Best Electric Bike Conversion Kits

A conversion kit turns a bike you already own into an electric one, usually for a lot less than buying a new e-bike. The catch is that the market runs from polished UK kits with proper support all the way to grey-import boxes of parts, and the legal line matters more here than anywhere else in e-biking. Fit the wrong kit and you can end up riding something that is, technically, an unregistered motor vehicle.

We ranked the kits below on the things that decide whether a conversion is worth it: how easy it is to fit, whether it stays EAPC-legal at 250W, the included battery and realistic range, the added weight, and the quality of UK support. Prices move often, so use the “Check price” links for the live figure.

How we chose

We shortlisted kits sold in the UK with a clear path to EAPC legality, then scored each on six factors: ease of fitting, motor and sensor type, included battery and real-world range, added weight, UK support and warranty, and value against rivals. We do not take payment from manufacturers, and a kit never moves up our list for a commission. Where a spec could not be verified from the maker, we have said so rather than guessed. Our full explainer on how these systems work sits in the conversion kits guide.

1. Swytch Go - best overall

#1

Swytch

Swytch Go

★★★★★ ★★★★★ 4.5 around £599

Best for: Best overall

Motor

250W front hub

Battery

Removable handlebar Power Pack

Range

Up to 30 miles (Go++ pack, claimed)

Weight

Around 3kg added

+ What we like

• Light and easy one-hour fit
• UK brand with proper support
• Removable battery charges indoors

- Watch-outs

• Front-hub feel is less natural than a mid-drive
• Shorter range than big-battery kits

Our verdict: The most approachable conversion you can buy. Light, legal and backed by a real UK company.

Check price

The Swytch Go is the kit we would point most people to first. You replace your front wheel with the Swytch motor wheel, clip a small battery pack to the handlebars and fit a pedal sensor, and most people are riding within an hour. It is light, it keeps your existing gears and brakes, and the Power Pack lifts off so you can charge it indoors or leave nothing worth stealing on the bike. As a UK company, Swytch also gives you support you can actually reach, which is rare at this price. The front-hub setup feels a touch less natural than a mid-drive on steep climbs, but for towns and commutes it is excellent.

2. Bafang BBS01B Mid-Drive Kit - best ride feel

#2

Bafang

Bafang BBS01B Mid-Drive Kit

★★★★★ ★★★★★ 4.4 from around £450 with battery

Best for: Best ride feel

Motor

250W mid-drive (programmable)

Battery

36V or 48V down-tube (choose your own)

Range

Up to 45 miles (battery dependent)

Weight

Around 5 to 7kg added

+ What we like

• Mid-drive feels like a true e-bike
• Strong on hills with a heavy load
• Huge choice of batteries

- Watch-outs

• Fitting is involved and needs the right bottom bracket
• Must be programmed to 250W to stay legal

Our verdict: The kit for the most natural assist, as long as you are happy to fit it carefully and keep it at 250W.

Check price

Bafang’s mid-drive kits mount the motor at the bottom bracket and drive through your chain, which is why they feel closest to a factory-built e-bike. The BBS01B is the sensible road choice because it is the lowest-powered of the family and can be set to a 250W, 15.5mph EAPC limit. Because the motor uses your gears, it climbs far better than any hub kit. The downsides are real: fitting needs the correct bottom-bracket width and some mechanical confidence, and you must program it down to 250W to ride it legally. Get that right and it is the best-riding kit here. Read our battery and range guide before choosing the pack.

Compare conversion kits with batteries

3. Cytronex C1 - best lightweight premium

#3

Cytronex

Cytronex C1

★★★★★ ★★★★★ 4.3 around £950

Best for: Best lightweight premium

Motor

250W front or rear hub

Battery

198Wh bottle-style

Range

Up to 35 miles (claimed)

Weight

Around 3.6kg added

+ What we like

• Very light and discreet
• UK-built with full support and fitting service
• Smooth, road-bike-friendly assist

- Watch-outs

• Premium price for a small battery
• Shorter range than heavier kits

Our verdict: The pick if you want a quality road bike to stay light and just get a quiet, gentle boost.

Check price

Cytronex is a UK company that has built its reputation on keeping converted bikes light. The C1 hides its battery in what looks like a water bottle, adds only around 3.6kg and gives a smooth, subtle hand on the pedals rather than a shove. That makes it the natural choice for road and hybrid riders who love their bike and do not want to ruin its balance. The 198Wh battery is small, so range and the price both reflect a focus on weight over capacity. If you would rather not fit it yourself, Cytronex will install it for a fee.

