Bosch releases new electric bike Smart System
Bosch has announced the new eBike Flow app as well as hardware that come together to form its new Smart System, which looks to introduce greater customisation to its electric bike motors and controls.
Centred around Bosch’s 2020 Performance Line CX drive unit, the Smart System brings updates to all the other aspects of Bosch’s electric bike systems, with a new handlebar-mounted controller and head unit. There is also a new battery called the PowerTube 750, which Bosch says offers the maximum range in its current electric bike battery portfolio.
Having spent ten years producing drive units and software for electric bikes, Bosch’s latest releases look to future proof the brand too, with the app set to gain more features down the line and act as a means for electric bike riders to keep their bikes up to date.
eBike Flow app
The eBike Flow app lets you change your electric bike’s motor setting and automatically record rides. Bosch
Previously, Bosch let you modify the functionality of your ebike via its eBike Connect app, but with the release of its new eBike Flow app, its new features and ability to update ebikes should mean new developments in the future. Users will be able to change the riding mode of their electric bike via the app by adjusting support, dynamics, maximum speed and maximum torque on the bike’s Bosch drive unit. Bosch says that this will allow riders to set up their bike to match the style of riding and also route they are planning to ride. Higher speeds, for instance, might be desired for longer weekend rides in the countryside, but not when cycling through town. Another feature of the cycling app is its ability to automatically record rides as soon as you start pedalling, and Bosch says that you won’t even have to take your smartphone with you for this to happen. Bosch hasn’t gone into specifics on this one, but we imagine you’ll have to have location tracking permanently on and have your phone and the bike connected too. These recorded rides will provide ride and fitness data that can then be shared with apps such as Apple Health after the activity. Underneath the more technical and wow-y features, the eBike Flow app will also show metrics and important information that will help keep you and your ebike going. These include current battery charge levels, the ebike’s next scheduled service appointment and the total mileage of the drive unit in its different modes. Of less interest to the end consumer and maybe more to bike brands, Bosch says electric bike manufactures will be able to customise the appearance of the app to match up with their own. Bosch says the app will be available from autumn 2021 as a download for Android and iOS. It will support English, French and German with more languages to follow.
Smart System remote, head unity and battery
The new remote lets you control the drive unit and tells you all the essential info you need to know via LED lights. Bosch
The eBike Flow app forms one part of Bosch’s new Smart System alongside multiple other hardware changes. One of these is the new LED Remote control unit. Bosch says the remote is easy and intuitive to use with your thumb and will let you control the ebike system without a head unit. It will display all the most important information for the electric bike and its drive system via LED lights, including the current charge and support level. The other change is an update to Bosch’s Kiox head unit, now called the Kiox 300. This is said to have a clear display that can be read in any riding situation and to present all the relevant fitness data. Unlike the previous Kiox, the new version has a buttonless design and is controlled via the LED remote, as well as being connected to the eBike Flow app.
The system also includes the new rechargeable PowerTube 750 battery which Bosch says is aimed at “long and challenging rides”. Bosch claims the battery offers the maximum range in the current Bosch battery collection and is optimised for plenty of climbing and distance, making it a good bet for the best electric road bikes and the best electric mountain bikes. Like Bosch’s other PowerTube batteries, the 750 is a lithium-ion battery that fits in the frame of the bike. Bosch says the battery is “characterised by a particularly high energy density” and that it can be charged to 50 per cent in just over two hours and fully in around six hours using Bosch’s fast charger. Unfortunately, at this time, Bosch hasn’t gone into specifics about range but considering the best performing battery in its current portfolio is said to go over 220km in ‘Active mode’, there is some potentially serious mileage available with the PowerTube 750. We also presume the ‘750’ means the battery is 750Wh.
Eyes on the future?
