[SOLVED] Bafang BBS02 : crackling noise when pedaling : any idea why ?

[dxradio]

I had the same problem and it drove me crazy for months. I ride (with no pedal assist for the first 10 miles) about 13 miles a day. Every day, I would listen to this bike squeak on every down thrust of the pedals yet when I let it freewheel, backpedal or e-throttle the noise never occurred. Over those many miles, the thoughts just rattled around in my head until I came to the conclusion that it could only be the bearing assemblies in the motor. However, when I went to take the motor out I realized that it was semi-loose and hitting the frame each time either pedal was pushed. Looking at the motor with a flashlight, I discovered wear marks on the motor and frame. I put a small rubber block between the motor and frame and re-tightened the nut. Just like magic, it disappeared. The noise was extremely loud and got worse with time. You would have sworn the pedals were making the noise but such was not the case. In this application, the Bafang was mounted to a GIANT ROAM frame and has been on the road for about 3500 miles now. Other than this squeak problem the combination of Bafang and bike has performed well.

 

[C-Jay]

I recently experienced the same problem. A sort of grinding noise as shown in the above video. As I started to remove the BBSO2 from the bike I discovered that the right side crank was loose. Tightened up the bolt hold it in place and voila! Problem solved.

 

[Old & Riding Again]

[EDIT]​

Solved on July 10th : as WilliamT suggested, it was most likely caused by the motor mounting bracket rubbing against the chassis, due to the mounting nut being slightly loose, or the motor having slightly dropped since first install.
At least I reckon. In any case, if you hear the same noise, try tightening the motor assembly to the chassis and giving it another try. If it keeps crackling, try spurting a little WD40 like WilliamT explained, it seems to have worked for him.
Don't go full-conspiracy mode and try to disassemble the motor because you suspect there's a problem with the freewheel like I did

[/EDIT]​

Hello everyone,

Recently, my Bafang BBS02 started making a crackling noise when pedaling with moderate force, even when the motor is off.

• The crackle always happens at the same spot (right pedal forward, pushing down).
• It doesn't crackle when using only the throttle, which leads me to believe that something is off with the pedal freewheel.
• However, I'm quite the newbie at diagnosing bafangs, and I was hoping some of you veterans could help me with your expert ears in case I'm mistaken.
• I intend on disassembling the motor some time this week to check the freewheel, but any alternative idea on the cause would be quite welcome.

Here's a 50 seconds video I recorded a few days ago to showcase this "crackling".

(link to the YouTube video with clickable timestamps)
See 0:12 to 0:30 for the slow crackle demo
See 0:37 to 0:46 for the regular-speed crackle

Additional notes :

• ignore the high-pitch screech, it's my rear brake. I maintained it slightly pressed with a rubber band in order to generate a resisting torque that would emulate normal pedaling with some actual load.
• This motor has done about 1000 km so far, without a hitch.
• I usually run it at 260 W when cruising, with some spurts at 500 W uphill, way below its rated power.
• I don't have brake sensors and there's been a few times where I had to suddenly brake as the motor was running.
• I think it started that one time when I had to brutally brake while launched at 25 km/h. I might have been pedaling at the time, I don't remember.

Thank you for reading, feel free to say whatever comes to mind and have a nice day

"I maintained it slightly pressed with a rubber band in order to generate a resisting torque.." Applying the brake disables the motor activation on my e-bike....

 

[tomjasz]

"I maintained it slightly pressed with a rubber band in order to generate a resisting torque.." Applying the brake disables the motor activation on my e-bike....

It's a common feature on safe eBikes.