bafang chain ring

Bafang BBS02 / BBS01and e-RAD Hodrodding and Upgrade Parts


The BBS02 is a well integrated system, but…is not so easy to pump massive power through it, like some of the hub motor guys do. That is because the BBS02 uses a built-in controller and integrated dashboard, which makes it hard to just plug-in a bigger controller. For this reason, the most you are going to get out of the Bafang BBS02 is roughly 1500 watts, but…the good news is that…1500 watts is a lot of performance on a  mid drive ebike…

There are easy and safe ways to squeeze more power out of the BBS02 without hurting the reliability of the drive too much. This changed the entire landscape of the DIY market when the Bafang went from a 750W decent powered mid drive to a 1500 watt beast. Here is how to get more power from your BBS02.

The BBSHD the Ultimate Upgrade for $500

If you really want to go with big power, the right way to do it is with a BBSHD.  The BBSHD changed everything for the ebike power nuts, when Luna Cycles released it in November of 2015.  Normally this would be an $800 kit (some dealers sell it for $1200) but Luna Cycle has found a way to offer a bolt-on upgrade for current BBS01, BBS02 or e-rad riders for just $500.

Check out the Luna Cycle $500 BBS02 to BBSHD Upgrade

The BBSHD is a newer and completely redesigned big-brother of the BBS02, but…all the accessories, crank arms, wiring harness, display, throttle, ebrake levers are the same!  Luna Cycle is taking advantage of this, and is now offering everything that a BBS01, BBS02 or E-rad user needs to upgrade to the BBSHD…which is the drive unit, controller and sprocket for only $500.

The BBSHD is the new 1000W unit from Bafang that is both more efficient and much more powerful than its little brother, the BBS02.  Also the BBSHD has proven itself to be reliable even at high power levels, in situation where the BBS02 can be more delicate (like climbing  along and steep hill in the wrong gear). Luna Cycles is offering a bare bones BBSHD drive and controller for people who have BBS02, BBS01 and E-rad, and want to upgrade to the BBSHD.

Since all the parts are interchangeable, you can easily swap out any of these drive systems in 30 minutes and have a BBSHD with all the power benefits. Also, this is an affordable way to upgrade to a fat bike if you have a bbs02 now instead of buying an overpriced $600 kit to make your BBS02 into a 100mm wide bottom bracket fattie (the kit consists of just a bottom bracket and spacers).  This price is good for regular sized bottom bracket bikes as well as fat bikes.

Hot Rod Programming

bbshd programming cable


The very first step is to upgrade the programming that comes in the stock drives. When completely stock, the drives are very limited and its impossible to get full throttle without pedaling. The very first thing that programming the bbs02 gives you is the capacity to get full throttle on demand. Stock programming only gives you partial throttle.

For a while many dealers such as E-rad were selling the BBS02 with these “special firmware settings” for ridiculous amounts of money ($1200). Karl from Electric Bike Blog turned the world upside down when he started publishing articles like this one that showed the public how they could buy a programming cable and hot rod their drives themselves.

Some USA dealers are offering the BBS02 with hot rod program settings such as Luna Cycles which sells the drive in the USA with a pre-hotrodded controller, keeping the BBS02 brand name, and not jacking up the price.

For those who bought a drive with the stock factory settings, here is what you need. You will need a programming cable for $20 and then you will need this list of links on how to program your drive.

Programming the BBS02 is fairly easy and straightforward (just changing some settings), and there are many  great resources you can follow on this page mostly written by Karl. If you have not found it yet Karl’s web site is the definitive site on BBS02 and BBSHD hot rodding. He is famous for riding the hell out of his fleet of BBS02 and BBSHD and writing amazing articles about it.



Make sure your BBS02 has an upgraded 3077 controller so it can handle the hot rod programming. IF not, or if you have a blown controller you can buy a new controller here.  Note the controller comes in two versions…so make sure you match the shapes to your old controller, or it will not fit.

Unlimiting the  Speed Limit


The Bafang Factory limits the MPH that the motor will kick-in at. This can be anywhere from 20-25 MPH, and then your BBS02 will stop dishing out power.

Depending on which display you have, you can raise the speed limit of your display by getting into the displays program settings. This is easy to do…research your display model for more information. All Bafang displays can be reprogrammed, but some displays have a cap that they can’t be reprogrammed past. This is because Bafang wants to sell kits in countries that have power limits, and their governments doesn’t want you to hot rod it yourself.

If you’re unlucky and your display has a capped speed limit, and you need faster…consider upgrading to the new Dpc-14 color display which not only has a very high 99-km/h cap, but also displays voltage and watts which is useful information for hotrodders.

