Editor note August 2015. We have re-written this story to make it more current as of today. “Spinningmagnets”  wrote the original version of this story two years ago, and predicted the BBSO2 would be a hot thing.  Now it is clear this is one of the best DIY Kits on the market…and definitely the most popular. 

Bafang has released a 750 watt mid drive system that has been making a big splash in the electric bike market in the USA and is now probably the most popular conversion kit available (more popular than any brand of hub motor kit).  We are very excited about this kit…and now its easier than ever for the do-it-yourself builder to have a powerful quality home built bike.  We are a big fan of this kit and have even decided to offer it on our new store for a reduced price of $525. This kit is so cool we think everybody should be able to afford to buy one.

Mid drives are the hottest feature of commercial bikes in 2014 (read our article on commercially available ebikes).

It seems build it yourself mid drives from easy to use kits such as the Bafang BBS02 and the Lightning Rods Kit is the thing for 2015.

Bafang has really raised the bar by making a very clean looking and small kit that is powerful. We are hoping they help start a title wave of cool and fast bolt-on hub kits. Read our  list of  currently available mid drives that you can bolt on your bike.


Why to buy a Bafang BBS02 in a Nutshell

  • The Bafang looks super cool and expensive when bolted onto a bike
  • A mid drive is the best option for off road riding such as single track
  • A mid drive has many advantages over a hub motor, like conquering steep hills (read our article)
  • The Bafang is among the quietest mid drives I have ridden….quiet is key
  • The Bafang BBS02 has a built in controller making for an ultra clean installation
  • The Bafang puts out as much as 1300 watts a full 3X as much power as the much more expensive Bosch or Panasonic Drive
  • A Bafang equipped bike becomes a true mountain climber…something a hub motor bike will never be

Bafang BBSO2 = Commercial ebike slayer

Before, if you wanted a mid drive…you had to buy a commercial ebike for over $5000 (such as the Bosch or Panasonic drive systems) . What’s the worst is that these expensive bikes were designed for the European market so they would only put out 300 watts max. These bikes look slick and clean, but are a real disappointment to ride (like wearing a condom), especially considering the price.

Currie Technology, a company known for selling affordable $500 ebikes from bargain basement stores, somehow became a distributor of these expensive mid drives in the USA and tried to explain the $7k price tags to  the american public by saying that…a 300 watt mid drive was so efficient and effective it was the same as a 750-watt hubmotor bike…the nice looking Bosch bikes offered by Currie only made a small ripple in the USA ebike scene, (see some of Currie’s  high end mid drive bikes) but were far too expensive to make a big splash…but check out how sexy they look!


As you can see, the Hai Bike  above has the Bosch power system that requires a special proprietary frame interface.  The frame is a full-suspension frame and a 10-Ah battery is just large enough to fit in the dolphin pack where the water bottle would normally go. This is about as nice as an ebike can look,  its too bad that the bike is limited to 400 watts maximum power. But many builders are able to achieve almost this look with a much  more afforable (and much  faster) Bafang BBSO2 system while using a larger battery pack…meaning more range.

Examples of some pretty BBSO2 Builds

Having access to beautiful bafang BBS02 drives and elegant new battery offerings such as 18650 Dolphin packs builders are coming up with some slick looking bikes that rival even the best commercial ebikes, and they are faster with larger battery packs for longer range. Click on the pics below to read about the build process of these bikes:



Read about the Byebyepetrol build by clicking on the pic


“SCFOSTERS” EBike creation uses a traditional rear mount battery pack


Karl of electric-fatbike.com

750 watts and Beyond….Power is King

In the USA we have a 750 watt limit to be legally considered an ebike.  That means you can push even more…go over the limit a “little” bit and still be totally legal.  (read our article on ebike law) An ebike putting over 1000 watts is a true joy to ride and what will make ebikes more mainstream in the USA market. 1000 watts in a mid drive is pure nectar because it uses the power so efficiently.

