• Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread

New Bafang Crank-Drives


1 GW
Dec 10, 2010
Bafang were showing two versions of their new crank-drives at the Shanghai show last week. The 250w version is available on Aliexpress as a kit now. I think the "750w" one was more to gauge customer opinion, but I'm sure it'll be available soon. I tried both versions in the area outside the halls, which is totally flat, but I was able to gain some useful info.

Both versions are smooth and quiet. No gearbox noise - just the normal motor noise. The 250w version felt a bit less powerful than a 250w hub-motor, but that might be just an illusion because you get a different feel between the high and low gears.

The 750w version had about the same power as my 350w 36v GeNG Gen 2 with 22 amps, although it was much smoother and quieter. It had a 48v bottle battery, so it was probably running with 15 amps. The two versions looked the same, but they told me that the 750w one was a little wider and had thicker wire.

These motors have programmable parameters in the controller, where you can set

There were also two other crank-drive motors at the show. One was from Ananda, which was a bit noisier, and another similar one - I forget the name. Both of these required a much larger (ca. 100mm) bottom bracket tube, so OEM only.

It seems to me that the Chinese are not very clever in their development. All the motors had crank-speed sensors on them to detect pedalling. Basically, they had applied their hub-motor technology to a crank motor, but then you get a problem with the motor running on after you stop pedalling, which messes up gear-changing. I reckon some customers had told them that European ones have torque sensors, so one or two had torque sensor versions, but they didn't change the controller software. It feels like they use the torque sensor to switch the power on rather than give a proportional amount. You still get the motor running on. They have to go some way before being able to compete with Bosch, Kalkhoff and Panasonic, but I'm sure that they're working on it.

edit by moderator, due to the length of the thread

These motors have many programmable parameters in the controllers' software so that you can adjust them to your way of riding. Theres a thread on how to program them here:

"Programming the Bafang Middrive BBS01+BBS02" (crossbreak, 36 pages)

"Bafang BBSxx - fault finding and fixes" (Slowrider, 21 pages)

"Bafang BBS01 & BBS02 Owners - POST REPAIR CLAIMS!" (teslanv, one page)

In July of 2014, the Bafang factory began using 9 FETs instead of six, in the 750W unit that has proven to be popular in North America (in order to spread out the heat, so each FET would run cooler, due to occasional heat-related failures).

In July of 2015, the Bafang factory upgraded the FETs to the cooler-running and more efficient 3077 FET (at the urging of em3ev.com). The identifying suffix number on the more desirable 3077 controllers is 206.1, rather than 206
I like it.
Simple cabling will suit users who don't want to mess with it.
Inbuilt controller and pedal throttle simplifies it further.

Not sure how I feel about a built in bottom bracket, but other than that I think it will do well.

*looks at wife's Giant CRX*. I wonder if she'd notice... ;)
very interested in this, as im going to build a lighter weight bike, more of a pedal assist than my current mac 8t 12s

D8veh could you please tell me more, personal experience wise, as to wether this would be nicer than a hub motor?

$420 to australia is pretty rich, i could get two cutes/swhx for that, will the price drop, is it worth waiting for the 750w?

I am just drawn to the mid drive idea, without the gng hassles


I only rode it round the car-park, but it had very similar power and other characteristics as the TCM motor unit, which looks very similar, and I had on loan for about a week. Overall power is a bit less than your average 250w hub-motor, but in first gear, you can climb pretty steep hills without too much effort, although slowly. Using the throttle without pedalling shows the relatively low power from the motor. You have to help it out with pedalling on hills.

As a motor, they're nice - very smooth and quiet, but the problem is the control system. It's adequate, but flawed. Basically, they've used hub--motor technology (sensors and controllers) and applied it to a crank-drive. The worst characteristic is that the motor runs on a bit after you stop pedalling, which keeps tension on the chain. The tension makes gear--changing a bit traumatic, and probably impossible with Shimano hub-gears. I tried one with a Nuvinci hub, and it was a perfect match because you can change gear under load.

