Electric Bike Buyers Guide for 2021

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A Comprehensive Electric Bike Buyers Guide for 2021


A lot has changed in the electric bike world since I first became involved in 2016. Motors and batteries are getting smaller, lighter and more integrated to the point where some e-bikes look almost indistinguishable from regular bicycles. There is also more choice than ever, and lower prices have made electric bikes more accessible . In this electric bike buyers guide for 2021, I will go over the basics, so you can make the right decision.

I’m sure most of the readers will know what an electric bike is, but for the benefit of those new to the e-bike world, I will cover the basics.

What is an Electric Bike (and how do they work?)

An electric bike (also known as an e-bike or pedalec) is basically a bicycle that has a small electric motor and battery fitted to provide the rider with assistance pedalling. For me, the e-bike is one of best inventions to emerge in the 21st century, as it enables people of all ages and abilities to start cycling again.

electric bike buyers guide

I live in a very hilly, rural part of Cornwall, in the South West of England and cycling in my area can be incredibly challenging if you are not reasonably fit. I have seen an explosion in the use of electric bikes in my area, and it is a great thing to see so many people out cycling and enjoying the countryside.

In recent years, prices for new electric bikes have come down considerably, which has made them much more accessible for everyone.

Types of Electric Bike Motor

Electric bikes use a small electric motor to assist the rider in pedalling. There are laws governing the amount of power these motors can produce and the speed at which they can produce it.

In the UK, Europe and Australia, the maximum power allowed by law is 250 watts (one third of a horsepower), with a maximum assisted speed of 15.5mph (25km/h). The electric assist can only be activated by pedalling and cannot be operated by just using a throttle.

There are exceptions to the use of a throttle, particularly electric bikes manufactured before 1st January 2016, and retro-fit e-bike kits fitted to used bicycles – the power and speed limit still apply.

In the USA and Canada, e-bike laws are different. The Federal Electric Bike law in the US allows for up to 750w, 20mph maximum speed and a throttle (as long as the bike has pedals). This law varies from State to State. In Canada the legal limit for an electric bike is 500w and 20mph.

There are several key components to the e-bike system, the most important of which are the motor and battery. There are two different types of motor employed in an electric bike – a hub motor and mid-drive or crank motor.

Electric Hub Motor

Electric hub motors have been around for a long time now, but they are still quite popular, particularly on budget e-bikes like the Carrera Vengeance E.

Recent advances in motor and sensing technology have also made them popular on some high-end electric road bikes like the Ribble SLe. The M1 motor (pictured below) is part of the Mahle X35 ebikemotion system, and is found on some very expensive road bikes.


ebikemotion x35 M1 electric hub motor for road bikes

The M1 motor produces around 40Nm of torque, which is low (by mid-drive standards) but the big appeal with this system is the low overall weight – The total system (including a hidden 250Wh battery) weighs just 3.6kg. The Carbon-framed Ribble Sle weighs in at just 11kg, which is about the same weight as a modern steel-framed road bike.

The Suntour HESC hub motor fitted to the Carrera range of electric bikes is substantially heavier, but it is a reliable motor all the same.

Mid-Drive Electric Motor

Mid-Drive or Crank-drive motors (like the Bosch) can be found on many production e-bikes. They are usually integrated into specially designed frames.

A lot of design and technology goes into these motors, and they are manufactured by prestigious names like Bosch, Yamaha, Shimano, Panasonic and Brose.

A mid-drive motor, transfers power to the rear wheel using the bikes drivetrain and gearing. This makes the motor not only more energy efficient, but also produces a higher torque output. This makes mid-drives especially suitable for applications like mountain biking.

decathlon stilus e-mtb

Nearly all modern mid-drive electric bike motors are incredibly sophisticated, for example the latest 4th generation Bosch CX motor has an assist mode that will adapt to the demands of the rider and terrain.

If you are riding on the flat at a steady pace the motor will be giving you a little help in proportion to the amount of effort you are putting in. When you come to a sudden steep climb, and start pedalling harder, the motor will compensate automatically, giving you more power. As soon as the trail levels off again, the motor will also give you less assist.

bosch cx 4th gen

The great thing with the above technology, is it makes the motor extremely efficient, meaning you will get a far greater battery range. I have ridden quite a few e-bikes with this feature, and it makes you feel like you have super strong legs!