So Bafang releases the BBS02 a kit that will bolt on to almost any bicycle and transform it into a mid drive power house.  What’s so amazing about this kit is that when you install it your bike really can look like a commercially available ebike.  The kit has everything you need except a lithium battery to transform almost any bike into a high end mid-drive ebike.  Lunacycle.com  offers high quality Samsung or Panasonic 48V and 52V battery packs in different configurations for a very affordable price.  Take a look at their 52V Dolphin pack made from cutting-edge Samsung 30Q cells for an especially clean solution. (see product now)

Here is an example of an ultraclean Bafang installation with Dolphin battery pack. A hardtail mountain bike with front suspension is a perfect platform for the Bafang BBSO2 because you have plenty of room to either mount with a dolphin battery pack or a soft triangle battery bag. How you mount your battery and how you hide your wires will really decide how commercial your ebike looks when installing the Bafang BBSO2. Read our article on battery mounting solutions.


So now finally you have an affordable ebike kit solution from a respected manufacturer that can look awesome when mounted to the bike. Not only that it is a mid drive which will give you all the off road and hill climbing capacity that a mid drive can bring.  

So it looks good, and at $525 (not including battery) the price is definitely right. If you have a good mountain bike around, you can buy one of these drives plus great battery set up for under $1000.

The Bafang BBSO2 is not only affordable, it is also more powerful than both the Bosch and Panasonic systems. The 48 volt version advertises 750 watts, but in reality, with a 52 volt battery and some controller setting tweaks?…you can easily get over 1200 watts on this system. Because mid drives are so efficient, 1200 watts is the equivalent of 2000 watts in a hub drive, and no hub motor can touch the hill climbing prowess of a powerful mid drive.

Pros of the Bafang BBSO2 over conventional hub motor kit:

  • The weight of the drive system is very low and is in the center of the bike providing perfect balance. When weight is low and centered like this it can actually make the bike more stable (like a keel on a sailboat).
  • Lightweight- This entire system with controller and components is only 8.5 pounds…significantly lighter than most hub motor kits
  • The ability to use the gearing of  the bike…so now you can climb big hills in low gear…or go fast in a high gear.
  • Very good climber…even as an off road climber
  • No more heavy weight in the wheel means the bike will be much more agile when going over off road terrain and the bike may even be able to do tricks.
  • The controller is built into the motor which means it is a tighter system with less wires to hide.
  • Integrated pedal assist.
  • The bafang includs a nicely integrated dashboard and throttle
  • Mid drives have a “cool factor” that hub motor bikes lack. 


Cons of the Bafang BBSO2

  • It is harder to install than a traditional hub motor kit.
  • It is not as reliable as a hub motor kit…care must be taken not to overheat controller (You have to make sure to shift the bike gears so the motor RPMs stay high, dont bog it down).
  • It is not as easy and smooth as riding with a hub motor (you need to think what gear you are in  etc)
  • It is more  expensive than a hub motor kit.
  • It cannot be hot rodded like a hub motor kit.
  • The pedal assist system is a cheap cadence sensor and we wish it had a torque sensor for a smoother riding experience.

As you can see here are many big advantages to a going with a mid drive such as the Bafang BBS02 .  But if your purpose is to just ride on flat streets, maybe you need the ease of a hub motor kit instead.  Until now, almost all conversion kits on the market were hub motor kits. We applaud Bafang for releasing a mid drive kit that can be installed on almost any conventional bike and transform it into a mid drive electric bike.



Here’s a view of the 750W mid-drive unit that shows how compact a 48V / one horse-power motor is, when it’s mounted to a common size and shape of frame. If this system was using only 24V, the motor would have to be twice as large to produce this level of power.

Ok but how fast will it go?

This is a very valid question. And we love it when its asked…welcome to the speed club.

For speed…if you go with a 52 volt battery on the higher gears you can easily achieve speeds of 30-MPH on paved flat ground. People have tried to get over 30-MPH but at this point the drive becomes unstable and incapable. This is a very sweet 25-30 MPH solution.  And we feel 30-MPH is just about the right speed for an electric bike in terms of fun, efficiency and safety. If you want more than this on a mid drive, then consider the Lightning Rods drive system which can achieve speeds as high as 50-MPH and burn up to 3000 watts and is like hell on wheels.  (read on the lightning rods system here)

The most special thing about a mid drive is not how fast it will go, but how slow you can go…with great torque, and not overheating the motor. You can shift into a low gear and go 12-MPH top speed with the motor winding at full rpm. This means that you can climb steep technical off road hills that you could never climb using a hub motor. The Bafang mid drive has the capacity to be an electric chair lift…take your mountain bike to the top of the mountain…so that you can scream down at whatever speed above 30-MPH that you dare.

