What Is an eBike and How Does It Work?
Since their invention, bicycles have served as a convenient and affordable means of transport and an exciting leisure and exercise activity.
With electric power, bicycles can be used for more jobs and by a larger percentage of the population, thanks to reducing the physical demands of riding in hilly areas, fighting headwinds, or carrying cargo.
Like almost all tech in the 21st century, electric bike technology took giant leaps in sophistication and dropped in price substantially.
The electric bicycle motor and battery are now lighter, more powerful, longer lasting, more efficient, and cheaper, making them accessible to many people in developed countries.
If you’re interested in buying an e-bike, this article will explain what they are and how they work, and finish by answering some common questions about them.
What Is an eBike?
Deciding whether or not an e-bike is right for you is pretty straightforward. Nonetheless, it is helpful to know the basics of what they are and how they work.
An e-bike is any bicycle with an electric motor that propels you forward through assistance while pedaling or using a throttle. This motor draws power from a rechargeable battery connected to the frame.
Each e-bike system is regulated by a mini-computer called a controller, which takes information from the battery, motor, control panel, and sensors.
The control panel is mounted on the handlebar or built into the frame, allowing you to select the amount of power you want. Pedal assistance systems (PAS) usually have three, four, or five power levels, such as Eco, Sport, and Turbo.
In the eyes of US law, an e-bike is a two or three-wheeled vehicle with functioning pedals, an electric motor with a maximum of 750W (1hp), and a max speed on motor power alone of 20mph. PAS can assist you up to 28mph, although 28mph bikes (Class 3) are subject to more regulations in some states.
Types of eBikes
Improvements to electric bike technologies made in the past decade mean an electric alternative for each bicycle type is now available. There is massive variation within the electric bike market and different products and designs to suit different needs.
Today, you can find numerous options in each category: road, gravel, MTB, touring, commuter and urban, cargo and utility, and folding. There is even a new category of hunting electric bikes designed to replace ATVs.
The most common of these types of electric bikes are urban and hybrid electric bikes, used for city riding, commuting, running errands, and general leisure.
These models are typically more affordable, comfortable to ride, and, in terms of performance, adequate for the demands of the average rider.
Sub-categories of urban bikes like folding, cruiser, and cargo e-bikes are more specialized to specific environments but are still versatile enough for most.
Non-performance e-bikes start as low as $500, go as high as $7,000 or $8,000, and represent most of the e-bike market. Some brands include Rad Power Bikes, Lectric, Ride1UP, and Aventon, focusing almost entirely on urban and commuter-style bikes.
Performance-based models like electic road bikes and e-gravel bikes are growing in popularity, appealing primarily to cyclists with experience in the given discipline or a similar one.
New, lightweight motors and batteries have made electric gravel bikes and road models much more desirable and nearly indistinguishable from regular models. Likewise, high-torque motors and high-capacity batteries are making eMTBs, and hunting e-bikes grow in popularity.
Generally, performance models will start at higher prices, around $2,000, and can cost upward of $15,000.
How Do Electric Bikes Work?
As mentioned, electric bikes work through an electric motor which uses the power stored in a rechargeable battery to drive the bike forward, either by turning the wheel directly (hub motor) or by turning the cranks connected to the drivetrain (mid-drive).
Modern electric bikes typically have a battery mounted inside the frame. However, cheaper or older models may mount the battery on the frame or under the rear pannier rack.
The motor and the battery connect to a central controller, which acts as the system’s brain. It also communicates with sensors and the display, if there is one.
The controller takes information from the sensors to determine how much power it should send to the motor. Sensors can measure the torque you are using, the speed the pedals are turning at (cadence), or a combination of both. When riding an eBike, higher torque or cadence will draw more power from the motor.
Each of the four components mentioned above feeds information to the controller. The controller then determines how much pedal assistance is required, regulates voltage from the battery, cuts power to the motor or shuts it off when necessary, and communicates battery and pedal assistance levels to the display.
Types of eBike Motors and Assistance
There are two distinct types of e-bike motors, each named for its position on the bike. The type of motor used dramatically affects the ride quality and also influences the price of an e-bike. Read our complete guide to ebike motors for more information on this topic.
Mid-drives are the more advanced of two, positioned between the cranks where the bottom bracket would be.
The direct connection to the cranks and the drivetrain results in a smooth and natural power transfer as long as the rider uses the gearing appropriately (low gears for inclines, higher gears for flats and descents).
Mid-drives are considered the premium choice as they’re more efficient, powerful, smoother, and longer-lasting. However, they’re also more expensive, and they cause the drivetrain to wear faster.
Hub-drive motors are located at the wheel’s hub, typically in the rear. These motors turn the wheel directly by spinning the axle (direct-drive) or turning a set of gears housed within the hub motor (geared hub).