Modular Electric Bike Systems

Modular e-bike systems are a relatively new concept and have been pioneered by the German company Fazua. The Fazua Evation electric bike motor is a mid-drive system, that has the primary motor gearbox and sensor located in an enlarged bottom bracket area.

fazue evation ebike drive system complete

The motor drive system and battery are housed in a recess on the underside of the bicycles downtube. The great thing about this system, is it can be removed at any time (apart from the gearbox).

The Fazua Evation has a total weight of only 4.6kg (3.6kg motor and battery + 1kg gearbox). This means you can have an e-bike and regular bike in one!

Bergamont E-Grandurance RD Expert Review

The only compromise with this system, is some riders do not feel it produces enough assist. I have ridden a few e-bikes with this motor, and I personally love it, but it definitely doesn’t have the raw power of the Bosch, Yamaha or Shimano Steps system. The best analogy I can come up with is in full power mode, the Fazua feels like a Bosch in Tour mode (level 2).

I would say this electric bike motor is more suited to someone who already has a reasonable level of fitness, and  wants to keep up with their faster friends on group rides, or maybe as a way to speed up a hilly daily commute.

Pedal Assist Technology

Cadence Pedal Assist Sensor

Pedal assist technology has come on a long way in the last few years. At first, you had a cadence-based pedal assist, which simply measures pedal rotation and starts the motor as soon as the crank starts spinning. These sensors are still used, but usually only on budget e-bikes or cheap electric bike conversion kits.

a typical pedal assist sensor fitted to an electric bike


A cadenced-based pedal assist may suit some riders better, particularly if you have knee problems. As you do not need to exert any discernible force to start the motor, just spin the pedals and away you go! These systems act very much like an on/off switch.

The main downside is reduced efficiency and sometimes the motor can kick in quite suddenly and overrun a little when pedalling stops (which can be a bit unnerving).

Torque Sensing Pedal Assist

Torque sensing pedal assist is usually found on higher quality hub motor electric bikes and all factory produced mid-drive e-bikes.

A torque sensor, measures the amount of force being applied to the pedals, and constantly adjusts the amount of power to compensate for the needs of the rider. The latest, most sophisticated pedal assist sensors can take 1000’s of measurements per second. This makes the transition to electric assist feel seamless, and when you first ride one of these bikes, you feel like a pro!

I absolutely love torque sensing pedal assist, and it is becoming increasingly available as standard on budget hub powered bikes like the Carrera Subway E.


Electric Bike Batteries

The battery is the most important part of the system, as nothing will work without it. In recent years, lithium battery technology has improved substantially, and the energy density of the cells has increased, meaning you can have a relatively small, lightweight battery that will integrate into the bikes frame.

Electric bike battery energy capacity is measured in Watt Hours (Wh) and Amp hours (Ah). To calculate the total energy capacity of a battery you simply multiply the voltage (V) by Ah – As an example a typical 36v 13Ah battery will have a total energy capacity of 468 Wh (36 x 13 = 468).

Most of the big e-bike manufacturers use the Wh figure, so basically the higher the number, the greater the potential range.


bosch powertube 625 battery

So how can you find out your battery’s potential range using the above information? This isn’t straightforward as no two rides are exactly the same,  you will get an approximate range, but that’s it. There are too many different variables to factor in like wind direction, tyre pressures, road surface, rider weight, hills etc.

One of the best battery range calculators, is provided by Bosch. Find out your potential battery range here (calculations based on various Bosch mid-drive motor and battery configurations).

For more information, I have written a separate post – electric bike batteries explained.

Benefits of Riding an Electric Bike

Riding an electric bike has many benefits. Realising that you no longer need to rely on the internal combustion engine and all the associated costs is a very liberating experience.

Then you have the obvious (and proven) health benefits. And I’m not just talking about physical health, but mental health as well. Getting out of your town or city and immersing yourself in the sights, sounds and smells of the countryside can have a very positive effect on your mind. And being able to do this without getting out of breath and sweating buckets is great!

Are Electric Bikes Cheating?

It always makes me laugh when I hear this one. I’ve been told many times, that I’m cheating by using an electric bike, although it’s usually light hearted and comes from a friend or acquaintance who doesn’t even ride a bike!

