New Bafang Crank-Drives

Looking at the video, i think the main problem with this kit is the ground clearance as it mounts under the bottom bracket. The GNG and Cyclone cuts are better because they mount higher up which gives more ground clearance.

Also i think the power will be limited by the big gear that is plastic ? Also it seems to use strait cut gears on the big plastic gear which could be noisy.
 
There are two reductions, the primary is a helical set of gears (seen at 2:22), Its not clear, but I will estimate the steel motor-sprocket is an 12T, and the other larger nylon gear is definitely a 32T (2.7:1). The secondary is a small pinion driving the larger diameter gear, and the secondaries do have straight-cut gears. At 0:21 it looks like 62T and 11T (5.6:1)

2.7 X 5.6 = a total reduction of 15.1:1

For the curious, the phrase "Das Freilegen des Getrieberad ist nicht notwendig hier nur als Einblick gedacht" at the 2:22 mark only means "Showing the gear is not necessary, but is provided here only for insight" (Danke Schoen, Google-translate!)

Yes, definitely an inrunner at 2:22 mark.
 
I do not have one of these drives, but it "looks like" it is not designed to allow two chainrings and a derailleur in front. However, it also "looks like" a resourceful fabricator could create an adaption and mount a second chainring to the first one.
 
Thanks.

From the pictures in for example:

http://www.aliexpress.com/item/8fun-mid-drive-motor-kit/910997760.html

one can see a piece that "looks like" a chainring. Is this a chainring that has to substitute the existing chainring/s of the bike (very often, there will be three, with a derrailleur, so all three have to go away), or is this a piece corresponding to the secondary transmission (or something similar)?

If it is the former (the piece is really a chainring), do I have to use that chainring, or I could use another one I may have, possibly with a different number of teeth?
 
The bore of the stock chainring appears to be unique to this kit. So, to add a second chainring, I would first try to drill a hole in each of the 5 arms of the stock chainring and place the holes in a common Bolt-Center-Diameter (BCD). The hole placement must be very precise!

Do you want to add a smaller chainring than the stock unit, or a larger one for higher top-speed on flat land? perhaps you want two chainrings that are different from the existing stock chainring?

Here is a Pic of Christerljung mating a larger chainring with 5 arms onto an existing chainring that is too small, but the stock unit has a custom bore:

file.php
 
spinningmagnets said:
There are two reductions, the primary is a helical set of gears (seen at 2:22), Its not clear, but I will estimate the steel motor-sprocket is an 8T, and the other larger nylon gear is definitely a 32T (4:1). The secondary is a small pinion driving the larger diameter gear, and the secondaries do have straight-cut gears. At 0:21 it looks like 68T and 11T (6.18:1)

6.18 X 4 = a total reduction of 24.7:1
Click to expand...

That seems to be correct... but reduction is 30:1 according to this : http://www.bike-emotion.org/Datenblatt BBS01.pdf.... very odd.... maybe just an error
 
Does anyone 'in the know' have any production information for the BBS02/BBT variants? When will they be available? Any links?

“BBS01”: motor type(speed sensor) - in production
”BBS02”: motor type(speed sensor with coaster brake)
”BBT": motor type (torque sensor)

Thanks!
 
nippynoo said:
Arbol said:
Does anybody know if the 250W and 350W motors are the same physically, just with different controller settings, or if the 350W is different (I imagine bigger) than the 250W one?
Click to expand...
The 250W and 350W are the same size.
Here's a drawing showing both : http://www.bike-emotion.org/BBS01 tech. Zeichnung.PDF
Motor casing diameter = 111mm
Click to expand...

So, you are saying the 250W and the 350W are in fact the same motor, just that with different stamps? And the 500W is physically more powerful? Or you are not saying so much?

Thanks.

Edit: the CST 350W kit at BMSbattery has a 12 FET controller, so 30A 36V!
http://www.bmsbattery.com/ebike-kits/562-q11-48v1kw-front-driving-hub-motor-e-bike-conversion-kit.html
 
spinningmagnets said:
Do you want to add a smaller chainring than the stock unit, or a larger one for higher top-speed on flat land? perhaps you want two chainrings that are different from the existing stock chainring?
Click to expand...

