How to Choose An E-Bike Conversion Kit: Everything You Need to Know
Want to convert your regular bike to an e-bike? Here’s what you need to know.
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You love riding your bike but are frustrated by other riders who fly passed you as you struggle up the slightest incline. Or maybe you’re just tired of showing up to work in a sweaty shirt.
Or maybe you’re a DIY’er and already have a perfectly functioning bike and want to upgrade to something with a little (or a lot) more pep. In either case, you want to join the e-bike revolution.
You’re in luck. E-bike conversion kits make it easy to keep your current bike while reaping the rewards of electric motors with minimal cost.
Motor Types and Strength
There are several ways to build a DIY e-bike, and they all depend on the kind of motor you choose in your conversion kit: mid-drive, direct-drive hub, or friction-drive. A mid-drive motor is integrated into the lower-middle section of the bike frame, generally in between the pedals. A direct-drive hub motor is integrated into the front or rear wheel hub. A friction motor is mounted with a roller that contacts your rear wheel.
Each motor type has pros and cons. Hub motors are less expensive and easier to install, but they offer less torque, and the added weight on the front or rear wheel can affect the bike’s balance. Mid-drive motors are more expensive and difficult to install but offer more torque and put the added weight in the center of the bike, making it more balanced. Friction motors are the easiest to install but offer minimal performance gains.
There are various e-bike classes, and e-bike conversion kits are no different. When comparing the power of different kits, you’ll be comparing the watts of each motor. Wattage (or the number of watts) refers to how much power a motor requires to run. Motors with more watts will deliver more torque. Most e-bike conversion kits fall between 250 and 1,000 watts, but some jurisdictions restrict e-bike motors, so check your local laws before buying.
How much power does your e-bike need? That depends. E-bike conversion kits with hub motors are usually better suited for flat roads and long distances. In contrast, mid-drive conversion kits are usually better suited for people carrying more weight or living in hilly areas. The amount of power your motor requires will also affect the range.
Ease of Installation
At first glance, e-bike conversion kits might seem daunting to install yourself, but these small, powerful kits can be very easy to connect.
Friction-drive kits are the easiest to install. For example, the Rubbee conversion kit attaches to your bike’s seat tube using a few bolts and rests on your bike’s rear wheel.
Direct-drive hub motor kits are the second easiest to install. All you need to do is replace your front or rear wheel with a new one that includes an integrated motor. It might take some ingenuity to find a place to mount your battery and electronics, especially in a way that keeps your bike looking clean, but anyone with a few basic tools and some zip ties can install this kind of kit.
Mid-drive motor kits are the most difficult to install but are still easy for people who are handy and can work on their bikes. The installation will generally require you to remove and reinstall your bike’s cranks, chain, and chainring and attach the motor and sensors.
Battery Capacity
When comparing the battery of different conversion kits, you’ll be comparing something called watt-hours (referred to as Wh). Watt-hours refers to the number of hours a battery can produce one watt of electricity. E-bike batteries can be anywhere between 500 and 700Wh.
E-bike kits will vary in the distance they can let you travel. The size and capacity of the onboard battery, combined with the power of the motor, determine the distance you can ride. While bigger batteries are usually better, several factors can influence the longevity of your battery between charges, including the weight you’re carrying and the speed you’re traveling. Under typical demands, one mile will cost about 20 watt-hours.
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
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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.
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.
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.
The 6 Best E-Bike Conversion Kits of 2023
Heidi Wachter was a senior editor at Experience Life magazine for 10 years. She has written for publications like Experience Life, Shondaland, and betterpet.
E-bikes are easier on the environment than cars. They’re also easier to pedal than a standard person-powered two-wheeler. You get as much exercise riding an E-bike as you do a traditional bike. Thanks to improved technology and more people interested in alternative transit methods, E-bikes are also becoming more available—and more affordable.
But no electric bike is as cheap as the bike you already own. If you’re trying to reduce your carbon footprint, live in a small space, or practicing minimalism, repurposing what you already have can be a win-win-win decision. So, if you love your current ride but want to add some juice for getting uphill or for powering your cargo bike when you’re carrying a heavy load, you can, thanks to electric bike converter kits. To electrify your bike, you need a battery, sensors, controls, and a motorized wheel or a drive unit.
Here are the best options for upgrading your bike with an e-bike conversion kit.
