Install Mid Drive Motor on a Bike

How to Assemble a Mid-Drive Motor on a Bike

There are several steps necessary to assemble a mid-drive motor conversion kit on your current bicycle. In short, you will need to install the motor, chain ring, cranks, pedals, speed sensor, throttle, display, brakes, headlight, and wiring. This process is not nearly as complicated as it seems!

Continue reading to find out how to easily install a mid-drive motor kit on your bike and convert it to electric power!

Items inside a mid-drive eBike conversion kit
Items inside a mid-drive eBike conversion kit

Before You Get Started

Prior to installing a mid-drive motor kit, you need to do a few things. Once you have purchased and received your motor kit, you will want to test everything inside to ensure it is properly functioning. Test the battery, the motor, the brake cut off, and the display. Head back to my website where you will find a video and article discussing how to properly test the components in your mid-drive motor kit.

Next, you will need to disassemble portions of your bicycle to ready it for motor and battery installation. Again, head back to the website where you will find a video and article detailing what portions and how to disassemble your bike. 

What Comes in a Mid-Drive Conversion Kit?

When you purchase a mid-drive conversion kit, several components will be included. The kit will come with the motor, the chain ring, the crank arms, the brake assembly with brake sensor switch, a triangle bracket for the motor, the bottom bracket lock rings, and all the necessary installation hardware (nuts, bolts, spacers, etc.) to fasten the motor to the bicycle.

RIDE eMTB Tip: Check out this article that’s got a video describing everything inside a 👉 Mid-Drive Conversion Kit

Most of the components in a mid-drive motor kit will be plug and play, meaning there are no complicated and complex wiring diagrams to follow. You will simply connect each component to the motor with a color coded wiring plug. Be sure to study the installation manual carefully as you attach each component to ensure you are wiring the motor and accessories properly.

Components You May Need to Buy

Some components will not be included in the mid-drive motor kit. If you have special ordered and personalized your mid-drive kit, as some manufacturers allow, you may not need to purchase as many extra components. However, some basic kits will lack items necessary for installation.

Mid-Drive Motor Installation
Mid-Drive Motor Installation

The first, and most vital component, is the battery. Many motor kits do not come with a battery. Ensure the battery you purchase is compatible with your motor. Each motor is rated for a specific voltage of battery. For example, the Bafang BBSHD 1000-watt motor kit is compatible with 48-volt and 52-volt batteries. Learn more about this kit here:

Additional components you may need include:

  • Zip ties (up to 20)
  • Loctite
  • Grease
  • Black electrical tape
  • Cable management tubing
  • Bottom bracket spacers (if they are not included in your kit)
  • Adhesive backed wire clips
  • Washers
  • Chain
  • Optional, but recommended: Shift sensor
  • Optional: Chain ring with different teeth (this is necessary if you cannot get the chain line straight)

Tools Needed

There are a variety of tools necessary for installing a mid-drive motor kit on your bicycle. These include:

Tools to Disassemble Bike for Conversion to Electric
Check out the tools needed in this article 👉 Tools to Disassemble Bike for Conversion to Electric
  • Hex wrenches; assorted sizes – For handlebar items and chain ring
  • Flathead and Phillips screwdrivers – For handlebar items
  • Chain removal tool – For installation of chain
  • 10mm wrench
  • 15mm pedal wrench – for reattaching the pedals
  • Bottom bracket lockring wrenches – 2 sizes; one for the main locknut and one for the cover locknut
  • Side cutters – For trimming zip ties
  • Blue painters’ tape
  • Recommended – Bike repair stand

RIDE eMTB: Read about all the tools needed to build your eBike in this article 👉 Tools for eBike Conversion

Before Installing the Motor

One of the most critical steps before you install the motor and assemble the conversion kit is to test the fit of the motor. It is incredibly frustrating to disassemble your bike and begin assembling the mid-drive motor kit only to realize the motor does not fit on your bike frame.

You will also want to test all the electrical components, as mentioned above. Please go back and read the previous article and watch the video attached to learn how to test all components before you begin assembly.

Spreading out the eBike parts and testing
Spreading out the eBike parts and testing

You will also want to test fit the battery. You will find printouts on my website that you can use as a model for testing the size of your battery. You can easily see if it will fit on your frame or if you need to make a new plan.

If you want to upgrade any components on your current bike, such as the brakes, derailleurs, shifter, cables, or wheels,  now is the time to do so. The bike will already be disassembled to facilitate the new eBike setup, so take this opportunity to install some new parts if needed.

