How to convert a bicycle to an electric bicycle?

- Part 1- by mid drive motor conversion kit


E-bikes, or electric-assist bikes, have become increasingly popular for getting around town, doing errands, commuting to work, and riding across fields or countryside. Though you typically still have to pedal an e-bike, the motor means it’s significantly easier than riding a traditional bike, whether you have a long commute or live in a hill-strewn area or need to haul heavy loads on cargo bikes.


For people who has his own traditional bike, how to spend less to convert it to an electric bike?

An electric bike conversion kit would help you to change your bike to an e-bike easily even though you may have little knowledge and experience about it.


Electric conversion kits come in several configurations, workable for all sorts of bikes such as mountain bikes, road bikes, beach cruisers, trikes, and much more.  

There are different kits, mid-motor conversion kits, all-in-one hub motor conversion kits, general hub motor conversion kits, and friction motor kits.

You could learn their comparison through Electric Bike Mid Drive Motor Vs Hub Motor

1.Mid motor conversion kits

There are many mid drive motor conversion kits with different brands, such as Bosch mid motor kits, YAMAHA mid motor kits, BAFANG mid motor kits.

Here we will see how to convert a bike to an e-bike with BAFANG BBS mid drive motor conversion kits.

 bafang mid drive motor kit BBS

Before choosing a mid-motor conversion kit, you need to know what kind of bottom bracket will fit in your bike, 68mm or 73mm or 100mm or others?


The BAFANG BBS01 or BBS02 or BBSHD mid-motor conversion kit has a bottom bracket shaft diameter of 33.5 mm and are designed to fit into the bicycle bottom bracket standard known as JIS or Japanese Industrial Standard, which is very similar to US standard referred to as "square tapered spindle", ISO/English, BSA, British, or "threaded".

There are 4 widths- 68 mm, 73 mm Oversize, 83 mm (for Some Downhill & FR bikes), 100 mm (for Fat bikes). Shell inside diameter is 33.6-33.9 mm. BSA has threads on the inside of the shell measuring 1.37 in x 24 TPI. Below is an example picture of the BSA threaded Bottom Bracket easily identified with the threads on the inside of the shell.

If your bike has a threaded shell like the photo below, you are in luck, now all you need to do is order a motor in the correct width.



The tools you may need.

 bike tools Pedal-and-Crank-tool



Step 1: Remove the pedals, crankset (crank arm, chain wheel), and bottom bracket from your bike.

Step 2: Install the chain wheel and its cover onto the BAFANG BBS mid motor, Slip the mid motor kit from the right side into the bike bottom bracket housing.

Step 3: Install the crank arm and pedal.( please note the “L”- left or “R”-right mark on them.)

Step 4: Install the chain on the chain wheel.

Step 5: Install the battery, display, throttle, brake lever or brake sensor.

Step 6: Connect all the cables well and have a test.


More details please refer to the BAFANG Mid Drive Motor kit BBS Manual.