Best Overall
BAFANG BBS02B 48V 500W Ebike Conversion Kit
Since 2003, Bafang has been a leader in manufacturing e-mobility components and complete e-drive systems. Its products offer outstanding performance and reliability, and the BBS02B conversion kit is no exception, making it our top overall choice.
This mid-drive motor kit is versatile and compatible with road, commuter, and mountain bicycles. All you need is a bike with a 68-73 millimeter bottom bracket and the battery of your choice. Installation is relatively easy, and the battery is included. Once the kit is installed, you’ll be ready to tackle any hill.
Although several different conversion kits are available online from Bafang, those with more than 750 watts of power will be considered motorcycles in the United States.
Price at time of publish: 466
Best Budget
BAFANG E-bike Front Hub Motor 48V 500W Bafang Brushless Gear 20/26/27.5/700C inch Electric Bicycle Conversion Kits
This front-wheel E-bike conversion kit is easy to set up and easy on your wallet. Electrify your bike in one hour by following the installation video and manual. Don’t forget to choose the correct wheel size!
After setup is complete, ride around the town with pedal assist or switch to E-bike mode for longer trips. Commuters, long-distance trekkers, and mountain bikers can cruise up to 24 miles per hour. The battery is not included.
Price at time of publish: 579
Best for Commuting
Swytch Universal eBike Conversion Kit
Daily riders will love this easy-to-install, lightweight e-bike conversion kit. It is compatible with most mountain, road, hybrid, and step-through bikes, and disc brakes.
It’s as easy to install as swapping out your front tire. The controller and battery are combined into a 34.2-Volt power pack, which is included in the kit and mounts to the handlebars. That makes it easy to remove and keeps thieves at bay, but our tester did miss having the use of a handle bar basket. The battery pack is fitted with indicator lights that tell you how much juice remains and what assist mode you’re in. Once the system is set up correctly, you’ll be able to top out at 15-25 mph.
In general, I love it. It makes my ride easier without feeling like I’m riding a giant bulky e-bike. It’s got a phenomenal amount of power for such a little machine and seems like it has a good battery life too. ~ Treehugger Tester
Best Premium
Ebikeling Waterproof Ebike Conversion Kit 36V 500W 700C Geared Electric Bike Kit
Do you want to go farther or faster? You can do both with this setup from Ebikeling, with its 500-watt motor. Ebikeling makes it easy to buy different compatible batteries and other accessories in an a-la-cart way. There are seven different batteries that come in different shapes (bottle, triangle, rectangular), so that you can pick the one that suits your bike and needs best.
The double-walled rim and motor are ready to install right out of the box—just swap them out for your original bike tire. An LCD screen is included to help you stay within your town’s speed limit. You can choose between a front or rear mount, as well as a thumb or half-twist throttle.
Price at time of publish: 390
Most Powerful
AW 26×1.75 Rear Wheel 48V 1000W Electric Bicycle Motor Kit
Thanks to a 48-volt, 1000-watt battery, the AW wheel E-bike conversion kit satisfies anyone with the need for speed. A thumb throttle makes speed control simple. This kit is available as either a front wheel or back wheel conversion option. It fits any 26-inch bike frame with a 3.9 inch front dropout spacing (for a front wheel conversion) or 5.3 inch rear dropout spacing (for a back wheel conversion). The rear wheel kit weighs 24.7 pounds, the front wheel kit weighs 23.5 pounds.
The aluminum frame offers durability and stability, which is essential when you’re rolling at top speeds of 28 miles per hour. Hand brakes turn the motor off automatically to both improve safety and conserve battery power.
Price at time of publish: 300
Easiest to Install
Rubbee X Conversion Kit
If you want the fastest conversion possible, and even the option to take a motor off your bike quickly, the Rubbee X makes it a snap. The Rubbee X gives you a boost by resting against the rear tire, and has a special release that lets you remove the motor without un-mounting the entire system. You control the power just by pedaling, as a wireless cadence sensor that gets mounted to the pedal crank sends information to the motor, which shifts automatically without any additional user interface.
This conversion kit has some other nice features. It has tail lights on the back of the motor, to give you some additional visibility when riding at night. The base model comes with one battery, which weight 6.1 pounds, gives you 250 watts of power and has a top speed of 16 mph. Upgraded models have two or three additional batteries, each offering more speed and power, but also adding more weight. It’s compatible with any frame type, and with tires that are between 0.5 and 2.5 inches in width and between 16 and 29 inches in diameter.
