How Does an Electric Bike Motor Work?

Proving popular with all age groups, electric bikes, also known as e-bikes, combine traditional pedal bikes with an electric motor. As you pedal, the motor automatically kicks in and gives you that extra bit of push, and speed, which is useful for hills and uneven terrain.

There are some basic rules that determine whether the bike can be classified as an electric bike. Legally, you must push the pedals of the bike to activate the motor, there is no way of controlling the power via the handles, unlike a moped, and the electric support must only increase the speed to a maximum of 20mph in the US (15mph in the EU, Australia and the UK). At this top speed, the motor should cease and it is the rider’s own efforts that will result in the bike going faster.

What type of motor does an electric bike use?

Electric bikes either have a crank motor, a mid-drive motor or a rear hub motor. The crank motor is preferred for two main reasons – the motor is more responsive and it gives the cyclist a more traditional bike ride. This is because the motor senses how hard you are pedalling and responds in kind, i.e. the more you pedal, the harder the motor works.

A rear hub motor, or wheel hub motor, has been used in electric bikes for a longer period of time and are a simpler set up. This type of motor is not as responsive and it is usually a simple on or off. A motor on the rear hub or wheel will also affect the way the e-bike handles and is balanced.

The positioning of the motor can make a difference to how the bike handles, particularly if mounted on a mountain bike which has to manage difficult and uneven terrains. Motors are generally located in the rear hub, the front hub or in the middle of the bike.

The two most popular positions are in the rear hub and the middle of the bike – these are known as mid-drive electric bikes. When the motor is in the rear hub, it sits quite low with the rider’s weight sitting over the back wheel. This results in a bike that has the extra weight and power of the motor at the rear of the bike, thereby reducing any adverse effect on handling.

Mid-drive motors are usually in the bottom bracket; as the rider pedals and the chain rotates, the motor is powered via the chain. Being located in the middle of the bike, the balance and weight distribution is far more even, resulting in better handling and stability.

A motor in the front hub is not favored as much for most bikes because it can impact the handling and steering. However, it is usually associated with hybrid and folding electric bikes, like the DYU D3F folding e-bike.

As well as being able to purchase electric bikes with the motors already fitted, it is also possible to buy kits to fit motors to a standard bike. Some of the best motors on the market are Bosch, Fazua and ebikemotion which can be fitted to affordable road bikes to help bike riders.

Combining e-bike motors and gears

Over the past few years, electric bikes have become extremely popular. Motors are getting lighter and more powerful, and the bikes themselves are built to accommodate an electric motor without affecting balance and handling. However, at the moment, there are few motors that incorporate a bike’s gears but this could be about to change with the announcement by Bafang of their new e-bike that has a rear hub motor that includes a two-speed automatic gear change.

Another aspect of electric bikes that is starting to gain traction is motors that are able to automatically adjust their power level according to the level of effort required. For example, the motor will be able to detect a hill in the road and adjust the amount of power needed to get up the hill, without changing the speed, automatically.

Smart motors

Smart motors have been a topic of conversation with the electric bikes sector, particularly with Bosch planning on launching a Smart system that is able to operate a mid-drive motor through the eBike Flow or the Bosch eBike Connect apps. Riders will be able to set their speed and level of power needed to help with hills and other terrains via the app on their smartphone. The app will also be able to keep riders updated on battery charge and power levels. This level of connectivity can also be applied to suspension and braking systems, such as ABS.

With the ever-rising pressure on climate change and net zero emissions, there is a big push towards electric bikes, particularly in more urban and city areas. Coupled with the health benefits and low maintenance, the popularity and capabilities or e-bikes is set to continue but affordability needs to be high on the agenda if electric bike manufacturers want more people to invest in an e-bike.

If, knowing all the useful tips and information we’ve provided you with, you’re still puzzled what to look for when shopping, here’s a nice list of affordable road bikes.