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Hollow bore motor bearing failure Thread


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Hollow bore/centreless/hubless motors will always wear out faster than traditional axle motors, given the same bearing material for the following reasons: Being further away from the centre, eac

I'd like to bring up two points that add to the shortcomings of the hollow motor design.   First, if you look closely at the black part, the outer housing of the motor you will see that ther

We're comparing two designs: MSuper with bearing size 6203 MSuper with bearing size 61824 Everything else about the bearing loads are equal: Same rider weight Same pedal

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On 1/29/2021 at 10:25 PM, EMA said:

After 1500km the knock sound started on my EX so I disassemble the motor to find out what’s happening:

As already described by @pontoonpete I can confirm that the sound is caused by a bearing moving into a misaligned motor, bearings are not hold in place but they can move laterally a bit.

In my case the side cover are not tight and don’t hold the bearing in place (the factory use something to hold them), on the left side I can even put and take out the bearing with my hands without heating the cover. I can move it with one hand…: https://www.dropbox.com/s/92pqfnn3taezi9y/bad side cover.mp4?dl=0

This problem is also amplified by some tolerance error in the bearing position, probably related to bad side cover. After closing the motor side the bearing is not completely in touch with the stator inside, I’ve 3d printed a tiny ring ( 0.4mm each side) to fit the gap.

With the spacing ring inserted in a good side cover the motor is centered even with only 1 bearing as you can see in the video: 

https://www.dropbox.com/s/pf8mzuicgj42b9x/cover_ok.mp4?dl=0

reference photos and videos here :

https://www.dropbox.com/sh/qgwx1mfok1osmfo/AACRCQSy8fY4ZJIjaWqqvfPka?dl=0

i've closed the motor and the knock is gone, it turns smooth and feel solid (it wasn't before), bearings seems fine, tomorrow i’ll seal the motor and try the wheel again

EMA, can you upload the 'stl' file of spacing ring to Thingiverse?. Thanks

Edited by Augus
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12 hours ago, Augus said:

EMA, can you upload the 'stl' file of spacing ring to Thingiverse?. Thanks

EX or RS ? i'm doing both btw

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  • 2 weeks later...

So I am just brainstorming here, but I got the knocking on my RS19 the other day due to a bearing misalignment. I replaced both bearings just ot be safe, rather than re-seat the old ones. While heating the rim to release the bearings it got me thinking, could the bearing alignment issue be due to different material expansion rates riding in colder conditions? I leave my wheel in the garage  on the concrete due to the fire issues, so it is colder when I start my ride. The motor housing is made out of aluminum and the bearings are steel. As the motor warms up the aluminum is absorbing the heat much faster than the bearings. So could the housing expand faster than the bearings, letting it loosen and shift? Just a crazy thought from a newer rider.

Edited by Zach N
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450km in on my rs and I just got the knocks after riding 10km on moist gravel... When lifting and freespinning the wheel it's oblivious that it's become unaligned. I store my wheel in the house if that helps anyone. 

In total I've ridden it once in heavy rain early on, and on moist road for maybe 100km total otherwise I've done maybe 20km of off road and the rest in dry conditions..

These bearings can't handle even the smallest amounts of moisture. Now I have to invest in some expensive ones. 

So all there is left now is waiting for it to burn my house down and kill me and my family :thumbup:

Edit: after rereading this entire thread I will try to disassemble the motor and reseat the bearings, possibly print one of those spacers if needed.. I'm no less furious at gotway but at least I possibly won't have to spend good money on expensive bearings.. Yet.. 

final edit: bearings didn't fail, they aren't even rusty. The problem was misalignment of motor to which i have found an, at least, temporary solution - read later comment

Edited by xiiijojjo
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21 hours ago, xiiijojjo said:

450km in on my rs and I just got the knocks after riding 10km on moist gravel... When lifting and freespinning the wheel it's oblivious that it's become unaligned. I store my wheel in the house if that helps anyone. 

In total I've ridden it once in heavy rain early on, and on moist road for maybe 100km total otherwise I've done maybe 20km of off road and the rest in dry conditions..

These bearings can't handle even the smallest amounts of moisture. Now I have to invest in some expensive ones. 

So all there is left now is waiting for it to burn my house down and kill me and my family :thumbup:

Edit: after rereading this entire thread I will try to disassemble the motor and reseat the bearings, possibly print one of those spacers if needed.. I'm no less furious at gotway but at least I possibly won't have to spend good money on expensive bearings.. Yet.. 

 

i know it's not a pleasure to open the wheel and the motor, but the knock is not a bearing failure and it's not related to rains, snow, moisture ecc ecc.

if you can open and align it with spacers, i have fix 3 motors and they are still running fine after this :fingercrossed:

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2 hours ago, EMA said:

i know it's not a pleasure to open the wheel and the motor, but the knock is not a bearing failure and it's not related to rains, snow, moisture ecc ecc.

if you can open and align it with spacers, i have fix 3 motors and they are still running fine after this :fingercrossed:

After an arduous day of disassembling and reassembling the euc i have fixed the misalignment. The bearings seem fine although i didn't want to remove the seal and take a closer look. Overall there seemed to be no rust anywhere inside but a lot of the gotway goop was on the the coils closet to the hall sensor so i removed as much as i could. 