Another “work around” on a factory speed limit, is to simply change the size that your tire is listed at. Tell your controller that you have a smaller wheel size and your  problem is  solved, but…now your speedo is not accurate. A lot of nifty people also change their speed read out to Kilometers per hour and then adjust their tire size until their KMH display is actually an accurate MPH gauge.

52 volt battery…instant turbo charge

mini cube 52v ebike battery


The BBS02 controller puts a maximum power of 25 amps. Make sure you battery has a continuous rating of 25amps if you want maximum power. To get more wattage you also want to up your volts since watts equals volts X amps.

The easiest way is to add more power to your BBS02 is to upgrade to a 52V battery using 18650 cells (read our article on the benefits of a 52v battery)

The BBS02 controller will take up to 60V and a “nominal” 52v 18650 battery charges up to full 58.8V, which is just at the limit and will get  you 1450 watts (25-amps X 58V) when full charged.  The 52V battery and hot rod programming is the secret to getting the maximum performance from your BBS02.

See Luna Cycle’s  large selection of 52v 18650 batteries here

Now you got it….now don’t fry it!

holligan ebike


Once you hot rod the BBS02 is is fairly easy to roast it, especially the nylon gears if you are not careful.  Nylon gears are easily replaceable and repairing your drive can be fun and fulfilling so you aren’t risking ruining your drive.

  • The BBS02 motor likes to spin fast. Keep your motors RPMs up, by shifting to a lower gear when climbing hills.
  • Think about going with an aftermarket chainring as listed below and the smaller the better if you want reliability.
  • Use a bicycle transmission with a wide range of gearing. Even consider a Rohloff, the $1200 ultimate BBS02 transmission.
  • Consider installing a temperature sensor to make sure you don’t overheat your motor. (read this guide)
  • understand that when your motor runs hot, you are more likely to strip your nylon gear so be especially careful to be in low  gear when drive is hot
  • Consider lubing your BBS02 with Mobil-28 (read this article on why and how)
  • Remember that Luna Cycle has replacement parts in case you do run your bbs02 too hard, so…don’t be too careful

Read our 1st review of the BBS02

Read our most current review of the BBS02 and how its changing everything


Aftermarket Chainrings

Somewhere along the way it was recognized the the BBS02’s stock chain ring looks like crap. Not only that, the BBS02 (like all electric drives) prefers high RPM’s and seems to be happier when spinning fast. This is especially true for hot rodders, who like the smaller chainrings (sometimes even smaller than the stock 42 tooth which can only be found in the aftermarket.

Enter the aftermarket chain-rings, which give you three great options.

Chain ring adaptor and Race Face Chain Ring 

race face bbs02R

read review here

This is a basic adaptor which allows you to use the raceface narrow wide chain ring. Total price around $100.


Lekkie Bling Ring

bbs02 bling ring

42 tooth, one-piece design Read Review

Buy it here

Luna Cycle Mighty Mini 

30 tooth, made in the usa but in short supply, due to high demand.

mighty mini

Read review

Buy it here


The BBS02 Fat Bike Upgrade (Obsolete)

Fatbikes with 4-inch wide tires often have a 100mm wide bottom bracket, so a stock Bafang unit will not fit. If you want to add a BBS02 you use to have to spend big money on a modified BBS02 kit  from companies such as “California Ebike

As of November 2016, Bafang has built an upgraded 1000 watt drive especially built for fat bikes. It also can be ordered  for standard bottom bracket sizes.

You can still find $600 kits on the market to transform the BBS02 into a fat bike kit. However, these kits were plagued with reliability issues such as bent axles etc, and the BBSHD makes that kind of trouble obsolete. Especially since you can now upgrade to a BBSHD and still use some of your old BBS02 parts, for  only $500.

Upgrading or getting repair parts for the E-Rad BBS02

The E-Rad is pretty much the  same as the BBS02  (I do not see how they are different)  and all parts mentioned here should be cross-compatible with it.  Make sure if you replace the controller you get one with a gear sensor cable.

Upgrade Resources

Electricbike Blog (formally  – this is the ultimate resource that all  ebikers wanting maximum performance out of their BBS02 or BBSHD, and you should subscribe to it to get the latest info.  This site has become a great resource for Bafang enthusiasts and please subscribe by filling out the box at the bottom of every page marked “Subscribe”  This forum consist of mostly BBS02 and BBSHD enthusiasts and is an excellent forum to join.

