Best electric bike conversion kits: Power up your ride

Whatever your reason for wanting pedal assistance – whether it makes cycling more accessible to you and your family or you think you'll have more fun with that boost  –  the e-bike market is vast and often requires a large upfront cost. So if you're struggling to find an e-bike that suits you, and already have a bike at home that's suitable for conversion, then you might consider choosing one of the best electric bike conversion kit instead.

Whichever option you go for, there's no denying that the best electric bikes make it easier for riders to explore and experience different terrains and riding environments. Plus they offer a cheaper and greener form of transport to get you from A to B at a higher pace for less effort than a conventional bike, which is especially beneficial for those who are commuting or using them for work. The best electric bikes for commuting can make for a speedier and altogether less sweaty cycle to work, not to mention the money saved when compared to soaring fuel or rail fare prices. 

But what if you're not sure about which option to go for? If you're weighing up an e-bike vs an e-bike conversion kit, consider whether you already have a bike that you love riding. Converting it means you can continue enjoying the same ride quality while introducing you to a new world of electrically assisted fun. 

To make all these decisions easier for you, we've outlined in our buyer's guide lower down this page the key things to consider when fitting an electric conversion kit to your own bike, including the various motor and battery options available. We've tested as many as possible in real-world riding conditions, assessing how easy they are to fit, and what kind of electric assistance they provide. 

So here are our findings and our roundup of the best electric bike conversion kits you can buy right now.

Quick list: Best e-bike conversion kits

Best electric bike conversion kits available now

Best e-bike conversion kit overall

The first on our list is one which really impressed us. The Cytronex electric bike conversion kit is extremely well thought-out, with great specs and top-notch engineering. You only need Allen keys to install it, it comes with an accompanying app to offer up basic diagnostics, and once it's set up it's a breeze to operate.

When purchasing, you'll go through a thorough process, which can feel a bit over-complicated, but in doing so it means the actual conversion is a straightforward one. We tested out the Cytronex on a Brompton T-Line and found it delivered smooth and intuitive power. Plus, our hands-on time with it leads us to believe it's strong and durable enough to use for commuting.

While it's pricier than some of the options listed below, one thing to consider is that it comes from a UK-based company that offers comprehensive customer support. You can pay less for a Bafang kit on Amazon, but buying direct from a company that can support you if anything goes wrong, makes it a smarter choice in our view.

For an in-depth look, check out our Cytronex review.

Best budget option

If you're on a tighter budget than the Cytronex or Swytch allow for, then as we mentioned above, getting a kit from Chinese manufacturer Bafang may be a better option. Plus, if you like the idea of an electric bike conversion kit but just don't want to have to deal with the added complexity of a mid-drive setup, then the Bafang Front Hub kit makes things much easier. 

Like the mid-drive system listed below, the Bafang Front Hub Motor kit covers everything required and gives tons of spec choices. We started by choosing our wheel size and display preference, then added the battery size and shape we wanted. 

We did find it more of a time investment, given the installation process was more complex than the Cytronex, Swytch and Rubbee, but this did allow us to achieve a powerful, high-quality set-up.  

To find out more about how we got on, read our Bafang Front Hub Motor review.

Best for easy installation

For easy installation, the Zehus system is hard to beat. Everything is enclosed in the rear hub, including the battery, so all you need to do is unbolt your current wheel and replace it with a motorised wheel. 

Better yet, there's decent range and at 3kg the motor-plus-battery weight is competitive. It's also a rare electric bike motor option that has regenerative braking, so you'll get a battery boost when riding downhill.

Charging is via a port in the axle and control is via an app, so there's no wiring needed, although Zehus does sell a separate wireless handlebar controller.

In the UK, the Zehus system is sold by Quella Bikes built into its rear wheel. That's rim brake only and singlespeed, so it needs singlespeed-style rear-facing dropouts to tension the chain, although there's a wide range of colours available for the deep alloy rim.

Blend in - it just looks like a normal bike

One of the easiest ways to convert a bike to electric is to swap out the front wheel for one with a front hub motor. This is the approach that Swytch takes, but there's more to a good system than just a motor and battery. From our time testing and reviewing it, it's clear to us that the team behind Swytch has considered the whole system in its design. 

The battery mounts to the handlebars and we found that a really useful detail. It is easy to disconnect and take it away for storage, so it doesn't get stolen when you are out and about, or to lighten the bike when, for example, it needs to be carried up a flight of stairs. 

The 2022 Swytch system, which we tested, makes use of a neat handlebar-mounted LCD display instead of the buttons on the battery it had before. There's also a cadence sensor that attaches to your bike. It's a well-thought-out system that looks and feels great. 

As well as the Air handlebar-mounted battery that we tested, there's a higher capacity Go battery now available. This can be mounted either to the bars or to the frame and adds greater battery capacity and potential range, but at the expense of extra weight. Unlike the Air, it can't be accepted on flights due to its charge capacity. 

To read all about how it works, and find out why we gave it four stars, take a look at our Swytch review.

Easy and plentiful configuration

Bafang is one of the largest and best-known electric bike motor companies in the world. It's been around since 2003, and in 2014 Bafang established a US arm to better support the US market. There are many well-known electric bike companies sourcing its components, so if you want to get in the game and source your own electric bike components, you won't go far wrong with Bafang.

This particular option covers everything you need for a mid-drive motor conversion kit. As long as the bike you are starting with has a bottom bracket sized between 68 and 73mm, this kit will work. From there you can choose the front chainring size, the battery size, and what display works for you.

If you're not sure whether or not a mid-drive motor conversion is what you need (or what other drive options there are), head down to our FAQs at the bottom of this article for an explanation of all the possibilities you can choose from.

