Grinding Motor Noise

[Scythelz]

Hey everyone. I pray to god someone can help me with this.
For months, I have tried multiple hub motors, multiple sine wave controllers/displays, tried all 36 phase/hall combinations on both and I CANT get rid of this grinding noise.
First 2 motors were unbranded and the grinding was constant. Controllers were unbranded. So thought, okay, let’s get a KT controller and display and a Bafang g060, now the grinding noise is even louder but shorter in its duration. I’ve read 100s of posts on here and other forums, watched countless videos of people with this noise and everyone says it’s hall/phase combos, but on every working combo I found, the noise is still there? I’ve spent hundreds of pounds on parts now trying to get rid of this noise and at this point I’m thinking of giving up ebikes all together.
TLDR; initially the bike came with a pretty crap 250w hub and unbranded controller and display, got a 500w hub off AliExpress, a YF controller and an sw900 display, noise still there. Grabbed another unbranded, noise still there. Gtabbed a MXUS, noise still there. Got another YF controller,and a UKC1 display, noise still there. Got a Kt controller with a lcd8h, 750w bafang g060, whole new wheel, noise still there. Spent hours going through all combinations with the chart on every motor/controller, noise still there. My friends have the same kind of bikes with the same motor, no noise like this. I see countless reviews etc from tailhappytv on YT, no noise like this.
The noise is 100x worse under load when I’m actually riding the bike, it’s almost embarrassing accelerating up a hill in public it’s so loud.
I’ve attached a video of it with just throttle and no load. Towards the end of the video I pulse the throttle so you can hear the rough grinding noise better.
Please, if anyone has any ideas I will be so so grateful because I’ve been at this for months and I think I might be going clinically insane and financially broke lol

 

[E-HP]

Have you opened the motor to verify that there’s sufficient lubrication/grease?

 

[Scythelz]

Have you opened the motor to verify that there’s sufficient lubrication/grease?

Yeah, sorry should’ve put that in the post. Done it on all motors, fully cleaned out and greased up. On one of the unbranded ones I even re glued the magnets down with JB weld thinking it was magnets scraping but no avail. Was hoping after splashing out on the bafang/KT combo the grinding would finally be gone. Just don’t understand it

 

[neptronix]

This doesn't sound super atypical for a geared motor; it would be useful to hear it under load.

What voltage and amperage are you providing to the motor?

Geared motors can make grindy sounds when starting up and given insufficient power or partial throttle.

How is the response ( outside of your noise problem ) to the throttle when you pin it? solid, or jittery?
Is there a lot of low end torque from a stall, or do you get jitters or an extremely slow start?

 

[Scythelz]

This doesn't sound super atypical for a geared motor; it would be useful to hear it under load.

What voltage and amperage are you providing to the motor?

Geared motors can make grindy sounds when starting up and given insufficient power or partial throttle.

How is the response ( outside of your noise problem ) to the throttle when you pin it? solid, or jittery?
Is there a lot of low end torque from a stall, or do you get jitters or an extremely slow start?

I’ll try and get an under load video tomorrow. It’s super hard to capture it well with the weather outside lately being so horrifically windy.
If it helps you can feel it vibrating all through the frame and your ass on the seat (lol) when accelerating, once it hits near full speed it’s perfectly smooth.
Torque is fine in all 3 working combos. It’s quite jumpy off the start but verified all hall sensors are working fine, actually forgot to mention I even replaced all 3 hall sensors on one of the unbranded hub motors.

One thing to note, unfortunately I don’t have anyway of reading amps, but I read that under no load it shouldn’t consume over 100w. Since installing the bafang 750w, if i blast the throttle on PAS 5, it goes up initially to about 300w then settles down around 120-150.

Voltage and amperage is 48v battery, 25A controller, although I normally have the controller limited to 20a.

I just don’t understand how other bikes my friends have with the same KT sine wave controller, bafang motor and lcd8h don’t have any of these grinding noises when starting up or accelerating. It’s absolutely baffled me.

 

[neptronix]

20a x 48v = 960 watts. That's kind of a low peak power level for a motor of this size.
Does startup get smoother when you run more power?

What battery are you running? ( amp hours & what kind of cell? )

 

[Scythelz]

20a x 48v = 960 watts. That's kind of a low peak power level for a motor of this size.
Does startup get smoother when you run more power?

What battery are you running? ( amp hours & what kind of cell? )

@ 25a noise is still the same.
But then I still had the same noise with the 500w motor and 250w motor.

From what I know about it, it’s a sabre plus 14ah with Samsung cells. It came with the bike and the company are useless and a nightmare so I can’t get much more specific info. Unsure about the BMS but I’ve looked at a bunch of sabre plus on AliExpress and they seem to be around 25/30a hence why I’ve played it safe with the 25a controller

 

[neptronix]

Okay, don't think you have a power delivery problem.

What size wheel do you have? do your friends with the same motor have the same size wheel?

 

[Scythelz]

Okay, don't think you have a power delivery problem.

What size wheel do you have? do your friends with the same motor have the same size wheel?

Yeah all 26x4 fat bikes. I just don’t get it because it sounds so much like hall/phase combo issues due to the fact the noise also vanishes at full speed, but every working combo is the same. It’s so confusing.

 

[neptronix]

Damn, sorry, i'm stumped too.
I don't see anything immediately off with your setup.