Regardless of the type, hub motors are cheaper and don’t wear down the drivetrain. However, they are slightly more inefficient, slower on hills, and can negatively impact handling and traction.
Assistance: Throttle and PAS
There are two ways to activate an electric bike motor: with a throttle or by pedaling.
Most e-bike throttles are a half-twist grip on the handlebars, mimicking those of mopeds and scooters. However, thumb throttles are quite popular as well.
Throttles are not legal in the UK and EU, so they are typically only found on US e-bikes. By law, these throttles can provide power up to 20mph.
PAS is the pedal assistance system that kicks in when you begin to turn the cranks. In the US, this system will support you up to 20mph or 28mph, depending on the bike. The EU has a 15.5 mph speed limit.
Electric Bike Batteries and Range
The most common batteries used in modern e-bikes are lithium-ion (li-ion), similar to those used in phones and other everyday devices. The other, far less-common type, is lead-acid, like those used in cars.
Li-ion is more expensive but stores more power, lasts longer, and charges faster. In addition, li-ion requires less care to maintain its function.
Watt-hours (Wh) is the best measurement for battery capacity. This number represents the total power stored in a battery, found by multiplying voltage (V) by energy capacity (Ah).
In general, it’s better to have a higher Wh rating. However, there is a trade-off. More Watt-hours means a larger, heavier, and more expensive battery.
Charging an e-bike battery can take between two and a half and nine hours. However, rapid-charge technology is available and becoming more widespread, so we expect average charging time to trend down in the coming years.
Battery position is another consideration as it impacts a bike’s handling, so to avoid adverse effects, most manufacturers mount it centrally and low on the frame.
The Factors Affecting Range: How Much Range Do eBikes Have?
The max and average range of battery-powered bicycles are the most challenging measurements to predict accurately. So many variables influence the range that accurate estimation isn’t possible, so take any manufacturer’s estimate with a pinch of salt.
The range an e-bike will return is not only down to the differences in motor and battery sizes. Bike weight, rider weight and size, riding style, gear choice, gradients, and weather conditions all play a part.
A typical range for a $1,000 to $3,000-range urban or hybrid e-bike is 20 to 45 miles; but reaching the higher end of the range requires highly favorable conditions, such as flat terrain and a 170lb rider, for example. Premium models may offer up to 70 or 80 miles.
Performance e-bikes or electric touring bikes often have significantly higher max ranges, sometimes up to 100 miles. This difference is mainly due to having higher-end electronics, better aerodynamics, and lighter build kits.
Some manufacturers offer extra batteries, dual battery capacity, or range extenders for more range.
Electric Bike Weight
One of the most notable characteristics of electric bikes is that they feel much heavier than traditional bicycles.
Electric bicycle motors and batteries are heavy, adding anywhere from 12 to 25lbs of extra weight to the bike. In addition, electric bikes typically have more resilient components such as reinforced frames, high-spoke wheels, thicker tires, and more cabling and mounting points. All of this adds additional weight.
Extra weight slows down the bike’s handling and makes it more challenging to pedal if the motor isn’t engaged. This isn’t a big deal for the average urban or commuter electric bike. However, if you’re looking for the best folding e-bike you plan to carry regularly, ensure it isn’t too heavy.
On the other hand, performance e-bike manufacturers will utilize lightweight drive systems to limit the effect of the electronics on how the bike rides, even though it sacrifices max range. The lightest options on the market are currently Mahle’s eBikemotion X35 Plus and Fazua’s Evation.
eBike Classes: How Fast Can e-Bikes Go?
In the United States, there is a classification system that relies on three electric bike classes based on assisted speed, motor power, and the presence of a throttle.
Classes 1 and 2 generally don’t have restrictions or limitations on where they can ride and who can ride them. However, in some states, you cannot ride Class 3 e-bikes on specific paths and trails and must be of legal age in order to ride them.
- Class 1 E-Bikes – Pedal-assisted electric bike (pedelec)
- Max speed with assistance: 20mph
- Motor power limit: 750W
- Class 2 E-Bikes – e-bike with throttle and pedal-assistance
- Max speed with assistance: 20mph
- Motor power limit: 750W
- Class 3 E-Bikes – Pedal assistance with an optional throttle
- Max speed with PAS: 28mph
- Max speed with throttle: 20mph
- Motor power limit: 750W
- Class 4 E-Bikes – Unrestricted e-bikes requiring licensing to ride on the road
- Max speed with assistance: None
- Motor power limit: None
There is no tiered classification system in Europe and the UK, but all electric bikes are restricted to 15.5mph, and throttles aren’t allowed. You can read more about electric bike laws and regulations in our full guide.
What Is E-Biking?
In 2019, cycling’s governing body, the UCI, introduced the first eMTB World Championship races for men and women. Notably, in 2022, former road World Champion Peter Sagan took part in the race, drawing much attention from the media.