Electric bike conversion kits 2023 – Give any bike a boost
Why pay for a brand new e-bike when electric bike conversion kits can easily give a boost to the bike you already have?
E-bikes have enabled people who need or want some pedal assistance to broaden the range and scope of their riding while making it easier than ever to choose sustainable and greener transport methods.
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, then you might consider an 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 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.
Best electric bike conversion kits available now
You can trust Cyclingnews
Our experts spend countless hours testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.
Reasons to avoid
A thorough purchase process ensures the product is easy to install, but it’s complicated so can take time
The first on our list is one we reviewed very recently and 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.
Reasons to avoid
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 have 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.
To read all about how it works, and find out why we gave it four stars, take a look at our Swytch review.
Reasons to avoid
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.
Reasons to avoid
There are a number of simple install options on the list but the Rubbee X takes it a step further. We were really impressed with how easy it was to attach the mount to the bike’s seat post and then click the unit into the mount. There’s no need to change the wheel like the Swytch system. Here the motor sits on top of the rear tyre and a roller pushes it around from above. There’s also a wireless cadence sensor, as this is a cadence-based system that adjusts based on pedalling cadence, rather than torque.
There is a slick-looking 250-watt motor with a single battery in the base kit. If the 10-mile range of the base unit feels a little constricting, another battery can be added to double the range. Rubbee also has a handy phone app that can be used to change assistance modes.
We’ve spent some time testing it out, so why not check out our Rubbee X e-bike conversion kit review for more details.
Reasons to avoid
Bafang is one of the largest and most well-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.
Reasons to avoid
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, such as the Rubbee X cadence-based system above, a torque-based system adds a percentage of power. The Max 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.
Reasons to avoid
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.
Types of e-bike conversion kits
Friction drive conversion
A friction drive e-bike conversion means there is a roller that pushes against the wheels 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. The Rubbee X is an example of a friction drive conversion kit system.
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.
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. 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.
Do all electric bike conversion kits come with a battery?
The short answer is ‘not always’. You need a battery, of course, so when browsing online, make sure the kit you select has one included. Since not all kits include a battery, you might find yourself browsing through options and landing on something at an unbelievable price. If that’s the case, double check it’s got the battery included. If not, then it is possible to source the battery yourself, but be sure about what you are getting.
How fast do electric bikes go?
This is hard to answer specifically as electric bikes are, on the whole, designed to assist pedalling rather than replace it, and it is the same with electric bike conversion kits. The measurement of the power of the motors is in wattage and, in effect, the higher the wattage of the motor, the faster speeds it will be capable of achieving.
However, the speed is often limited as a result of country-specific regulations. In the UK, the assistance an e-bike can legally provide is up to 25kmph (15.5mph) and, after that point, the bike can go faster but without any assistance from the motor. Anything faster would not meet the UK’s electrically assisted pedal cycles (EAPC) criteria, would be classed as a moped or motorcycle, and need to be licensed and taxed appropriately. The laws are different depending on the country, with the United States, for example, allowing more powerful motors – although individual states have their own legal frameworks.
Which bike is best for electric conversion?
You should consider the condition and componentry of your old bike. With an electric motor dramatically increasing the torque, using a low-quality or worn drivetrain will result in poor performance, with shifting being affected and the chain skipping or even snapping. Another important consideration is the brakes, adding the extra weight of an electric bike conversion kit and increasing potential speeds will put more stress on the brakes as they try to curtail momentum. We recommend choosing to convert a bike that has disc brakes as they will provide far better braking performance.
I haven’t heard of a lot of these brands, are they safe to use?
In the world of electric bikes, there are a lot of brands you may not have ever heard of. There’s been a boom going on for a while, so new brands are popping up all the time. Not only that but Europe, and especially the US, are playing catch up to the trend of electric bikes. You will probably stumble across a lot of unfamiliar brand names.
Consumers have a tendency to look away when they encounter a new brand. It’s not a bad strategy most of the time but in the electric bike world, including conversion kits, you’ve got to be more open than that. If you aren’t open to names you’ve never heard of you will find the options limited. A lot of the names you may come across are unfamiliar to you but have a solid history behind them.
That doesn’t mean you should go forward blindly. Do your research and be careful with your money, like always. The only thing that might be different is the need for being open to new companies. At the very least be willing to look a little deeper, read reviews, and do some research. The brand you’ve never heard of might actually be a well-established brand from a different part of the world.
Is converting my bike to an electric bike worth it?
There are plenty of reasons to install an electric bike conversion kit to your current bike, but the question of whether it’s worth doing is going to depend on your circumstances.
For many kits, once the installation has been completed, it will be an arduous task to remove it again, so one of the questions you’ll need to ask yourself is whether or not you want to retain the ability to use the bike as a ‘normal’ bike. If you expect to be flitting between the two (powered and non-powered) then a kit that can simply be folded out of the way – like the Rubbee X – might be perfect, but you might instead prefer to simply buy a second bike for the convenience.
The second question is to assess the state of your current bike. If you don’t yet have one, then the cost of buying a bike, buying an electric bike conversion kit and then fitting it, is probably not going to be worth the time, effort, or money involved. However, if you have a bike that is in reasonable repair, then the value for money – and effort – will be greater.
