How does an electric bike work

How Does an Electric Bike Work? A Comprehensive Guide

Bicycles have come a long way since their inception in the early 19th century, and now, we have electric bikes that offer us an eco-friendly, cost-effective, and healthy way to commute. Electric bikes, also known as e-bikes, are propelled by a motor and battery that give you an extra push while cycling. But how do they work? In this comprehensive guide, we will break down the components inside an electric bike and explain the science behind how they work.

Basic Components of an Electric Bike

The basic components of an electric bike include the frame, motor, battery, handlebars and brakes. The frame is the backbone of the electric bike and supports all of the other components. It is usually made from aluminum or steel and can be folded up for easy storage. The motor is a small electric device that provides power to the bicycle by transferring energy from the battery to turn the drivetrain. The battery powers the motor and supplies electricity to run accessories such as lights and displays. Handlebars provide steering control while brakes help slow down the bicycle when needed.

The Motor:

The motor is the most crucial part of an electric bike. It converts electrical energy into mechanical energy to help the bike move. Most e-bikes have a hub motor that is attached to the center or rear wheel. The motor is powered by a battery that is usually mounted on the bike frame.

Understanding the Motor in an Electric Bike

The motor on an electric bike works similarly to motors in other types of vehicles. It is connected to the battery and uses electricity from it to turn the drivetrain. This gives the rider a boost when pedaling, helping them go farther with less effort. The motor can also be used to propel the bike without pedaling at all, which makes electric bikes great for flat or hilly terrain. Depending on the type of motor and battery setup, some electric bikes can reach speeds up to 25 mph (40 km/h).

Types of Motors Used in Electric Bikes

Hub Motors

Hub motors are the most popular type of electric bike motor due to their simplicity, reliability, and low cost. They are situated inside the wheel hub and are relatively easy to install. Hub motors come in two types: geared and direct-drive. Geared hub motors are more efficient, lightweight, and produce more torque, making them suitable for hilly areas or off-road terrain. However, they are also more complex and prone to wear and tear. In contrast, direct-drive hub motors are simpler, quieter, and have a longer lifespan, making them ideal for urban commuting.

Mid-Drive Motors

Mid-drive motors are located near the e-bike’s bottom bracket and replace the chainring. They work by directing power through the bike’s drivetrain, providing more efficient power delivery and a better experience on steep terrain. Mid-drive motors also allow for better weight distribution and a more natural pedal feel, making them an excellent choice for mountain biking or long distance touring. However, they are more complicated to install and maintain, and usually come with a higher price tag than hub motors.

Friction Motors

Friction motors, also called friction drives, consist of a motorized roller that presses against the rear tire, propelling the bike forward. They are less common than hub or mid-drive motors, but some riders prefer them for their simplicity, low cost and minimal installation requirements. They also allow the rider to easily switch between motor-assisted and traditional pedaling modes. However, friction motors have several disadvantages, such as less efficiency, lower power output, and reduced traction on slippery surfaces.

Torque-Sensor Motors

Torque-sensor motors are the latest and most advanced type of electric bike motor. They are integrated with the bike’s pedal system and use sensors to measure the rider’s pedaling force and adjust the assistance level accordingly. This results in a more natural and intuitive riding experience that feels almost like a traditional bike. Torque-sensor motors are also more efficient and provide longer battery life compared to other types of motors. However, they are also the most expensive, and not all e-bike manufacturers offer them.

Dual Motor Systems

Some electric bikes feature dual motor systems that combine two different types of motors for increased power and performance. For example, a mid-drive motor can be combined with a hub motor to provide better hill-climbing ability or top speed. Dual motor systems can also improve handling and stability, especially on uneven terrain. However, they are more complicated to install and control, and may reduce the bike’s range due to increased power consumption.

The Battery:

The battery is what provides power to the motor. They are usually made up of lithium-ion cells and can be easily removed and charged. The average range of an e-bike is approximately 30-50 miles per charge. However, this range can vary depending on factors such as terrain and rider weight.

Types of Batteries Used in Electric Bikes

Lead Acid Batteries

Lead acid batteries are the oldest and most commonly used type of electric bike batteries. They are cost-effective but have a low energy density, which means they are bulky and heavy. Lead acid batteries use sulfuric acid as an electrolyte, which is highly reactive and can pose a health hazard if not handled with care. Moreover, these batteries have a low cycle count, meaning they have a short lifespan and need frequent replacements.

Nickel Cadmium Batteries (NiCad)

NiCad batteries are an older technology that has largely been replaced by newer and better-performing batteries. They have a high energy density and low self-discharge rate, but they suffer from the “memory effect.” This means they tend to lose capacity if they are not fully discharged before recharging. NiCad batteries also contain toxic materials and require careful disposal.

Nickel-Metal Hydride Batteries (NiMH)

NiMH batteries are a relatively new type of battery that has become popular in recent years. They have a higher energy density than NiCad batteries and are less prone to the memory effect. NiMH batteries are less toxic and more earth-friendly than NiCad batteries, but they are more expensive to manufacture.