Riding an e-bike definitely isn’t cheating, unless you’re riding a competitive event with a hidden motor. When I first started riding an electric bike in 2016, there still seemed to be a bit of a stigma associated with it –  ‘e-bikes are for lazy people, blah, blah, blah…’

ebike ridden up a steep hill

In 2020 the attitude to electric bikes has changed dramatically. Electric bikes are now welcome on a lot of cycling club group rides, and are even allowed in some events like Sportives.

I know loads of regular cyclists, who view e-bikes as a positive force in the world of cycling. Not only have they given a new lease of life to the cycling industry, but they have also helped countless people get out of their houses and on to two wheels.

Using an Electric Bike for Commuting

Out of all the great uses I can think of, using an electric bike for commuting is probably one of the best. Picture the scenario: You have a 10 mile commute to work in your town or city centre and this journey usually takes a good half an hour, maybe more due to traffic. Riding an e-bike to work can not only save you a bit of time, but also spare you the misery of being stuck in traffic.

Cycling infrastructure has been vastly improved in a lot of European towns and cities, as local governments try to encourage more people away from cars and onto more environmentally forms of transport.

using an electric bike for commuting

The saving on fuel and other expenses itself can justify the cost of an electric bike. I remember I built an e-bike for a customer a few years back, and he calculated that it paid for itself within 6 months!

There are plenty of schemes across Europe who will help spread the cost of purchasing an e-bike, like the cyclescheme in the UK. These schemes are supported by retailers and employers alike and offer an easy way to buy the perfect electric bike for commuting.

But what about the weather? I here you say. Well, I’ve ridden in excess of 10’000 miles in the last two and a half years (in the UK) in all the seasons, and modern cycling gear does the job of keeping the elements at bay. Read my article on the 9 best tips for riding an e-bike in winter.

Choosing the right Electric Bike

If you’re new to the world of e-bikes, it can be a bit overwhelming with all the choice currently available. Types of electric bike cover the full spectrum of bicycle styles, ranging from road bikes through to mountain bikes and recumbent bikes.

To add to the confusion, the are sub-categories within each type of e-bike, for example – A hybrid bike used to traditionally be a mixture of mountain bike and road bike, but now you have trekking hybrids, urban hybrids, sport hybrids, and so on..

carrera crossfuse review

Another consideration is the type of frame you need. If you have problems getting your leg over a standard bicycle frame, may want to consider a step-thru (or easy-entry) electric bike. These styles of bike have a beefed-up downtube and no top-tube, making getting on and off the bike easy.

Step-thru electric bikes are great because anyone regardless of age or gender can use them. They are especially popular in European towns and Cities.

Cube touring hybrid one 400 step thru review

Electric Bike Sizing

Getting the right bike for your size is an important consideration. The problem with this, is sizing and frame geometry can vary from manufacturer to manufacturer. Another thing to consider is, we are all shaped differently. Some of us have long legs and short arms or the opposite.

If you haven’t cycled for some time, and you aren’t sure of the correct frame size. I would recommend going to your local bike shop to get an idea of the correct bike size for your build.

Types of Electric Bike

Electric Hybrid Bike

Decathlon Riverside 500 electric bike review

The Electric Hybrid Bike is by far the most popular style of e-bike. This is because the word ‘hybrid’ encompasses so many different styles of bike.

At one extreme, you can have a heavy duty hybrid that has beefier forks, chunky tyres and a high-spec components – these are almost mountain bikes (but not quite!) At the other end of the spectrum you have hybrid bikes that are more road orientated. These are often called urban or sport hybrid bikes – they have much lighter frames and drive systems (like the Fazua or X35) and usually look like road / gravel bikes with flat, narrow handlebars.

boardman hyb 8.9e electric bike review

Depending on your intended usage, there is a hybrid for everyone. If you are going to be spending most of your time riding on smooth tarmac, then a road bike orientated hybrid would be ideal. If you are riding rough country lanes, and gravel tracks, then you might want something more robust and with decent front suspension.

Check out 10 of the best electric hybrid bikes under £3000

If you are looking for something for the daily commute, or touring, then a bike already fitted with mudguards, pannier rack and lights would be useful.