Beyond the financial and practical element, the question of ‘is it worth it’ will also depend on the amount of use you get out of it. E-bikes can be incredibly motivating and enjoyable and if converting your standard bike to electric helps you to ditch the car on a regular basis, then the answer becomes clear.
If you want a monetary answer to this question, then there are ways to work out whether the investment is worth it. Take a moment to think about your current car usage and work out the cost per day/mile, including fuel, parking and running costs. Try to work out how many journeys, days or miles you will use the bike for after it is converted. Once you know this, you should be able to work out the reduction in car running costs per mile/day and, with that, you should be able to work out how many miles/days it will take for the electric bike conversion kit to pay for itself.
Should I just buy an electric bike instead?
Remember to consider all your options. You have a bike in the shed you haven’t touched for many years and it seems like a perfect candidate for conversion to an electric bike. It might be, but it’s also just as possible that it’s a better candidate for a sale. Sometimes it’s better to take the money from that sale and put it towards an electric bike someone else built.
As with anything, consideration for the end-use during design and build can have advantages. A quality electric bike conversion kit might end up being very close to the price of a complete electric bike. If a company starts with a clean slate and designs an electric bike, it’s easier to keep costs low and integration high. Really consider why you are thinking about converting your bike and whether it makes sense compared to what’s on the market. In some cases, it will but in others, it won’t.
Are electric bike conversion kits legal?
The kits themselves are entirely legal, and fitting them to your bike is equally so. However, the question of legality arises in relation to where you then plan to use your newly powered electric bike. The answer will vary hugely, depending on where in the world you’re based, and which kit you choose.
For example, in the US, there are different classes of e-bikes that vary by their power, speed limitations and whether or not they have a throttle, and each class is subject to different rules. Things are a little more simple elsewhere, with the UK stating that anything with a speed limiter of over 25km/h is classified as a moped, while anything up to 25km/h (15.5mph) is classed as a bicycle.
Before you complete any purchase, make sure you have an understanding of the local laws that govern electric bikes, which is where our guide to e-bike classes comes in handy.
How do you install an e-bike conversion kit?
Sadly, there is no single and simple answer to this question. Each electric bike conversion kit works in a different way and therefore fits onto your bike in a different way too.
The most simple options are the friction-drive kits, such as the Rubbee X, which place a roller onto your rear tyre. In the example of the Rubbee, you simply need to mount the device onto your seat post, with the roller placed against the tyre. However, more complex systems require the removal of drivetrain components and wheels, and the installation of wiring. These are far from impossible, but they may require some tools and a bit of patience.
How much does an electric bike conversion kit cost?
will depend very much on the conversion kit in question. Some are available for as little as £250 (350), while the more high-spec and integrated kits can fetch as much as £750 (900).
Will a bike shop fit my electric bike conversion kit?
It’s understandable that you might not want to take on the arduous task of fitting your electric bike conversion kit yourself. You might not have the tools, the know-how, the confidence, or simply the time to invest. Luckily, almost all bike shops will be happy to fit it for you.
Some systems, such as the Pendix kit listed above, are only sold via physical stores and the fitting is sold as part of the overall package. However, with kits bought online such as the Bafang kit, the shop will charge you for the time it takes, which will add to the cost of the overall conversion. In our opinion, knowing that it’s been done correctly and safely is worth spending extra.
Some bike shops or workshops also may refuse to install a conversion kit to a bike they consider unfit for purpose or potentially unsafe. If you plan to have your local shop fit a kit it may be worth consulting with them on the job first to make sure they are happy to do it for you.
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.
How to Charge an E-Bike for Maximum Battery Life
From safe charging to the longest possible lifespan, here’s everything you need to know about your electric bike’s power source.
If you bought a bike in the last couple years, chances are good it’s an e-bike. Electric bicycles are the fastest-growing type of bike in the U.S. today; in 2021 they surpassed road bikes as the third biggest category of bikes overall and in 2022 e-bike sales were over 800 million. E-bikes still outsell electric cars, and for good reason. The lightweight electric motor on an e-bike gives a powerful boost to all kinds of riding, especially utility cycling like commuting and errands. (Plus, there is a nice tax incentive for some e-bike riders.)
At the heart of that system is a powerful lithium-based battery. Taking proper care of that battery and knowing how to properly charge it is key to safely getting the best range and long-term battery life. Here’s what you need to know about charging your e-bike battery.
Safe charging basics
You should charge your battery inside, on the proper charger, and with the motor system powered off, says Kunal Kapoor, senior manager for quality and compliance at Bosch, a leading supplier of e-bike motor systems. While e-bike motors, batteries, and wiring are weather-resistant, “chargers aren’t intended for outdoor use,” he notes.
Using the proper charger is primarily a safety issue. With a modern lithium battery, Kapoor continues, when the battery signals it’s ready to accept a charge, “the battery monitoring system in the charger makes sure that the temperatures inside the battery are optimum to receive the charge,” and shuts off if needed. An off-brand charger—even rated to the same output—doesn’t have all the features of that battery management system, so current can flow to the battery even if temperatures rise, which is a fire risk.