There are a few things to keep in mind before you buy. First, the product ships from the European Union, so there may be an additional import tax. Second, you’ll want to make sure you have plenty of room on your seat post to connect the motor.
Price at time of publish: 612
Whenever you’re buying a newer technology, sticking with a known brand makes sense. That makes Bafang’s E-bike conversion kits a sound choice—in terms of quality and price. If speed is what you’re after, the kits from Ebikeling.
What to Consider When Shopping for an E-Bike Conversion Kit
Battery
Is the battery included? You’ll need something to power and charge your e-bike conversion kit. Many kits include a battery. Cheaper kits may not, though, which means you’ll need to source a compatible battery separately.
Power
You’ll also want to think about your power needs. The higher the motor wattage, the more power you’ll get. A 250-watt motor is typically plenty of power to make the daily commute less sweaty. If you want to take your converted bike out on tougher mountain trails, you’ll want more power.
Keep in mind that according to U.S. federal regulations, e-bikes with more than 750 watts of power are considered motor vehicles and require a motorcycle license.
Local Laws
You’ll want to check your state and local laws as some cities and towns have banned e-bikes from bicycle paths, so if that’s where you want to ride, you’ll want to make sure your town allows your upgraded bike to cruise around on them.
E-bikes come in three classes:
- Class 1 E-bikes that assist you while you pedal and top out about 20 mph.
- Class 2 E-bikes have a throttle that assists you regardless of whether you pedal and have a top speed of 20 mph.
- Class 3 E-bikes assist you while you pedal and top out about 28 mph.
Drive Type and Installation
There are several kinds of e-bike conversion kits, and the ease of set-up and installation varies.
- Friction Drive Conversion is a simple strategy. A roller pushes against the tire on the wheel. When the roller turns, the wheel turns. It’s a reasonably easy system to set up but sometimes isn’t the most effective.
- Mid-Drive Conversion is the technology that the best e-bikes tend to use. A weight sits at a low point on the bike frame, and the power is applied to the crank. These can be more expensive, but the technology is typically better. There’s no standardization, however, which can make figuring out exactly what you need to make your bike work a little more challenging. Adding the parts is also a bit more complex than friction drive conversion.
- Electric Bike Wheel Conversion swaps out a non-electrified front or rear wheel with an electrified one. The process is simple depending on where and how the battery mounts—such as on a rear rack. Once installed, weight distribution can feel natural. However, powering the front wheel may impact your bike’s handling.
The difficulty of installation depends of the type of conversion kit, as well as your comfort with the tools required. But generally speaking, converting your bike is a DIY project. Many manufacturers offer how-to videos that show what’s involved, so you can see ahead of time what you’ll need to do.
You’ll need a bike tool, crank arm tool, adjustable wrenches, and a screwdriver along with your electric bike conversion kit. These demos can show you how to install your e-bike conversion kit.
A visit to your local bike shop mechanic is a helpful step in the decision-making process. They can help you determine if your bike is a good candidate for electric technology. Your old bike may not be able to be converted because adding a motor can increase torque. You’ll want to make sure your bike’s drivetrain can handle it. The extra weight from adding an electric motor also impacts your brakes, so you’ll want to make sure they are effective for stopping at a higher speed. E-bikes tend to have disk brakes for this reason. If your current bike is in disrepair, has old parts, or needs other improvements, it may be more cost-effective to sell your trusty old ten speed and buy an e-bike. Also, consider that a quality electric bike conversion kit can be nearly the cost of an electric bike. Do some comparison shopping between the price of a conversion kit and a fully-loaded e-bike before you decide which way you want to roll. Our picks for the best e-bikes may help guide your decision.
Why Trust Treehugger?
Treehugger has reported on dozens of e-bikes and e-bike conversion options over the past decade. To make this list, we deeply researched the market by reading other third-party reviews, user Комментарии и мнения владельцев, and enthusiasts blogs. We also considered the product’s value and the manufacturer’s reputation.
Author Heidi Wachter has been writing about travel and adventure for over a decade. When she’s not writing, you’ll likely find her riding one of her six bicycles—even in the winter.
You Can Build an Ebike. Yes, You.
