Electric Bike Parts

Electric Bikes Buyers Guide: Chapter 2

There are three main electric bike parts which separate an electric bicycle from a traditional bike; the battery, the motor/hub and the controller which acts as the brain for all the electrics.

In this, you'll find Electric Bikes Experts discussing what makes a quality electric bike

Quick Read & Watch: Chapter 3: Choose Your Electric Bike
A quick checklist and the single best piece of advice for choosing an electric bike

Now, you need to know more above what kind of parts and about the different types of bicycle you can buy or adapt:

Types of Bicycle

electric bike parts

Folding Electric Bicycle

Excellent for the commuter who needs to pack a bike away into a rucksack, on a train or into the corner of an office, and still travel home for pennies.

Electric Road bike

Built for speed and comfort, electric road bikes are perfect for getting across town quickly. A long distance commute becomes very easy on a decent road bike.

Electric Mountain bike

Your mountain excursions and leisure rides will be even more fun with that extra bit of “oomph”. And you’ll still have enough energy to make the trip home.

Electric Hybrid Bike Not to be confused with a petrol/electric ‘hybrid car’ A mix of a road bike with a bit of mountain bike pedigree, hybrid bikes are becoming more and more popular with commuters who enjoy leisure rides at the weekends.

Although they’re rare, you can also get tandem electric bikes for two riders.

From these types of bicycles, you get two types of electric bikes.

You can also convert your existing bicycle to an electric bike with the help of a conversion kit. Perfect for DIYers, cyclists who already have their perfect bike, and it can save you money.

Experts discuss the Pros and Cons of Electric Bike Conversion Kits

Two Types of Electric Bike

The first type, is the pedal-assist electric bike. You ride it just like you would a normal bicycle, but it uses a torque sensor to add power according to how hard you pedal. Excellent for climbing up hills, sweat-free commuting and very useful if you want to improve your fitness by putting in more effort.

The alternative is the throttle-assist electric bike which is more like a moped. You have a throttle on the handlebars or a button which connects to your motor, and you add power as well as cycling. This works really well if you’re not so agile and don’t always want to be pedaling.


Most bikes will use ‘v-brakes’. These work by using rubber and clamping the metal wheel. However, with an electric bike that is usually travelling at higher speeds, its better to use disc brakes for the faster stopping time, like you have on a car.

Many electric bikes have disc brakes, but the difference really is personal. Try electric bikes with and without the disc brakes and see if you notice the difference.

Frame Sizes

Bikes come with different frame sizes. Your perfect bike depends on your height and length of your legs. Taller people with longer legs will need larger frame sizes. Take a look at the frame size calculators here.

Electric Bike Battery

Remember, the battery is a critical component of any electric bike. Make sure you buy a branded battery where possible, with at least a two year guarentee.

Generally, lithium-based batteries offer the best mix of performance, size and weight. You’ll find them standard on most reputable electric bikes. Lithium-based batteries are really future-proofing your investment since they don’t require nearly as much maintenence or looking after compared with othe batteries.

Lithium-ion, lithium-polymer and soon lithium-sulphur batteries are all popular amongst good electric bike manufacturers. If you want to read more about the science of batteries, read Battery University. Batteries don’t normally work as well with fast charging.

For everyday commuters, an overnight charger is perfect but for those pushing the mileage like couriers, leisure riders, police officers a second battery might be a worthwhile investment. Also consider getting a pedal-assist electric bike for the extra range, since it encourages you to work as hard as the motor.

Look out for the battery replacement costs, which can surprise you. You’ll maybe need to replace your battery every three years depending on usage and quality, but despite the high initial costs, it’s much cheaper than petrol!

Electric Bike Motors

Typically, you have a motor attached directly to the centre of the wheel - either a front hub motor or a rear hub motor. Hub motors are usually less-effective on hills compared to crank-drive motors, and often come with more limited gears.

A rear hub motor is great for general use, although if you’re going offroad, a front wheel hub motor has the advantage of givng you ‘all-wheel-drive’ which really helps with traction; a big plus for electric mountain bikes.

There is a third way. The Panasonic drive system is designed to be low and in the middle of the bike which lowers the centre of gravity helping with stability. Since it works with the bike chain, you can have a full range of gears which helps when you’re going up hills.

The Panasonic drive system uses an electric torque sensor which measures how hard you’re pedalling and gives you a boost to match the level of effort you’re putting in without interferring with the chain and causing any kind of drag.

The Science of Volts, Watts and Amps

The easiest way to explain volts, watts and amps is to think of a waterfall. A waterfall has a moving volume of water:

  • Voltage is the speed of the water
  • Amps is the volume of the water moving
  • Watts is the total amount of water cascading over the waterfall over a given time

A huge river could be going over a waterfall really slowly, and still have the same amount of water as a smaller river moving faster. The same works with volts, amps and watts; a huge current (amps) could be flowing very slowly, and still have the same amount of energy as a smaller current moving very quickly.


The voltage of an electric bike will typically be between 12 and 36 volts, which isn’t high enough to give you an electric shock (230 volt mains electricity can kill you on the other hand!). Higher voltages are better because electricity passes far more efficiently than at lower voltages.


Amps (or amperes) are a measure of current. Think of the volume of water moving. You can expect an electric bike motor to work between 10 and 60 amps depending on the model.


Watts are a measure of total power. A small, fast river can have the same “power” as a larger, slow one. Currently, electric bikes are legally limited to 250 watts in the UK, or you’ll need to get a moped licence.

The next chapter will help you decide what kind of electric bike is best for you.

Next: Chapter 3: Choose an Electric Bike

Go back to the main Electric Bike Buyers Guide Contents Page

Return from Electric Bike Parts to Electric Bikes Experts and read the full story

Go to the Next Chapter

  1. Benefits of Electric Bikes

  2. Why are electric bikes the fastest, cheapest and most fun way to get around town?

  3. Electric Bike Parts

  4. What makes a quality electric bike? Do you need to be technical?

  5. Choose an Electric Bike

  6. A quick checklist to consider when choosing an electric bike, and the best piece of advice experts give for choosing an electric bike

  7. Best Tips to Buy Electric Bikes

  8. What are the best places to go and buy electric bikes, and five tips for saving money on your electric bike.

Want more? Buy the Book

David Henshaw of A to B Magazine, and cycling author Richard Peace have co-written an excellent book on the history, best practices and technology all in one handy book. Available on Amazon for a very reasonable price.

Convert Your Bike to Electric

Did you know you can convert your existing bike to an electric bike using a conversion kit? Watch this video where experts argue the pros and cons of conversion kits.

Visit our Trusted Electric Bike Dealers

Wondering where you can go to try out and buy electric bikes? Here's our list of recommended dealers.