Loud clicking noise MAC 12T hub

A

andrius

10 µW
Joined
Sep 18, 2019
Messages
6
After driving with no issues for a couple of months a MAC 12T (53621HR-CD) hub developed rather loud and seems random clicking noise:

Video1 (10s):
[youtube]wD8NTQ6dujg[/youtube]

Video2 (1m):
[youtube]wFajt3UVBHg[/youtube]


I've disassembled the hub partially and gears / bearings seem fine visually:
[attachment=2 width="100"]20190918_012720_HDR.jpg[/attachment]
[attachment=1 width="100"]20190918_012743_HDR.jpg[/attachment]
[attachment=0 width="100"]20190918_023405_HDR.jpg[/attachment]

Videos are post re-assembly with re-lubrication. It also does not seem to be freehub issue as the cassette is not engaged in the videos. There is no sound on low RPMs. It does not matter how much load is on the wheel - free-spinning or fully loaded - it makes same exact sound.

Reading around there seems to be three options: bearings are at their end of life, clutch is broken or the hub magnet(s) got detached.

This is my first build so don't have much experience in mechanical hub failures - has anyone seen (heard!) this failure before?
 

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Which controller are you using, does it make that clicking when you're not driving the hub with power?
 
Jatem said:
Which controller are you using, does it make that clicking when you're not driving the hub with power?
Click to expand...

Would be surprised if it's the controller (VESC 6+) - it still makes the sound even if it's powered down / disconnected and the wheel is spun by hand. It's loud "mechanic" noise rather than "electric".
 
AHicks said:
My guess would be it almost has to be in that hub somewhere.
Click to expand...

Agreed. I am also thinking that it could be a bent axle causing ball bearings to constantly slightly shift /snap in their slot and cause the noise.
 
One way or another, it almost has to be broken down completely to figure it out. Myself, I can't just throw parts at a problem like this. I would need to figure out/see exactly what's happening.
 
Sounds like motor stutter. check your wire connections.
 
dogman dan said:
Sounds like motor stutter. check your wire connections.
Click to expand...

Shouldn't be - issue persists even when the motor is fully disconnected and wheel spun by hand.
 
Have you tried to get in touch with the people you bought the hub from to see if they may have an opinion?
 
AHicks said:
Have you tried to get in touch with the people you bought the hub from to see if they may have an opinion?
Click to expand...

Great idea, just did, thanks! Let's see what they say...
 
Every time I've heard that sound, it's either a cracked bearing race or a loose (metal) object bouncing around inside.

Since the latter is unlikely since you've opened it up and presumably found nothing loose, I'd go over the visible side of the cover/axle bearings with a magnifying glass in the sunlight.

It can't be anything that's just part of the motor itself if it happens with or without power. (clutch, gearing, motor, magnets, etc), so it has to be something in the casing/cover or the wheel itself.


It doesn't have the right sound for a nipple rattling around inside the rim, but you could check for that, too.
 
Vendor agreed to fix under warranty and also thinks that it's most likely a bearing - will update the post when I know more.
 
That's a good one for sure. Seems like a bearing issue would be more regular, and would change with the load placed on it. Anything is possible though. Please do share your findings!
 
Any update yet?

I ask as I believe my 3 month old MAC 12T may be developing an issue. Clacking noise (nothing huge but noticeable, just enough to be irritating) from about 7-8mph up. It continues with the cruise control set, no pedaling, so there's little doubt something is going on in the hub or wheel, not something in the drive train. Will also make the noise when just spun up with the rear wheel off the ground. All spoke make a "ting" when tapped with something metal. No dull "thuds" among them, so I've ruled out a spoke issue. Brake disk is tight as are the screws that hold the case halve together. Tap the brake to kill the cruise and the noise stops. So it's only happening under power. It's not an installation or set up issue as the noise wasn't there when new.

Pretty sure it's a bearing or something loose internally. Strange piece is it's only doing it under power. It's dead quiet while coasting.
-Al
 
Is the noise synchronous with the wheel rotation, or is it synchronous with the internal motor RPM? (meaning, if the wheel is spinning at say, 100RPM, is the noise at that speed, or is it the RPM that would be equal to the planetary gear ratio multiplied by the wheel RPM?

If hte former, then it's something directly connected to the wheel or hub shell or planetary output.

If the latter, it's something directly connected to the motor or planetary input.
 
This noise would be synchronous with wheel speed I believe. Happens under power only, and makes no difference if the wheel is loaded with my (rather substantial) weight on it, or when spun up with the tire off the ground. So that means the noise occurs only when the clutch is engaged. No noise when free wheeling.....

That kinda points towards an issue with the clutch....

Thanks for that thought! That does help narrow the possibilities down.

I am dreading the loss of use if I have to send this back to EM3EV for a fix, but the thought of riding it as is, with the potential for it to get worse is a thought I dread even more. I'm a dyed in the wool DIY'er as a rule. I will very likely pull the motor down myself to whatever level it takes to get to the bottom of the issue. Pretty good at figuring stuff like this out when it's spread out in front of me.
What I will NOT do is to throw parts at it hoping one of them fixes it.

Thanks again! -Al
 
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