Just like regular bikes, electric bikes experienced a pandemic boom, giving more people an alternative way of commuting, picking up the kids, or just getting outside. But you might already have a functioning bike and wonder if you need to invest in (or make room for) another. If you’re willing to put in some light to medium work, you might not have to. How do I know? Let me tell you—I’ve done it myself.
My wife likes to commute by bike to her job in Washington, DC. There’s just one obstacle: Capitol Hill. Not legislation, but the actual, elevated land feature. It’s no Colorado mountain, but it is a challenge, especially when she’s hauling work gear on a swampy day.
I, a bike nerd, leapt at the chance to draft her into the ebike brigade. But my local shop had maxed out its waitlist months before. Even if I could find an ebike, we’re apartment dwellers, and our building’s bike-storage area only has so much room. We would have to choose, it seemed, between her familiar 1990s hybrid or a new purchase.
Or, it turned out, I could just make an ebike.
I could replace a wheel or the bottom bracket of my wife’s bike, run some cables with Velcro and zip ties, and attach a battery. True, the task requires moderate research, light to medium wrenching, and variable fiddling. But if that sounds like a good trade to get some lithium-ion pedal power, let’s go over how to add some DIY range or hill power to your own bike.
Where should the motor go on your bike?
Ebike conversion kits come in three main kinds, which I’ll list from least to most complex in terms of installation:
- Front hub (shown above): This process entails swapping in a new front wheel with a motor at its center.
- Rear hub: You make a similar swap, but for your rear wheel (in addition to a new freewheel or cassette cogs).
- Mid-drive: You install a motor beneath your pedals (in your bike’s bottom bracket).
Each setup has its pros and cons (see the tables below). The more you know about your bike, and how hilly and far your typical ride will be, the easier your choice will be. The hard part is forecasting how much power and range you’ll want once you’re into ebiking, said Adam Ostlund, managing partner at Electrify Bike Co., an ebike seller and shop in Utah. Ostlund gets customers saying that they haven’t ridden in 20 years, and that they only want to take weekend rides with their spouse—but a year later, they’ve hit 3,000 miles and want upgrades. “Once someone starts riding ebikes, they’re always going to want more. So we try to start them at ‘more,’ so they don’t regret it later,” he said.
Front hubs
| Pro | Con |
| Easiest install | Torque arms—additional metal bracing to secure the axle in the bike’s frame—advised for more than 250 watts, complicating flats and repairs |
| ”All-wheel drive” (when also pedaling) on flat roads | Less traction on steep hills and poor road conditions |
| Lower cost than rear hubs or mid-drives | Easier to overheat motor on hills or spin-outs |
| battery-placement options (using smaller batteries) | Trickier handling and balance for inexperienced bikers |
| Discreet look thanks to a smaller motor | Limited in power (500 watts or less recommended, especially with aluminum or carbon forks) |
Rear hubs
| Pro | Con |
| Easier install than mid-drives | Changing tires becomes more inconvenient |
| Better weight balance and traction for hills and rain | Larger motors make heavier bikes |
| Higher power ranges available | Torque arms needed for higher wattages |
| Fits bikes with irregular bottom brackets | Drivetrain and wheel components may be cheaper quality than original bike parts |
Mid-drive
| Pro | Con |
| Allows you to use your bike’s gears to shift between torque and speed | Faster drivetrain wear |
| Better weight distribution | Less clearance under the bike |
| safe power configurations | Best to avoid shifting while motor is engaged |
| Better for mountain/trail/hill riding | intensive install with specialty tools (and sometimes frustrating bottom-bracket sizes) |
Most DIY ebike enthusiasts prefer mid-drive motors, which leverage the bike’s gears to alternate torque and speed, unlike the blunt push of motorized hubs. They’re generally safer for your bike’s frame, especially with newer bikes made of aluminum, carbon, or alloys instead of older, tougher steel. They make more efficient use of battery power, especially on hills. And a mid-drive motor’s weight sits evenly in the middle of the frame, rather than at the front or back. If you’re planning to tackle hilly trails, off-road conditions, or long ranges, a mid-drive setup is definitely best.
But hub motors have their place. They start at lower than mid-drives. They’re notably easier to install than mid-drives, and they let you avoid dealing with installing a motor into your bottom bracket—a bike part that can be notoriously varied in kind and size. Hub motors are a decent choice for commuting on paved streets with light to medium hills, when you’ll be using your legs most or all of the way. Just make sure that you brace your bike frame properly.