I tried increasing the current on the TCM, but it didn't make much difference. From 14 amps to 18 made a bit of difference, but 18 to 24 only made the motor hotter. The Bafang might be different. I' haven't had a chance to play with one yet, but I suspect that it'll be similar.

So, if you want to give it a try, think about a Nuvinci hub, or at least decent derailleur gears - definitely not the cheaper ones or other hub-gears. Try turning the current up to about 18 amps, and it should make a nice lightweight solution with strong hill-climbing. If you don't have steep hills, a hub-motor is better.

The 750 watt one is not three times the power. It's more like the difference between a 250w hub-motor and the 350w Bafang BPM motor, and very similar to the 350w GNG unit. It's better if you want to ride with throttle only.
These look quite promising, need to source the 750w version and likely go with external controller surgery for my own but I love how its all integrated to the BB, much cleaner :)

Hello all,

After some research in the Asian market, wholesale and even the announcement ware I can only find a very few mentions of this system, they almost all claim 24v and 250w, one vendor lists as 36v and 250w which could be 1.) Incorrect information, 2.) Indicating that there are various winds of the enclosed motor and obviously to volt up amp down and if a lower kV version exists, use it for increased torque or 3.) More vendor claims which are total BS!

Now the long and short is I see nothing in English, Chinese or Korean which indicates a 750w rated model is coming our way but after discussing with several online vendors of eBike Kits and many custom builders such as myself I got in touch with the people over at bpm to see about a 750w sustained capable version of the drive, obtaining 2 samples for comparison and evaluation... These would be fantastic if available in our power needs and very subtle (not the battery pack standing up behind it but, you get the idea).

If I hear back on availability I will get specs and order samples EMS expressed over here :)

So the new crank drive system from Bafang works well and is a very clean mid drive that is compatible with most bikes with bottom brackets. I have been testing several variations of these since they first produced samples a few months ago. The "750w" one that was at the show was a 48v version that was running 10 amps of continuous current once it got going and up to 15 amps or so at startup. The units that I have been testing are "350w rated" units with 36v 18a and 48v 15a max current controllers. They usually set the working or continuous current at about 1/3 of the max current on these motors to preserve the gearing and controllers. The motors themselves have a thermal sensor that will shut them off if they overheat. I also have tested some souped up 48v versions with 10 and 15 amps of working or continuous current and they are much more powerful. The 15 amp continuous one will do 30 mph on a mountain bike with street tires, however it is definitely pushing the limits of the motor and controller and it gets quite hot pushing it to these levels. You can run these with 12s lipo, however, the lvc on the controller will start to cut your power at about 44-45v so you won't be able to get all the capacity out of them.

Just to clarify, the only motors in production do not have torque sensors. This is why there is a slight delay when you stop pedaling and when the motor stops when using the PAS mode. According to Bafang, they were not satisfied with any torque sensors on the market so they are developing their own for this motor, but it is still 6 months away from production.

I'm going to start a separate sales thread as I have several of these 36v and 48v complete kits in stock and ready to sell now, and already have the 48v ones ordered in quantity to be delivered next month. The production versions have a 48v 15 amp controller and a continuous current of 10 amps. They have 3 levels of pedal assist as well as an option to turn it off. The throttle is always on when the system is on and provides max power. There are three waterproof plugs coming off the controller/motor for the speedo sensor, battery, and cable to the handlebars. The cable to the handlebars has 4 waterproof connections for the two brake levers (can just not use them if you don't want) as well as the LCD display and throttle. I also will have various downtube and rack mounted battery solutions available for these.

This is one installed on an old full suspension bike with 12s 3p Lipo, 15 amp continuous, 30mph top speed pedaling.
View attachment 1

This is one installed on a carbon road bike with 12s 1p Lipo, 6 amp continuous, 25mph+ top speed pedaling...whole bike weighs less than 30 lbs.
We are getting more and more mid drive options in the last 2 years... i wonder if the hub motor is truly doomed at this point.
Care to explain what you mean by that comment?

