Electric Bike Conversion Kits

If you already own a bike you like, an electric bike conversion kit is the cheapest route to electric assistance. Instead of spending £1,000 or more on a new e-bike, you add a motor, a battery and a sensor to the bike you already ride, often for a few hundred pounds. Done well, a converted bike rides almost like a factory e-bike. Done badly, it can be heavy, unbalanced or, worse, 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, and we flag where figures are claimed rather than independently measured. Prices in this market move often, so 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, and that single choice shapes everything about how the bike rides, what it costs and how hard it is to fit. We break down the three types below. The battery either bolts to the frame, sits on a rear rack, or in the neatest kits clips to the handlebars. The sensor is usually a simple cadence sensor that switches assistance on when the cranks turn, or, on better kits, a torque sensor that matches power to how hard you push.

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, mount the battery and sensor, and you are done, often in 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, and very light front forks may not be rated for the extra torque.

Rear hub kits

A rear hub motor replaces the back wheel. It puts power where your weight already sits, so traction and balance feel more natural, and torque for hills is usually stronger than a front kit. The trade-off is a more involved fit, because you have to deal with the cassette, gears and sometimes brake disc, so many riders have a shop do it. Rear hub kits also tend to be the heaviest option once you add a battery.

Mid-drive kits

A mid-drive motor, such as the Bafang BBS series, sits at the bottom bracket where the pedals meet the frame and drives the chain directly. Because it uses your existing gears, it climbs the best and gives the most natural, bike-like power delivery, with the weight low and central. The catch is that mid-drives are the most expensive and the hardest to install, and they put extra strain on the chain, cassette and chainrings, so those parts wear faster.

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, because 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, and 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, like a bare Bafang mid-drive at around £300, look cheap until you add a quality battery, which can easily cost £250 to £450 on its own. That route gives you more control over capacity and cell quality, but it is for confident builders. If in doubt, buy a complete kit with the battery included.

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, not 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. Because the motor is built into the front wheel and the battery clips to the bars, fitting is genuinely beginner-friendly. The Go pack suits short town hops, while the larger Max pack is the one to choose if your ride is longer or hilly. Lead times have at times been long, so 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

If you own a good road or hybrid bike and do not want to ruin its feel, the Cytronex C1 is the premium pick. At around 3.6kg added it is one of the lightest kits available, and the bottle-style battery keeps the look clean. Power delivery is smooth and the UK-based support is a real advantage if something goes wrong. The single bottle pack means range is modest, so 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

For the best ride feel and the strongest hill climbing, a Bafang mid-drive is hard to beat. Driving the chain through your existing gears gives a natural, bike-like push, and the spares and tuning community is huge. Two important caveats: choose the 250W UK-legal version, not a higher-powered model, and budget separately for a good battery. The bottom-bracket install is the most demanding here, so 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

If your priority is a complete kit with a battery for the lowest outlay, a Cyclotricity rear hub bundle does the job. The rear motor gives decent torque and balance, and bundles that include a 36V battery keep the total cost down. The trade-offs are weight and a more involved rear-wheel install, but for budget commuting and flatter routes it is a sensible buy. For more options at this price, see our best conversion kits roundup.

Is a converted bike road legal in the UK?

This is the part too many kit sellers gloss over. To be road legal as an EAPC, your finished bike must meet the same rules as a shop-bought e-bike. The motor must be rated at 250W continuous, motor assistance must cut off at 15.5mph (25km/h), the bike must keep working pedals, and the rider must be at least 14 years old. A compliant converted bike needs no licence, tax, insurance or registration, and you can use it on roads and cycle paths.

The traps are power and throttles. A kit set above 250W, or one with a twist-and-go throttle that drives you above walking pace (6km/h) without pedalling, is not a legal EAPC. 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, but they are for private land only, not UK roads.

For the full rules on what makes any e-bike legal, including age limits and where you can ride, see our UK electric bike law guide. If you are still weighing a kit against a complete bike, our main electric bikes guide covers both.

Conversion kit or a new e-bike?

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

A complete e-bike makes more sense if your current bike is old or worn, you want a warranty on the whole machine, or you want the cleanest integration with a hidden battery and matched components. Mid-drive factory bikes in particular are engineered as a whole, which a kit cannot fully match. Before deciding, read our electric bike batteries and range guide to understand how far any setup will really take you, and our motors explained guide to choose the right drive type. If you do go the kit route, buy a 250W UK-legal system, match the battery to your real-world distance, and fit it carefully, or have it fitted, so it is safe as well as legal.