Bafang BBSxx - fault finding and fixes

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tomjasz   10 GW

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Re: Bafang BBSxx - fault finding and fixes

Post by tomjasz » Dec 15 2015 1:04pm

opperpanter wrote: Indeed no '2' on my small gear.
I hope we can pin this down. Unfortunately my contact is crazy busy. Frustrating, as I've been trying to pin this down for months...
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Bafang BBSxx - fault finding and fixes

Post by opperpanter » Dec 15 2015 1:29pm

staldor wrote: Clinking noise without any load.
https://goo.gl/photos/yAy8TcU7D4osr22R6

The noise I get when there is load on the motor, notice the low frequency grinding/roaring in the beginning when the motor starts to spin the wheel:
https://goo.gl/photos/gS13PBCvpyHmVAHn8

What do you think? The motor is practically new, only driven a couple of km's.
opperpanter wrote:
opperpanter wrote: I have the same thing. I tried greasing the metal gears, but that didn't help. Going to send it to em3ev for repair.
Paul asked me to send it to someone in London.
Serial: 1412260523
staldor wrote: If you experience the same symptoms, did Paul mention the problem that causes it?

I would also be interested to hear if someone in London can fix this. I'm based in Norway. My reseller (greenbikekit.com) has not mentioned something about this. Just that i can get the spare parts I need..

Not sure yet if it is the magnet rotor, or if I have bearing problems with the iron gears.

And how difficult is to fix this myself? Do I need to take the whole motor apart?

My serial is 1509083899.
No, Paul didn't tell me more. I was ready to open it up for him.
I'll post updates here, I hope to send it out this weekend. Although repair may take a while due to Xmas.
Last edited by opperpanter on Jan 25 2016 1:39pm, edited 1 time in total.

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Re: Bafang BBSxx - fault finding and fixes

Post by kfranchoo » Dec 18 2015 4:43am

Hi,

I've done some 300km this past weekend and found no issues. It's running really good, but I do still have the noise from the outer gears.

Now I've seen the 2 videos from Bruno ElectricBike where he shows what type of grease he uses and how much of it.
He also says Lithium grease is a definete no - go:
https://www.youtube.com/watch?v=khW5l-FdPU0
https://www.youtube.com/watch?v=3lVRTRFueUU

Firstly, I didn't use that type of grease. I used a rather yellowish grease. Secondly, I definitely didn't apply that much grease.
I'll go to my carshop and ask some of this moly grease.. and give you guys an update on how that works out for me.

Quoting Bruno:
I have seen many completely destroyed pinion gears, all because it was running "dried" without enough lubrication (it was the first problem I had with my BBS02 and first problem many people experienced as well), the damage extends to the big flywheel rounding all gears and you have to replace both. Talking about major service pulling everything apart. The resistance increase would be a problem if we were talking about a very low powered motor like 100/200w without gear reduction. The BBS02 pulls a good 1100w with the factory settings, that means at least 1.3HP on the motor shaft (after thermal loses) and after the 1:21.9 reduction gear we are talking about extreme torque on the flywheel, capable of pulling a heavy rider + bike + battery up hill in wrong gear. Grease resistance mean nothing in this case. Running two metal gears with very high torque is just the perfect recipe for mechanical problems. =]

Another Quote:
Myself and Karl (electric-fatbike.com) are always talking about Bafang mid-drive issues and testing some things to find solution for many problems. Karl tried a heavy duty grease on the nylon gear long time ago and liked the results so he recommended on his website and many people did the same (he is a really nice guy with good intentions). I understand about greases and gears as I worked with million dollar industrial printers and electromechanical systems so I knew heavy duty grease would weaken the nylon and cause premature failure so I refused to do the same, Karl was so happy telling me via Skype conversation and the article was already published for a while so I didn't want to say anything. Many people did put heavy duty grease and had nylon gear failure, obviously everyone blamed Bafang for using plastic gears. Everyone now talks about the plastic gears like it is a problem or weakness in this mid-drive. After loooong time Karl figured out that the heavy duty grease was causing this failure so he rushed to make this article and correct this information so everyone would get this update. I dont criticise Karl at all, he is doing a FANTASTIC job trying so many new things, spending all his money and sharing all his experiences with everyone, we need more people like Karl.
Back to the grease, the first stage is what people called the internal gears, this is located inside the mid-drive and is the contact between the motor shaft and the nylon gear. This is nylon on metal so it requires white lithium grease. The big metal wheel I show in this video is called flywheel, very easy to access from outside, this is the second and final reduction gear. The small pinion gear is also metal so when it comes to metal on metal, moly grease is the ideal as it coats / impregnates the metal providing a long lasting performance (molybdenum is not suitable for plastic).
There is an issue that after many kms a very small quantity of the black grease will leak from the second stage towards the first stage via the bearing seals on the pinion gear. This will only reach the side of the nylon gear and not the actually area where the motor shaft makes contact with the nylon gear. It is unlike that this would cause problems. There is a lot more white grease there so the black grease will be diluted in white grease.
I think this is the longest and most complex reply ever, deserves a video =]