I've been on this forum for a while now. Look at the GNG threads. The amount of posts in those are insane. It looks like mid drives are becoming more popular to me, as they become more affordable, more reliable, and more powerful.

Yeah, we have some great DD hubs available to us now, but maybe it's just my perception - it just seems that people are talking about and building more mid drives than ever before.
A thing to bear in mind is that as you go up through the gears, the speed goes up, but the torque goes down, so these mid-drives don't hang on to their top speeds like a hub-motor, but on the other hand, you can get power at any speed that the gearing will allow, which is great for going down-hill. If you look at the size of the motor in the Bafang 750w crank-drive, you can see that it'll never be able to compete with the sheer grunt of a 500w hub-motor, which is twice the size, and will happily run twice the current at the same voltage. I think crank-drives have their place, and are great if you want light-weight or restricted power, but having tried most of those available, I prefer my 500w geared hub-motor, which is simple, robust, user-friendly and reliable. It's difficult to put into words the difference, but the crank-drives don't give such a relaxing ride.
I have a MAC motor on 1500W.. have been running it for almost 3 years now, it's my favorite hub motor by far.. great on flats, and most hills but on the ludicrously steep hills ( the ones that would make you pant and take periodic breaks to walk up ), it just stalls and makes all kinds of heat. I've demagnetized my motor pushing it hard, dropping down to like 33%-50% of it's loaded speed. This leaves something to be desired.

I guess most of the world is pretty flat. But i have lived next door to the rocky mountain range / wasatch mountain range for a while, long enough to pine for a mid drive :lol: beats walking my ebike up some of the hills this way.
Very cool indeed if they finally start offering up BB kits that will do 750 or more watts! I figure if it will do 750 continuous, then 1200-1500 peak should be possible and that is where it gets fun on a mid drive in my opinion!!
Whiplash said:
Very cool indeed if they finally start offering up BB kits that will do 750 or more watts! I figure if it will do 750 continuous, then 1200-1500 peak should be possible and that is where it gets fun on a mid drive in my opinion!!

this should be possible, but efficiency will be horrble :x
even so whith lipo you can carry easily enough to go pretty far
I wonder if the hub motor is truly doomed at this point.

I can foresee the sales pressure keeping common hub kits about $100 less than popular mid-drives. Both the GNG kits are around $400 (minus bikes, battery, and charger), so if common hub kits settle in just above $300...I still think that's a good thing. Also, even though it's clear that giving the motor some gears is a benefit (especially on steep uphills), there will always be some builders who want more power than bicycle chain can provide.

The Cromotor seems to be capable of 45-MPH scooter levels of amp-flow. If I wanted to use one as a non-hub, I'd have to use 415H chain to a left-side drive. If that ever broke I'd have to use Luke's recommended 428 chain. I can't imagine running the Cro through a derailler, it would have to be in the rear wheel, or a left side drive.

On the plus side for non-hubs, the GNG V1 has moved the motor weight from the rear wheel to center of the bike, and that is reported to make the feel clearly more nimble and balanced for off-roaders.

Starting a build-log of BBS02 owners:

Teslanv http://endless-sphere.com/forums/viewtopic.php?f=6&t=56512
kepler: http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&start=900#p842065
rassy: http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&start=850#p839620
Tom L: http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&p=835718#p836746
freeride: http://endless-sphere.com/forums/viewtopic.php?f=28&t=55856
coachstevo: http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&start=950#p842971
full-race geoff: http://endless-sphere.com/forums/viewtopic.php?f=28&t=55339
covert: http://endless-sphere.com/forums/viewtopic.php?f=28&t=58343
kepler's second BBS02 bike http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&start=2600#p902762
fk100extreme http://endless-sphere.com/forums/viewtopic.php?f=28&t=60418
Aushiker http://endless-sphere.com/forums/viewtopic.php?f=28&t=58770
Supertux1 http://endless-sphere.com/forums/viewtopic.php?f=6&t=61721
I think if we continue to see rising neodymium and copper prices, the smaller motors will win out over the years, just based on economics alone. Especially if the parts for the gear reduction come down in price due to mass production - which we are starting to see.