The risk of battery fires is low, but Kapoor recommends people not leave batteries unattended while charging. You can leave the battery on the bike to charge or take it off, as long as it’s not sitting on or near flammable stuff (like the spare gas can in the garage, for example). If you’re looking at lower-priced e-bikes with house-brand or unbranded motor and battery systems, make sure the battery and charger carry a UL 2849 certification stamp from Underwriters Laboratories. This is the industry-wide standard for safe electric systems and battery charging for e-bikes. Some bike shops won’t work on e-bikes with motor and battery systems that lack this stamp, citing fire risk when left overnight in the store.
How to optimize battery range and lifespan
Let’s start with some definitions. Range is essentially runtime: how long a battery will last on a single charge, expressed in miles of riding. Range, even on the same bike, will vary; a flat commute to the office with just a light backpack will see better range than a fully loaded uphill ride home from Costco. Most e-bikes today get between 25-75 miles of range, depending on these factors.
Lifespan is how many times a battery can be discharged and recharged before it starts to lose significant capacity. When capacity starts to dip, you won’t notice less power while riding, but you will see range start to shrink. A common lifespan benchmark for e-bike batteries is 500 “full” discharge/re-charge cycles (if you use half the battery capacity and recharge, that’s half a cycle), which works out to about three to five years of normal use before capacity begins to drop noticeably.
Even though battery range and lifespan aren’t the same thing, they are linked, and actions that reduce range will also, over time, shorten lifespan. A big culprit, Kapoor says, is running the motor hard, like leaving it in Boost or Turbo mode all the time, which means a ride of a given distance relies progressively more on motor power than at lower assist levels. You’ll run the battery through charging cycles more quickly, which will shorten its life.
A less-obvious factor that strains motors and batteries is pedal cadence. Most e-bike motors are optimized for efficiency around a 70-90 rpm pedaling cadence. You can lower efficiency by pedaling too fast (Bosch motors, for instance, max out at 100-120 rpm depending on the system). common is sub-optimal efficiency from pedaling too slowly in a large gear. This is the same as “lugging the engine” in a car; whether gas or electric, the motor works harder. “Choose your gears wisely,” says Kapoor, to stay in that 70-90 rpm sweet spot.
Mistakes that kill your battery
When you buy a new e-bike, you should charge the battery to full before riding it because it’s likely been inactive for a while. But lithium batteries do not have “memory;” that is, they do not need to be fully discharged and fully recharged every time to hold their full capacity. In fact, it’s best if you don’t run a battery to zero, says Kapoor. “If you let the battery deplete completely, that may permanently damage it,” he says, and it will never recharge to its full original capacity.
If you’ll go a few weeks or more without riding the bike, store it (or at least the battery) in a dry, room-temperature space with the battery between 30-60 percent of full charge, says Kapoor. That’s the most stable level for long-term storage, and will lower the chance of a deep discharge that would damage your battery. Don’t leave your battery plugged in to the charger for long periods. It’s not necessary, and can create a short discharge/recharge cycle that will eventually reduce capacity. If you go long periods without riding the bike, check the battery charge monthly and partly recharge when it drops below 30 percent.
Lithium batteries are less affected by cold weather than other types of battery and you shouldn’t see reduced range while riding unless the temperatures are truly arctic. But researchers at the Department of Energy recently found storing lithium batteries below freezing for longer periods can damage part of the battery’s cathode, which will reduce its capacity. Lithium batteries also won’t charge effectively in cold temperatures. If you store your bike outside or in an unheated space and live in an area with sub-freezing temps, says Kapoor, bring the battery inside when not in use.
Also, keep your battery protected from extreme heat, like sitting next to a sunny window or a hot car. Excess heat can raise battery temperature enough to damage its components; in an extreme situation, it can contribute to what’s called thermal runaway, where a battery enters an unstable, uncontrollable self-heating state that can result in fire.
You don’t need to recharge after every ride. Topping off your battery sounds Smart, but over time it will reduce capacity more quickly. If you get 50 miles of range from a charge and ride 10 miles a day, you only need to recharge every three to four days.
When it’s time to replace
Even if you take great care of a battery, over time it will lose capacity. You’ll notice this on your bike’s range estimate on the controller unit. Capacity is a primary indicator of the health of a battery, so if you notice your range dropping to 70 percent or less of what it was when your bike was new, that’s a sign to start planning a replacement. If your battery is less than two years old and is well under original capacity, it might be a warranty claim (terms vary by manufacturer).
If it’s not a warranty issue, the decision on when to replace is personal preference, says Kapoor. “If you got 50 miles (of range) out of the battery originally and let’s say now you get 40, I wouldn’t classify it as ‘end of life’ if you can live with that 40-mile range,” he says. A battery with reduced capacity should still be safe, Kapoor adds.
Always purchase a name-brand replacement for your battery. Just as batteries and chargers should be paired, batteries and motors are designed to work together. And, says Kapoor, never try to repair a damaged battery or let someone else do it. Despite guides that claim you can, this is not just corporate greed or legal butt-covering by manufacturers. While e-bike batteries are almost always made from standard 18650 cells that are widely used in various products (even electric cars), those cells have a variety of different chemistries, capacities, and amperages, and that’s before we even get into connecting a string of them and repackaging the battery in the housing. The slightest mistake in any of that increases fire risk. If you need a new battery, just buy one.