4. Yose Power 250W Front Hub Kit - best budget kit with battery

#4

Yose Power

Yose Power 250W Front Hub Kit

★★★★★ ★★★★★ 4.0 from around £300 with battery

Best for: Best budget kit with battery

Motor

250W front hub

Battery

36V 13Ah to 15.6Ah down-tube

Range

Up to 40 miles (claimed)

Weight

Around 6 to 8kg added

+ What we like

• Complete kit with battery for the money
• Stocked and shipped from the UK
• Front-wheel fit leaves your gears alone

- Watch-outs

• Cadence sensor feels basic
• Heavy battery adds notable weight

Our verdict: The best way to get a motor and a real battery on your bike without spending much.

Check price

If the budget is tight, Yose Power is the brand that keeps coming up, and for good reason. You get a complete front-hub kit with a 36V down-tube battery, display, pedal sensor and brake cut-offs from around £300, with stock held in the UK so returns and spares are straightforward. It comes in the common wheel sizes, so a 26 inch or 28 inch conversion is easy. The assist is basic, the cadence sensor switches power on and off rather than reading your effort, and the battery is heavy, but as a low-cost way to add real electric range it is hard to beat. For other low-cost routes, see our cheap electric bikes guide.

5. Dillenger Street Legal Rear Hub Kit - best rear-hub kit

#5

Dillenger

Dillenger Street Legal Rear Hub Kit

★★★★★ ★★★★★ 4.1 from around £549 with battery

Best for: Best rear-hub kit

Motor

250W rear hub

Battery

36V down-tube or rack battery

Range

Up to 40 miles (claimed)

Weight

Around 7 to 9kg added

+ What we like

• Rear-hub traction climbs better than front
• EAPC-legal out of the box
• UK support and clear fitting guides

- Watch-outs

• Needs your cassette refitted to the new wheel
• Heavier than a hub-only kit

Our verdict: A solid, legal rear-drive conversion with the grip front kits lack, backed by UK support.

Check price

A rear-hub kit puts the motor in the back wheel, which gives better traction on hills and a more planted feel than a front conversion. Dillenger’s street-legal kits are sold as EAPC-compliant from the start, which takes the legal guesswork away, and the company offers UK support and clear fitting instructions. The main extra job over a front kit is moving your cassette onto the new motor wheel, so it suits riders who are comfortable with a little spanner work. It is heavier than a Swytch or Cytronex, but it is a dependable, road-legal middle ground.

6. Swytch Air - best ultra-light

#6

Swytch

Swytch Air

★★★★★ ★★★★★ 4.2 around £999

Best for: Best ultra-light

Motor

250W front hub

Battery

700g Air Power Pack

Range

Up to 15 miles (claimed)

Weight

Around 1.5kg added

+ What we like

• Tiny 700g battery is barely noticeable
• Keeps a road bike feeling like a road bike
• Quick to fit and remove

- Watch-outs

• Short range from the small battery
• Premium price for the lightest option

Our verdict: The lightest kit here, ideal for short hilly commutes where you want almost no extra weight.

Check price

The Swytch Air is the kit for riders who care about weight above all else. Its Power Pack weighs just 700g, so the whole system adds barely more than a kilo and a half, and a converted road bike still feels like a road bike. That makes it brilliant for shorter, sharper commutes where you want a hand up the hills without lugging a heavy battery. The trade-off is obvious: a tiny battery means a short claimed range of around 15 miles, and you pay a premium for the engineering. For longer trips, one of the bigger-battery kits above makes more sense.

What to expect from a conversion kit

The right kit depends on your bike and your route. Front-hub kits are the easiest to fit and leave your drivetrain alone, rear-hub kits grip better on climbs, and mid-drive kits feel most like a proper e-bike but demand the most work. Whatever you choose, the non-negotiable is legality: a 250W continuous motor with assistance cutting out at 15.5mph keeps you within EAPC rules, so you need no licence, tax or insurance. Anything badged 500W, 750W or higher is not road-legal in the UK unless restricted.

Weight and battery size are the other big decisions. A small battery keeps the bike light but limits range, while a big down-tube pack adds usable miles at the cost of several kilos. If you would rather skip the build entirely, our roundup of the best electric bikes under £1000 shows what a complete e-bike costs, and our UK e-bike law guide covers the rules in full before you ride.