How to Turn Your Regular Bike Into an Electric Bike

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TL;DR: Yes, you can convert your regular bike into an electric bike using an e-bike conversion kit. The process involves fitting a motor wheel, a battery, a controller, and a display to your existing frame. It typically costs between £150 and £500 depending on the kit, takes a few hours to install, and the result rides just like a regular e-bike. This guide walks you through every step.

So You Want to Go Electric

A few years ago, converting a bike to electric felt like something only engineers did in garages on weekends. Now it is a genuinely practical option that thousands of UK cyclists are choosing every year. Maybe you already love your bike and just want to stop arriving at work sweaty. Maybe the hills near you have always been a bit much. Whatever the reason, an e-bike conversion lets you keep the bike you know and trust while giving it a serious upgrade.

The good news is that the kits have come a long way. They are lighter, more reliable, and far easier to fit than they used to be. This guide covers everything you need to know before you buy: what kit to choose, how the installation works, what UK law says, and when it might just make more sense to buy a purpose-built e-bike instead.

What Is an E-Bike Conversion Kit?

An e-bike conversion kit is a bundle of components designed to add electric assist to a standard bicycle. Most kits include a motorised wheel hub (either front or rear), a rechargeable lithium battery, a controller, brake sensors, and a handlebar display that shows your speed, battery level, and assist mode.

There are three main types of conversion kit:

  • Front hub motor kits - the motor is built into a replacement front wheel. These are the easiest to fit and generally the cheapest. Ideal for commuters and casual riders.
  • Rear hub motor kits - the motor sits in the rear wheel and provides a more natural riding feel because the power comes from behind. Better for hilly terrain.
  • Mid-drive motor kits - the motor fits at the bottom bracket and drives the chain directly. The most efficient option for off-road riding and climbing, but the most involved to install.

UK Legal Requirements for Converted E-Bikes

Before you buy anything, it is worth getting familiar with UK rules on e-bikes. Under current legislation, an electrically assisted pedal cycle (EAPC) is legal to ride on public roads and cycle paths without registration, tax, or a licence, as long as it meets all of the following:

  • The rider must be 14 years old or over
  • The motor must not exceed 250W continuous rated power
  • Electric assistance must cut out at 15.5 mph (25 km/h)
  • The bike must only assist when you are pedalling (no throttle-only riding above 6 km/h on public roads)

Any kit you buy should clearly state whether it is EAPC-compliant. If it is not, your converted bike would be classed as a motor vehicle, which means it would need to be registered, taxed, and insured like a moped. Always check before purchasing.

What You Need Before You Start

Not every bike is equally well-suited for conversion. Before ordering a kit, run through this quick checklist:

  • Frame condition - the frame should be free of cracks or significant rust. A conversion kit is wasted on a frame that will not hold up.
  • Wheel size - most kits are available in 26", 27.5", and 700c. Make sure the motor wheel matches your current tyre size.
  • Dropout width - this is the gap at the end of your fork or rear frame where the wheel axle sits. Standard road and hybrid bikes are usually 100mm front and 135mm rear. Check the kit specs match.
  • Brake type - most kits include sensor cables that plug into your brake levers to cut the motor when you brake. Check compatibility with your existing brakes.
  • Battery mounting space - most batteries mount to the down tube of the frame using bottle cage bolts. Make sure there is a suitable space.

How to Convert Your Bike: Step by Step

Once you have your kit, the process is straightforward for a front hub conversion. Here is how it works:

Step 1: Remove the Existing Wheel

Release the quick-release skewer or undo the axle nuts on your front wheel and remove it. Transfer the tyre and inner tube to the new motor wheel, making sure everything is seated correctly before re-inflating.

Step 2: Fit the Motor Wheel

Slot the motor wheel axle into the fork dropouts. Most hub motors have a torque arm that needs to be bolted to the fork to prevent the axle from spinning. Do not skip this step as it prevents damage to your fork and potential accidents.

Step 3: Mount the Battery

Attach the battery mount to the down tube using the bottle cage bolts. Slide the battery onto the mount and make sure it clicks into place securely. Route the main power cable along the frame, using the cable ties provided to keep everything tidy.

Step 4: Install the Controller

The controller is the brain of the system. It usually fits inside a bag that straps around the frame or mounts behind the battery. Connect the motor cable, battery cable, and the cables that will run to your display and brake sensors.

Step 5: Fit the Display and Controls

Clamp the handlebar display and the assist level control button onto your handlebars. Connect the cable to the controller. Most displays require a simple plug-in connection.

Step 6: Connect the Brake Sensors

Clip the brake sensors onto your existing brake levers. These send a signal to cut motor power the moment you pull the brakes, which is a legal requirement for UK road use.

Step 7: Test Before You Ride

Turn the system on and walk the bike forward to check the motor engages smoothly when you pedal. Test the brakes and confirm the motor cuts out immediately. Go for a short test ride in a quiet area before taking it on the road.

How Much Does an E-Bike Conversion Cost?

Budget kits start from around £150 and will get you a basic front hub motor and a modest battery capacity of around 250Wh. Mid-range kits in the £250 to £400 bracket typically offer better build quality, longer battery life, and smoother assist. Premium kits can push past £500, particularly for mid-drive systems.

