Bafang 48 Volt 500 Watt hub motor making a hooting sound under throttle

[bcolins]

Hi all, my first post here although I have been here just reading threads from time to time. I have a Sondors Fold X7 with about 900 miles on it. Its about 2.5 years old. It has a Bafang 48 volt 500 watt hub motor. I have a new sound that has been getting louder and louder, and initially was intermittent,...it is becoming more and more constant. The sound is like a who-who-who-who-who-who sound (hooting) and initially occurred only when the bike was under power, either by throttle application or by pedaling with some assist turned on. On my last ride yesterday,....it was hooting even when I was coasting or pedaling with the power shut down completely. Pic of the rear hub info

 

[AngryBob]

Fascinating. Maybe you have an owl trapped in your battery box?

Flip it upside down, spin the wheels, listen and look for something rubbing, brakes most likely, deformed tire, bent rim, bearing? Vary speed of the wheel and compare to frequency of sound, this is to nail down it is rotational, which is most likely.

 

[bcolins]

Well, I'm embarrassed to say I fixed the problem,......somewhat by accident. I had become accustomed to the squeal of the disc brakes,...so when this new hooting sound started and only occurred when under assist, I assumed it had to be in the hub. Today I pulled the wheel off with the intent of pulling the hub cover off for a look around,...however my freewheel removal tool was nowhere to be found,....so I put things back together, and decided I might as well throw on a new set of brake pads,.....which looked OK under quick visual inspection,.....when I pulled the brake pads off, I noticed that one was heavily worn on one side,.....Hmmmm,...in any case, put the new (resin) pads in, adjusted things up, and took it out for a 20 mile ride,....and no hooting! Thinking that was the problem,....I'll give it a few more rides before I call it fixed for certain.

Brian in Austin

 

[AngryBob]

Now that I know you have disk brakes, I can also suggest you check VERY carefully for a warped disk rotor, which would cause the uneven wear you are seeing.

Hooting is apparently an optional symptom. Chirping is much more common.