Dealers that sell your brand of bike can order you a direct replacement for that bike or motor brand. Costs vary depending on battery size and brand, but plan on spending 400-800 for a new unit.
A dealer can also recycle your old one. A new program from Call 2 Recycle offers free e-bike battery recycling (paid for by bike and motor brands) through partner shops in almost every major city and many smaller ones. No participating dealers near you? Request an easy DIY shipping kit online.
Why recycle? Even a spent battery contains raw materials that can be re-made into fresh ones, at moderately less energy cost and less environmental damage than producing from virgin materials. Spent lithium batteries also have a fire risk in landfills and can leach toxic metals and other chemicals into the soil and air.
In case of fire
Though rare, battery fires do happen. If your battery gets hot to the touch while charging, unplug the charger from the wall immediately. If you can, put the battery in a metal container like a bucket (better yet, one filled with sand) away from anything flammable.
But if it’s not safe to handle, call 911 right away and tell the dispatcher that you have a lithium battery fire, which requires different firefighting methods than conventional fires. Don’t pour water on a battery fire; water and lithium react to produce hydrogen, which is highly flammable. A standard fire extinguisher may help, but in the event of a fire, special tools may be needed.
How to convert a bike to electric power | Electric bike conversion kits explained
The best electric bike conversion kits will enable you to add a motor to your existing bike simply and relatively cheaply – at least compared to the price of buying a whole new electric bike.
There are an increasing number of ebike conversion kits out there, and they’re getting more sophisticated and easier to install on your bike, making for a practical alternative to a new purpose-built electric bike. An electric bike conversion kit will include the motor to drive you along and the battery to power it. It also needs to include the apparatus to control the power output level. This usually takes the form of a bar-mounted display.
In addition, a kit will include sensors to detect how fast you’re travelling and your level of pedal input to ensure the power supplied matches your needs. We’ve tested a few electric bike conversion kits here at BikeRadar, but there are lots more we’re yet to try. A full test of the best electric bike conversion kits is in the works – stay tuned. If you want a more detailed explanation of the different types of kit available and things to consider when purchasing an electric bike conversion kit, then head to our explainer further down the page.
Best electric bike conversion kits 2022: our picks
Swytch electric bike conversion kit
Swytch says its electric bike conversion kit can convert any bike into an electric bike. Stan Portus / Our Media
- Pros: Very compact; easy to install; variety of range options
- Cons: 100mm threaded front axle only; not compatible with thru-axles
London-based Swytch makes a conversion kit that, it says, is the lightest in the world at 3kg total weight. It can convert any bike into an ebike.
The kit includes a 40Nm brushless hub-based motor that comes pre-laced into a replacement front wheel. The lithium-ion battery pack connects to your handlebars and also acts as the system controller and LCD display.
There’s a crank-mounted cadence sensor, and that’s all you need to fit to your bike to get going.
There’s a Brompton-specific kit available too, with an adaptor for the Brompton’s front luggage mount.
Depending on the range you want, there are three sizes of battery pack available, which provide a claimed range of 35km, 50km or 100km.
Swytch has recently unveiled an even more compact kit with a.sized battery that weighs just 700g and, Swytch says, gives 15km of range.
Cytronex electric bike conversion kit
Cytronex makes electric bike conversion kits for Bromptons, as well as standard bikes. Russell Burton / Immediate Media
- Pros: Clever sensor tech; decent range
- Cons: Not much onboard info on battery level and range
Weighing between 3.2kg and 3.6kg, the Cytronex ebike conversion kit is another front-wheel conversion to house a hub motor, but in this case, the battery is designed to fit in a standard bottle cage.
We tested the kit on a Cannondale Quick hybrid and reckon that conversion takes around 30 minutes. The charge level is displayed via LEDs on the battery, which also houses the system controller. We got up to an impressive 48 miles on a charge.
We’ve also tested the kit on a Brompton P Line lightweight folder, where the total weight undercut the C Line-based Brompton Electric. Fit it to a C Line and it’s also cheaper than the Brompton Electric.
Electric bike conversion kits: different types explained
Electric bike conversion kits come in styles to suit all types of bike. Russell Burton / Immediate Media
There are a number of ways to electrify your existing bike for assistance up those hills: you can fit a powered wheel, either front or rear; you can attach a drive unit to the bottom bracket; you can fit a motor above the rear wheel and drive it via friction; or, most sneakily, you can conceal a motor in the seatpost.
Whether you ride a hybrid, mountain bike, road bike or even a folder, tourer or gravel bike, it should be possible to convert your bike.
Many can even be fitted by a competent home mechanic if you’re feeling handy and have an afternoon spare.
So, what are your options? Let’s take a look at the different ways to convert your non-assisted bike into an electric bike.
Powered ebike wheels
The Swytch is a good example of a readily available universal electric bike conversion kit that uses a motor at the front hub. Swytch
Fitting a powered ebike wheel is probably the most practical option for many people.
A powered ebike wheel is built around a special hub that contains a motor. This is usually powered by a separate battery.
This sounds simple, but the main downside is that it adds rotating mass to your bike, which feels harder to accelerate than non-rotating mass.
There’s a steady stream of front- and rear-wheel conversion kits on Amazon and eBay, all looking suspiciously similar, priced from around £150 and with names you’ve probably never heard of.