Luna Cycle BBS02 Parts Section –  The largest supply of BBSo2 parts in the world, at the best prices, and based in the USA.  (sister site to

Awesome Video Resources

Brunos Youtube page – The best video source for thrilling BBS02 and BBSHD videos.  Bruno is a true hero in the scene.

Luna Cycle You tube page –   Many install videos to help you with changing or upgrading parts or installing your BBS02

More technical info about hotrodding the bbs02 and bbs01


As you can see, this is a production unit, not a prototype. 48V X 20A is 960W, so the factory is optimistic about this model (even though it’s labeled the “500W”). However, if you are riding on a long uphill while drawing max amps…the over-heat protection circuit may cut the power just when you need it most. Since your hills may be steeper than my hills, start out with the amps being limited, and then slowly raise the max amps until heat becomes an issue.


In the picture shown, the “1307090018” number on the motor housing means:

130709 = 13 (2013), 07 (July, 7th month), 09 (9th day)

0018= Serial number, this is the 18th unit produced in 2013 that is a BBS02-48V-500W


The “JSCF0034.0” and “13070012” refers to the controller.

I do not yet understand the JSCF designation, but the 13070012 seems to mean that this controller was manufactured in 2013, 7th month, serial number 12. So far, there are seven stock controller/stator combination options:

250W = 24V X 18A

250W = 36V X 15A

350W = 36V X 18A

500W = 36V X 25A

350W = 48V X 15A

500W = 48V X 20A

750W = 48V X 25A


BBS01 Performance

ES member mwkeefer adjusted the shunt on a stock 15A controller, and was able to raise the amps to 17A without eddy-current losses or stator-saturation (on the narrower BBS01 stator), but then he also bypassed the stock controller and used a 6-FET for a quick test at 24A, which showed that significant heat was immediately being produced . The torque at 17A was a very healthy 68-NM / 50-ft lbs.

To be clear, if you put 25A into the BBS01 motor, it will provide more power than if you were limiting it to 17A, but some of the amps will be converted into heat instead of work, so you can only do this for short bursts (and to be fair, it does shed any accumulated heat very well). A long uphill with an unlimited controller allowing 25A will cause the over-heat protection to cut the power at some point, which will protect the motor and controller from being damaged.

Maximum efficiency (best battery range) was attained near 11A (roughly 520W @ 48V). The stock controllers capacitors were rated for a max 63V, so there’s no room for voltage upgrades unless you want to swap-in different capacitors, and also add a stand-alone Low-Voltage-Cutoff (LVC). The possibility exists that the stock controllers FETs would also have to be upgraded for higher voltage, but that has yet to be determined.

If you want an external controller so the motor could take more heat (in stock form, the motor and controller are both producing heat inside the same case), then a Lyen 6-FET controller could run more amps than the motor, so a larger 9-FET or a 12-FET would be un-necessary.

All this technical jargon just means that no extra performance was “left on the table” for hot-rodders to access. The performance was good, but if you need more than a continuous 816W  (48V X 17A) at the BB to be happy, you’ll need a completely different motor. However, this also means that…if you are happy with 750W, then the BBS01/BBS02 is probably the smallest possible package in which to reliably get that level of performance.

Edit: a friend installed a BBS02 on his bike with 16-inch wheeled Moulton, and reported that the hill-climbing torque was so great, it was actually too much because the bike would wheelie way too easily, due to the short wheelbase and smaller diameter wheels. I recommended that he install the 48V drive on one of his larger bikes.

I recommended that he perhaps purchase the 36V X 25A = 500W version, and then use a lower assist setting, to limit the amps (there are 9 levels of assist). For a small-diameter wheeled bike, a 36V battery is more than enough and would be more affordable than 48V.



The BBS01 housing cracked open, showing the primary reduction. The white plastic driven gear is much longer than it at first appears. The steel smaller-diameter drive-gear shows the length of their engagement. The green circular circuit-board is for the hall-sensors.


The primary reduction (shown above) reveals the secret to the BBS01 and BBS02’s quiet operation: the high-RPM half of the reductions gear-set uses wide helical gears with a synthetic-polymer driven gear. The drive gear is metal for longevity, but the less-loaded driven gear uses a strong plastic to absorb resonance, and the helical shape of the teeth softens the contact between each tooth as it spins. The surprising length of the primary reduction gears means that two helical teeth are engaged at all times at any given moment, which enhances the strength of the connection and further softens the power transmission. This is a brilliant design.

The secondary reduction (pictured below) uses steel gear-set that also has slightly helical teeth.