Bosch is keen to stress how the new app and Smart System will evolve over time with new updates being introduced to the app and the app being able to send updates “over-the-air” to the system itself (downloaded to the app via the internet and sent to the bike via Bluetooth). Claus Fleish, CEO of Bosch eBike systems, says this will offer electric bike users extra value when they purchase an electric bike with the Bosch system: “They can update their eBikes themselves at any time and equip it with new features that we will develop in the future. This means that the eBike can be enhanced even after purchase and that it stays current throughout its entire service life”
Bosch says that over the coming years it will release many more features to make electric bikes smarter, more customised and safer. This will inevitably involve updates not just to software, but to electric bike hardware too. One of the examples of future hardware that Bosch has outlined is its ConnectModule, which will provide theft protection.
Compatible electric bikes will in the future be able to be retrofitted with the system. It will likely deter thieves with an audible alarm and let owners track the location of the bike via the eBike Flow app if the thief does ride off on the bike.
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 Extend the Life of Your Bosch eBike Battery
New batteries are no longer that complicated, but here is a guide on how to extend the life of your eBike Battery focusing on the Bosch range of products.
The 300Wh, 400Wh, 500Wh 625Wh PowerPacks used on Bosch-powered eBikes are amongst the most advanced batteries currently on the electric bike market. They offer a superior range, reliability longevity compared to many other batteries. However, this all comes at a price; with a replacement pack currently costing around £600. Some people are put off by the price of a replacement battery, thinking that it will have to be replaced every other year, but this is just not true.
Bosch actually guarantees their batteries for 2 years or 500 charge cycles (whichever comes first). This doesn’t mean your battery will pack up after 2 years and 1 day. In fact, Bosch themselves state that the battery should be good for around 10 years or 1500 full charge cycles. After 1500 cycles the battery will still work, but any battery will age over time so it will start to lose capacity and therefore not power your electric bike as far.
Also, it’s worth pointing out now that many people think that a part charge counts as a full charge cycle in Bosch’s terms. Unfortunately. it doesn’t! If you just top the battery up a small amount, only this is recorded and will not be counted until there are enough of these partial charges to count toward a full charge cycle.
As a registered Bosh eBike dealer, when a Bosch-powered eBike visits our workshop we can use our diagnostics tool to read the battery itself. The Bosch battery is a very clever unit and records many different parameters, these are then saved within the system for us to analyse and consider depending on any issues presented. Also, we can tap into the system and see exactly how many ‘Full Charge Cycles’ this particular battery has had. Furthermore, we can view many other variables within the Bosch software, for example – maximum/minimum battery temperature, charge state, usage, etc.
Here are some of the most common questions we hear regarding Bosch batteries:
If your eBike came from us, we normally charge the battery fully just before letting it out of the workshop as we know you’ll be itching to ride it the minute you receive it. This helps condition the battery and gives it a starting point from which to gauge the rest of its operation. If you find it’s not fully charged, please charge it to 100% before riding. This applies to all brands of electric bike batteries too.
How often should you charge your Bosch eBike battery?
The new Lithium cells used within the Bosch battery packs are very advanced. Unlike the older style batteries where you had to completely discharge the battery and then fully charge it back up again, the new Bosch PowerPacks do not need this. In fact, it’s much better to just top up the battery after every trip. So if you have just cycled 10 miles on your electric bike, it’s better to top it back up to full when you get home rather than incorporating a few trips before charging fully.
Can I still clean my bike?
Yes, as with any bike – it is good to keep all components of your eBike thoroughly clean. If the exterior case or shell of the battery and motor is dirty, which will happen, this does not affect the performance of the internals. The best way to clean the battery is with a specialist bike cleaner, wet sponge (or soft paintbrush!), and low-pressure hose. A typical garden hose is perfect for washing away grime without applying too much pressure, once the area has been lightly agitated with the bike cleaner and sponge/paintbrush.
Although the Bosch batteries are weatherproof, it is never advised to use any sort of high-pressure jet/pressure washer on your bike. This pressure can force water into the battery case itself and potentially cause damage. It can also force water into other parts of your electric bike where you don’t want water to be (motor, bearing internals, suspension seals, etc.). So although it may be quicker to clean please don’t use pressure washers at all.
Will my battery range be affected if using an inverter from my vehicle or motor home?
