BBSHD grinding noise issues

Jul 22, 2018
41
0
London
#1
As in the subject line, recently my BBSHD started to make grinding noises when starting up, the chain ring does not spin for about a second or two but then it feels like it ‘gets in the gear’ and is back to normal again. This seems to be an internal issue, nothing seems wrong with bike’s drivetrain/chain. It only occurred a few times, typically at the beginning of a ride when the motor is cold (I keep my bike outside, and temperatures drop to near zero at night). Any ideas what it may be, could it be gears wearing out, insufficient grease or just cold grease not lubricating motor well enough? I’ve only done about 600 miles since purchased in September, most of it on flat although I do tend to ride it mostly throttle-only (though not very enthusiastically and I check the motor case temperature after every ride, it has never been more than barely lukewarm). I don't think it would be up for service so soon but it's definitely not working as it should.

Any suggestions would be appreciated, thanks
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,378
133
Tyne and Wear
#3
IIRC, the nylon gear inside the housing has a one way bearing to prevent the motor from being turned whilst the secondary gear is turning during pedalling. Maybe this is the cause of the noises and the reason why it takes a few seconds for the motor to provide drive to the chainring.

If the bearing is coated in some kind of grease, then the low temperature will cause it to thicken and the bearing may not function normally until warmed up.
 
Jul 22, 2018
41
0
London
#4
Thanks both. I suppose the first step is to open up the motor and have a general look around... I will check both nylon gear & bearing, and whilst there I should probably apply some fresh grease - any product you recommend for this application?

I used my bike this morning and same issue occurred - grinding sound, and when I lifted off the throttle and once motor slows down the gears/something seems to catch on and it's back to normal again. Cycled for few hundred yards, came to stop and same thing happens when trying to launch again. Though the problem seems to go away after about a mile into the journey. Suspect grease thickening being an issue but a bit weird having this problem now since there was a few cold weeks back in December and that issue hasn't occurred then...
 
Sep 18, 2018
68
18
#5
I had a similar issue of noise. Clicking when taking off from a stop or when I put a lot of torque through the pedals. I suspected the clutch. When I had clear space to look back, I noticed the derailleur moving when the noise happened. Adjusted it and it's been fine since. YMMV.
 
Jul 22, 2018
41
0
London
#6
Thanks, but in my case when the noise occurs there is no movement of the chain ring, hence I would exclude any problems with bike's drivetrain and narrowed it down to BBSHD internal issue. To my untrained ear it sounds like a slipping gear of some sort...
 
Sep 18, 2018
68
18
#7
Was what I was experiencing. Sound of it was much more higher frequency though. It wasn't the chain ring but the bottom of the derailleur.
 
Jul 22, 2018
41
0
London
#8
This is how the sound looks like - more or less. Though this guy seems to have a continuous problem and his chainring is spinning, whilst in my case the chainring does not move and the problem goes away as soon as I lift off the throttle.

 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
1,127
136
55
Devon/Dorset
#9
If the motor is running and the chain ring dosn't turn, I would prob. check the clutch pawls first. I very much doubt you have stripped a gear, as you would more than likely lose drive completely. Bear in mind these noises generally sound much worse than they are as they resonate through the whole frame of the bike.
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,378
133
Tyne and Wear
#11
I believe you need to be looking in the area of the nylon gear and pinion gear, rather than the secondary gear assembly. Broken secondary gear assembly pawls would still allow the motor to turn the chainring, as the secondary gear is driven directly by the pinion gear. Broken pawls in the secondary gear assembly would only cause a lack of drive via the pedals to the chainring.
 
Last edited:

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,378
133
Tyne and Wear
#14
I think one way of establishing what area needs to be looked at, is by carrying out a little test.

Pedal the bike totally unpowered for a distance, and if you have issues where the chainring is not turning with the pedals, then the clutch/pawls/secondary gear assembly needs attention.

Then ride the bike powered up on throttle only (no pedaling), and if the chainring is failing to turn, or intermittently fails to turn, then you need to check out the pinion/nylon gear side of the motor.
 

jimarno

Just Joined
Feb 5, 2017
3
0
76
Barnsley South Yorkshire
#15
I have a BBS01B ( 1000miles approx) and have a similar problem but in reverse!!The crank and thus pedals will not stop turning once the motor is started either by the wheel sensor or throttle.The only way to stop the motor turning the crank , is by brake lever or exceeding 15mph.I suspect this is due to the pawls in the clutch being jammed and damaged (I had a similar problem with a kalkhoff impulse 1.0 motor ).The good news is that a replacement clutch and drive shaft unit is available for about £70 for the Bafang BBS01or 2 B motor .Kalkhoff would only supply a new motor at a cost of £600.
 

Advertisers