How will you control the motor?
Your decision depends on what kind of riding you do. Most kits offer three main ways to control how much power your bike’s motor supplies and when: a throttle, a cadence sensor, or a torque sensor. Some bike kits include both a throttle and a sensor for your choice or combination.
A throttle is what it sounds like: a button, lever, or handlebar twist that lets the rider manually apply power with no need to pedal. Throttle riding is what you see delivery riders using in major cities. It uses a lot more power. It’s also a useful backup if the bike, or the rider, starts to fail during a ride.
A cadence sensor turns your motor on when you are pedaling and off when you stop, increasing its output the faster you pedal. It’s usually paired with a kind of shifter for the rider to choose the level of assist (you’ll see this system on most shared city ebikes). It’s more hands-free than a throttle, but it can be a bit awkward in low-speed situations, such as when you’re starting from an intersection.
A torque sensor gives you more power when you’re pressing harder on the pedals, whether you’re climbing a hill or pushing for speed. Torque sensors feel the most natural—they push hard when you push hard—but require more work to install and maintain.
How much power and battery do you need?
Once you’ve chosen a kind of motor, you decide how much motor you want, as well as how much battery you want behind it. Motors have watt ratings, batteries have voltage and amp-hours—it’s a dense thicket for a newcomer. Micah Toll, an engineer who writes at EbikeSchool.com and Electrek, helped me FOCUS on what matters.
First lesson: Ebike motor ratings are mostly nonsense. Some countries cap ebike motors: 250 watts in much of Europe, 750 watts in much of the US. Not coincidentally, motor makers and sellers advertise a motor’s “continuous” power instead of its peak rate. The more clear way to compare ebikes is to look at the voltage and current (amperage) for hill-climbing and top-speed power and to consider watt-hours for battery longevity.
You can tweak the voltage and current with different battery controllers, gaining more speed, more hill power, or different assist levels. The power you need depends on a lot of factors, including your body weight, the bike’s weight, and your pedaling power. Bicycling magazine has a deep dive on how to understand ebike motors and power (presented by Bosch, which makes its own ebike motors). Generally, Toll suggests, 24- and 36-volt setups are for casual riders who plan to pedal a good deal and don’t face lots of hills, while setups at 48 volts and above are useful for hills and no-pedal throttle riding.
I went (very) small for my wife’s roughly 650 ebike kit from a company called Leeds: a 250-watt, front-hub motor, powered by a 24-volt battery with 5.2 amp-hours, roughly the size of a squared-off 16-ounce beverage can. But watt-hours (Wh) offer a better battery comparison than amp-hours (Ah) do. You get watt-hours by multiplying the battery’s voltage (in this case, 24) by its amp-hours (5.2), so for my wife’s kit, that works out to about 125 Wh. Technically that means her fully charged battery can run her 250-watt motor at full power for about half an hour. It’s a useful comparison, but ebikes pull “full power” only during hill climbs and acceleration, so their batteries usually last much longer. On a paved-road commute, your legs can likely put in 100 to 200 watts of power on their own, so using a low-key kit like this is like having an on-demand tandem partner.
For such “assist” rides, 250 Wh is a better starting point these days, according to Toll. If you’re going to be riding your throttle most of the ride, 500 Wh (that is, a 48 V, 10 Ah setup) is your starting point.
If you want something close to an electric moped experience—almost entirely throttle, 25 to 28 miles per hour—you’re looking at a 750 Wh setup. At that point, you should be checking your local laws and also considering whether you ought to simply buy a dedicated ebike, because in terms of price, design, and safety, you’re likely better off with one.
My wife’s ebike is working well. Because she can safely store her bike at work and at home, she removes her battery only about once a week for charging. She gets most of the exercise of biking but can push a button to get a faster start at intersections or to tackle hills. It has made her more confident in biking around the city, which means the local bike shops still get some business in accessories, lights, and more.
Do you need to upgrade your brakes?
If you’re installing a lightweight battery and motor that you expect to use mostly as an assist to active pedaling, your current brakes may be fine. Disc brakes provide better stopping power, especially in wet conditions, but a good rim brake can suffice for commuting-focused rides. Toll said he spent three years riding a DIY 1,000-watt ebike with mechanical V-brakes (the kind you might see on a 10-year-old mountain bike), and it worked out well. “It’s more about the quality of the brake,” he said. At a minimum, though, check your brake pads and performance, or have a shop do a tune-up, when you’re installing a kit.