Thanks,
Regards,
Karel

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Re: Bafang BBSxx - fault finding and fixes

Post by alfantastic » Dec 18 2015 12:06pm

kfranchoo wrote: Firstly, I didn't use that type of grease. I used a rather yellowish grease. Secondly, I definitely didn't apply that much grease.
I'll go to my carshop and ask some of this moly grease.. and give you guys an update on how that works out for me.
Lith-Moly grease is perfect for the final drive, as it is a high pressure grease designed to minimize friction between two sliding metal surfaces.
That's why it's widely used to pack out car CV joints.

Make sure you remove all traces of the yellow stuff you've got on there first. A box of cotton buds (Q-Tips) will be your friend when doing this :wink:

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Re: Bafang BBSxx - fault finding and fixes

Post by Jkeum » Dec 18 2015 9:41pm

Perhaps someone can elucidate this question I have about the BaFang Mid drive. Mine is a 750 unit circa 2015 I believe. It was installed professionally by a local E bike outfit to a Santa Cruz 29er hard tail.

After the week of commuting, I go back and forth work about 15 miles in total each day. When I was pedaling uphill, I sort of felt one of the pedals "slip" under me, too excessively but somewhat dangerously. I thought the crank was slipping through the shaft and with my entire body pushing down, I thought there was something wrong with the unit gears etc...

I took the unit back to the shop and the mechanic did some diagnostics and he who is a much heavier and bigger guy could not get to reproduce the problem. The one thing that he did notice was that were was a little play in the unit meaning that depending on the cranking done, the chain might attempt to ride up the crank and slip back, giving this slipping feeling. So, he went on to tighten all loose parts, and said that used loctite in some areas to make sure they do not come loose.

The slipping problem issue had faded away until recently, I am not around mile 450 and I am feeling the slipping feeling again. The interesting part is that I have noticed a one time slipping sound when I do not pedal but use the throttle. The rear gear is in the smallest, the most difficult gear and I hear that slipping sound, a sharp thudding sounding when the unit is starting and going up hill.

The unit has a 1 year warranty from the dealer but if this becomes an ongoing issue, I need to know to make sure I do not have to deal with this problem again. It seems that these units are being sold left and right by outfits pre installing them on their bikes to be sold. I suspect that if the reliability is a problem, they would not sell so many. But then, who exactly knows.

Any pointers and feedback would be appreciated.

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Re: Bafang BBSxx - fault finding and fixes

Post by alfantastic » Dec 18 2015 9:56pm

Karel, check this video out:

https://youtu.be/3lVRTRFueUU

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speedmd   100 MW

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Re: Bafang BBSxx - fault finding and fixes

Post by speedmd » Dec 18 2015 9:57pm

Sounds like chain is jumping the rear cog. You need a new chain and cassette- cog. If you run in the tiny gear all the time it will wear out in a few days even with enough lube to keep it all wet.

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Re: Bafang BBSxx - fault finding and fixes

Post by Jkeum » Dec 18 2015 10:38pm

Speedmd, thanks for the heads up. Do you think that the cog and chain wear was due to the excessive torque that the BaFang provides or it is because they were already on the way out when I set the mid drive up? The Santa Cruz HighBall I installed the mid drive in, I fetched lightly used in Ebay years back but when I first rode it around for a couple of weeks, I had to replace front brake pads because they were worn unevenly. It makes me think that the bike was more than lightly used before. Also, another question I have, if I replace the cog and the chain, and everything is lubed properly, what is the lifespan that I should expect from these expendable components?

Thanks, Paul from NYC.

PS: Hell, if it just involves a cog and a chain change, I would be knocking on wood.