Well, I have two concerns, one general and another one more specific:

- The general is that of course I am used to 3 chainrings. In steep hills, I often need to use the "nanny gear" otherwise I need to get out of the bike. I am concerned with only one chainring, I either risk being unable to climb steep hills if my battery is down (if chainring has too many teeth) or that I will not be able to enjoy full speed biking if the chainring is too small
- The specific is that one of the bikes I am considering is the Birdy. In fact, I opened a post on this bike http://endless-sphere.com/forums/viewtopic.php?f=7&t=52092 but it did not get traction. The Birdy is foldable but apparently more resistant than say a Brompton. With so many burglars in my city, it seems a foldable makes sense. There is a Birdy with a motor, but it is too expensive. I see locally a second hand Birdy, but the basic model, the Europe, with only one chainring of 56T and 8-speed Shimano, 11T-30T http://evobike.hu/termekek/nev/Birdy-Europe/termek/1148/lang/english

The issue is that it seems 56T is a bit odd, and probably the Bafang crankset is not 56T, altering the gears of the bike. That may be, or may not be, a problem. But I was wondering if one could keep the existing crankset and not using Bafang's crankset.

The Birdy seems ideal to use the BBS-01, I do not know if it has enough clearance / space to fit it in.
 
Arbol said:
nippynoo said:
Arbol said:
Does anybody know if the 250W and 350W motors are the same physically, just with different controller settings, or if the 350W is different (I imagine bigger) than the 250W one?
Click to expand...
The 250W and 350W are the same size.
Here's a drawing showing both : http://www.bike-emotion.org/BBS01 tech. Zeichnung.PDF
Motor casing diameter = 111mm
Click to expand...

So, you are saying the 250W and the 350W are in fact the same motor, just that with different stamps? And the 500W is physically more powerful? Or you are not saying so much?
Click to expand...

I misread the PDF, sorry, which I thought said 250W/350W - but in fact only show the two voltage variants 36V/48V :oops: .
But this information from MWMotor does show the same physical drawing for both 250W/350W motors..
http://www.aliexpress.com/item/36v-8fun-central-BB-motor-kit/911007748.html
http://www.aliexpress.com/item/8fun-mid-drive-motor-kit/910997760.html
And they are the same price.
So I'm 95% sure they are the same size and its just a voltage/controller difference.
 
Hi all,
I'm looking to buy the BBS01 350w bafang motor.
Now I have an rear hub motor with 12s 12Ah Lipo nanotech.
Does the 36V BBS01 work with 12s Lipo or is it a higher voltage?
Does bafang sell the 48V version or do I need to modify the 36V one?
If 48V exists, which is the cut off of the controller?
Thank you all. :D
 
When I was at the Shanghai Bike Show, Bafang demonstrated two versions of the crank-drive. One was the 250w one, and the other had a 48v battery, which they said was the 750w version. They told me that the 750w motor was slightly wider and had thicker wire in the stator.

I think that the 350w version is that 750w one because it wasn't as powerful as my 350w GNG.
 
Just been discussing the fitting of the Bafang BBS01 with a bike-mechanic at my LBS and he warned me that the bafang doesn't use the threads in the bottom bracket, only pressure plates at each end, so there would eventually be a tiny bit of free play, caused by the shaft alternately pressing on the outermost threads whenever pedalling torque is applied. He says the threads in the bottom bracket would soon be knackered by this repeated movement of the shaft. The pedalling forces are quite high and the threads would become damaged. And it would eventually knacker the frame itself, maybe a fatigue crack around the bottom bracket housing. Is there anyting in what he says? He actually doesnt want to sell me an expensive bike to try the conversion, but is recommending I buy a much cheaper (heavier/solid) bike as he's convinced the bottom bracket housing wont last long.
Video showing assembly http://www.youtube.com/watch?v=irmyv9G9WyU
I'd be really interested to hear any comments?
 
nippynoo said:
Just been discussing the fitting of the Bafang BBS01 with a bike-mechanic at my LBS and he warned me that the bafang doesn't use the threads in the bottom bracket, only pressure plates at each end, so there would eventually be a tiny bit of free play, caused by the shaft alternately pressing on the outermost threads whenever pedalling torque is applied. He says the threads in the bottom bracket would soon be knackered by this repeated movement of the shaft. The pedalling forces are quite high and the threads would become damaged. And it would eventually knacker the frame itself, maybe a fatigue crack around the bottom bracket housing. Is there anyting in what he says? He actually doesnt want to sell me an expensive bike to try the conversion, but is recommending I buy a much cheaper (heavier/solid) bike as he's convinced the bottom bracket housing wont last long. Anyone care to comment?
Click to expand...
Sounds like pure BS too me because it is threaded on both sides of the bottom bracket in other words you have to thread it into the frame of the bottom bracket.
 