Be wary of systems controlled by a throttle (also called ‘twist-and-go’) though. Legally, they’re classified as electric motorcycles rather than ebikes, and need to be taxed and insured. Take a look at our guide to ebike laws for more information.
Rear-mounted friction drive ebike conversion kit
Readers of a certain age may remember earlier incarnations of these in the 1980s/90s: a box that sits on your rear wheel and powers it via friction with a rubber flywheel driven by a motor.
The idea hasn’t gone away, and lives on in devices such as the Rubbee, which promises bolt-on electric assistance for nearly any bike.
Rubbee’s base model has a claimed weight of just 2.8kg, with a 16km range that can be extended up to 48km with the top-spec, 4kg version.
It works with any wheel diameter between 16in and 29in, has an integrated carrying handle and clips on and off your seatpost. start from €579.
Concealed ebike conversion kit
The Vivax Assist hid a motor in the seat tube of the frame and applied power directly to the axle of the crank. Vivax
Now we come to the low-key way to do it – hiding a motor inside your bike so no one knows it’s there.
The Vivax Assist was the best-known device for doing this, although the company has now ceased trading. It’s the system that was used by Belgian cyclocross pro Femke Van den Driessche in 2016 to power her way to victory in her home championships. She was found out at a subsequent race, got a six-year ban and quit racing.
Vivax Assist may be no more, but we reckon this idea still has legs – at least for the budding cyclocross cheat.
Mid-drive ebike conversion kit
eBay and Amazon are awash with mid-drive motor electric bike conversion kits like this one from TongSheng. TongSheng
Many commercially available ebikes are powered with motors mounted around the bottom bracket, near the pedals.
These have the advantage of placing the weight low down on the bike, making it more stable.
This isn’t just a ready-made option though – you can also buy aftermarket conversion kits with mid-drive units.
Bafang is a brand that is increasingly focusing on complete ebikes, but it also offers a mid-drive conversion kit on Amazon, as well as wheel hub motors.
Priced from £360, Bafang says the conversion is easy to install using only a few tools to remove the bottom bracket and fit the drive on the front of the down tube.
As above, be careful of throttle-controlled kits that won’t pass the UK ebike regulations and will legally be considered a moped.
You’ll find other mid-motor systems on Amazon too, such as that from TongSheng, which is claimed to fit 95 per cent of standard bike frames and be 30 per cent lighter than a Bafang unit.
It uses a torque sensor, so should fall within the ebike regulations, and is priced from around £350 – although that doesn’t include a battery.
German brand Pendix has a mid-drive system priced from €999 to €2,190 that weighs from 5.4kg for a 28km range. It replaces a BSA bottom bracket and can be fitted to folding bikes as well as a wide range of regular machines.
Folding ebike conversion kit
The Brompton electric conversion from Electric Concepts is one of many kits available to electrify an existing Brompton. Electric Concepts
What can you do if you’ve got a folding bike and want to join the electric revolution?
Well there’s good news if you’ve got a Brompton – a number of ebike conversion kits are available. They generally work with a powered hub in the front wheel and a battery carried in a bag mounted on the front.
As discussed above, Swytch and Cytronex can both be used to convert a Brompton. Swytch’s Brompton kit is priced at £999, although discounts of up to 50 per cent are sometimes available on the site.
As with its other systems, there’s a front wheel hub motor, a clip-on power pack and a bottom bracket torque sensor. Quoted range is up to 50km.
Swytch will also build wheels for folders with other wheel sizes and different fork blade widths, such as Dahon’s models.
Are electric bike conversion kits legal?
If your electric bike uses a throttle, it is technically classed as a moped, and must be taxed and insured as such. Simon Bromley / Our Media
Most electric bike conversion kits are legal to fit to a bike, although the precise rules differ depending on where you live.
In most of the world, the motor needs to be limited to a maximum of 250 watts of continuous power output, unless the electric bike is only used on private land.
You also need to be pedalling for the motor to work – a throttle can only operate at low speeds and assistance needs to cut out once the speed exceeds 25kph. There may be a minimum age to ride an electric bike: in the UK it’s 14.
The rules are different in the US, where higher power outputs and higher speeds are usually legal, while Australia has some variants as well, so it’s worth checking that your electric bike conversion kit is legal where you live before purchasing.
Is converting an electric bike worth it?
An electric bike conversion kit is not cheap, so you want to be sure it’s going to work for you.
You need to have a candidate bike in decent condition to justify taking the kit route.
If you’re going to have to buy a bike to fit the kit to, or going to need to make a lot of repairs to your bike to make it roadworthy, the total cost is probably going to mean it’s not a lot cheaper than buying a complete electric bike.
You need to be confident you can fit the kit yourself as well. If you’re going to have to pay a shop to fit the motor or sort things out if the conversion goes wrong, your savings over purchasing a new electric bike may dwindle quickly.
It’s also worth noting that an electric bike conversion kit may affect your bike’s handling, particularly if there’s a heavy motor and battery mounted somewhere where the bike was not designed to carry it.
Drivetrain components may not be adequately beefed up for the extra power they need to transmit and may wear or break. Factors such as torque steer may be a problem, and cabling and sensors can be unsightly.