Many ebike kits and motors come with replacement brake levers, or sensors that can attach to your existing levers. These shut off the motor when pressed so that your motor stops pushing immediately when you mean to stop. I haven’t found them helpful on my own 250-watt setup (more on that in a bit), but there’s no harm in installing them.
Where should you buy a conversion kit?
There’s no one ebike kit that I—or anyone—can recommend for most riders and bikes. But Adam Ostlund, Micah Toll, and Karl Gesslein, ebike enthusiast and author at ElectricBike.com, all offered one bit of buying advice: Never try to “save money” by hunting for cheaper batteries. A cheap battery is almost always disappointing—and sometimes dangerous.
Bike batteries usually consist of a series of 18650 cells that are connected to one another and a battery-management system and then packaged into various shapes. Reputable battery makers and ebike-kit sellers use the best-quality cells from brand names like LG, Panasonic, and Samsung. In contrast, most discount sellers use lesser cells, from lesser-known makers, that have diminished capacity, voltage, and longevity, and their controllers can be equally suspect. Buy from a dealer with an established presence and return policy.
You can often find motors, batteries, controllers, wires, throttles, sensors, and other accessories sold separately, but unless you have a few conversions under your belt, you’re better off with an all-in-one kit. Kit makers have spent a lot of time testing how components work together, and they should be available for troubleshooting. Ostlund noted in our interview that Electrify Bike custom-programs some of its kit controllers so riders aren’t stuck with the often aggressive acceleration curves of some motors that are meant more for delivery workers than for weekend warriors.
Ebike-kit companies that were mentioned by the experts I talked to, are linked in ebike-enthusiast subreddits, and have generally built a good reputation include:
- Luna Cycle (affiliated with ElectricBike.com and Gesslein)
- Electrify Bike Co. (Ostlund’s shop)
- Grin Technologies (batteries, motors, and kits)
- eBikeling, Leeds, Hilltopper, Dillenger (hub kits)
What about Swytch kits?
Search online for ebike kits (or in the Комментарии и мнения владельцев posted on this article after its original publication), and you’ll see Swytch mentioned a lot. It’s a UK-based company, but it has a US warehouse for returns and distribution, as well as a one-year warranty on most parts. The company offers 250-watt, front-hub-based full conversion kits for bikes with 26-inch and 700c wheels, as well as for Brompton folding bikes. You have to preorder your customized kit, and you might wait a while, as Swytch prepares and ships kits in batches.
Swytch’s main hook is its unique battery and connector, which clicks on and pops off your front handlebars at the press of a button. Most people have room on their bikes there, and the design simplifies removing the battery when you’re locking up. Swytch recently announced the smartphone-ish–sized Air battery for those who value even more portability, and lighter weight, over range.
Swytch sent me a test kit for my own bike—a 2018 Norco belt-drive hybrid with 700c wheels—with a Pro battery (30-mile range) and both a cadence sensor and a throttle. After jumping on a video call to double-check my fork dropout width measurement (an important detail for any conversion kit), I ran the cables and installed the kit without much hassle.
My bike is already on the heavy side, and I’m biking for errands or recreation more than personal records, so the roughly 3 pounds of difference that Swytch’s motorized front wheel adds is tolerable. You’re more likely to notice the 4-pound battery on the handlebars, but that feeling soon disappeared for me—and so did hills, and starting on an incline, and feeling weighed down by cargo.
There are better ebikes for those committed to riding electric every time or for those interested in commuting longer (or steeper) distances with less pedaling, but I’ve enjoyed the versatility of the Swytch kit for weekend trips and weekday errands. If hauling a battery around will be a pain, or the ride is real short and my knees feel great, I can skip it. If I want a faster, smoother ride, I can grab the battery and head out. If bike space and versatility are a priority for you, the Swytch kit is worth considering.
If you’re unsure about any aspect of your conversion, look for your bike model on the Endless Sphere forum or the r/ebikes subreddit, or simply search the web for your bike name plus “ebike.” Bike owners who have stealthily converted their bikes into electric-powered dynamos love to tell people about it. Not that I’d know anything about that.
This article was edited by Christine Ryan.