Hopefully someone with knowledge of the g060 chimes in.

 

[Scythelz]

Damn, sorry, i'm stumped too.
I don't see anything immediately off with your setup.

Hopefully someone with knowledge of the g060 chimes in.

No problem appreciate the help a lot

The fact it’s the same kind of noise across all of the hub motors and controllers is probably what makes it the most confusing. I did try sensorless but that was horribly noisy lol

 

[E-HP]

Sorry, sort of tired today, so just trying to verify the facts. To be clear MXUS doesn’t make controllers, only motors. Can you verify the below?

3 different motors (couldn’t tell if it was 4)
5 controllers (wasn’t sure if 4)

Noise exists using combinations of these components.

Sounds odd, but I’d try adding rubber grommets to the rack mounts, or just temporarily remove the rack and fender.

You could also try duct taping some ballast along the seat stay and rack.

 

[neptronix]

i didn't think about resonance in the frame. Quite possible. Some frames are much noisier than others. What's attached to the frame can change that resonance.

 

[E-HP]

i didn't think about resonance in the frame. Quite possible. Some frames are much noisier than others. What's attached to the frame can change that resonance.

My thought is that if the original motor was 250W, then those chain stays and seat stays may not be very beefy or rigid.

 

[Scythelz]

Sorry, sort of tired today, so just trying to verify the facts. To be clear MXUS doesn’t make controllers, only motors. Can you verify the below?

3 different motors (couldn’t tell if it was 4)
5 controllers (wasn’t sure if 4)

Noise exists using combinations of these components.

Sounds odd, but I’d try adding rubber grommets to the rack mounts, or just temporarily remove the rack and fender.

You could also try duct taping some ballast along the seat stay and rack.

So 1 250w unbranded hub, then 2 different 500w unbrandeds a MXUS 500w and then a bafang 750w.
1 unbranded controller that came with the bike, 1 unbranded off amazon, 2 YF controllers, then a KT sine wave controller. Sorry I’ve gone through so much money and parts I think even me myself am losing my mind.

Was hoping the bafang/KT combo would finally erase all my issues. But same grinding noise in all. Just to different degrees. Have tried removing all bike accessories, rack, fender etc.

This persons video has a very similar noise to what I get under load.

 

[Scythelz]

My thought is that if the original motor was 250W, then those chain stays and seat stays may not be very beefy or rigid.

If quite a tough frame I believe to be honest, it’s an identical copy of the original Wired Freedom cruiser

 

[neptronix]

if we want to rule out the frame then you need a small DD motor, like a 27mm wide 9C.

DD motors can produce some resonance inside the motor and also into the frame. This is usually a lower frequency or buzzier sound than geared motors. Said frame might also be louder on bumps.

2 of the 10 frames i've owned had an unusual amount of nasty sounds coming out of the motor, If i remember right, they were aluminum and of lower quality.

What's this frame/bike look like?

 

[Scythelz]

if we want to rule out the frame then you need a small DD motor, like a 27mm wide 9C.

DD motors can produce some resonance inside the motor and also into the frame. This is usually a lower frequency or buzzier sound than geared motors. Said frame might also be louder on bumps.

2 of the 10 frames i've owned had an unusual amount of nasty sounds coming out of the motor, If i remember right, they were aluminum and of lower quality.

What's this frame/bike look like?

Currently working on phase/hall combos as we speak as you can see lol.

Excuse the fake Wired decal, I hate the company I bought my bike from after they gave me hell and I love Wired bikes but can’t get them in the UK, so, sprayed over the original logo and put a decal on lol

 

[E-HP]

Do your brake pads drag? If hydraulic, does the rear brake lever feel mushy at all?

 

[Scythelz]

Do your brake pads drag? If hydraulic, does the rear brake lever feel mushy at all?

Brakes are pretty damn perfect in all honesty. Hydraulic. Not mushy at all. 180mm up front and 160mm in the back, experimented with different brands of rotors too incase any of the resonance scraping/grinding sound could’ve been that.

 

[Scythelz]

Found the perfect video of the identical noises I get under load.

 

[Papa]

If it helps you can feel it vibrating all through the frame and your ass on the seat (lol) when accelerating, once it hits near full speed it’s perfectly smooth.

Nearly all hub motors vibrate to some extent - some more than others. And since the motor's axle is rigidly coupled to the frame's dropouts, it amplifies the vibrations and noise throughout the frame.

Sounds odd, but I’d try adding rubber grommets to the rack mounts, or just temporarily remove the rack and fender.

You could also try duct taping some ballast along the seat stay and rack.

Yes.
He can also try wrapping & wire tying 1/2"or 5/8" automotive heater hose to individual frame members - especially near the rear wheel.

 

[Scythelz]

Thanks so much to everyone for your help.
Just an update;
Went back to one of the YF 25A controllers and a SW900 display today just as a random try, noise is completely gone. Went out for a good ride, blasted it up some nasty hills and it was beautiful. Can’t get the speed to read at all for the life of me on the SW900 with the Bafang G060. Regardless of P07 setting. Just instantly jumps to 62mph. Also drops to 0mph when coasting but with the other motors and the KT/Bafang combo speed would still register while coasting. Maybe something going on with the speed sensor?

Either way, the noise has randomly vanished with the SW900/YF Controller so it’s a step in the right direction