Electric Bike Conversion Kits

An electric bike conversion kit is the cheapest route to electric assistance if you already own a bike you like. A motor, battery and sensor add to your existing bike for a few hundred pounds. That is often far less than a new e-bike costing £1,000 or more. A converted bike done well rides almost like a factory e-bike. A bike converted badly can be heavy, unbalanced or illegal on UK roads. This guide explains how kits work, what they cost in 2026, the law you must follow and which kits are worth buying.

We have grounded the specs and prices below in current UK retailer listings and the leading cycling titles. We flag figures that are claimed rather than independently measured. Prices in this market move often. Treat every number as a guide and check the live price before you buy.

What is an electric bike conversion kit?

A conversion kit is a set of parts that adds pedal-assist power to an ordinary bicycle. Every kit has four core components: a motor, a battery, a controller that manages power, and a sensor that tells the system when you are pedalling. Fit them to your existing frame and you have an e-bike for a fraction of the cost of a new one.

The motor lives in one of three places. That single choice shapes how the bike rides, what it costs and how hard it is to fit. We break down the three types below. The battery bolts to the frame, sits on a rear rack, or clips to the handlebars on the neatest kits. The sensor is usually a cadence sensor that switches on assistance when the cranks turn. Better kits use a torque sensor that matches power to how hard you push instead.

Front hub, rear hub or mid-drive?

The motor location is the biggest decision you will make. Each type trades cost, install difficulty and ride feel differently.

Front hub kits

A front hub motor is built into a replacement front wheel. You swap your front wheel for the motorised one. Then you mount the battery and sensor. The job takes about an hour with basic tools. This makes front hub kits the easiest to fit yourself and the friendliest for first-timers. The downside is that pulling power through the front wheel can feel slightly odd on loose surfaces or steep climbs. Very light front forks may also not be rated for the extra torque.

Rear hub kits

A rear hub motor replaces the back wheel. Power goes where your weight already sits. Traction and balance feel more natural as a result. Torque for hills is usually stronger than with a front kit. The trade-off is a more involved fit. You have to deal with the cassette, gears and sometimes the brake disc. Many riders have a shop fit a rear hub kit instead. Rear hub kits also tend to be the heaviest option once you add a battery.

Mid-drive kits

A mid-drive motor sits at the bottom bracket. That is the point where the pedals meet the frame. The motor drives the chain directly. The Bafang BBS series is a well-known mid-drive kit. Mid-drive motors use your existing gears. This gives the best climbing and the most natural, bike-like power delivery. The weight also sits low and central on the frame. The catch is cost and install difficulty. Mid-drives are the most expensive and the hardest to fit. They also put extra strain on the chain, cassette and chainrings. Those parts wear faster as a result.

Kit type	Ease of fitting	Ride feel	Typical UK price
Front hub	Easiest	Good, slightly front-led	From around £300 to £1,100
Rear hub	Moderate	Balanced, strong torque	From around £350 to £700
Mid-drive	Hardest	Best, natural and climbs well	Motor from around £300, plus battery

Kits with a battery vs motor-only kits

The phrase “conversion kit with battery” matters. Some listings sell only the motor. A complete kit with a battery, controller and sensor included is far simpler: everything is matched and you avoid pairing the wrong pack to the wrong controller. All-in-one front-wheel systems like the Swytch bundle the motor wheel, the battery and the sensor. Prices start from around £499. Budget rear hub bundles from brands such as Cyclotricity can include a 36V rack or frame battery from roughly £350.

Motor-only kits look cheap at first. A bare Bafang mid-drive costs around £300 for the motor alone. A quality battery adds £250 to £450 on its own. This route gives more control over capacity and cell quality. It suits confident builders only. Buy a complete kit with the battery included if you are unsure.

Browse conversion kits with battery

The best electric bike conversion kits for 2026

These four kits cover the main routes into conversion: the easiest all-in-one, the lightest premium option, the best ride feel, and the best value rear hub. Ratings are our editorial scores based on specifications, value, owner feedback and reputation rather than lab testing.

Swytch

Swytch Go / Swytch Max

★★★★★ ★★★★★ 4.4 from around £499

Best for: Easiest all-in-one kit

Motor

250W front hub

Battery

Handlebar Power Pack (around 180Wh Go, larger Max)

Range

Up to 15 to 30 miles (claimed)

Weight

Around 3 to 4kg added

+ What we like

• Front wheel, battery and sensor in one kit
• Light and quick to fit in about an hour
• Removable handlebar battery pack

- Watch-outs

• Smaller packs have limited range
• Order lead times can be long

Our verdict: The simplest way to convert a bike. One box, an hour of work and a removable battery make it ideal for first-timers.

Check price

The Swytch is the kit we point most people to first. The motor is built into the front wheel. The battery clips to the bars. Fitting is genuinely beginner-friendly as a result. The Go pack suits short town hops. The larger Max pack is the better choice for a longer or hillier ride. Lead times have at times been long. Order ahead of when you need it.

