How to Build an Electric Bicycle Motor with a Kit

There are a number of electric bicycle motor kits on the market. The right one for you depends on your budget, the distance you want to travel, and how much payload you want to carry. The most common kits come with a wheel with a pre-installed hub motor, a battery, and a throttle controller. A competent hobbyist familiar with simple electronic wiring and bicycle maintenance can install the average hub motor electric-assist kit in just a couple of hours.

Choose an electric assist kit that meets your needs. There are three main types from which to choose. Hub -- front or rear -- motors are the quietest, simplest and most common kits currently available. Frame mounted chain drive systems use your bike's existing drive train to allow for a lower wattage motor to deliver hauling capabilities comparable to much higher wattage hub motors that draw more power, but they require greater mechanical skill and experience to install correctly. Rear axle chain drive kits are inexpensive, but are rapidly falling out of favour due to advances in hub motor technology. You also need to determine how far you intend to travel and how much power you want the bike to have. Ensure the kit you want will be street legal in your area. Some jurisdictions have restrictions on power, speed, and assist technologies.

Remove the appropriate wheel on your bicycle if you have decided to buy a hub motor. Replace it with the one supplied in your conversion kit. Front wheel kits are the easiest to install and give the best front/rear weight distribution. Front wheel kits are also a good choice if you'd like to easily switch between riding your bike in its normal configuration and adding the hub motor for longer trips or heavier loads. Rear wheel hub motors are a good choice if you want to remove your front wheel when locking up your bike, have front suspension, or prefer the feel of a rear-drive set-up.

Install the motor controller and the rack that hold the battery on your right handlebar. Install the wiring harness connecting the battery, motor, and controller. Ensure all wires are routed away from the brakes, wheels, and chain and secured to the bike frame with zip-ties or tape.

Charge the battery and test ride your new e-bike. Be sure to double check all bolts for tightness and ensure you've reattached your brake cables before heading out. With electric-assist, your bike will weigh more, accelerate more quickly, and go faster than a regular bike, so it's crucial to keep your brakes in top condition.

Store your new e-bike in a dry place. Moisture is hard on electronics. and while most e-bike motors are built to withstand rain and weather, prolonged exposure to moisture will accelerate corrosion and result in the need to replace parts long before they are worn out from normal wear and tear.


Choose the lightest, most powerful batteries you can afford. This will increase the distance you can travel on a single charge. Consider a regenerative hub motor for added range. This type of motor feeds electricity back to the battery when not in use --travelling downhill or during braking. A regenerative system will add as much as 10 per cent more range to your system and offers slightly less wear and tear on your brake pads, but it does require a specialised, 2 quadrant, motor controller. A regenerative system makes it slightly harder to pedal when you are not using the motor. If you plan on riding at night, consider a motor controller that can also distribute power to a lighting system. You can install lights that are brighter than normal bike lights, which are primarily for being seen, rather than increasing visibility down the road. You won't need to buy a separate battery system, or rely on environmentally unfriendly disposable batteries.


Every jurisdiction is different. Local laws vary regarding maximum power and top speed. Throttle- controlled kits are not allowed at all in some countries. Check with your local motor vehicle regulations to ensure you don't need to have a motorcycle license and helmet to ride your bike on public streets. Also be aware of any restrictions regarding motorised vehicles on bike paths.

Things You'll Need

  • Electric assist bicycle motor kit
  • Bicycle
  • Allen key set
  • Metric wrench set
  • Multi-head screwdriver
  • Pliers
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About the Author

Chris Keam has worked as a writer and editor in Vancouver since 1989. He has been published in a wide range of magazines and online publications including "Momentum" Magazine, "Pedal," "SkiTrax," The Tyee, "Mountain Bike Action" and Granville Online. Chris also works as a video editor and producer. His education includes post-secondary college courses, training in writing topical promotions, film editing, mediation, and desktop publishing.