No, you can use inverters to charge your electric bike – for example – from the cigarette lighter port in most cars. This can be handy if you are out and about or wish to charge on the move. But please make sure that the inverter itself is rated for the correct output for the Bosch charger. You can normally find this information on the inverter’s packaging or on a sticker on the inverter itself. The Bosch charger is designed for a rated voltage between 207 – 264 volts with an output of 42v.
The charger only charges the battery at a low 4 amp current; this is fine for most inverters and car batteries. Please check these values to make sure the inverter is compatible before plugging it in. One point to remember is that depending on the inverter itself, the battery may take a little longer to charge than if it was plugged into the mains.
Most importantly of all make sure the vehicle engine is running whilst the battery is on charge because it could drain your vehicle battery faster than you think.
How you can extend the life of your eBike battery easily:
In very simple terms, the harder you use your eBike the faster the battery will discharge. You can maybe classify this as the trade-off between fun and economy! Remember, the power of the motor can peak at 500w (depending on the specific Bosch motor) so it can draw power from the battery quicker and put a higher load on it the harder you push, and the assistance required.
The faster it discharges, then the more you will be charging it back up. This means that you could end up performing many more charge cycles than someone who is using their eBike lightly in the same time period. After a long period of time, the capacity of the battery will gradually drop. You could, therefore, be in the position of replacing it sooner if you’re riding your eBike close to capacity for the majority of the time (this is especially prevalent in de-restricted bikes).
We would recommend using an assistance level that works for you. Quite honestly you don’t ‘need’ to use the eBike flat out in ‘Turbo’ all of the time (even though it is fun!). The use of ‘Eco’ ‘Tour’ modes for the majority of riding is generally more than enough, with ‘Turbo’ mode assisting on the very toughest of climbs or in tough conditions.
You can also utilise the eMTB mode on your Bosch system, which will vary the motor’s input depending on what you are putting in yourself. eMTB mode is always optimally adapted to you, the incline, and the terrain – regardless of rocks, roots, or steps. This will give you the most bike-like ride feel and will give you an even drain on your battery.
Obviously, everyone’s fitness levels are different so you will need to work out what works for you, it is far too easy to hit ‘Turbo’ mode for the majority of your ride. The bike won’t go any faster (mph) but it will have more ‘grunt’, in fact, the eBike will only go as fast as you pedal, it’s just the amount of assistance the motor gives you that changes.
I’m putting my eBike away for the winter, will this damage the battery at all?
No, we know that some riders may not want to cycle through the cold, wet, and grim UK conditions found in the winter. You can store your bike away, it’s not a problem, however, there are some steps you can take to keep your battery healthy during these times.
If you are keeping your eBike outside in a shed or garage, then it’s always best to bring your battery indoors. The Bosch batteries are capable of being stored in temperatures between.10 through to 60 degrees centigrade. But the cells don’t like to be stored in very low or very high temperatures. In fact, the best possible temperature for storage is room temperature – around 15-20 degrees.
Once in the house at room temperature, store the battery in a dry and secure place. Sticking it on a shelf in the kitchen above the kettle runs the risk of moisture traveling up from the kettle and into the battery case. So we probably wouldn’t recommend this as a location for storage! The perfect place is tucked away in a cupboard where it’s kept at optimum temperature, away from moisture, and where it’s not vulnerable to being knocked at all. We know it can make a very good doorstop, it’s tempting; but not good for your battery. Just make sure you remember where you left it when you come to want to ride it again…
When storing your eBike battery for long periods of time it’s best to keep the battery partially charged. If you store the battery completely flat then you run the risk of damaging the internals of the cells themselves. Also if you store the battery fully charged this can leave the cells under more pressure. So it’s best to keep the battery stored in between.
For the Bosch battery in particular the optimum charge state to leave it in is 60% (Or 3 LED’s lit on the battery level indicator). Try to check the capacity every 6 months or so. When the battery reaches 1 LED showing, then top it back up to 3 LED’s again. Many people think it’s best to keep the battery on charge so it’s always topped up in storage, but this is simply not the case. The Bosch charger won’t ‘overcharge’ the battery at all and does not trickle charge.
Will it harm the battery if I run it completely flat on a ride?
