The best electric bike conversion kits will enable you to add a motor to your existing bike simply and relatively cheaply – at least compared to the price of buying a whole new electric bike.
There are an increasing number of ebike conversion kits out there, and they’re getting more sophisticated and easier to install on your bike, making for a practical alternative to a new purpose-built electric bike.
An electric bike conversion kit will include the motor to drive you along and the battery to power it, obviously. But it also needs to include the apparatus to control power output level. This usually takes the form of a bar-mounted display.
In addition, a kit will also include sensors to detect how fast you’re travelling and your level of pedal input to ensure that the power supplied matches your needs.
All electric bike conversion kits need to cut out when you’re not pedalling and they have to be speed limited to 25kph in the UK, Europe, Australia and most of the rest of the world. In the USA, that figure is 20mph.
We’ve tested a few electric bike conversion kits here at BikeRadar, but there are lots more out there that we’re yet to try. Check back soon for a full test of the best electric bike conversion kits.
If you want a more detailed explanation of the different types of kit available, then head to our explainer further down the page.
Best electric bike conversion kits 2022: our picks
Swytch electric bike conversion kit
- Pros: Very compact, easy to install, variety of range options
- Cons: 100mm threaded front axle only, not compatible with thru-axles
London-based Swytch makes a conversion kit that, it says, is the lightest in the world at 3kg total weight. It can convert any bike into an ebike.
The kit includes a 40Nm brushless hub-based motor and replacement front wheel. The lithium ion battery pack connects to your handlebars, and also acts as the system controller and LCD display. There’s a crank-mounted cadence sensor, and that’s all there is to fit to your bike.
There’s a Brompton-specific kit available too, with an adaptor for the Brompton’s front luggage mount.
Depending on the range you want, there are three sizes of battery pack available, which provide a claimed range of 35km, 50km or 100km.
Swytch has recently unveiled an even more compact kit with a pocket-sized battery that weighs just 700g and, Swytch says, gives 15km of range. The new kit will be officially launched in May, with pre-orders expected to open soon after, but the existing Swytch kit will remain available until late summer 2022.
Cytronex electric bike conversion kit
- Pros: Clever sensor tech, decent range
- Cons: Not much onboard info on battery level and range
Weighing between 3.2kg and 3.6kg, the Cytronex ebike conversion kit is another front-wheel conversion to house a hub motor, but in this case, the battery is designed to fit in a standard bottle cage.
We tested the kit on a Cannondale Quick hybrid and reckon that conversion takes around 30 minutes. Charge level is displayed via LEDs on the battery, which also houses the system controller. We got up to an impressive 48 miles on a charge.
We’ve also tested the kit on a Brompton P Line lightweight folder, where the total weight undercut the C Line-based Brompton Electric. Fit it to a C Line and it’s also cheaper than the Brompton Electric.
Electric bike conversion kits: different types explained
There are a number of ways to electrify your existing bike for assistance up those hills: you can fit a powered wheel, either front or rear; you can attach a drive unit to the bottom bracket; you can fit a motor above the rear wheel and drive it via friction; or, most sneakily, you can conceal a motor in the seatpost.
Many can even be fitted by a competent home mechanic if you’re feeling handy and have an afternoon spare.
So, what are your options? Let’s take a look at the different ways to convert your non-assisted bike into an electric bike.
Powered ebike wheels
Fitting a powered e-bike wheel is probably the most practical option for many people – swap out one of your normal, non-powered wheels for one with a special hub that contains a motor, adding a battery and the gearing needed to turn it. An oversized hub drives the bike and there’s a strap-on battery pack.
This sounds simple, but the main downside is that it adds rotating mass to your bike, which feels harder to accelerate than non-rotating mass.
Be careful of systems controlled by a throttle (also called ‘twist-and-go’) though. Legally, they’re classified as electric motorcycles rather than ebikes, and need to be taxed and insured. Take a look at our guide to ebike laws for more information.
E-Bikes Direct offers a few front-wheel conversion kits, priced from £399. There’s a choice of wheel sizes from 20in up to 700c and a 10Ah battery with a claimed range of 20 to 40 miles. It’s another throttle-operated ‘twist-and-go’ system though.
Then there’s the €1,199 FlyKly Smart Wheel, which is also operated via a smartphone app. It comes in three sizes: 28in for city bikes, 26in for mountain bikes and 20in for folding bikes.
It has a claimed range of 25 to 60 miles / 40 to 100km, and will assist you up to 16mph / 25kph with its 250-watt motor.
Rear-mounted friction drive ebike conversion kit
Readers of a certain age may remember earlier incarnations of these in the 1980s/90s: a box that sits on your rear wheel and powers it via friction with a rubber flywheel driven by a motor.
The idea hasn’t gone away, and lives on in devices such as the Rubbee, which promises bolt-on electric assistance for nearly any bike.
Rubbee’s base model has a claimed weight of just 2.8kg, with a 16km range that can be extended up to 48km with the top-spec, 4kg version.
It works with any wheel diameter between 16in and 29in, has an integrated carrying handle and clips on and off your seatpost. Prices start from €579.
Concealed ebike conversion kit
Now we come to the low-key way to do it – hiding a motor inside your bike so no one knows it’s there.
The Vivax Assist was the best-known device for doing this, although the company has now ceased trading. It’s the system that was used by Belgian cyclocross pro Femke Van den Driessche in 2016 to power her way to victory in her home championships. She was found out at a subsequent race, got a six-year ban and quit racing.
Vivax Assist may be no more but we reckon this idea still has legs – at least for the budding cyclocross cheat.
Mid-drive ebike conversion kit
Many commercially available ebikes are powered with motors mounted around the bottom bracket, near the pedals.
These have the advantage of placing the weight low down on the bike, making it more stable.
This isn’t just a ready-made option though – you can also buy aftermarket conversion kits with mid-drive units.
Bafang is a brand that is increasingly focusing on complete ebikes, but it also offers a mid-drive conversion kit on Amazon, as well as wheel hub motors.
Priced from £360, Bafang says that the conversion is easy to install using only a few tools to remove the bottom bracket and fit the drive on the front of the down tube.
As above, be careful of throttle-controlled kits that won’t pass the UK ebike regulations and will legally be considered a moped.
You’ll find other mid-motor systems on Amazon too, such as that from TongSheng, which is claimed to fit 95 per cent of standard bike frames and be 30 per cent lighter than a Bafang unit.
It uses a torque sensor, so should fall within the ebike regulations, and is priced from around £350 – although that doesn’t include a battery.
German brand Pendix has a mid-drive system priced from €999 to €2,190 that weighs from 5.4kg for a 28km range. It replaces a BSA bottom bracket and can be fitted to folding bikes as well as a wide range of regular machines.
Folding ebike conversion kit
What can you do if you’ve got a folding bike and want to join the electric revolution?
Well there’s good news if you’ve got a Brompton – a number of ebike conversion kits are available. They generally work with a powered hub in the front wheel and a battery carried in a bag mounted on the front.
As discussed above, Swytch and Cytronex can both be used to convert a Brompton. Swytch’s Brompton kit is priced at £999, although discounts of up to 50 per cent are sometimes available on the site.
As with its other systems, there’s a front wheel hub motor, a clip-on power pack and a bottom bracket torque sensor. Quoted range is up to 50km.
Swytch will also build wheels for folders with other wheel sizes and different fork blade widths, such as Dahon’s models.