Lithium-Ion Batteries (Li-ion)

Li-ion batteries are the preferred choice in most modern electric bikes because of their high energy density, lighter weight, and better performance. They have a longer cycle life and can provide longer distances on a single charge. However, Li-ion batteries have a higher upfront cost than other types of batteries, and their capacity can be affected by temperature changes.

Lithium-Polymer Batteries (LiPo)

LiPo batteries are a variation of the Li-ion battery but have a different electrolyte composition. They are more energy-dense than Li-ion batteries, and they can be shaped to fit the size and shape of the bike frame. LiPo batteries have a higher discharge rate, which makes them better suited for high-performance electric bikes. However, they can be expensive and have a shorter lifespan than Li-ion batteries.

The Sensors

The sensors on an e-bike detect the movement and speed of the bike. There are three types of sensors: cadence sensors, torque sensors, and speed sensors. Cadence sensors detect the motion of the pedals and will activate the motor when they sense movement. Torque sensors detect the amount of force being applied to the pedals and will activate the motor accordingly. Speed sensors detect the speed of the bike and will increase or decrease the assistance based on the speed.

List Of Sensors Included In E-bikes

Wheel speed sensors: These sensors are used to measure the speed of the wheels and help the motor to provide the appropriate amount of power.

Crankset-based speed sensor: This type of sensor is typically used in mid-drive motors and is mounted on the crankset. It measures the speed of the chain and helps the motor to provide the appropriate amount of power.

Torque sensor: A torque sensor is used to measure the amount of force that is being applied to the pedals. This information is then used by the motor to provide the appropriate amount of power.

Pedal assist sensor: A pedal assist sensor is used to detect when a rider is pedaling and then provide a boost of power accordingly.

Power meter: A power meter is a device that measures the power output of a rider. This information can be used by the motor to provide the appropriate amount of power.

Throttle and Pedal-Assist Systems in Electric Bikes

Throttle Systems

Throttle systems are the more straightforward of the two. They work by engaging the motor to propel the bike forward when you twist the throttle grip on the handlebar. Like a motorbike, you don’t have to pedal for the motor to work. This makes throttle systems ideal for individuals who want to cover long distances without breaking a sweat. They also come in handy when cycling up steep inclines and makes for joyful cruising.

Pedal-Assist Systems

On the other hand, pedal-assist systems are more like a typical bike, but with an electric assist. A motor is installed, in this case, in the bike’s bottom bracket, and it senses the rider’s pedaling pressure and speed. The system then adds assistive power accordingly. You ride the bike as you normally would, but the motor takes over when you need it. This makes it ideal for individuals who want to maintain a consistent level of exercise or want to cover longer distances with less strain on their legs. It is worth noting that pedal-assist bikes are easier to regulate and offer greater safety since the rider maintains complete control of speed and stability.

Power Output

The power output of both throttle and pedal-assist systems varies widely. Throttle systems usually have stronger motors, often between 500 and 1,000 watts, while pedal-assist systems are typically around 250 watts. The stronger the motor, the more power you get delivered to the wheels, making it easier to power up inclines or maintain a faster speed. This should be a significant consideration if you intend to explore hilly terrain or travel long distances regularly.

The Brakes

Finally, there are the brakes. e-bikes have different types of brakes, including mechanical and hydraulic disc brakes. When you hit the brakes, they disengage the motor to prevent the bike from moving forward.

Type Of Brakes Used In E-Bikes

Disc brakes: Disc brakes are the most common type of brake used on e-bikes. They work by using a set of pads to grip onto a metal disc that is attached to the wheel. Disc brakes are typically more powerful than other types of brakes and are less likely to overheat when used frequently.

Rim brakes: Rim brakes are another type of brake that can be used on e-bikes. They work by using a set of pads that grip onto the metal rim of the wheel. Rim brakes are typically less powerful than disc brakes but can be more effective in certain situations, such as when riding on wet roads.

Drum brakes: Drum brakes are a type of brake that is often used on heavier e-bikes. They work by using a set of shoes that press against the inside of a metal drum that is attached to the wheel. Drum brakes are typically very powerful but can be more difficult to maintain than other types of brakes.

Regenerative braking: Regenerative braking is a type of brake that is becoming increasingly popular on e-bikes. Regenerative braking works by using a motor to generate electricity when the bike slows down, which can then be used to recharge the battery. Regenerative braking can help to extend the range of an e-bike and make it more efficient overall.


Electric bikes provide a clean, green way to commute, and they’re a fun way to get around town. Now that you know how these bikes work, it should be easier for you to maintain them and make informed purchasing decisions. Whether you’re looking to purchase an electric bike for commuting, leisure or exercise, there’s a model for everyone. We hope this guide has given you a better understanding of how an electric bike works and how to take care of one. Get pedaling!

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