Best for bike shop support

If you like the idea of a mid-drive system and you want it to have torque-sensing pedal assist then you've got a few choices. The challenge with a system like that is complexity. For some people, it's no big deal to take apart a bottom bracket, but for others, it's a slightly more intimidating prospect. 

The Pendix system does the same thing as other kits but there is a dealer network that handles sales, support, and installation. This comes with an extra cost attached, but the benefit is that you can feel comfortable that the system is correctly installed and ready to ride.

Best for natural ride feel

The most natural-feeling electric bike conversion kits are going to be those with a mid-mounted motor. If that works for you and you also like the idea of doing some pedalling, then the very best is a mid-mounted motor paired with a torque sensor. 

Instead of the system knowing you are pedalling and adding power, as with cadence-based systems, a torque-based system adds a percentage of the power you are putting into your pedalling. The maximum torque available on this TongSheng system is 80Nm but depending on your chosen assist level, that 80Nm will add between 36 and 300 per cent to your pedalling power. 

To keep it simple, think about it as an amplifier. If you pedal harder you go faster, just like a normal bike, but now your muscles have extra support, so you can go further with less effort.

Best for non-technical set-up

Gboost uses a friction drive system under the bottom bracket, with a compact motor that's clamped in place with a single bolt and turns your rear wheel via the  tyre. The battery sits on your down tube and there's a thumb lever on the handlebars to engage or disengage the motor. Keep Gboost engaged when going downhill and it will recharge the battery.

There's a range of three battery sizes available giving a range claimed at up to 90km. Gboost also sells two motor options, with the more powerful providing assist, where legal, up to 32km/h.

The disadvantages of a friction drive system, however, are likely to include higher tyre wear and the risk of slippage against the tyre in wet weather, although Gboost says that its patented pressure regulator avoids this even in the wet. 

Best removable option

The Skarper motor/battery unit fits to the left chainstay of a disc brake bike and powers it through a beefed-up replacement disc rotor. It's designed to be easy to remove and take with you, avoiding the risk of theft.

Swapping your disc rotor is relatively quick, although you'll need specialist tools: either a Torx screwdriver for six bolt rotors or a Centerlock tool for Centerlock rotors. There's a retainer to bolt onto your chainstay and a pedal sensor to add.

The motor and battery together weigh 4.5kg and there's another 600g added to your bike weight by the rotor. Skarper reckons you can get up to 50km from the drive if you select the Eco mode, with a full charge taking 2.5 hours and 30 minutes charging adding up to 15km of range.

Types of e-bike conversion kits

E-bike conversion kits fall into three main categories, as we'll explain.

Mid-drive conversion

The best electric bikes tend to be mid-drive because this delivers the most natural ride feel, and the same is true of conversion kits. The weight sits low in the frame and the power gets applied to the crank for a more natural power delivery sensation. The only downside is pricing and packaging, plus it can be complex to set up yourself. Different standards make it challenging to figure out exactly what you need, as well. The Bafang Mid Drive Motor Kit is an example of this.

Electric bike wheel conversion

Swapping either a front or rear wheel for one with a hub-mounted motor is a good balance. The conversion process is very simple and, depending on how the battery mounts, the weight distribution can be quite good. Powering the wheel does change the way the power delivery feels, and making the front wheel heavy can affect the handling of the bike. If mid-drive seems overwhelming, this is an excellent option. Cytronex and Swytch are examples of this.

Friction drive conversion

A friction drive e-bike conversion means there is a roller that pushes against the wheel's tyre. So when the roller turns, the wheel turns. It's not the most efficient strategy, but it's simple and it works. There is very little involved with regard to making it work but, at the end of the day, it doesn't work as well as other systems out there. Gboost uses a friction motor.

Best electic bike conversion kits summary

How to choose the best electric bike conversion kit for you

If you're interested in fitting an electric bike conversion kit to one of your own bikes, you should consider your own personal requirements first and do plenty of research. You're in the right place, as this guide will help you with a lot of that. 

Before anything, familiarise yourself with the laws regarding e-bikes in your region. Stats such as power output, throttle assist and maximum speed may be regulated by law.

Then you may want to choose a conversion kit based on your range and journey needs. If you live in a hilly city, for example, you may want something with a little more top-end power. Lastly, check whether or not the system is compatible with the bike you plan to fit it onto. If you don't feel comfortable doing this yourself, think about getting a quote for installation from a reputable bike shop.  

How do we test the best electric bike conversion kits?

Like all of our buying guides, our advice is gained through countless hours of using products in the real world, often back to back against their peers to compare them, but ebike conversion kits have an additional need. 

If a conversion kit is too tough to install, it will cost you more as you seek the help of a professional. Therefore, with our testing, we also spend time fitting the kit to the bike in the first place, judging how long it takes and how intuitive it is. 

Once that's done, we do the real-world testing, judging the range, the ease of use and the durability of the product in question. 

There's more detail of our testing methods in our guide to how we test.

Individuals carrying out the instructions in this guide do so at their own risk and must exercise their independent judgement. There is a risk to safety if the operation described in the instructions is not carried out with the appropriate equipment, skill and diligence and therefore you may wish to consult a bike mechanic. Future Publishing Limited provides the information for this project in good faith and makes no representations as to its completeness or accuracy. To the fullest extent permitted by law, neither Future Publishing Limited, its suppliers or any of their employees, agents or subcontractors shall have any liability in connection with the use of this information, provided that nothing shall exclude or limit the liability of any party for personal injury or death caused by negligence or for anything else which cannot be excluded or limited by law.