For comparison, a purpose-built e-bike from a reputable brand starts at around £800 to £1,000. If your existing bike is high quality and well-maintained, converting it can be a genuinely cost-effective alternative. If the bike itself is worth less than £200, you may be better off putting that money toward a new e-bike instead.

When a Conversion Kit Makes Sense (and When It Does Not)

Conversion is a good option if:

  • You already own a decent bike that you love riding
  • You want to reduce your commute effort without buying a new bike
  • You enjoy the process of working on your bike and want full control over the components

A purpose-built e-bike may be the better choice if:

  • Your current bike is old, heavy, or structurally compromised
  • You want a fully integrated, warranty-backed solution from day one
  • You prefer a cleaner aesthetic with no external cables or battery packs strapped to the frame

ElectroCity Bikes Conversion Kits Worth Considering

If you have decided a conversion kit is the right move, here are four of the most popular options available from ElectroCity Bikes right now. There is something here whether you are a daily commuter, a weekend trail rider, or someone who wants serious off-road power.

1. Conversion Kit + 48V Battery, Rear Cassette, MTX Rim, 1000W — From £289

A solid all-rounder that works across 27.5", 29", and 700c wheel sizes. This rear hub kit comes with the battery included, a reinforced MTX rim, LCD display, pedal assist sensor, and brake cut-off levers. The 48V system gives you a dependable range for commuting and weekend riding, and the installation is straightforward enough for a first-time converter. A great entry point if you want everything in one box without overspending.

Best for: commuters and casual UK road riders. 

Conversion Kit + 48V Battery, Rear Cassette, MTX Rim, 250V, 1000W, 27.5/29/700C

2. E-Bike Conversion Kit with Battery 1000W Sine Wave MTX — From £249.99

One of the most popular kits in the range, this 1000W rear hub system uses a sine wave controller for quieter, smoother motor operation compared to cheaper square-wave alternatives. It is available with battery capacities from 48V 10Ah all the way up to 52V 28.8Ah, so you can dial in the range you actually need. Dual stainless steel torque arms are included to protect your frame dropouts, and a waterproof controller box keeps the wiring clean and protected from British weather.

Best for: riders who want a quiet, refined motor with flexible battery options. View Conversion kit

3. E-Bike Conversion Kit with Battery 1500W Sine Wave MTX — From £299.99

Step up in power without going into off-road-only territory. This 1500W kit is the sweet spot for riders who tackle hilly terrain regularly or carry heavier loads. The sine wave controller keeps operation whisper-quiet, and the heavy-duty MTX rim with stainless steel spokes is built to handle the extra motor stress. Battery options go up to 52V 28.8Ah for serious range. Compatible with 27.5" and 29" wheels and standard 135mm to 142mm rear dropouts.

Best for: hilly routes, hybrid bikes, and longer weekend rides. 

E-Bike Conversion Kit with Battery 1500W Sine Wave MTX

4. E-Bike Conversion Kit 2000W 45A MTX — From £329.99

For off-road use on private land, this 2000W kit is where performance builds begin to get serious. It ships as a complete package with display, throttle, sensors, and cable management included, so there is no hunting for additional parts. Battery options include up to 60V 25Ah in a triangle frame configuration for improved weight distribution and maximum range. The MTX rim uses riveted spokes for extra structural strength at higher power levels. Note: this kit is not road-legal for UK public roads in its full 2000W configuration.

Best for: off-road, private trail, and performance build enthusiasts. 

E-Bike Conversion Kit with Battery 2000watt 45A MTX

Ready to Go Electric?

Whether you go the conversion route or decide a ready-to-ride e-bike suits you better, ElectroCity Bikes has you covered. Browse our full range of electric bikes to find the right ride for your commute, weekend adventures, or everything in between.

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FAQ's

Can any bike be converted to electric?

Most standard bicycles with a steel or aluminium frame can be converted, including road bikes, hybrids, and mountain bikes. Carbon fibre frames are generally not recommended because the dropout areas cannot always handle the torque forces from a hub motor. Very old or structurally worn frames should also be avoided.

Is it legal to convert a bike to electric in the UK?

Yes, as long as the converted bike meets EAPC regulations. The motor must be rated at 250W or below, assistance must cut out at 15.5 mph, and the bike must only assist when pedalling. Kits that exceed these limits would require the bike to be registered as a motor vehicle.

How long does a conversion kit battery last?

Range depends on battery capacity, terrain, rider weight, and assist level. A typical 36V 10Ah battery (360Wh) will give you between 20 and 40 miles of range per charge. Higher capacity batteries of 500Wh or more can stretch this considerably. Most lithium batteries remain in good health for 500 to 800 charge cycles.

How long does it take to install an e-bike conversion kit?

For a front hub motor kit, most people complete the installation in two to four hours on their first attempt. Rear hub and mid-drive installations take longer and may require more mechanical experience. Having a basic set of spanners, Allen keys, and cable ties to hand makes the process significantly smoother.

Is a converted e-bike as good as a purpose-built one?

A well-chosen conversion kit on a quality base bike can get very close to the performance of a mid-range purpose-built e-bike. However, purpose-built models benefit from integrated engineering, meaning the motor, battery, and frame are all designed to work together. For reliability over many years and a cleaner finish, purpose-built bikes tend to have the edge.