Cytronex

Cytronex C1

★★★★★ ★★★★★ 4.5 from around £1,100

Best for: Lightest premium kit

Motor

250W front hub

Battery

Bottle-style frame battery (around 198Wh)

Range

Up to 30 miles (claimed)

Weight

Around 3.6kg added

+ What we like

• Very light, keeps the bike feeling natural
• UK company with strong support
• Smooth, intuitive power delivery

- Watch-outs

• Expensive for a single-bottle battery
• Range shorter than larger frame packs

Our verdict: The choice for riders who want assistance without spoiling a nice bike. Light, refined and backed by UK support.

Check price

The Cytronex C1 is the premium pick for a good road or hybrid bike you do not want to spoil. At around 3.6kg added it is one of the lightest kits available. The bottle-style battery keeps the look clean. Power delivery is smooth. UK-based support is a real advantage if something goes wrong. The single bottle pack means range is modest. It suits shorter, sportier rides rather than long touring days.

Bafang

Bafang BBS01 Mid-Drive

★★★★★ ★★★★★ 4.3 from around £300 (motor only)

Best for: Best ride feel and hills

Motor

250W mid-drive (UK-legal version)

Battery

Add separately, 36V frame or rack pack

Range

Depends on battery, typically 25 to 50 miles

Weight

Around 4 to 5kg added

+ What we like

• Mid-drive power feels natural and climbs well
• Uses your existing gears
• Wide spares and support community

- Watch-outs

• Fiddly bottom-bracket install
• Battery is an extra cost

Our verdict: The enthusiast's choice. Buy the UK-legal 250W version, pair it with a quality battery and accept the harder install.

Check price

A Bafang mid-drive is hard to beat for the best ride feel and the strongest hill climbing. Driving the chain through your existing gears gives a natural, bike-like push. The spares and tuning community is huge too. Two important caveats apply. Choose the 250W UK-legal version rather than a higher-powered model. Budget separately for a good battery. The bottom-bracket install is the most demanding here. Factor in a shop fit if you are not confident.

Cyclotricity

Cyclotricity Rear Hub Kit

★★★★★ ★★★★★ 4.0 from around £350 (with battery)

Best for: Best value with battery

Motor

250W rear hub

Battery

36V rack or frame battery on bundle options

Range

Up to 25 to 40 miles (claimed)

Weight

Around 5 to 7kg added

+ What we like

• Affordable complete kit with battery options
• Rear motor adds grip and balance
• Good torque for the price

- Watch-outs

• Heavier and bulkier setup
• Rear wheel install is more involved

Our verdict: The value pick if you want a complete kit with a battery for the least money and do not mind the extra weight.

Check price

A Cyclotricity rear hub bundle does the job for a complete kit with a battery at the lowest outlay. The rear motor gives decent torque and balance. Bundles that include a 36V battery keep the total cost down. The trade-offs are weight and a more involved rear-wheel install. It remains a sensible buy for budget commuting and flatter routes. Our best conversion kits roundup covers more options at this price.

Is a converted bike road legal in the UK?

Yes, but only if the finished bike still meets the same rules as a shop-bought e-bike. This is the part too many kit sellers gloss over. Your finished bike must meet the following to be road legal as an EAPC:

• The motor must be rated at 250W continuous.
• Motor assistance must cut off at 15.5mph (25km/h).
• The bike must keep working pedals.
• The rider must be at least 14 years old.

A compliant converted bike needs no licence, tax, insurance or registration. You can use it on roads and cycle paths.

The traps are power and throttles. A kit set above 250W is not a legal EAPC. Neither is one with a twist-and-go throttle that drives you above walking pace of 6km/h without pedalling. Walk-assist up to 6km/h is fine. The government looked at relaxing these limits in 2024 but confirmed in early 2025 that the 250W and 15.5mph rules stay. High-power 48V, 52V or 72V kits and 1000W to 2000W motors exist and are sold widely. They are for private land only. They are not for UK roads.

Our full electric bike law guide covers age limits, where you can ride and how a kit compares against buying a complete e-bike.

Conversion kit or a new e-bike?

A kit makes most sense in three situations. You already own a quality bike. You want to keep its frame and feel. You are happy to fit it yourself or pay a shop to. You can often convert for £350 to £700 all in. That is well under the price of a decent factory e-bike. It is also the greener choice. You reuse what you already have.

A complete e-bike makes more sense in three situations too. Your current bike is old or worn. You want a warranty on the whole machine. You want the cleanest integration with a hidden battery and matched components. Mid-drive factory bikes in particular are engineered as a whole. A kit cannot fully match that integration. Our motors explained guide helps you choose the right drive type before deciding. Our batteries and range guide is also worth a look to understand how far any setup will really take you. Buy a 250W UK-legal system if you do go the kit route. Match the battery to your real-world distance. Fit it carefully yourself or have it fitted. That keeps the bike safe as well as legal.