You can also see in the pic above that the motor is a radial-flux, permanent-magnet brushless DC inrunner. Bosch, Panasonic, and GNG have all shown how this style can shed heat well if designed properly, since the stator (the hot part) has a wide area of contact that is bonded to the aluminum motor shell. A BB-drive gives the motor some gears, so it can keep the motors’ RPMs up regardless of the bicycles speed. This helps the power system to avoid creating excessive heat in the first place.

The primary reduction (high-RPM 32T:12T = 2.7:1) uses a helical gear (shown at the 2:22 mark in the video listed below), which dramatically helps the noise level. The lower-RPM secondary reduction also uses helical-cut teeth (62T:11T = 5.6:1), and the total reduction from the motor to the chainring is 15.1:1.







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. However, also notice that the pedals pass by lower than the motor case.


Also, this kits PAS mode uses a common speed-sensor, so when you stop pedaling, it takes a moment for the power to sense the change in the wheel speed and change the power that’s being applied. This is something you need to be aware of when shifting. Torque-sensors perform better, but are typically more expensive. Bafang has stated that they are developing a torque-sensing option for this drive that should be available soon.

The proprietary single one-piece drive-sprocket is either a 46T or a 48T, and when it wears out you may need to order a new one from the dealer you bought the kit from. Since it is not a chainring attached to a central spider, it would require a custom adaptation to drill precise holes in the sprocket arms to allow you to swap-in a larger or smaller chainring. This is the one thing I would have changed about this kit, it should be using a 110-BCD or 130-BCD spider that has a chainring mounted to it.


Update: the French electric bike company

Update: the French electric bike company is now making 4-arm 104-BCD spiders for sale. Chainrings from 32T to 48T are readily available in that format.


The crank spindle is 159mm-wide to allow for the wider 750W stator. Several owners have contacted me and verified that they have taken serious jumps with this drive, and the spindle is quite strong. I would recommend that if you are taking jumps, to use  a full-suspension frame, but even on a hardtail E-bike, this drive seems to be holding up well (so far).


Our friend Kepler sent us more ride reports:

“…I have had the opportunity to give the [750W BBS02] drive a good workout on a variety of single track over the past 2 days. Clocked up 60km of purely single tack with with plenty of tight twisty uphill together with lots of bone jarring tree roots, logs and ruts. Have had an absolute ball and now really understand what a mid drive is all about. The way the bike handles and skips over the rough stuff is such a nice change from [the weight of] hub motors…Most of the ride was on setting 5 (out of 9)…No problems with motor temp with the motor housing only reaching luke warm on even the hardest part of the ride…”

A friend of his also had a BBS02, and one wire shorted due to a manufacturing defect (found here), and fortunately for us, he decided to take pictures when he did the surgery!



Stator dis-assembly pics courtesy of ES member “Kepler”. He has reported that the laminations are the more desirable 0.35mm thickness, instead of the common thicker 0.50mm that are found on most E-bike hub motors.



The permanent magnet brushless inrunner rotor on the left, connected to the steel primary helical drive gear. The driven gear is the white nylon helical gear on the right. The roller-bearing seen inside the driven gear is a clutch-bearing, which allows this part to freewheel in one direction, and drive in the other direction.



The housing is aluminum, so if you heat it rapidly with a torch, you can wear a glove and tap it so that the steel stator drops out. This must be done with quick timing before the steel in the center gets hot and expands too. The stator is only a press-fit into the housing, and the assembly bolts prevent rotation within the housing.



The stator is 802 grams, the ID is 59.9mm, the OD is 98.0mm, the air-gap radius is 29mm, the tooth face is 8.2mm X  29.7mm. Per the published information, the BBS01 stator is 5mm thinner, so that would be 24.7mm…



The Pedal-Assist-System (PAS) uses a sensor on the right, and four tiny magnets on the left, to tell the direction and speed of the spinning pedals.


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.



Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.

  • eric12325

    good read i am saving this one, i bought my bafang 750watt bb02 ,4 months ago and i love it ,it does get warm but not hot and i live in Pittsburgh pa plenty of steep hills here and it pulls me up them all with no problem like i’m on level ground with a light pedaling ,or just with the throttle alone. i bought a huffy cruiser with 7 speeds and i start out in 7th gear on level ground with ease, even on steep hills i use 4th or 3rd gear at the lowest on the street,off trail in ruff terrain up hills i do use 1st to keep the speed down.

  • Mr CSharp

    Can the Bafang BBS02 motor be mounted above the bottom bracket in between the the frame triangle with bike frames similar to the Hudson Cruiser? If there is lateral room at the bottom of the frame, why not just rotate the whole motor above the bottom bracket rather than rotate the motor down lower towards the ground? Anyone with experience on putting together this kit want to elaborate on why this can’t be done?