To compare prices and specifications of nearly 100 different brands and model of electric hybrid bike, visit my sister site ebikepricecomparison.com

Electric Mountain Bike

decathlon stilus full suspension electric mountain bike

Electric mountain bikes come in two categories (thankfully!) – hardtail or full-suspension. Electric mountain bikes or e-MTB’s for short are also incredibly popular with consumers.

The reason for their success is rugged versatility, and adaptability. You can quite easily use an electric mountain bike on the road, and just fit some road-friendly tyres, and maybe a pannier rack and some mudguards.

I think of e-MTB’s as the SUV of the ebike world! If you get a decent one, you can ride it practically anywhere, whereas hybrids do have their limitations.

cube reaction ex625 electric mountain bike in green with gumwall tyres

I know a lot of riders who choose to use an electric mountain bike for their daily commute, simply because the wider tyres and longer suspension travel help take the sting out of potholes and road debris.

Electric mountain bikes also have their extremes. At one end of the pricing scale you have bikes that are sold and marketed as e-MTB’s, but the last place you would want to take these bikes is anywhere near a mountain! At the other end of the price range, you have pro spec electric mountain bikes that are just as capable as their non-assisted counterparts.

Ultimately it depends on what you want from your e-bike. If you’re a beginner to off-road riding, then it’s pointless going out and spending 1000’s on a top of the range full-susser. On the flip side, if you’re an experienced mountain biker then you are going to want to spend a bit of money to get an electric mountain bike that can handle the abuse.

To compare prices and specifications of over a 100 e-MTB’s, check out my sister site: ebikepricecomparison.com

Electric Road Bike

Electric road bikes are relatively new to the e-bike world. Giant were the first major company to recognise the demand for sporty, drop handlebar electric bikes with their Road E+ range of bikes.

ribble sle electric road bike

More recently there have been some interesting developments in e-bike technology that has allowed for some absolutely amazing e-road bikes.

The Fazua Evation system as mentioned earlier in this article is one such innovation, and also the Mahle X35 ebikemotion system (as fitted to the Ribble above).

boardman adv 8.9e electric bike review

Both of these electric bike motors have been specifically designed with the road cyclist in mind. Most electric road bikes don’t even look like e-bikes. They’re relatively light (compared with other e-bikes), and they can be easily ridden with the motors switched off.

I have ridden several electric road bikes, using both drive systems, and apart from the slight weight penalty, you don’t really feel like you’re riding an e-bike with the motor switched off.

E-road bikes are generally aimed at the road cyclist who needs a bit of assistance once in a while, or maybe rides with some ridiculously fit friends and struggles to keep up with them on hills.

They can help if you struggle with endurance over longer distances, and are also a great way to get to work faster, particularly if you have a couple of steep climbs on your way.

I think e-road bikes are great. They are helping people get back into the saddle and are a great training tool, especially if you have been off your bike for a while due to an illness or injury.

Compare prices and specifications of nearly 50 different e-road bikes on my sister site ebikepricecomparison.com

Electric Cargo Bike

kona electric ute review

The Electric cargo bike is the fourth and final category in this electric bike buyers guide.

E-cargo bikes are designed to carry loads that you wouldn’t fit on a regular bike. This makes them incredibly useful for a multitude of tasks. You can use them for shopping trips, taking a couple of young children to school and even work as a bicycle courier.

tern gsd s10 folding electric cargo bike

If you live in an urban area, with good cycling infrastructure, you could quite easily replace your car with one of these! I have ridden both models above, and they ride like normal bikes.

I think electric cargo bikes are great, and if you need an all-purpose e-bike that can cope with the extra weight and volume of goods (or little people), then they are indispensable!


So, there you have it. My electric bike buyers guide for 2020. If you have any questions or need any advice buying an electric bike, please feel free to leave a comment below and I will get back to you (usually within 24hrs).

E-Bikes are great fun, and I believe they have the capacity to change peoples lives for the better. No more struggling on hills, no more worrying about turning up for work sweating buckets!

When electric bikes first became available, many people said they were a passing fad. The last couple of years have shown they are definitely here to stay.

Ride safe!


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Passionate E-Bike advocate and enthusiast. 5 years experience converting bikes for customers primarily using Bafang and Tongsheng electric bike motors.