No – it’s never recommended to run the battery completely flat – but for longer rides, we know it can happen. The Bosch Battery is protected by its onboard BMS (Battery Management System). This means it’s protected for deep discharging, the BMS won’t allow the battery to run completely flat.
It may seem that you have no power left, but the BMS will have already shut off the power to the motor before it can hurt itself. We all know that the beauty of the Bosch drive is you can still ride without any resistance with the power switched off. On a side note here, if you are running lights directly powered from the Bosch motor and you do run out of power, the BMS will allow a small amount of power still to the lights so you will still remain visible!
I ride in very cold conditions during the winter, will this affect my battery life and performance?
The simple answer is yes. Similar to fuel MPG in a traditional car, Bosch says economy can be affected up to 30% in sub-zero conditions. So if you are consistently riding in these conditions it can really affect not just your range but will decrease the overall lifespan of the battery as well. There are certain actions you can take to prevent this, such as wrapping an external Bosch powerpack in a specific neoprene sleeve to keep it as temperature as possible.
Should I remove the battery when transporting my bike on the bike rack of my car/motor home?
Yes, this is strongly advised, put it in a dry safe place inside the vehicle. It is less likely to get knocked and lessens the chances of the battery flying off the bike on the motorway if it’s not secured properly.
The best place to store the battery is under the driver’s seat, this means it’s out of the way and also shouldn’t move around too much. Wrap it in a towel to prevent any knocks. Do not leave the battery on your parcel shelf, if you end up braking hard, the 2kg battery is the last thing you want hitting you in the back of the head.
Also, by storing it in the car it keeps the battery from getting wet. Although the battery is rainproof, people don’t realize that if you’re traveling at 70mph down the motorway, the water air traveling over your car is then doubled in speed as it wraps around the back of your vehicle. This means the battery could be being sprayed with water at around 140mph! This is stronger than a pressure washer and can force water into the battery and components of the bike itself.
I dropped my Bosch battery and the case is cracked, what shall I do?
If your Bosch battery (or any eBike battery for that matter) is damaged in any way, then it should be looked into being replaced. Even if it seems OK on the outside one or several of the cells inside may be damaged, this can then move on to other cells and the whole pack can become a ticking time bomb. The battery could seem fine and work but weeks later the effects of the damage could become apparent. The battery could heat up or even ignite in extreme circumstances.
Do not under any circumstances ship this battery anywhere. A faulty Lithium cell can reach temperatures of 1000 degrees. It’s really not worth the risk, visit us in-store and have it replaced.
So, how many miles can I ride on a Full Charge?!
Well this is the million dollar question we get asked over and over again. And to put it frankly, there is no one fits all answer to this question! You see, there are multiple factors at play which affect the distance capable on an eBike.
Tyre pressures, total system weight, type of bicycle, tyre tread, battery capacity, motor system, cadence, environmental conditions, riding mode, average riding speed and even road surface choice will have individual and then combined factors on what you can get out of your Bosch motor battery.
Bosch have a fantastic tool on their website, classified as Range Assist which can help you calculate the range for your next eike ride or tour. This takes into account all of the above factors, for you to determine by the sliding tools, and it will calculate the estimated range for you! Bosch Range Assistant – Here
When was your eBike last serviced?
Something as simple as a brake pad rubbing can slow you down considerably. With the extra assistance on an electric bike, you may not even notice the extra drag. But the motor will be working much harder to assist you and therefore will drain the battery faster. It’s best to get your eBike serviced at least once a year to keep it in good shape which can pay dividends to battery health.
I think my battery needs replacing, what shall I do?
You should visit a Bosch dealer and have the battery capacity checked properly. We won’t take a meter near it, we will plug the entire bike into our computers and be able to give you a decision straight away if the battery needs to be replaced. On request, we can also print diagnostics reports for your records. When a new battery is purchased it comes with a new Warranty from a Bosch dealer, so be sure to keep the receipt of the purchase date safe.
Remember if you treat your Bosch eBike Battery well, it will treat you well in return. We hope that this guide will help you to extend the life of your eBike Battery!
Visit our specialist page for everything you could possibly want to know about eBikes and how they can help you.
Why not also take a look through our eBike options?
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.