Installing the mid-drive kit will require some patience. While the bike can be ready to test ride within the hour, when you are dealing with electrical components, there is always the possibility a cable will be pinched, or something will break. Ensure you tighten everything down prior to testing the eBike once it is assembled!

Bafang Mid-Drive Electric Bike Conversion
Bafang Mid-Drive Electric Bike Conversion

Did you Know You Can Convert a Regular MTB to Electric?

Bafang a leader in DIY electric bike conversions has a mid-drive kit that will fit on most regular bikes. I’d recommend the BBSHD kit, it’s a complete setup with a huge capacity battery and a 1000 watt motor. Why this setup?

  • Heavy duty 1000 watt motor (built for cargo bikes)
  • +50 volt 17.5 Ah battery for speed and distance
  • Easy installation with provided tools.

If you’re considering a conversion, do what I’m doing get the BANFANG BBSHD 1000w eBike Conversion with Battery

Assembly Steps for the Mid-Drive eBike Conversion

1.      Insert motor into the bottom bracket

The first step is to insert the motor into the bottom bracket. Be sure the gear reduction housing is on the drive side (right side) of the bike. Once the motor is in the bracket, check for clearance between the motor housing and the chain stay. On my bike, the motor housing very slightly touched the chain stay.

This can be remedied with the use of a spacer. A spacer will kick the motor out a few millimeters (depending on how many spacers you need) and eliminate any interference between the motor housing and chain stay.

Test fit mid-drive motor for electric conversion
Test fit mid-drive motor for electric conversion

2.      Install the chain ring

Place the chain ring over the newly inserted motor (still on the drive side). Check for clearance between the chain ring and the chain stay. Use a dab of Loctite and tighten the bolt.

3.      Install the right-side crank arm

Using a dab of grease, install the right crank arm (most arms are labeled L or R to indicate which side of the bike they belong to). Tighten the bolt with a hex wrench.

4.      Install the right-side pedal

Using a pedal wrench, or 15mm wrench, install the right pedal. Tighten the pedal down.

5.      Install the chain

Grab your chain and stretch it over the newly installed pedal and onto the chain ring teeth.

Install chain onto chainring
Install chain onto chainring

6.      Install the triangle bracket

Moving to the left side of the bike, you will now install the triangle bracket. This bracket fits onto the bottom bracket where the motor is hooked to the bike. The raised ridges on the backside of the bracket go toward the bike frame. The ridges will dig into the frame and more tightly hold the motor on.

Installing the triangle bracket on a mid-drive conversion
Installing the triangle bracket on a mid-drive conversion

Place a spacer or two on the other side to compensate for the spacing on the right-side of the bike. Place them between the bracket and the two mounting points on the motor. Tighten the bracket with a hex wrench, just tighter than finger tight.

7.      Add the bottom bracket locking bolt

Add and tighten the locking bolt that holds the motor in place. 40 to 50 nm is the proper torque for this bolt. I recommend using a rubber mallet with your wrench to ensure the bolt is good and tight. A cover will go over this. It does not need to be as tight as the locking bolt.

8.      Install left-side crank arm

Ensure you are adding the left crank arm the opposite direction of the right crank arm. Place the crank arm on and tighten it.

9.      Install the left-side pedal

Using a pedal wrench, or 15mm wrench, install the left pedal. Tighten the pedal down.

Installing pedals on ebike conversion
Installing pedals on ebike conversion

Congratulations! Your mid-drive motor is now installed! Once you complete the motor installation, you can move onto installing the handlebar components, such as the LCD display, the brakes, the shifter, the throttle, and the grips.

Finishing Up

Make sure you follow along with the video and article to ensure proper installation of your mid-drive motor kit. You will also want to carefully read the instructions that come with your motor kit.

I recommend setting everything out on a table and taking stock of each component and for what it is used. Lay out all your tools along with the components for the motor. It is much quicker and easier to install the motor when everything is organized and laid out.

RIDE e MTB Pro Tip: With eBikes growing in popularity learning all the terms and definitions can be a bit overwhelming. Let me help with this comprehensive glossary. 👉 eBike Glossary

David Humphries Author at Ride e MTB

Hi David Humphries here the guy doing all the pedaling behind the scenes with this blog. I’ve been in the MTB world for a while and recently started getting into eMTBs. You can check out more about me HERE and on my other passion project –