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Re: Bafang BBSxx - fault finding and fixes

Post by speedmd » Dec 18 2015 11:40pm

If your hearing clacking it is most likely just the chain jumping cog teeth. The other item than can slip is internal (sprag bearing) which should be more quiet when it slips. Running on the small cogs (under 15 teeth) will tear them up quickly. The 12 tooth and below you can trash in a few hundred miles. Quicker if the chain is stretched. You can gauge chain stretch with a caliper easily or get yourself a chain gauge if you don't want to do the math.

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Re: Bafang BBSxx - fault finding and fixes

Post by Jkeum » Dec 19 2015 12:15am

speedmd wrote:If your hearing clacking it is most likely just the chain jumping cog teeth. The other item than can slip is internal (sprag bearing) which should be more quiet when it slips. Running on the small cogs (under 15 teeth) will tear them up quickly. The 12 tooth and below you can trash in a few hundred miles. Quicker if the chain is stretched. You can gauge chain stretch with a caliper easily or get yourself a chain gauge if you don't want to do the math.
I will change the gearing one day for a larger cog and see if I can repeat the problem. In any case, if I want top speed, which is almost always the case, I guess the small cog will be chewed up. I will take it to the E bike shop to see if there is some noticeable wear.

If I use a larger cog and I do not experience the slipping or jumping I felt, that all will be fine. Lets see.

Thanks for the replies.

Paul from NYC

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Re: Bafang BBSxx - fault finding and fixes

Post by speedmd » Dec 19 2015 11:55am

At this point, you most likely need a new chain and cog set regardless. When it starts jumping you are well past what you should be riding anymore. You could go with a larger chain ring in the front, slightly higher battery voltage (depending what your running) also as a way of getting top speed without relying on the tiny rear cogs for all grades. It is a little mid drive designed to use a variety of gears and cover varied terrain. If all you do is city commute and want it to go like a motor bike, go with something like a leaf 1500 watt hub motor setup and your chain and cog issues will go away unless you pedal most of the time with a rusty chain.

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Re: Bafang BBSxx - fault finding and fixes

Post by Jkeum » Dec 19 2015 2:46pm

speedmd wrote:At this point, you most likely need a new chain and cog set regardless. When it starts jumping you are well past what you should be riding anymore. You could go with a larger chain ring in the front, slightly higher battery voltage (depending what your running) also as a way of getting top speed without relying on the tiny rear cogs for all grades. It is a little mid drive designed to use a variety of gears and cover varied terrain. If all you do is city commute and want it to go like a motor bike, go with something like a leaf 1500 watt hub motor setup and your chain and cog issues will go away unless you pedal most of the time with a rusty chain.

Thanks for the clarification. I will take it to my local shop to get a chain and cog replacement and hopefully the problem with be resolved. Since I have already invested in this mid drive and it is fairly new, I will attempt to solve this in the least obtrusive way possible. I should have studied the situation more rather than jumping into a mid drive setup, which I felt has all the advantages and little to no disadvantages, one of the main ones being a heavy backwheel setup.

Paul from NYC

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Re: Bafang BBSxx - fault finding and fixes

Post by cwah » Dec 19 2015 3:25pm

kfranchoo wrote:Hi everyone,
I mounted my kit only since last week, and have only taken it for a couple of spins.
The kit is installed on a Specialized Sirrus and the engine makes no noise as seen in the videos posted here. So no complaints there..
It does however make a noise while I pedal. It makes the same noise with the chain off.


I'm attaching the youtube link for your reference:
https://youtu.be/mSubg6xoMRI

Is this normal? Has anyone else encountered this?

Thanks,
Karel
Has that beeb fixed?
Help me find my stolen electric brompton: http://bit.ly/1a0vbBC and Bosch Sinus B3 http://bit.ly/1eV0WQz

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Re: Bafang BBSxx - fault finding and fixes

Post by kfranchoo » Dec 21 2015 4:37am

cwah wrote:
kfranchoo wrote:Hi everyone,
I mounted my kit only since last week, and have only taken it for a couple of spins.
The kit is installed on a Specialized Sirrus and the engine makes no noise as seen in the videos posted here. So no complaints there..
It does however make a noise while I pedal. It makes the same noise with the chain off.


I'm attaching the youtube link for your reference:
https://youtu.be/mSubg6xoMRI

Is this normal? Has anyone else encountered this?