In contrast, if you buy a complete electric bike from a reputable brand, it will have been engineered around the motor and battery, and you’ll know what the finished product looks like.
Can you convert any bike into an electric bike?
There are designs of electric bike conversion kit that will work with pretty much any type of bike. Kits are available that are engineered specifically for certain bikes, such as the folding bike conversion kits we’ve talked about above.
A design such as the Rubbee should be mountable on most bikes. However, tyre wear may be an issue with a road bike with narrower tyres, and wet-weather grip between the motor’s drive wheel and the tyre may also be a problem.
But some kits, such as those that work with a specific bottom bracket configuration, may not fit on some bikes. An unusual wheel size may also limit available options, so it’s worth checking the compatibility of your planned solution before buying.
- Email to a friend
The best electric bike conversion kits 2023 and how to fit them
The best electric bike conversion kits can give you an extra boost of power without the expense of purchasing a new electric bike. We’ve fitted some of the best e-bike conversion kits ourselves, so will walk you through the process, how easy it is and how the different systems perform.
E-bikes are soaring in popularity – and for good reason. The best electric bikes replace a car for running errands around town and greatly increase the distances it’s possible to ride on one of the best commuter bikes. An e-bike can also be a great tool for boosting your fitness, whether that’s enabling you to ride with a greater range of people or offering the motivation of a greater range of roads to explore.
But is an e-bike worth it,? As the best ebike conversion kits promise to add power to an ‘analogue’ bike for a lot less than a full ebike, it’s an easy, cheaper way to get an electric boost.
In this guide we’ll take you through the surprisingly broad range of benefits an e-bike conversion kit has to offer and – most importantly – how to perform an e-bike conversion, based on our hands-on experience. For a walk-through on how to do it, you can check out the video above or read on for a step-by-step guide – it genuinely is so much simpler than you would think.
When buying an ebike conversion kit there are a number of factors you’ll need to consider. Most importantly you’ll need a kit that will fit your bike. To help with this it pays to take a few frame measurements, notably the width of your forks and the width of the rear stays, as well as noting the wheel size and the type of brakes. You can then match these details to the kit specifications.
Naturally you’ll also need to consider the cost and how much you chose to spend on an ebike conversion kit will be dictated by not only your budget but also your needs. If you’re unsure of just how much you’ll use the converted bike then it’s prudent to opt for a cheaper kit. you can always upgrade down the road.
You’ll also want to consider where the motor will be located, and match this to your bike and your mechanical prowess. Front hub motors are typically the easiest to fit, while mid-drive motors require more effort. A rear hub motor lies somewhere in between the two, and like a front hub option is applicable to a wide range of bikes.
Other considerations include the type of battery and the wattage rating. 36 or 48 volt battery is standard, with wattage usually running from 300 to 600 watts.
The Swytch kit is super-simple: just swap out your front wheel, wire up the controller and battery and you’re off. The battery is also very compact, allowing you to remove it from the bike easily to carry with you.
The TongSheng kit positions the motor at the centre of the bike, so it will fit to a wide range of designs. It’s lightweight for its high torque and power output, although you’ll need to buy the battery separately.
The Voilamart kit is an inexpensive rear wheel conversion option, although you’ll have to source a battery separately. It’s slightly fiddly to fit as well and requires additional waterproofing if you plan to ride in wet weather.
The best electric bike conversion kits
You can trust Cycling Weekly.
Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.
Wheel sizes: Each wheel is custom built – specify your required size at checkout (Bromptons also catered for)
Reasons to avoid
The newly updated Swytch system is one of the simplest conversion kits to fit out there. The latest version, launched in August 2022, has a smaller, neater battery pack that improves the bike’s dynamics and lowers its weight. There’s the choice of the Air battery (700g, range 15km) or the Max battery (1,100g, range 30km). Both use the same mount, which places the battery to the front of the handlebar.
The motor sits in the front hub and we found it to be pretty discreet. Incidentally, the new batteries will work with the original motor and pedal sensor, so if you already own the original kit you can upgrade it with just a new battery without having to buy the whole kit again.
The Swytch kit is incredibly easy to fit. It took us around 30 minutes working at a steady pace.
We tested it on both a reasonably light two-speed steel bike and a heavier Pinnacle utility bike. It transformed the ride of the two-speed bike, making it fast, nimble and responsive. We also found the stated range to be conservative: after 20 miles on setting number two (medium assist) it had only used two bars out of five on the battery.
With the heavier Pinnacle on maximum assist (and on draggy routes) we were getting slightly under the 30km for the Max battery. As with all e-bike batteries, range depends on the terrain, weight of bike and level of assist.
Great customer support makes this one of the best kits for people who are new to working on their bike and who aren’t familiar with electrics. And even if you do have a strong background in both those areas, a simple system is always appreciated.
Reasons to avoid
Like the Bafang mid-drive system below, the TongSheng offers the same benefits of compatibility with a wide range of bike designs and a high torque for steep hills and off-road terrain. However, the TongSheng mid-drive does manage to be a little lighter than the Bafang for approximately the same power.
This model doesn’t come with a battery included, so you’ll have to source your own 36v item. As a rule of thumb, around 10Ah will give a range of 29km / 18mi, whereas going up to 18Ah will typically give around 53km / 33mi, so be sure to factor that in when you’re making your choice.