wineboyrider said:
nippynoo said:
Sounds like pure BS too me because it is threaded on both sides of the bottom bracket in other words you have to thread it into the frame of the bottom bracket.
Click to expand...
Click to expand...
Not true. The BBS01 just slides in. Then there is a nut on one side only. Watch this video and you'll see how the threads are not used..
http://www.youtube.com/watch?v=irmyv9G9WyU
 
Typical LBS stuff. On a soft, not heat treated aluminum frame the threads could get beat up quickly if the the assembly is allowed to run loose and move around. If snugged down the movement will be kept in check and very little thread flattening should occur. If your worried about it just wrap tape around the bb insert so the threads are snugly against soft material, or use a softer/ weaker loctite thread sealer to help fill the voids and give you more support area, and kill any chance of movement. You will hear lots of noise if loose so you will get warning before anything gets trashed assuming you don't ride with buds in your ears. :)
 
speedmd said:
Typical LBS stuff. On a soft, not heat treated aluminum frame the threads could get beat up quickly if the the assembly is allowed to run loose and move around. If snugged down the movement will be kept in check and very little thread flattening should occur. If your worried about it just wrap tape around the bb insert so the threads are snugly against soft material, or use a softer/ weaker loctite thread sealer to help fill the voids and give you more support area, and kill any chance of movement. You will hear lots of noise if loose so you will get warning before anything gets trashed assuming you don't ride with buds in your ears. :)
Click to expand...

I may be completely wrong but my understanding of conventional bottom brackets is that any movement is bad news, and will just get worse. The BBS01 just slides in, and keeping the shaft "in check" with tape/filler seems like it wont last long.. The slack will just increase over time.. This is why conventional BB's need to be tightly fitted. The BBS01 is slack from the moment its fitted - after the first really hard push on the pedal. This is all hypothetical of course... and we havent tried it (I havent bought one yet)... but is my LBS mechanic right?
 
This kit has a self supported BB within the bike bb shell. Not the same thing. No slop in bearings. The shell should lock up very well and not relying on the bikes bb threads to maintain bearing tolerances. It acts more as a solid. Filler, most any most likely will eliminate any slop between the two shells. Tell Orvil he has nothing to worry about unless it is loose.

cheers
 
speedmd said:
This kit has a self supported BB within the bike bb shell. Not the same thing. No slop in bearings. The shell should lock up very well and not relying on the bikes bb threads to maintain bearing tolerances. It acts more as a solid. Filler, most any most likely will eliminate any slop between the two shells. Tell Orvil he has nothing to worry about unless it is loose.
Click to expand...

Not sure I understand. I'm not saying there will be slop in the actual bearings themselves, but between the shell and the frame housing. When you say "self-supported" what do you mean?

Is a sliding fit and a single nut going to stop the bafang unit from working its way loose? I dont see how a single nut can possibly apply enough friction on the ends of the frame to resist the bending forces, without some slipping, which will over time become larger and larger.

Anyway Orvil (who by the way services motors on Bosch e-bikes) is making me worry, and I've started to look again at the GNG Gen2 solution, which doesnt suffer the same weakness as it uses the bikes existing BB, and shouldnt come loose. I'd appreciate a definitive technical answer if anyone can think clearly about the fitting of the bafang unit .. Will it, or wont it, eventually wobble?
 
Orville or Wilbur, what ever his name is, in not working on airplanes. Most every screw in the world is a slip fit as you described and things are not falling out of the sky, at least that often. Your car wheels, and most everything on the bike is like this. Having a slip fit has little to do with it. It is more how the ends will form into each other and seat when properly torqued. As long as there is a radius at the bottom of the barrel there should be no play. On the nut side a bit of teflon tape as he and most would apply with standard external bearing cups to eliminate creek will take any play out for the service period. And that if it is a loose fit. I like Loctite. GNG is no better a setup when it comes to this. I don't think it is good to hang stuff in the bering cups, but it works ok.

With this setup, you will be compressing the shell on the bike and the internal bb shell will be in a nice even tension assuming your bikes shell is faced properly. Seems much better then conventional separate bearing cups relying on the treads to align and hold them from moving. Time will tell, but not having seen it in my hands it sounds a bit suspicious.

It seems obvious he wants you on a bosch. I have seen this with mechanics many times. I would not trust him with it.
 
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