New BBSHD, unusual markings, resistance when turning cranks.

Hi, sorry my first post here is regarding a potential issue, I'm hoping some of you knowledgeable helpful people may be able to help me out with some questions I have regarding a BBSHD I purchased last week. The first strange thing I came across when fitting the motor were the markings on the motor casing. I have looked at pictures of other HD's and I also own a BBS02B which bears the standard well known Bafang serial number format and model designation, which allows easy identification and also gives the date of production. This BBSHD however has a different style and format for the case markings as seen in these pictures (it also has separate markings on the controller).



These are the markings on the gearbox or main casing.



This sticker was on the side of the motor.



This is on the top of the controller casing.


I suspect this may just be something that Bafang are doing with their latest motors as the markings appear to relate to model codes listed on Bafang's own website (which is sketchy at best). I don't know if anyone else can shed any light on why my motor markings are different to others I have seen? Also another point worth noting is that this particular controller doesn't have the extra wires added for the gear sensor or the headlamp output that I believe some later HD's have.



Now on to the second and (for me) most concerning issue regarding my new motor. During fitting I noticed there was a strange uneven resistance felt when turning the cranks by hand with the unit unpowered (and no chain installed). It feels as though one of the gears, possibly the nylon gear is running eccentrically or out of true. Like the mesh between 2 gears gets tight and then loose, creating multiple unpleasant tight spots during a full crank rotation. When back pedaled everything feels fine so that rules out the axle bearings. I checked the large reduction gear to make sure it was properly greased, which it was. I have also noticed about 1mm end float in the crank axle which seems a little excessive compared to my BBS02.



After finding that the vendor I bought my motor from had no contact telephone number and didn't seem to be very good at responding to emails or his own website contact form, I decided to assemble the bike anyway and see how things were after a few miles, which would give everything a chance to bed in. I now have about 60 miles on the odometer and it still feels the same. When riding slowly with low pedal inputs and low power from the motor, sometimes there is a strange sensation of the pedals dropping away from your feet as the resistance comes and goes (although this is not noticeable at higher pedal input and motor power levels). At certain power levels and cadences I sometimes hear and even feel through the pedals a strange oscillation/vibration.



Making a direct comparison to my BBS02B the new motor feels as though there may be a problem, as the BBS02 has always been silky smooth right from new and now has about 1k miles on it. Is this normal for a BBSHD or should I try to return it for a replacement?
(if I can ever get hold of the company that sold it to me that is).




Thanks in advance for any help/advice, and just for the hell of it here is the motor on my bike.

I got my HD pretty early in production. I also have an 02.
Neither really have much mileage. The 02 has a few hundred and the HD less than 50 or so.
I did remove the chain and power from the HD, while rotating by hand I felt no uneveness or binding. It was smooth but did have the small resistance inherent in the design.
My serial number is different and only claims 750w though it was sold as a 1000w?
In regards to crank end play IIRC I just snugged up a collar in the spindle assembly itself and that was resolved.

A note for others. If you already have the BBS02, the difference in the HD wont be too noticeable. Well not if you weigh 260 lbs not including the bike or gear

Btw, nice looking ride and set up.
Did you run the 02 on the same bike?
I did and actually went faster on flat ground with the BBS02 with all else being the same (battery, gearing, tire pressure, road etc). Not sure if the acceleration was different but if it is, it is undetectable.

To those reading this and thinking it is a slam to the HD, it is not. Both models are so similar it isnt worth debating.

Fastest1 said:

I got my HD pretty early in production. I also have an 02.
Neither really have much mileage. The 02 has a few hundred and the HD less than 50 or so.
I did remove the chain and power from the HD, while rotating by hand I felt no uneveness or binding. It was smooth but did have the small resistance inherent in the design.
My serial number is different and only claims 750w though it was sold as a 1000w?
In regards to crank end play IIRC I just snugged up a collar in the spindle assembly itself and that was resolved.

A note for others. If you already have the BBS02, the difference in the HD wont be too noticeable. Well not if you weigh 260 lbs not including the bike or gear

Btw, nice looking ride and set up.
Did you run the 02 on the same bike?
I did and actually went faster on flat ground with the BBS02 with all else being the same (battery, gearing, tire pressure, road etc). Not sure if the acceleration was different but if it is, it is undetectable.

To those reading this and thinking it is a slam to the HD, it is not. Both models are so similar it isnt worth debating.

Click to expand...

Hi, thanks for the reply.

I think I am going to have to return my HD then because as I suspected the issue I have is not normal. I have spoken the seller via email now and I am waiting to see what he wants me to do. I would take a guess that the nylon gear is not properly formed but I'm not going to disassemble it unless he asks me to so. The Trek frame is one I picked up especially for the HD as the chain line would be very poor on my Kona due to having to space the motor out from the bottom bracket to clear the suspension pivot. I also have a Haro werx 7 which both my motors fit onto very well but unfortunately there is not space to mount my battery on that frame and I don't always want to carry my battery in a backpack. Once my issue is resolved I may fit the 02 onto the trek and put the HD back onto my Haro as that bike is awesome through my local woods downhill sections.

I have started to run a battery in my camelbak. Mostly for the stealth of it.
I definitely suggest a small backpack over the camelbak I am using. Just need some larger straps and support.


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I use a small 20l hiking daypack for my battery as it allows me to carry other things besides my battery when its expanded but also ties up into a more compact form when I don't need the extra capacity. It has very well padded shoulder straps as well as chest and waist bands, plus it has a fancy support system that keeps the pack from touching your back which avoids the dreaded sweaty back.

This is the one I have:

https://lowealpine.com/uk/airzone-z-20-6

That looks nice. I use a mule. Though a decent hydration pack, the waist belt is not enough for the additional weight of the battery.


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Just to update this thread, I had my drive unit swapped out by the vendor and the new one has been working as expected for the last couple of months. No uneven resistance when turning the cranks by hand but there is still a mm or so of end float on the pedal axle. I keep meaning to shim it out but I have not gotten around to it yet as it doesn't seem to be causing any issues. I am now using the motor on my upgraded Haro Extreme X7 and it is working very well so far. The replacement motor also has the newer style markings.