Hub motor kits will go much faster when hotrodded…but only on streets…on off road hilly terrain there is no contest…a mid drive is better.


How does the BBSO2 compare to expensive commercial mid drive ebikes?

I actually owned a $12,000 Optibike a few years back (read my review) and I actually like the Bafang BBSO2 conversion bike better.  Why? it is quieter and it is more powerful, while being an effective mid drive .

I also have test rode the Hai bike and other high end Bosch drives and I prefer the BBS02. Why? The Bosch drives are amazingly smooth and quiet but they have a maximum 400 watt output and feel extremely wimpy after riding a BBSO2. After you have had this kind of power you won’t want to go back. The fact that you can have that power at a fraction of the cost of a commercial mid drive such as the Bosch or Optibike really makes it an easy decision for me.

 The Bafang IS Quiet!!

I have owned some ultra thrilling mid drives. But one thing that always brings me back to hub motors is I cannot stand a noisy electric bike. To me riding an electric bike on a single track where other bicyclists might be, I think it is essential to be stealth. I don’t like to be hissed and snickered at and unfortunately most mountain bikers are not accepting of electric bikes.  Also when I am riding in nature, I like to take in the sounds…I hate ruining the tranquility of nature with a loud obnoxious electric motor (my Optibike use to sound like a weed eater).  I love that the Bafang is powerful and yet quiet.  Of course it is not the most powerful mid drive I have ridden…but I am willing to trade off a lot of power just to have a quiet system that makes me forget it is there…and makes me feel like Superman with legs of steel.

Is the BBSO2 Compatible with my bike?


Here's a 750W unit attached to an Electra Townie step-through frame.

Here’s a close-up of a 750W unit attached to an Electra Townie step-through frame.


Your bike must have 68-73mm bottom bracket width. That means this kit will bolt onto most standard bicycles. But not fat bikes.  Also if you have a bike with a step-through frame (ladies bike), the position of the “S”-shaped downtube may require that the motor position be rotated downwards, and this may reduce the ground-clearance to an unacceptable level. The drive fits best when mounted to a common diamond-frame.



This frame is a Hudson cruiser bicycle, and you can see how on some frame shapes, the motor must be rotated downwards to fit. This reduces the ground clearance, so you should not go curb hopping on and off the sidewalk like this.


Also many people have found that the Bafang can actually be mounted to many types of trikes, which can be fun since many trikes are not good candidates for hub motor kits.

In any case trust me…this kit is worth buying a bike special just  for it…go out and find the perfect hard tailed mountain bike you always dreamed of…its never a bad idea to add a good horse to the collection.

What about Fat Bikes?



The stock BBSO2 is not compatible with fat bikes because of the extra wide 100mm bottom bracket. But do not give hope there are solutions and a mid drive is an excellent thing to have on a fat bike. There are a few American companies offering fat bike conversion kits for the Bafang BBSO2. Check out the great article on electric-fatbike.com for more information from a writer who is unbiased on all the offerings

Ease of Installation

This is not the easiest kit to install.  You are going to remove the bottom bracket of your bike and put this motor in its place. If you have ever done bicycle maintenance removing a bottom bracket, is not a dummy proof job and does require some special bicycle tools. Any bicycle shop should be able to help you out with the installation if you can convince them that installing the kit is as simple as installing a new bottom bracket…it kind-of is that easy, except this bottom bracket is a bit cumbersome and the weight is 8.5 pounds.

If you are going to attempt the job yourself, you are going to need a crank-puller to get the old crank off.  Getting the old bottom bracket off is by far the hardest part of the job.

A fair estimate of how long it takes to install a BBOS2 is 2 hours after you have removed your old bottom bracket. Depending on your mechnanical skills, the bike you are dealing with, and what tools you have removing your old BB can take up to two hours.

We really recommend getting a bike shop to at least remove your old bottom bracket if you have not done this before. For a skilled bike mechanic with proper tools this is a 10 minute job.

For a complete guide on installing the BBSO2 check out the  electric-fatbike.com guide. 