Thanks,
Karel
Has that beeb fixed?
No. I ordered the moly grease on ebay. Its due to arrive next week..
uploadfromtaptalk1450690647079.jpg
uploadfromtaptalk1450690647079.jpg (122.36 KiB) Viewed 2088 times

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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Dec 21 2015 4:44am

From memory that has petroleum base in it. Not a great mix with Nylon (if it gets next door).

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Re: Bafang BBSxx - fault finding and fixes

Post by alfantastic » Dec 21 2015 6:06am

Lurkin wrote:From memory that has petroleum base in it. Not a great mix with Nylon (if it gets next door).
Shouldn't be a reason for it to get into the main housing. It should be fairly well sealed at the bearings.

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Re: Bafang BBSxx - fault finding and fixes

Post by kfranchoo » Dec 21 2015 7:24am

I've seen the video from Bruno and he really stuffs it with moly. I'll take my chances with it going next door.

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Re: Bafang BBSxx - fault finding and fixes

Post by tommie » Dec 21 2015 8:02am

I suggest you drill and tap a grease nipple into the casing, saves pulling things apart later.

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Re: Bafang BBSxx - fault finding and fixes

Post by kfranchoo » Dec 21 2015 1:02pm

tommie wrote:I suggest you drill and tap a grease nipple into the casing, saves pulling things apart later.
Any pictures of how and where you installed that grease nipple?

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Re: Bafang BBSxx - fault finding and fixes

Post by tommie » Dec 21 2015 3:51pm

kfranchoo wrote:
tommie wrote:I suggest you drill and tap a grease nipple into the casing, saves pulling things apart later.
Any pictures of how and where you installed that grease nipple?
was just thinking aloud kfranchoo, i`m sure it can be done tho`

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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Dec 21 2015 8:33pm

alfantastic wrote:
Lurkin wrote:From memory that has petroleum base in it. Not a great mix with Nylon (if it gets next door).
Shouldn't be a reason for it to get into the main housing. It should be fairly well sealed at the bearings.
When I pulled mine apart after ~3,500 kms, it had snuck into the other side. Why risk it if there are other greases out there that can be used instead?

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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Dec 21 2015 8:36pm

tommie wrote:
kfranchoo wrote:
tommie wrote:I suggest you drill and tap a grease nipple into the casing, saves pulling things apart later.
Any pictures of how and where you installed that grease nipple?
was just thinking aloud kfranchoo, i`m sure it can be done tho`
Yah been done before. Requires drilling the BB as well (assume you are meaning the BB/crank bearings)

https://endless-sphere.com/forums/viewt ... 25#p995396

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Re: Bafang BBSxx - fault finding and fixes

Post by alfantastic » Dec 22 2015 4:35am

Lurkin wrote:
alfantastic wrote:
Lurkin wrote:From memory that has petroleum base in it. Not a great mix with Nylon (if it gets next door).
Shouldn't be a reason for it to get into the main housing. It should be fairly well sealed at the bearings.
When I pulled mine apart after ~3,500 kms, it had snuck into the other side. Why risk it if there are other greases out there that can be used instead?
Not sure it's all doom and gloom, Tamiya manufacture it for their models:
Tamiya.png
Tamiya.png (140.43 KiB) Viewed 2017 times

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Re: Bafang BBSxx - fault finding and fixes

Post by cwah » Dec 30 2015 10:59am

On my BBS02, I have this problem:
- Motor works perfectly fine on throttle only
- When I pedal with motor turn off, I have a "clac" sound on every pedal turn.
- When I turn the pedal with my hand (and bike is upside down) so that it freewheels, there are no noise.

Anyone has an idea on what's the problem and how to sort that out?

Thank you
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Re: Bafang BBSxx - fault finding and fixes

Post by tomjasz » Dec 30 2015 11:23am

Real world, working information.

Still haven't seen the actual Bafang data, but this is where I'm going with my 4 units.


Mobilgrease 28 & BBSHD/BBS02 : Because A Good Mid-drive Is Better Seen And Not Heard
http://electric-fatbike.com/2015/12/23/ ... not-heard/

Hardy Boys Solve The Mystery Of The Nylon Gear Failure On The BBS02
"In the future I plan on only using lithium (white) non-petroleum based grease on both the nylon gear side and the secondary reduction gear (axle) side. This way even if the grease seeps through the bearing it will not cause the nylon gear to fail. The grease I am going to use is Mobil Grease 28 which is safe with nylon and aluminum and should last about 10 years."

http://electric-fatbike.com/2015/11/22/ ... the-bbs02/
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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