Motors make a rubbing noise AFTER detection

Hey guys, I might need some help here. I’m rebuilding my brothers board and he runs a full flipsky drivetrain. I’ve updated the FW to 5.3 and redid the motor detection, and while the motors are detecting they sound fine, but afterwards they make a kind of rubbing noise (see video).

I checked the FOC settings and the motor resistance looks a bit high to me, could that be the culprit? The motors sound fine when I turn them by hand, so the problems seem to be electric, not machanic. Also I’m not sure if they did sound like that while driving before on other FW versions.


for comparison, normal sounding motors:

FOC detection results (other motor looks similar):

Screenshot 2022-03-02 101059

Honestly I don’t hear anything out of the ordinary here. If you had posted that video without context, I wouldn’t have been able to say anything was wrong just from listening to it.

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They look a little bent and dirty, but they sound like normal sensorless motors :person_shrugging:

Mhm maybe I have to compare it to normal sounding motors, because its definitely there. Give me a moment.

Okay, I added a comparison to normal sounding motos, hopefully you can hear it now. :sweat_smile: Because I definitely do. :sweat_smile: There is this “ssshhhhh” sound before they start turning.

Motor resistance detecting wrong is a known issue with FW 5.3 I believe. I recommend sticking with FW 5.2. Especially that 1 motor stuttering and not knowing which direction to spin – are both sensored? yikes


Okay, could the high resistance result be the culprit for this sound? And yes, they are both sensored and the sensors are detected, dunno why its stuttering and turning in the wrong direction though. This board has been neglected by my brother… ^^

Yeah ok, I downgraded to 5.2 and ALL the problems went away. Thank you @rusins, good advice.


L in the 50μH range looks way too high.

But I second @rusins, I would not use firmware 5.3

What motor values does 5.2 show?

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Haven’t checked since the problems were immediately resolved, sorry.

It looks like that right side is having problems from the beginning. I would check all bearing and then make sure your wheel nut is not too tight. Is there still problems with 5.3 ? I haven’t seen it work properly yet. Every time I have tried it has been problematic.

All problems have been resolved since I downgraded to 5.2 :slight_smile:

Well there are certainly problems on this FSESC 6.6.

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