After building a few e-bikes, I've picked up some tricks and definitely made some mistakes along the way. Time to share what I've learned! This guide gives you the knowledge you need to build your very own eBike:
Step 1: Prepare Your Bike
There are 2 main things you need to prepare for when looking to build a DIY hub motor ebike;
- Dropouts: Check that your bike frame has the correct dropouts and axle spacing to fit your new hub motor (most hub motors have a 135mm rear dropout width) and is compatible with your hub motors braking system (disc or rim brakes).
- Battery: Measure space for your battery; Make sure you know where your choice of battery is going to fit.
Step 2: Gather Your Components
Here is a list of parts and accessories you will need:
- Tools: Adjustable spanner, Allan key's, Cable ties (Zip ties), Bike pump, Scissors or Wire cutters (or both), Tape (optional). You might need a star shaped screwdriver if your disc brake bolts or other bolts require it.
- Suitable Battery: Lithium-ion batteries are the standard for e-bikes. Determine the voltage and amp-hour (Ah) capacity your setup demands. Find a battery that suits your needs or consider building your own DIY battery pack if you're experienced with electronics.
- Controller: Controllers manage how much power is pulled or "asked" from your battery and put into the motor, measured in "amps". You can choose between sine wave or square wave types. Make sure the controller matches your battery power and motor specifications, think volts, amps and watts.
- Hub Motor: Hub motors are placed into the front or rear wheel dropouts. Choose a hub motor with a power rating (Voltage and Watts) appropriate for your personal needs or local regulations if your going to be riding on public roads. 250W-1500W controllers, motors and conversion kits are the most common choices for beginners.
- Pedal Assist Sensor (PAS): A PAS lets you power the motor by pedalling. Note: Many countries around the world require this for legal road use.
- Throttle: On demand acceleration and top speed control, Options include; full twist throttles, half twist throttles and thumb throttles. Note: Thumb throttles are required in specific country's in order to pass for road use.
- Display (optional): An optional, but highly recommended, component providing speed, battery status, and other useful data.
- Torque arm: Optional for builds under a 1000W rating but we highly recommend for builds equal to or over 1000W!
- A bike frame: Of course!
Step 3: Installing the Hub Motor
- Important for Powerful Builds: If your controller pulls equal to or more than 1000W from your battery, your e-bike will generate enough torque to potentially damage the frame. In this instance we highly recommend installing a torque arm. This prevents your axle from twisting in the frame dropouts under sudden high torque loads, potentially causing your hub motor to come out of the frame whilst riding. (this is not good for obvious reasons!)
- 1: Find the best spot to place your battery and controller relative to your bike frame. Options include a rear pannier rack, the frame's downtube, or custom battery and controller bags.
- 2: Remove your existing front or back wheel on your frame by unbolting it or loosening the quick release.
- 2: Carefully place the motor axle into the bike frame dropouts.
- 3: Make sure your new hub motor is properly aligned within your frame and any loose wires away from moving moving parts. After that secure the motor using nuts and washers, usually provided with the motor. Once you have your hub motor bolted in properly its time for step 4!
- Note: Some frames will require you to make more space for the new hub motor axles to fit in by doing some light filing. Usually only a problem when installing with 14x10mm or 16x10mm axle dimensions. If you have a issue like this and are unsure what to do next please feel free to leave a comment at the bottom of this article or contact us directly.
Step 4: Mount the Battery and Controller
- Find the best spot to mount your battery and controller. Options include a rear rack, the frame's downtube, or a custom bag.
- Be creative and use the best mounting methods for your situation to prevent these components from shifting during rides.
Step 5: Connect the Components
- Refer to the included wiring diagrams for your motor, controller, and other components. Color-coding as standard; Battery - black for negative, red for positive. Motor wires - Yellow, Green and Blue. If you need any specific diagrams, feel free to leave contact us or leave a comment below.
- Use appropriate connectors, your typical ebike conversion kit will come with the good quality connectors as standard such as XT connectors for battery's, and Lug connectors for your motors phase wires. A solid connection that has been tightened properly will prevent issues.
- If needed, watch additional online tutorials for wiring specific components.
Step 6: Install Pedal Assist Sensor (if applicable)
- Follow the included instructions with your kit or pedal sensor package to mount this sensor properly, this can require extra tools to remove your crank arm opposite to your chain ring (chain side) of your bike frame.
Step 7: Install Throttle and Display
- Secure the throttle to your handlebars for convenient access.
- Mount the display unit in a readily viewable location.
Step 8: Test and Fine-Tune
- Before a test ride, safely elevate it and give it a spin test or pedal test!
- Carefully spin the wheel and test all component functions – throttle, pedal assist, brakes, display, etc.
- Before a full test ride, make sure your hub motor is secured by using your new eBike on the highest power or pedal assist setting and pedalling or "full throttling" at a slow speed. This test will make sure your hub motor is staying in place, using the maximum torque output of the bike whilst minimizing your risk of any accidents. After a couple successful tests check to see if your axle has moved positions. Everything good? Now try going up a hill! Now your controller will detect this and your ebike will draw its max power. If everything is okay then you have successfully built a solid, working ebike. Congrats!