There’s a huge range of batteries sold on Amazon, but Green Cell is a particular brand we’d recommend.
We found fitting to be reasonably easy. As with most mid-drive systems, you replace your crank and chainring with the one provided in the kit. There’s an LCD display for attaching to your handlebars and you’ll need a battery to be hooked up to the motor.
Read more: TongSheng TSDZ2 conversion kit review
Reasons to avoid
A mid-motor drive system offers a number of benefits over hub-driven conversion kits. With the power delivered at the cranks it can produce more torque, making it more effective on particularly steep and bumpy terrain.
Another perk is that the compatibility is much greater – no concern about wheel diameters, hub widths, axle standards and brake type. No matter whether you’re running rim brakes or disc, quick release or thru-axle, the crank driven system is compatible with all.
The only proviso is that the frame material must be alloy and the bottom bracket width is 68–73mm – but that covers most bikes you’re likely to be fitting this system to.
There are a few aspects to be aware of, the first being that this system doesn’t include a battery and that typically makes up about half the cost of a conversion kit. Finding an e-bike battery is quite straightforward with many being sold on Amazon, with Green Cell being among those we’d recommend.
Just make sure to get a 36V one for this motor as a higher voltage can damage it. Also you should be aware that capacity of 10Ah will give you a range of about 29km / 18mi, while a capacity of 18Ah typically gives about 53km / 33mi – so be sure to factor in the distances you’re planning on riding.
Reasons to avoid
This radically different approach from Rubbee makes for an e-bike conversion with much fewer parts. The battery and motor are housed in a single unit which powers the bike directly turning the rear wheel with its integrated roller.
Not only is the initial installation notably fast and easy, the quick release system means that you can take off the unit for rides that you don’t wish to be assisted on. At 2.8kg, it doesn’t add much weight to that of the bike, making the bike easier to handle.
The range of this model is quite low, limited to Eco mode it only offers a range of 16km / 10mi – although taking the device off to charge at the other end is easy to do and it only takes an hour to top up. There is the option to increase your range by buying additional battery modules that fit into the base unit.
Up to three can be accommodated, which in turn increases the maximum range to 48km / 30mi, or around 23km / 14mi with moderately heavy use. However, unlike many other e-bike systems, the Rubbee X supports regenerative braking, allowing you to scrub back some power on the descents.
Reasons to avoid
Bafang is a well established maker of electric bike motors and offers a front hub based motor, if you’re not a fan of the bulky profile a mid motor conversion system creates. You can buy this kit without a battery – although why would you? – but if you sensibly also opt for a power-pack there’s a choice of amp hours, and you can select either a downtube or a rear-rack mounted version.
The setup follows the same principles as most front-wheel e-bike conversions. First you need to set up the wheel with a disc rotor, tyre and inner tube and install that into the bike. Then attach the cadence sensor – so it can tell when you’re pedalling and need assistance – then attach the battery and the LCD display and you’re essentially good to go!
It’s worth bearing in mind that although this conversion kit comes in many different wheel sizes, it is only compatible with bikes that have a front disc brake and a Quick-Release axle. If your disc brake bike is a newer, more expensive model, it might not be compatible, so worth checking first.
Remember, that in the UK electric bike laws mean that e-bikes are not permitted to have a power output of more than 250w and shouldn’t propel the bike when it’s travelling more than 15.5mph – you’ll have to make sure you select the right model with the relevant limitations.
Reasons to avoid
We’ve also tested the Voilamart kit, which comes with six main parts: the replacement rear wheel, the replacement brake levers, the control screen, pedal sensor, throttle and the control box. It doesn’t come with a battery however.
On review we found the kit pretty straightforward to fit, although you’ll need to remove the bike’s crank to fit the pedal sensor and this element of the conversion was a bit fiddly. Another potential drawback is that the connectors, which link to control unit, aren’t waterproof, with only a bag supplied to house the delicate electronics. While it does a good job of keeping everything tidy, we decided to buy a plastic enclosure, cut the wires to length, solder the connections and then heat shrink for added protection.
As for the ride, the rear wheel kit delivers plenty of power. However, since the pedal sensor only detects when you’re pedalling rather than how hard you’re pedalling it delivers the power as soon as your start to turn the crank arms. Fortunately, you can quickly adjust the level assistance, with five power options available.
All in all the Voliamart rear wheel kit is an affordable way to ‘go electric’, although it requires you to be mechanical competent to fit it and you’ll need to factor in the additional cost of a battery.
How to convert your bike to an e-bike in four steps
Here’s our step-by-step guide to how to add an electric bike conversion kit to your pedal-powered bike.
Swap the tyre and tube
Firstly, remove the tyre and tube from your current front wheel and then install them on the new wheel from the kit. Make sure to check if the tyre is directional, if it is, ensure that the tyre is mounted so that the cable sticking out of the hub is on the left-hand side (non-driveside) when the wheel is installed in the bike – otherwise it’ll be powered in the opposite direction to your direction of travel!
To swap the tyre and tube over, you will need some tyre levers and a pump. If you want to go over how to do these, we have a guide that can be accessed here.