Look at what you can buy a cheapo RC motor for, which can output equivalent continuous power that a cromotor could. The cost of the smaller motor is let's say a fifth - this leaves lots of $ left over for gear reduction and such.

A multi gear system is the best way to stretch out a smaller motor even further, keeping it within it's power band, thus keeping the torque high, efficiency high, and the heat at a minimum. A very large DD motor is okay with these high load / low efficiency types of situations we see when climbing hills or accelerating, because it has a crazy amount of thermal mass to dissipate and average out the heat. The smaller motor does not have this advantage.

Running a cromotor through gears would be crazy even if you could do it. I mean if you had a 2:1 spread in your gear cluster, then you'd be delivering twice the torque to the rear wheel. What about running half the motor and doubling your torque through the gear cluster instead? You wouldn't have as high of a top speed, but who needs to go >40mph on a bicycle on a daily basis, really? :mrgreen:

Yes, bike chain is limited in how much power it can handle, but there is the possibility of using Steel BMX sprockets + BMX chain on a shimano-style freehub. You could have a 3-5 speed system this way. 1/8" gears would be at least 25% stronger than the usual 3/32" bike gears. That could make for reliability in the 1000W-1250W range.


Optibike is pushing maybe 2000W peak, 1000-1250W continuous using BMX chain to their 14 speed Rohloff hub. That bike will do some major wheelies in 1st -3rd gear. That kind of power will push 30-40mph. I say that there is room for improvement with DIY built mid drives. The best is yet to come.

The Optibike MBB is by far much cleaner and powerful than the other double chained, mid drives. Once they offer better battery configurations and bike styles with the MBB, it will be interetsing.
Well having ridden all current versions of the Optibike within the last month including the 1100 watt version I will tell you that the Bafang unit feels like a much more polished and refined drive system although the 350w is a little less powerful than the 850+ Opti's. The Bafang is also quiet, even quieter than many geared hub motors, especially at normal pedal cadence.

The Optibikes are built well and good looking bikes, but the MBB is noisy and feels home brew with the way that the power is delivered so abruptly. Also, no brake cutoffs, or LCD screen for the drive system feels weird on a bike that price. The Bafang has an optional LCD which displays real time power usage and is very slick and of course offers pedal assist as an option as well. Soon there will be a version available that will rival the Opti 1100 for power.
I rode the optibikes and echo your sentiments. They have not figured out how to build or tune the controller properly. It acts like an older EB2 on a high eRPM motor such as the MAC and BMC motors. The throttle is like an on-off switch.

As a result, it is not smooth to control the throttle at all. There is an internal clutch somewhere making a banging sound every time you hit the throttle in the gears that have higher reduction ratios.

It's a nice clean system and i like it. It ticks all the boxes for what i'd want otherwise. Well, except the price.
Yes, their system looks very good because it is basically a large sealed unit containing the motor and gear reduction inside.

I really believe we can build better things. They might not look OEM, but they'd have the same function.
From my interaction.

250W in production
500W production starting
750W in RnD stage along with a Torque sensing capability.

Concur sentiments with dev8h about chain tension, as does Tora from Juiced Riders.

Ananda mid drive was indeed nosier, but it had a OLED display!
That other brand was 'Bofeili' and needs a custom BB (unlike the BF)

From riding at China Cycle I found:
The Bofeili 'felt' better than the Bafang, but the Ananda felt the most powerful (but wasn't silent like the BF)
I too also found the Nuivinci hub to be an excellent match for the BF, the ideal setup is gears one side and throttle on another (kinda like driving manual)
Will be trying the 250W with a Nexus with Gates Belt drive on a customers folding bike soon, should be interesting.

As for the bottle battery placement, I'll let this photo do the talking.....

Now the real question is who will be first to put this on a bike with dual hubs for a motor trifecta!
t3sla said:
As for the bottle battery placement, I'll let this photo do the talking.....
No comment :lol:
Wait until hyena samd or aussiejester sees it
Your GF must feel lucky :lol: