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Guide to Electric Bike Systems: Everything You Need to Know


Man riding an electric bike

Electric bikes have grown in popularity in the U.S. due to their convenience, minimal operating costs, and lower environmental impact. With more than $1 million in expected annual sales, people across the country are exploring e-bikes as an alternative method to get around town and see the great outdoors. 


However, because e-bikes are relatively new in the U.S., many people need to become more familiar with how they work or what to look for when choosing an e-bike. By familiarizing yourself with the types of e-bike systems, how they work, and their pros and cons, you can find the perfect model for your needs. 


Types of Electric Bike Systems


The core of an electric bike is the type of electric motor it uses to propel the bike forward. Most electric bikes fall into three categories: mid-drive motors, hub motors, and friction-driven motors. 


You can find the type of motor under “Electric specifications”' section when exploring different Upway bike models. 


Mid-Drive Motors

The battery powers the motor of the e-bike. It stores the electric power that drives the motor, allowing the rider to travel further and faster than with just pedal power alone. Most e-bikes use lithium-ion batteries, which are lightweight and long-lasting.


The battery can be found at different locations on the bike. Integrated batteries are built into the bike’s frame, providing a more balanced ride and better handling. Most high-end models from big bike brands feature integrated batteries. 


You can also find e-bikes with batteries mounted on top of the down tube. This is common in entry-level e-bike models and makes the bike more affordable. 


Electric Motor 

The electric motor powers the bike, providing extra assistance to the rider while pedaling. Electric motors are divided into three classes: class 1 and 2 are limited to 20 miles per hour, while class 3 bikes can reach up to 28 miles per hour. Hub motors and mid-drive are the two main types of electric bike motors. 


Hub motors are found on the bike’s rear hub and provide direct power to the wheel. Mid-drive motors are mounted next to the pedals and provide power to the chain, providing more torque. You’ll typically find mid-drive motors on electric mountain bikes because they are more efficient for steep hill climbs. 


Hub Drive Motor

Hub motor electric bikes have an electric motor fitted to one of the bike’s hubs, directly powering the attached wheel. There are two types of hub motor e-bikes: front-hub motors and rear-hub motors. Front-hub motors power the front wheel, whereas rear-hub motors send power to the rear wheel. Although the overall performance between both subtypes of hub motor e-bikes is usually comparable, the differences can affect your purchasing decision.


On front-hub e-bikes, the electric motor on the front wheel helps give the bike better weight distribution because the battery packs are typically mounted to the rear. They are also less mechanically complex, resulting in more affordable electric bikes than their rear-hub counterparts. For those riding the bike, this can feel like the motor is pulling the bike forward. 


On rear-hub e-bikes, the motor is on the rear wheel. This location means the front wheel is free of electric bike-specific components, making e-bike maintenance and repairs easier. Rear-hub motors are also more durable and tend to require less maintenance. When the motor engages, handling characteristics are the inverse of a front-hub model; the motor pushes the bike instead of pulling it.


You can find information on the hub motor on “Engine location” section of your bike model’s product page. 


Friction-Drive Motors

Friction-drive (FD) electric bikes feature motors that connect directly to the rear bike with spring-tensioned rollers. When the motor is on, it sends power to the rollers, turning the wheel via friction. 


Friction drive motors are the most mechanically simple and the easiest to fit on a bicycle. Many FD systems are available as conversion kits, letting riders convert standard bicycles into e-bikes.


You can find information on the friction-drive motor on the “Engine location” section of your bike model’s product page. 



How Electric Bike Systems Work

The essential parts of a modern e-bike system are the electric motor, the controller, and the battery. Depending on the model and the operating modes, e-bikes may also feature additional parts, such as torque sensors, which measures how much force is applied to the pedals and dictates the amount of power the motor produces.


When the rider begins pedaling, if the bike is set to a mode drawing electrical power, such as pedal-assist or electric-only, the electrical energy leaves the batteries and starts flowing. Before reaching the motor, the energy must pass through the controller, determining how much power flows to the motor and wheels. The amount of power transmitted depends on the bike’s power modes.



Class I

Class I e-bikes, also known as pedal-assist e-bikes, are a popular form of electric bicycles that offer riders an added boost while pedaling. These bikes have a motor that helps with pedaling up to a maximum speed of 20 mph, and require the rider to pedal to activate the motor. Class I e-bikes are allowed on bike paths, streets, and most other places where traditional bicycles are permitted.

Class I e-bikes use various types of pedal-assist systems, such as standard pedal-assist and pedal-assist with torque sensor. In standard pedal-assist models, like the Gazelle Arroyo C8, the controller uses a cadence sensor to detect when the rider is pedaling, and the rider can manually adjust the electric motor's assistance level.

Pedal-assist with torque sensor measures the force applied to the pedals and automatically adjusts the motor's assistance level accordingly. These systems provide a seamless riding experience and make Class I e-bikes a great choice for those looking for an easy-to-use, efficient mode of transportation.


Class II

Class II e-bikes, also known as throttle-assist e-bikes, have a motor that can be activated without pedaling by using a throttle on the handlebar. They can reach a maximum speed of 20 mph, similar to Class I e-bikes, but can be propelled without pedaling. Class II e-bikes are allowed on roads and bike lanes but may not be permitted on some bike paths. They offer an effortless riding experience and are a popular choice for commuters and recreational riders seeking a faster and more comfortable ride.


Pros and Cons of Electric Bike Systems

Although electric bikes are more popular than ever, it is critical to understand each system’s benefits and drawbacks when choosing an electric bicycle. This information can help you understand which e-bike model fits your needs based on range, ride quality, and performance. 


Mid-Drive E-Bikes: Pros and Cons

Choosing a mid-drive electric bike offers riders many benefits. These include: 


Electric range

Most mid-drive electric bikes have better battery packs than other models, offering 10 to 15 miles of additional range compared to a hub-motor equivalent.


Ride quality

Mid-drive systems deliver power more smoothly than any other e-bike system, resulting in a safer and more comfortable ride.


Performance

Mid-drive e-bikes typically offer the best handling due to the motor’s placement. They can negotiate climbs and hills more efficiently, and the best models can achieve the highest top speeds.


Mid-drive e-bikes may also have the following drawbacks:


More maintenance needed

Mid-drive power delivery systems stress the e-bike’s drivetrain systems more than hub-motor and FD models, requiring riders to maintain them more frequently. Additionally, mid-drive motors are more complex and have more moving parts, potentially requiring riders to service them more often.


High cost

Due to their complexity, mid-drive systems are the most expensive, making them less accessible than hub-motor or friction-drive equivalents.


Hub Motor E-Bikes: Pros and Cons

Hub-motor electric bikes are the most common e-bike category on the roads. The primary benefits they offer include:


Mid-range pricing

Although not as inexpensive as FD models, hub motor e-bikes are more reasonably priced, offering a balance of features and performance for a more attainable price.


More models

Hub motor e-bikes are the most common, meaning riders can access a wider array of models and features.


Wide selection of options

Hub motor e-bikes are available as front-hub or rear-hub models. Options for both types include regenerative braking, throttle control, torque sensors, and many more.Hub motor e-bikes are available as front-hub or rear-hub models. Options for both types include regenerative braking, throttle control, torque sensors, and many more.


While they are commonly available, hub motor models possess the following potential downsides:


Weight Concerns

Overall, hub-motor e-bikes tend to be heavier than any other system; the motor alone may weigh up to 20 lbs. Rear-hub models distribute most of the weight to the bike’s rear, which can be destabilizing for less experienced riders. Alternatively, the handling characteristics of front-hub models may not be as good as other e-bikes.


Lower efficiency

Hub motor e-bikes can’t take advantage of a bike’s gears, resulting in more wasteful power usage and draining the battery more quickly than a mid-drive or FD system.



Friction-Drive E-Bikes: Pros and Cons

FD e-bikes offer several advantages for those looking for an affordable electric bike that feels similar to a manual bicycle. These benefits include:


Low cost

The primary benefit of FD e-bikes is their cost. These systems are the most affordable, often significantly cheaper than hub-motor or mid-drive systems, making them a perfect entry into electric bicycling. 


Weight

FD systems are typically the lightest, making friction-driven e-bikes the closest in weight to a standard bike. The combination of low weight and motor power equivalent to hub motor and mid-drive models also means FD e-bikes have a better power-to-weight ratio (PWR).


Ease of installation and removal

The FD system on an e-bike can be installed and removed in minutes, allowing you to easily convert your e-bike into a regular bicycle. It also makes it easier to repair and service the system.


FD e-bikes have a few disadvantages to consider, including:


More tire wear

When the motor is engaged, the rollers on an FD system will accelerate wear and tear on your rear tire, requiring you to replace it more often. 


Sensitive to water

Riding an FD e-bike in rainy or snowy conditions or through water puddles may cause the rollers to lose friction, reducing or cutting power transmission from the electric motor to the rear wheel.


Choosing the Right Electric Bike System for Your Needs

While all e-bikes are convenient and environmentally friendly, not all e-bikes suit every rider’s needs. The three crucial factors to consider when choosing an e-bike model are local terrain, intended use, and budget preference.


Local Terrain

The type of terrain you intend to ride your e-bike determines the features and motor system your model should possess more than any other factor. Electric bikes fall into various categories based on their intended terrain, environment, and usage. The most popular categories are:

This e-bike typically features wider tires, knobbly treads, suspension systems, and an upright seating position. They are best suited for off-road applications, including riding on dirt, gravel, and grass.

This category of e-bikes features smoother, narrower tires and a more aerodynamic seating position. Most electric city bikes lack suspension systems. They are best suited for use on paved roads and streets.

This type of e-bike is also known as electric city bikes. A hybrid combines some of the features in eMTBs and electric city bikes, providing riders with a model capable of taking on both paved and dirt roads. They work best for riders who want an e-bike that can go nearly anywhere.

This category of e-bike combines the advantages of a typical electric bike with the convenience of a folding mechanism, allowing riders to fit the e-bike in narrow spaces, such as inside car trunks or while riding the train.

Also known as cargo e-bikes, utility e-bikes feature baskets and mounting points for saddle bags. Some models, called long-tail cargo e-bikes, may fit a second passenger. These e-bikes are suitable for riders whose primary method of transportation is the e-bike or those who need extra carrying capacity.


Intended Use

Two factors can help you determine the best features for your e-bike riding needs: how often you intend to use your e-bike and the intensity of the average riding session.  


For instance, if you intend to use your e-bike to commute to and from work in a flat, urban environment, you might want a model with a lower-powered motor (250 to 500 W) and batteries with enough range to complete a back-and-forth trip. E-bikes with an electric-only mode allow you to travel without pedaling, turning the commute into a more leisurely ride and preventing unnecessary fatigue.


If you enjoy using e-bikes for sport or working out, look for models with pedal-assist systems and higher-powered motors (500 W or more). While pedaling on this type of e-bike is no less of a workout than with a classic bicycle, pedal assistance lets you negotiate uphills or reach higher speeds easily.


Budget Preference

Electric bike prices typically range from $900 for entry-level models to over $5,000 for high-performance options. Upkeep and service costs typically increase along with the purchase price, as the more expensive options usually need more maintenance. 


Consider factoring the cost of safety and maintenance equipment into your budget, such as a helmet, light-reflective tape, or tool sets.


Electric Bike Maintenance and Repair

When choosing an e-bike, consider how long do electric bikes last and the type of maintenance you may have to provide to keep it in good shape. Generally, the average lifespan of an e-bike is about ten years. However, your maintenance and repair schedule significantly affect your e-bike’s lifespan. 


Knowing how to look after your e-bike and properly care for its essential components is crucial to get the most out of it. Follow this checklist of e-bike maintenance basics to extend its lifespan:


Keep it clean

Washing your e-bike and keeping it free of dirt, mud, and grease is essential to prevent premature wear and tear. Regularly cleaning your e-bike’s drivetrain is crucial to ensure optimal performance.


Lubricate the chains

If you own a regular bicycle, you may already know that keeping your bike chains lubed helps protect them from damage and corrosion. E-bikes require more frequent chain lubing, preferably once after every ride.


Inspect and replace wearable parts

Most e-bikes use stronger components than standard bicycles to withstand the additional torque and higher speeds. Even then, these parts can wear out. Check your e-bike for loose bolts and inspect the other components for signs of damage or excessive wear. Keep every bolt tightened and replace worn chains, sprockets, and brake pads. If one or both tires are flat, you can repair and replace them yourself.


Care for your battery

E-bikes can’t provide their best functions without their batteries. Although all rechargeable batteries eventually lose effectiveness, you can extend their life with good charging habits. Keep them fully charged when not in use, and do not let the battery discharge completely.


Don’t open your motor yourself

E-bike electric motors are typically factory-sealed units that should only be opened by qualified personnel. If your motor has an issue, visit your dealer or a reputable e-bike repair shop to have it inspected.


Electric Bike Safety Considerations

A responsible e-bike rider should always keep their safety and that of other road users in mind. In addition to standard bicycle safety, you should follow these additional tips and precautions to ride your e-bike safely.


Read the manual first

Every electric bike model is different. Familiarizing yourself with your e-bike’s features and manual of operations is critical to ride it as safely as possible.


Obey all e-bike-specific traffic laws

In addition to standard road safety rules, ensure you know your local jurisdiction’s e-bike laws. Each state has different laws and statutes regarding e-bikes, such as class systems, helmet requirements, or registration requirements. Specific states may regulate e-bikes as electric mopeds or scooters, requiring a license to operate legally.


Mind the weight

An average e-bike weighs 22 pounds more than a standard bicycle, making them significantly heavier. Due to this, be careful when mounting and dismounting your e-bike. Studies have shown that numerous e-bike injuries occur during mounting and dismounting, especially among elderly riders.


Practice safely

If you’re new to riding electric bikes, take it to a safe environment, such as an empty parking lot, to practice riding and get used to your e-bike’s speed and handling characteristics.


Make your presence known

Install a bell and a horn on your e-bike, and always wear brightly-colored, fluorescent, or light-reflective gear when riding to improve your visibility. These will help other road users see and hear you.


Brake earlier

When using an e-bike in pedal-assisted or electric-only mode, you can reach much higher speeds than on a standard bicycle: up to 20 mph or more, depending on the model and class. Practice braking earlier to account for the higher speeds.


Wear an e-bike helmet

Bicycle helmet manufacturers offer e-bike-specific helmets, which provide superior impact protection when riding at e-bike top speeds. If you intend to use a high-performance or off-road e-bike to its fullest potential, don’t rely on your standard bike helmet; choose an e-bike-specific model instead.


Shop Quality Certified Pre-Owned E-Bikes at Upway

Whether you are new to cycling or have experience riding bikes, there is an electric bike model for you. Choosing an e-bike that meets your needs, riding style, and budget is primarily about selecting a model with the right features. Understanding what each e-bike system can do and how the right one can benefit your riding style is critical.


Buying a pre-owned electric bike can be an excellent way to find the right model while saving money and reducing waste, helping preserve the environment. At Upway, we are committed to helping riders find the right e-bike for an affordable price. Browse our inventory of used e-bikes and join the e-bike revolution with Upway.

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Upway offers the widest range of certified pre-owned electric bikes, reconditioned by professional mechanics. Thanks to Upway, you'll get a great electric bike at a price that's 20-60% off retail, with a one-year warranty!