A guide to converting your own e-bike

E-vehicles are becoming more and more popular with riders, and we want to ensure you have all the information you need to ride safely. This includes tips on modifying your own regular bicycle to ensure that it meets all legal requirements.

What counts as an ‘electrically assisted pedal cycle’ (EAPC)?

An EAPC must have pedals that can be used to propel it.

It must show either:

  • the power output
  • the manufacturer of the motor

It must also show either:

  • the battery’s voltage
  • the maximum speed of the bike

The electric motor:

  • must have a maximum power output of 250 watts
  • should not be able to propel the bike when it’s travelling more than 15.5mph

An EAPC can have more than 2 wheels (for example, a tricycle).

Converting your own e-bike

UK law says that an e-bike must not exceed 250W to be road legal, and must stop giving assistance at 15mph. If you’re buying an e-bike online, it’s your responsibility to ensure that it complies with all UK laws, otherwise you’re liable to fines, and your vehicle could be seized.

If your e-bike doesn’t comply with these rules, it will need to be registered, insured and taxed as a motor vehicle. In this case, you will also need a driving licence, and you must wear a motorcycle helmet.

Kits will often include everything you need apart from the battery, which you can buy separately. Batteries are usually either mounted to the frame, or sit under the seat in either a bag or rack. 

Front hub kits are easier to fit, as you don’t have to interfere with the gears on your bike. 

  • Remove your old bicycle wheel and replace it with your new motorised wheel. You may need to transfer the tyre and inner tube as well – remember to partially inflate the inner tube to ensure smoother installation on your new wheel.
  • Add the LCD screen and brake levers (if included) to the handlebars. 
  • If your kit includes pedal assist, you will need to remove the pedal and cover washer. Install the sensor and secure it with the washer. Next add your magnetic ring, making sure the magnets are facing out. Reattach your pedal.
  • Attach your frame mounted battery to the bolts where your drink bottle holder would be.
  • Bolt the controller onto the frame, or secure it in a bag under the seat.
  • Connect all the wires to their appropriate partners. Note: if you purchased your controller and battery from different vendors, the connections may be different and will require further modification.
  • Ensure any wires are out of the way and zip-tied to the frame so they don’t catch on the pedals or other obstacles.
  • You’re ready to ride! Don’t forget to wear a helmet. 

 

Mid drive kits look neat and you get to keep your original wheels. However, they are more difficult to install and are not as well suited for commuting in flat areas as hub bikes. They work much better on steep hills.

  • Remove BOTH pedals from your base bracket
  • If you have more than one gear on the base bracket, you may need to remove a shifter as well
  • Install the motor where your pedals were previously
  • Put on your crank wheel (placing it loosely at first to ensure all the screws fit, then tighten them). 
  • Attach your chain
  • Reinstall your pedal bars
  • Attach your frame mounted battery to the bolts where your drink bottle holder would be
  • Add the LCD screen, control panel and brake levers (if included) to the handlebars. 
  • Attach your speed sensor to the rear wheel
  • Ensure any wires are out of the way and zip-tied to the frame so they don’t catch on the pedals or other obstacles.
  • You’re ready to ride! Don’t forget to wear a helmet. 

 

Please bear in mind the information above is meant to be used as a guideline. Each kit may be slightly different and require a slightly different set up depending on your components. If you have any difficulties, we would recommend contacting the manufacturer of your conversion kit. 

How to get the most out of your battery

  • Fully charge the battery before you use it for the first time. 
  • Never charge the battery in freezing conditions.
  • Letting the battery run empty on a regular basis will shorten its lifespan considerably. If possible, try to charge the battery when there is between 30-60% remaining.
  • Don’t leave your battery on charge for an extended period of time – such as several days. Set a timer on your phone to remind you to take it off the charger.
  • If you’re going to take a break from riding, don’t store the battery empty. At least 50% capacity remaining is ideal.

Things to keep in mind

  • Double check the size of the wheel to ensure it can fit the frame of your bike
  • When building your own e-bike, you don’t get the same warranty and support that you would if you bought it in-store.