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Can you make a normal bike electric?

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In short

Yes. Most sound, steel or aluminium bikes with standard wheel sizes and good brakes can be converted with a front hub, rear hub or mid-drive kit. Carbon frames and forks, very old or worn bikes, and bikes with weak brakes are poor candidates. To be road legal in Great Britain, the finished bike must stay within the EAPC rules of 250 W and 15.5 mph.

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If you already own a bike you like, converting it can be appealing. You keep the fit and feel you know, and add a motor for hills and longer trips. Not every bike is a good candidate, though, and some kits sold online would make your bike illegal on UK roads. This guide explains which bikes convert well, what to check on yours, and how to stay within the law. If in doubt, ask a bike mechanic to look over your bike before you buy a kit.

How a conversion kit turns a bike electric

A kit adds the same core parts found on a factory e-bike: a motor, a battery, a controller, a pedal-assist sensor, brake cut-off levers and a display. The motor goes in the front wheel, the rear wheel or at the cranks (mid-drive). The controller reads the pedal sensor and sends power to the motor while you pedal.

Front hub kits are usually the simplest to fit. Rear hubs give better traction. Mid-drives use your gears and suit hills. Our hub motor vs mid-drive guide compares them.

  1. 1Motor wheel or mid-drive unitFits: Front or rear dropouts, or the bottom bracket
  2. 2Battery with mountFits: Down tube bottle bosses or a rear rack
  3. 3ControllerFits: Battery mount or a frame bag
  4. 4Pedal-assist sensorFits: Behind the chainring, on the crank axle
  5. 5Brake levers with cut-offFits: Handlebar, in place of your levers
  6. 6DisplayFits: Handlebar, next to the stem
The parts of a typical conversion kit and where each one fits on the bike.

Bikes that usually convert well

Good candidates share a few traits: a solid frame, standard parts and brakes that are up to the job.

BikeSuitabilityThings to check
Steel or aluminium hybridUsually goodDropout widths, brake condition
Hardtail mountain bikeGood, especially with mid-driveBottom bracket type, fork for front hubs
Touring bikeGoodRack mount for the battery
Folding bikePossible with specific kitsWheel size, hinge strength, weight
Full-suspension mountain bikeTrickyBattery space, frame design
Carbon road or mountain bikeNot advisedCarbon dropouts and forks are not designed for motor loads
Conversion suitability at a glance

What to check on your bike

Measure before you buy. Kit makers list the dropout widths, wheel sizes and bottom bracket types they support.

If your bike needs significant repairs before converting, compare the total with a factory-built bike. Our conversion kit vs new e-bike guide looks at that trade-off.

  • Frame and fork material: steel or aluminium, with no cracks or heavy corrosion.
  • Fork dropouts: front hub motors need sturdy dropouts; avoid carbon and suspension forks with lightweight lowers unless the kit maker approves them.
  • Brakes: the bike will carry more weight; good disc or well-adjusted rim brakes matter.
  • Wheel size: the kit wheel must match your existing tyre size.
  • Battery space: a water bottle mount, rack or handlebar position for the pack.
  • Overall condition: worn chains, bearings and tyres should be replaced first.

Making a mountain bike electric

Hardtail mountain bikes are popular for conversion because they are strong and have room on the down tube for a battery. A mid-drive kit works well off-road because it uses your gears for steep climbs. Front hub motors can work on a rigid fork but are less suited to suspension forks and loose ground.

If you would rather buy a ready-made bike, our electric mountain bike guide covers bikes built around a motor from the start.

Keeping a converted bike road legal

In Great Britain a converted bike is treated as an electrically assisted pedal cycle only if it meets the EAPC rules. Kits rated at 1000 W or more, or set to assist above 15.5 mph, turn the bike into a motor vehicle that needs registration, tax, insurance and a licence for road use. Our explainer on conversion kit law covers this, and the UK e-bike law check tests a given setup.

Note:To stay road legal in Great Britain, a converted bike must meet the EAPC rules: a motor with a continuous rated power of no more than 250 W, assistance that cuts out at 15.5 mph (25 km/h), and no throttle that works above walking pace. Kits sold as 1000 W or more, or set above 15.5 mph, make the bike a motor vehicle on roads. Brakes and wiring are safety-critical, so we recommend having a bike mechanic fit the kit or check your work.

Frequently asked questions

Is it cheaper to convert a bike than buy an e-bike? It can be if your bike is in good condition. If it needs new brakes, wheels or drivetrain, a factory-built e-bike may make more sense.

Can any bike be made electric? Not any bike. Carbon frames and forks, very worn bikes and bikes with poor brakes are best left alone.

Does converting a bike void its warranty? It may affect the frame maker's warranty. Check with the maker before fitting a kit.

Will a converted bike be heavy? Kits add the weight of the motor and battery, so the bike will be noticeably heavier than before.

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