Battery Options

There is no doubt about it the best battery solution for the BBS02 is an 18650 battery pack using the latest high density cells (the same cells that Tesla uses in their cars).  Your voltage is an easy decision as well…48 volt or 52 volt which are the only 2 options in an 18650 pack for this particular drive.

To get the maximum wattage of 1300 watts we would highly  recommend going with a 52 volt pack.  At some point you are going to wish you had that extra power.

The only thing left to decide is what size. This all depends on where you are gong to mount the pack and how much space you have. You can fit 20-Ah of battery in a triangle bag.  A 10-Ah pack is much smaller and is easier to mount…even in a dolphin pack which is little larger than a water bottle…and the dolphin mounts on the downtube same place as the water bottle. Dolphin packs are popular on this kit because they give the bike a very finished commercial ebike look to them.

Of course the place we recommend to  buy 18650 batteries is Lunacycle.com which uses name brand cells, top performance BMS, and has affordable prices in the USA.

 Display Options


c961c963 c965 bafang display


There are 3 possible display options that come with the BBSO2.  The C961, the C963, and the C965.  There is no big difference between the features of these three, and none of them can manage to do what is so hard for the Chinese factories to incorporate into one…adding an accurate watt meter gauge into their displays.  You can read on more detail on the displays on this article posted by electric-fatbike.com

Transmission Options


One of the sweetest things about a mid drive such as the BBSO2 is  you can choose what kind of bicycle transmission you want in the back wheel for the motor to go through. A really good option to consider is an IGH (internal gear hub) and run all the gears in a transmission contained in the rear hub with no messy deraillers and a completely straight chain line.

By far the sweetest option is the Rohloff pictured above. (read our article Rohloff on an electric bike) Rohloff’s are expensive…over $1500, but…once you equip one on a home built mid drive you have a really sweet ride that commercial ebikes could not touch for any price under $10,000.

Of course there are more affordable IGH solutions, and because the Bafang is not crazy powerful, any of these transmissions below should be sufficient to handle its moderate power:

  • Alfine 8 (quality click shifter, with electric shift optional)
  • Rohloff  (14 speed) read article
  • Nuvinci 360  (variable)
  • Nuvinci harmony (automatic transmission)
  • Shimano Nexus (the most affordable, with 3, 5, and 7 speed models available)

Pedal assist and Throttle Options

The way the BBS02 comes out of the box, it is mostly a pedal assist system (PAS), meaning the drive senses how fast you are pedaling and applies power accordingly. This is not as sweet of a solution as a torque sensor which senses how hard you are pedaling and is found in more expensive systems such as the Bosch. No need…the bafang also has a throttle…and after you are moving you can use the throttle to apply more power when you need it. The dashboard has different levels of motor assist depending on how much you want the motor to help out. We really wish Bafang would have provided a torque sensor instead of a cadence sensor on this drive, but…you can’t have everything (especially at this incredible price). Having a throttle makes up for a lot.

There are no throttle only modes with the way this system comes out of the box. However, it is possible to have the drive custom programmed by retailers such as LunaCycle.com so that you can have a throttle mode which makes it so you can easily get the 1300 maximum watts this drive is capable of.  However once you do this you reduce the reliability of the system, and should be careful not to fry your controller (a $75 replacement item).

Starting from a dead stop on a steep uphill when you are in a high gear will make the controller VERY hot. If you have a 7-speed derailleur, you should shift through at least three gears to keep the heat down.

Hot Rod Programming the BBSO2


8Fun is Bafangs marketing name.


No surprise the BBS02 came from China and China never sees the sense in why anyone would want to go over 20-MPH on a bicycle (why not buy a scooter instead?). This thing comes programmed from China with no balls.  The good thing about this is…this is a very durable unit if you keep the factory settings. However it is not as fun to ride, and you can’t squeeze out the full 1300 watts out this unit is capable of.  Lucky it is easy to hot rod using an optional and cheap programming cable…and some retailers such as Lunacycle.com are offering hotrodded BBS02 drives as an option before it arrives at your door.

Here is the ultimate programming guide from our friend Karl Gesslein at electric-fatbike.com if you choose to hot rod yourself.

Is it Durable?

The BBSO2 is not as durable as a direct drive motor?…of course not, since it has many more moving parts, and you never have to remember to shift into the proper gear with a big and heavy hubmotor.

For any  lightweight powerful system like this, it requires some user care to stand the test of time.  If you want lightweight, powerful, and also reliable…you are going to have to live as though this thing can be delicate. If you don’t want delicate then don’t change the factory programming. Keep the amps and heat down to an actual 750W.

If you are riding in difficult off road single track conditions involving a lot of climbing without a lot of pedal assist, and you decided to go for the wild ride of going with a hotrodded program

  • Like all electric motors, when pulling a load the BBSO2 likes to spin fast. ALWAYS select a gear that keeps the motor spinning fast when climbing or when starting from a dead stop.
  • Consider a smaller chain ring to keep your RPMs up high
  • Install a temp sensor and monitor your controller temps. (see this link on how)
  • Do not hit your drive when going over logs etc.
  • Don’t tweak the programming settings to hot rod it, if you dont want to take a chance.

Read this article for more information on the subject from electricfatbike.com

How Easy Is it to Repair?

The Bafang BBS02 has a very good construction with the controller still being very accessible. Since the controller is the weakest link in the system, it is important that you can swap it out by yourself with ease.

Even more good news is that Bafang has released a stock controller with beefy upgraded mosfets to make it a lot less delicate (as of July 2015). So if you ever do fry your controller you can replace it with one that is more bulletproof. We mention this because Googling this drive will reveal a lot of stories of fried controllers between 2013-2015.

Other items that you might need to replace are the nylon gears which can be stripped if you are running in a programmed mode off road and are not careful applying too much throttle. Nylon gears are cheap ($30) and are a relatively easy component to replace.

Compared to the Bosch or Panasonic mid drive, which you could not dream of repairing yourself (and we heard a Bosch repair will cost you a mandatory  $1000 and is just a trade out), the BBS02 is a breath of fresh air…for an enclosed mid drive you actually have a chance to do most repairs yourself and not incur expensive repair costs.


The Bafang BBSO2 makes a quality mid drive electric bike affordable for anyone…where as just a year ago the equivalent would have cost over $5000 for a commercially available mid drive bike that wasn’t even as fast as a BBSO2 drive installed. The BBSO2 makes it possible for anyone to own a high end mid drive electric bike at an affordable price.


For more information on the BBSO2

Special thanks goes to Karl of electric-fatbike.com for helping me with information for this story.  Karl is a true BBSO2 fanatic.  You might have noticed that there is a lot of links in this article to his site. That is because his web site is the ultimate resource on the BBSO2  and probably deserves a lot more links. I recommend all BBS02 users to frequent his site. You will find a wealth of information on how to get the most out of your BBSO2..



BBS02 on a stand, shifting gears


BBS02 riding uphill on 30% grade


BBS01 being dis-assembled by the German distributor for the European market, www.bike-emotion.org


Declic Eco (from France) just posted a dis-assembly video for the BBS01/BBS02




Look at our article that documents the performance capacity a mid drive offers.

European BBS01 250W owners manual in PDF form:


Dimensional blueprint of Bafang 350W BBSo1:


The endless-sphere discussion thread on the 350W/750W Bafang BB-drives:



Here is an article on mid drive kits to compare the BBS02



Here is a pic of the BBS02 mounted to a recumbent tadpole trike. The pic is courtesy of Declic Eco,  a French company specializing in custom electric bikes since 2008.


A BBS02 on a recumbent tadpole trike, courtesy of Declic Eco…Merci!


ES member eride lives in Denmark, and he is producing and selling 130-BCD spiders and extra-large chainrings with 70T, 75T, and 80T, for small-tire recumbents using the BBS02.


a 130-BCD spider, and chainrings with tooth-counts of 70T, 75T, and 80T are now available.

A 130-BCD spider, and chainrings with tooth-counts of 70T, 75T, and 80T are now available. Of course, the steel spider in the center can also mount a more common 38T-60T chainring


endless-sphere.com forum member “crossbreak” (in Germany), is also making 4-arm and 5-arm spiders (104-BCD and 130-BCD), along with spacers. He can be contacted on that forum, or also on his personal email: io9487@gmx.de



5-arm 130-BCD spiders from crossbreak, and he also makes 4-arm 104-BCD spiders