E-bike terminology explained

Whilst e-bikes often look very similar to the bicycles that we have all known and loved all of our lives, the technology behind them is relatively new and comes with a whole set of terms and jargon to be familiar with.

This is what electric bikes are all about and virtually all e-bikes operate utilizing pedal-assist, otherwise known as pedelec. On an e-bike, when you pedal the motor engages to help, giving you a power boost. Generally, the harder you pedal, the more power the motor provides to help. There are different sensors that determine how power is applied - more on this later. For this, all you you need to know is that pedal-assist means that the e-bike motor makes pedaling easier.

E-bikes have sensors that determine pedal-assist levels based on rider input. Speed or cadence sensors provide motor assistance based on how fast you pedal. With a speed sensor setup, to go faster using the motor, you don't need to pedal harder, just faster. Speed sensors are common on hub-drive motor e-bikes.

Torque sensors on the other hand determine how much motor assistance to provide based on how HARD you are pedaling. To go faster, you need to pedal harder. This is more similar to how a traditional bicycle operates. To go faster, pedal harder. Torque sensors are more often found on mid-drive motor e-bikes as they offer more control over how much assistance the motor provides.

E-bikes are divided into 3 different classes based on how the motor works to assist the rider and the top speed available with the motor engaged. Rules and regulations can differ based on the class of your e-bike so it's important to have an understanding of them. There is a whole article on the 3 different classes that you should be familiar with here.

Most e-bikes offer different modes that are controlled using a switch on the handlebars and can usually be seen on a handlebar mounted display. Each mode provides a different level of pedaling assistance from the motor. There are commonly 3 modes available - Eco, Standard or Trail and Boost or Turbo. You can think of these as Low, Normal and High. Low (Eco) provides the least amount of assistance and longest battery life, High (Boost or Turbo) the highest level of pedaling assistance but reduces battery life.

Some e-bikes offer a throttle that allows you to operate the motor without pedaling at all. This is usually done with a lever on the handlebars that you operate with your thumb or by twisting a throttle on one of the handlebars - as you would on a moped or motorcycle. These can be good if you have a maintenance issue on a ride like a broken chain for example as you can continue on without having to pedal or if you have limited ability to pedal due to injury, age or other physical limitation. Be sure to research your local laws and regulations before purchasing an e-bike with a throttle option as some jurisdictions consider them to be mopeds and have minimum age and licensing requirements or do not allow them at all. For more information see the article on e-bike Classes.

Riders may be faced with situations where they have to walk their bike - around sharp corners, up stairs or in other situations where you may have to walk beside your e-bike. Because of the battery and motor, e-bikes are quite a bit heavier than regular bicycles. Many modern e-bikes now have a low power push assist mode or walk mode that will give you just a little help from the motor when walking your e-bike.

Electric bikes aren't electric bikes without motors. These come with their own set of terminology to be familiar with.

There are 2 main types of electric motor that modern e-bikes use. The first and most common are mid-drive motors. These are located between the pedals at the base of the frame and are the most efficient motors at low speeds so are good for climbing hills and in e-mountain bikes. You can learn about them and their pros and cons here.

The other type of electric motors commonly used in e-bikes today are hub-drive motors. These can be either direct-drive or geared and are located on either the front or rear hub of the bike, more commonly on the rear wheel. Pros and cons of hub motors can be found here.

Torque is defined as a turning force that causes rotation. Think about pedaling on a bike. If you are just cruising along and pedaling easily, the torque that your legs are applying to the pedals is minimal. If you are standing up and pushing down hard on the pedals, the torque that you are applying is much higher. Torque is measured in Newton meters (Nm). Most e-bikes with mid-drive motors are rated at 75-90Nm whereas smaller mid-drive and hub-drive motors on lightweight bikes are usually rated at 35-40Nm.

Power is how much work the electric motor can do and is measured in watts. It is calculated by multiplying torque by RPM (revolutions per minute - in cycling terms, cadence or how many times the pedals are rotating every minute). Most pedal-assist e-bikes use 240-250w motors. To give you an idea of what this means, fast amateur cyclists can maintain power at 250-300w for an hour and pros can hold up to 400w.

Unfortunately no-one has worked out how to run a motor on air alone yet so e-bikes rely on batteries as their power source. These introduce a slew of new jargon that we need to have some understanding of.

Voltage measures how much power flows from the battery to the motor. Most e-bike batteries list Watt-hours explained below which means that Voltage is not super important to understand. Good enough to know that most e-bike batteries use 36v or 48v batteries with a few that use 24v or 52v versions.

Amp-hours is a measure of the capacity of the battery. Again, not super important to know because of Wh (below), just know that most modern e-bike batteries have capacities of between 11-14Ah.

This is the important one to understand as it is the metric most often provided by e-bike manufacturers. Watt-hours can be thought of as how big the battery is. It's calulated by multiplying voltage by amp-hours - V x Ah = Wh. For example, a battery that rated at 52v and 14Ah has a capacity of 728Wh - 52v x 14Ah = 728Wh.

Watt-hours describes how big a battery is and how long it will last before being drained. In theory, a battery rated at 500Wh running a motor rated at 250W (see Power-watts above) consistently will be drained after 2 hours of operation.

As you might imagine, batteries with high Wh ratings are larger and heavier. Most e-bike batteries fall in a range between 300-900Wh with 500Wh being the most common. Smaller Wh batteries are found on lightweight e-bikes and larger Wh ones on e-bikes designed to carry cargo or cover long distances.

Range is the distance that can be traveled or the time that a battery will last before being drained. It's impossible to define accurately because there are a number of factors that influence it including the weight of the bike and rider, the terrain (flat vs hilly) and the drive mode being used (Eco vs Turbo). Because of this some manufactures don't provide a range estimation at all or will give a wide range eg. 30-100miles. Safe to say that the higher numbers assume flat terrain in Eco mode at moderate speed. Some e-bikes display an estimated range remaining on the handlebar display - something to look for when shopping for an e-bike.

Batteries don't last forever. How many smart phones and laptops have you had to replace over the years because the batteries died or wouldn't hold a charge for very long? Unfortunately, the same limitations apply to e-bike batteries.

Charge cycles refers the number of times a battery can be drained and recharged before it will need to be replaced. Most modern lithium-ion e-bike batteries are rated 800-1,000 charge cycles. This means that a battery should last most prople who ride regularly 3-6 years before it will need to be replaced.