
In general, hub motors with cadence sensing are more commonly used in affordable models because they replace the regular hub and do not have the additional cost of a torque sensor mechanism and more complex controller programming. The entry threshold for manufacturers is relatively low. However, many consumers prefer mid-drive motors, most of which are equipped with torque sensors. Torque sensors are used to detect your pedaling force and transmit the information to the controller, which then calculates and issues instructions to the battery on how much current to output to drive the motor.
What difference does it make whether or not there is a torque sensor? An electric-assisted bicycle without a torque sensor relies on the pedal speed (cadence) + bike speed to tell the controller whether or not to assist the motor power. Along with switching the level of assistance to tell the motor how much to assist. This logic cannot fully reflect the assistance that the rider really needs. For example, when climbing uphill, the pedaling speed may not be fast, but the rider needs more assistance. It is also criticized that there may be too much motor assistance, causing the rider's feet to not keep up and resulting in a feeling of free pedaling.
On the other hand, an electric-assisted bicycle with a torque sensor is based on detecting the size of the pedaling torque to allow the controller to calculate how much electrical current the battery should output to drive the motor. It also has assistance control levels that can manually control how much the motor should assist. In short, an electric-assisted bicycle with a torque sensor is smarter, not only providing a better riding experience but also resulting in longer mileage.
There are many different types of torque sensor mechanisms available on the market. Some use the amount of deformation of the frame components to determine how much force is applied to the pedal, while others use the changes in chain tension. There are also those that use electronic detection directly on the pedals. However, the most mature technology collects data based on the force applied to the pedals, and it is important to note whether it detects on one side or both sides. For consumers, it can be difficult to judge from appearance alone, so it's important to "test ride" before making a purchase.
I do not recommend that consumers purchase front-wheel drive electric-assist bicycles, even though they are usually the sweetest in price. It seems that they do not conform to the logic of design and usage! The mid-drive motor configuration with dual-side torque detection is the highest rated. However, if your budget is not sufficient, the rear-wheel drive can also be considered. It would be even better if the rear-wheel drive model is equipped with a torque sensor!
2)Battery set
The constituent components of a battery pack include battery cells, a battery management system(BMS), an outer case, nickel stripes with connecting wires and terminals, cell holders, and other protective spacers. In addition to the quality of all individual components, a critical factor that affects the safety and lifetime of a battery pack is whether the assembly/sealing and testing procedures are performed properly.
The quality of the battery cells is the foundational factor that determines the efficiency, safety, and lifespan of a battery pack. It is recommended that consumers choose battery cells from world-class manufacturers such as Panasonic, Samsung, or LG, which are highly rated in the market. Although using cells from unknown manufacturers can save more than 40% of the cost of a battery pack, it may compromise its efficiency and lifespan, and even pose risks of battery explosion or fire.
The battery management system is the most crucial safeguard for safety protection. Overcharging, over-discharging, low/high-temperature protection, and cell balancing are all necessary elements.
Nickel strips are conductive plates that connect the battery cells, and their purity is related to the smoothness of current flow. The stability of the fusion between the nickel strips and the cells is also an essential factor. The wire material and terminals of the connecting wires must be considered, as well as their compatibility with waterproof and anti-reversal designs. The cost of these components also has a significant impact.
The cell holders are structural components that stabilize the arranged battery cells in their positions and prevent them from colliding due to vibrations during movement and thermal expansion/contraction during charging and discharging. Protective spacers also contribute to this function.
The outer casing acts as the armor of the entire battery pack and connects it with controllers, motors, instruments, and the interface of the bicycle structure. In recent years, embedded design has become mainstream on the market.
Finally, the assembly/sealing and testing procedures, if not executed properly, will result in significant after-sales service costs. Many brands have failed in the industry, and the failure of battery packs is a major factor.
- Battery Specification
Battery specification is normally to be shown as Ampere/Hour or Watt/Hour; and the Voltage, for Example as below,
24V(Voltage)15Ah(Ampere/Hour), represents the rated power is 360Wh(Watt/Hour) (24*15)
36V15Ah, the rated power is 540Wh (36*15)
48V15Ah, the rated power is 720Wh (48*15)
Some products will indicate their maximum value, which is calculated based on a fully charged battery of 24V reaching 29V, 36V reaching 42V, and 48V reaching 54V. So it will be,
24V15Ah, the Max. power is 435Wh (29*15)
36V15Ah, the Max. power is 630Wh (42*15)
48V15Ah, the Max. power is 810Wh (54*15)
Many brands will describe their range as 60, 80, or 100 kilometers. However, the factors that affect range goes beyond just battery capacity, and include:
- Load: the weight of the bike, rider, and any cargo being carried. The heavier the load, the more energy is consumed.
- Terrain: the distance and gradient of hills are among the main factors that affect energy consumption.
- Riding habits: many riders tend to use the maximum assistance level regardless of whether it's necessary or not, which can deplete the battery faster.