Final points are to do up the nuts on the wheel’s axle to keep it firmly in place in the forks and to check that the brakes are correctly adjusted for the new wheel. If you’re unsure how to do that, we have another guide here.
Attach the bracket to the handlebars
There is a strap that needs to be attached to the bars to keep the bracket in place and stop it rotating around. There are also some adaptors included in the kit which can be used if your handlebars are a little skinnier.
But essentially all that’s needed to be done here is a couple of screws to clamp the bracket tightly to the bars.
Attach magnet disc and sensor
The magnet disc has a split design so it can just clip around the inside of the left (non-driveside crank) and is then held in place by its retention ring. Next, stick the sensor on the frame directly in line with the magnets – this will ensure that the sensor can tell when the cranks are moving.
Plug in the cables
The thickest one is the main power cable and that just needs to be plugged into the cable extending from the hub. The other orange cable attaches to the cadence sensor and this just needs plugging in as well.
It’s then a good idea to use some cable ties to tidy up the lengths of the cables a little bit, so they aren’t flapping about and risk getting caught on the spokes or on the cranks.
The blue cables, you don’t need to worry about, these are for an optional brake sensor upgrade kit.
Why convert your bike to an e-bike?
What types of conversion kit are available?
You can get conversion kits that power your front or rear wheel or power the bikes via the cranks.
Wheel-based systems usually have a hub motor and require replacement of your existing wheel with a compatible motorised one.
The alternative is a system like the Rubbee that drives your wheel by pushing on the tyre. Tyre wear can be an issue here though.
Finally, there are systems that power the e-bike via the bottom bracket.
Usually the e-bike’s battery will bolt onto your frame or be attached to your handlebars, although sometimes you can fit a battery pack to a rear rack.
We’ve more on compatibility. which can be an issue. below.
How much does it cost to convert a bike to an e-bike?
vary depending on the type of conversion kit and the size of the battery. To give a rough Band, you can expect to pay a total of between £500 and £800 from a reputable brand, but there will be outliers at either end.
Is it worth converting a bike to an e-bike?
There are many reasons to upgrade your bike to offer a little e-assistance. On the one hand, it can greatly increase the usefulness of your bike, enabling you to replace short car journeys – such as around town, to the shops, or to work – with going by bike instead.
It’s a lot more environmentally friendly getting about on two wheels than in a two-ton metal box. It can also save you time – bikes are able to take more direct routes and are less affected by traffic, as well as eliminating the need to search for a parking space at the other end.
But beyond just their practical benefits, e-bikes can also be a potent tool for boosting your fitness. Consistency is key when it comes to exercise, so making commitments with friends is a great way to ensure you’re heading out the door. Previously, differing fitness levels could make it difficult to find a riding partner but with an e-bike levelling the playing field, getting in a productive workout (for both of you) with a friend is much easier to do.
Added to that, an e-bike can be much more motivating in that it opens up a far greater range of roads than you’d be able to access just under the power of your own two legs. Exploring new roads is part of the fun of riding a bike and an e-bike can help preserve that.
Can you convert any regular bike to an e-bike?
Most bikes can be converted to an e-bike – it just requires getting the matching the right conversion kit to match the specification.
For conversion kits where the motor is located at the wheel’s hub, you’ll need to consider the wheel’s diameter, the width and axle standard of the hub and whether it uses rim or disc brakes. For instance, a 700c (AKA, 28”) disc brake wheel with a 100mm wide quick-release hub is a relatively common spec. Once you’ve determined what type of wheel you need, the conversion is quite a straightforward process
Crank driven systems are generally easier in terms of determining compatibility; the requirements are typically just an alloy frame and a bottom bracket width of between 68 and 73mm – which is the standard for all road and mountain bikes, it’s only specialist bikes that have a different spacing there. In replacing the crankset, these systems are a bit more involved to fit than a hub system, but still well within the remit of a home mechanic.
Other kits, such as those that directly drive the rear tyre, have almost universal compatibility – provided your tyres aren’t too heavily treaded.
Are electric bike conversion kits any good?
You won’t be getting the very best motors and the largest, seamlessly integrated batteries with an e-bike conversion kit. But with that said, e-bike conversion kits are much cheaper than purchasing a whole new e-bike and they do deliver many of the same benefits.
Converted e-bikes are great for commuting and utility cycling, giving that extra boost to help flatten hills, motor along the flat and lug about heavy loads. E-bike conversions are also good for leisure cycling, helping to moderate your effort level as needed and greatly extending the range you can explore.
For more specialist utility needs, buying a new cargo e-bike would help boost your carrying capacity and range. Equally, for the aesthetically conscious, the latest breed of e-road bikes are almost indistinguishable from a non-powered bike at first glance. Then again, both those options are much more expensive than a conversion.
How we test
Where we’ve been able to link to a review, it means that we’ve put the ebike conversion kit through its paces. We’ve assessed how easy it is to fit and maintain as well other factors such as quality of the components and battery life and charge time. Riding the bike once fitted with the kit, we’ve taken into account the ride quality, the ease of use and the battery range.
Where we haven’t yet had the chance to review an item, we’re still confident in recommending it as one of the best, because we either know the brand really well, and have probably tested another product or the previous version and can still happily recommend it as one of the best.