3)Display
Riders operate the electric assist bike's electronic control system through a display panel, while also obtaining real-time information such as speed, assist level, and battery level from the same display. In the market, there are generally two types of display panels: LED panels used in low-priced models, which can only provide a rough estimate of the battery level and the assist level through illuminated indicators; and advanced LCD panels, which can provide more complete and accurate information, including error codes and records of the distance traveled in a single ride or cumulatively. In recent years, there have also been high-end LCD color screens available.
Now that we have covered the basic knowledge of electric assist bikes, we can start exploring how to choose the right one that suits your needs. The author has summarized the following five major considerations for your reference.
1. Decide on the type of e-bike that suits you based on your usage:
Like buying a traditional bicycle, the first thing you need to do is to think about the usage scenario you want. Do you want a road bike with an electric assistance system? Or an electric mountain bike? Or is your usage scenario more like most cyclists, leaning towards urban leisure riding? You need to clarify this general direction first, because, in addition to the differences in the frame design, appearance, and component configuration that everyone may be more familiar with, there are also different design arrangements for the electric system of electric assist bicycles or e-bikes. For example, the motor performance, specifications, controller assistance ratio, real-time/delayed setting of assistance force, battery capacity setting, and display of the status of the instrument panel, etc.
So, first, think about the majority of the usage scenario when you use this electric assist bicycle.
2. A reliable electric system, motor-control-display
The front-wheel drive system is the least recommended by the author, although the most attractive reason for this type of system is its price. As the weight of electric-assisted bicycles and electric bicycles is mainly located in the middle or rear of the bike, and the power of the front-wheel drive motor is not in the transmission mechanism, which relies on pedaling with a chain or belt through the front chainring to the rear sprocket. Additionally, uphill or slippery road conditions are not favorable for front-wheel drive systems.
The rear-wheel drive system is currently the most popular in the market, mainly because of its affordability. It is a good choice for the design of electric bicycles because it follows the direct drive concept. However, in the design of electric assisted bicycles, the power generated by pedaling starts with the front chainring and is transmitted to the rear wheel through the chain or belt. When the motor power exceeds the pedaling power, it can create a feeling of coasting.
The mid-drive motor is the most highly rated in the market and generally has a torque-sensing function that determines the amount of motor assistance based on the force of pedaling. It is the most user-friendly structure based on logical use.
Given the current market options, the author provides the following table as a reference for the applicable range of motor system specifications. Control systems that have torque detection data and an LCD display are a bonus.
3. Confirm the safety of the battery pack & calculate the mileage you will need
Most importantly, the first step is to understand whether the battery pack of your preferred bike model uses reputable battery cell brands and what safety features the battery protection system has. These are some of the safety-related factors to consider.
Next, once you have determined how you will be using the electric-assisted bicycle you are looking to purchase, you should have a rough idea of the battery range you need from a full charge. Based on the factors that affect the battery range mentioned above and the explanation of battery capacity, the following reference can provide you with an approximate guide for selecting an electric-assisted bicycle with a battery capacity that meets your needs.
4. Consider structural safety, frame, fork, and wheels
The aforementioned considerations are all related to the electric components. But what are the things that must be taken into account in relation to the bicycle components?
Structural safety is the most important. The design of traditional bicycles may not be enough to support the additional weight and power of the motor system, battery, and other components when riding on bumpy roads or during braking. Therefore, I do not recommend purchasing so-called DIY systems to retrofit traditional bicycles. In terms of structural strength, the following components need to be considered:
- Frame: The frame design for traditional city bikes and the lightweight frame used in high-end sports bikes must be re-inspected and tested to see whether it is safe enough to be used on the bikes equipped with a motor system.
- Front fork: In addition to the frame, the strength of the front fork must not be overlooked. Especially with aluminum alloy and carbon materials, one must be very careful, and the unseen portion of the fork’s upper column, which goes through the headtube of the frame, should not be taken lightly.
- Wheels: It is generally not recommended to use single-layer rims for the wheels. It is also recommended to upgrade from the 14G spokes used in traditional bicycles to 13G or even 12G, depending on the wheel sizes and specifications of the motor system.
5. Stronger braking power is necessary
Some electric-assisted bicycles may come equipped with V-brakes due to cost considerations, which is very concerning! Although electric-assisted bicycles immediately cut off electricity and power when you stop pedaling, they still require the corresponding motor's inertia braking force. The author recommends purchasing one that comes with disc brakes.
Summarize:
In summary, some bicycle media outlets have predicted that in the future, all bicycles, except for top-tier racing bicycles, will be equipped with electric systems. The author does not have such an extreme vision but strongly agrees that electric-assisted bicycles can assist people in more conveniently using bicycles, especially in hilly environments or for longer rides, bringing more riding pleasure. If you have read the above five major considerations, you will no longer prioritize price or only believe in famous brand bikes. Besides safety, factors such as wheel size, storage, practicality, and appearance must also be considered. Additionally, the author once discovered a row of words on a European customer's bike logo "good-looking and good to ride." This confirms why electric-assisted bicycles had been popular in Japan for 10 years, but have not been able to be promoted to the international market back in the 1980s. However, European-designed bicycles have already started a global trend in just 10 years time since the late 1990s. This also clearly tells us that appearance design is just as important as the above five major considerations.
Have you started researching the electric-assisted bicycle you want? Remember to ride in style!