I suspect my fix will be temporary as i don't own a printer to print those spacers on there yet. I "simply" removed the cover of the motor to expose the stator and knocked the bearing back into the motor cover(only a couple millimeters) and reattached it. Only saving grace to this whole thing is how relatively easy the motor is to get out and open from previous models. 

Also i suspect the cover would not have needed to be pulled off at all for this to effectively halt the knocking sound as i suspect a few taps with a mallet would have knocked it back in place. 

Fingers crossed this solution lasts a while. 

Edited by xiiijojjo
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Wondering if anyone saw the below video of a v11 bearing replacement and hub modification. 

Before the bearing housing is re-installed, the guy drills a hole in the hub and appears to plug it up with some sort of rubber tubing that he caulks into place.  According to the comments, he does this because after the temperature inside the housing heats up, the only place for the heat to escape is through the bearings.  However, when it bearing housing is cooled quickly, like when riding through water, a vacuum is created drawing moisture into the interior through the bearings.  The moisture cannot escape easily causing buildup and premature bearing failure (rusting out).  By allowing the air pressure to equalize through the hole it eliminates the vacuum and prevents moisture buildup thereby preserving the bearings.  Would love to know the material he uses in the video to plug the hole and what he's using to glue it into place.  From the EcoDrift website, it looks like rubber tubing is used with foam rubber glued into the ends.   Also, it looks like the guy in this video uses a thin layer of automobile differential sealant to seal up the bearing plate to the wheel.  EcoDrift says this might not be necessary but it can't hurt (they use grease instead of sealant).  Any thoughts on this "fix"?  Should this be done to all hollow bore motors? 

 

Edited by Wise Rides
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With total lack of information from manufactures it seems community awareness and consensus is becoming more clear.

For all hollow motors (Begode/Inmotion) it's not a matter of if but when the bearings will fail due to the frail protection of a small rubber seal, the seal on the bearing is just not enough to protect the bearings from dirt or moisture ingress over time, you can be lucky and the wheel will run thousands of km/miles before a problem or unlucky and just ride couple of km/miles as we have seen. Changing the bearing or motor just restarts the problem and it will happen again in time.

The only way to protect the bearings is from custom 3D printed seals fitted with waterproof grease, now this also opens up problems of it's own because you need to find someone who can 3D print it for you, use the correct material (we need to think summer and at least some heat resistance due to outside heat, motor heat + friction) and then it's the matter of taking the wheel apart fitting the seal and perhaps maintenance over time, everyone with a hollow motor should do this to protect their wheel but it's doubtful everyone will.

Personally I regret my V11 purchase, not because I don't like riding it because I can't ride it until I have said 3D printed seal, so right now I have an expensive toy sitting there for months without use because I already changed motor and don't want to go through that process again and I also bought it from Ali which would be a pain if it breaks again (that's on me I know).

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7 hours ago, Rawnei said:

With total lack of information from manufactures it seems community awareness and consensus is becoming more clear.

For all hollow motors (Begode/Inmotion) it's not a matter of if but when the bearings will fail due to the frail protection of a small rubber seal, the seal on the bearing is just not enough to protect the bearings from dirt or moisture ingress over time, you can be lucky and the wheel will run thousands of km/miles before a problem or unlucky and just ride couple of km/miles as we have seen. Changing the bearing or motor just restarts the problem and it will happen again in time.

The only way to protect the bearings is from custom 3D printed seals fitted with waterproof grease, now this also opens up problems of it's own because you need to find someone who can 3D print it for you, use the correct material (we need to think summer and at least some heat resistance due to outside heat, motor heat + friction) and then it's the matter of taking the wheel apart fitting the seal and perhaps maintenance over time, everyone with a hollow motor should do this to protect their wheel but it's doubtful everyone will.

Personally I regret my V11 purchase, not because I don't like riding it because I can't ride it until I have said 3D printed seal, so right now I have an expensive toy sitting there for months without use because I already changed motor and don't want to go through that process again and I also bought it from Ali which would be a pain if it breaks again (that's on me I know).

There are a lot of 3D Printing services on the internet now.  I found this website that compiles a list: https://all3dp.com/1/best-online-3d-printing-service-3d-print-services/

Of the list, I've heard of Shapways: https://www.shapeways.com/ They seems to do small, consumer size orders. 

If I ever get my v11 (back ordered on ewheels) I'll try and have a bearing seal/flange printed up based on some plans I found on this forum.  I'll then install the "breather hole" and the bearing seal and it should significantly extend the life of the bearings.

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@xiiijojjo tnx man, really appreciate your words.

of course i've uploaded the RS spacer becouse the motor is way more popular but i can share also the same spacers for the EX 

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I have tested my the solution over 4 weeks and several trips in rainy weather / wet conditions / rides through 3-5 cm water puddles . No issues so far, no strange noises from bearings. I won't offer warranty but I can say that for reasonable wet conditions / rainy weather / wet rides my solution works OK. 

There is already second set of my protection installed, and next two will be installed soon, so next update in around 2-3 weeks

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  • 2 weeks later...
Just now, xiiijojjo said:

@EMA Where did you find that ring specifically? 

inside the motor, RS-T, it's like the ring i've 3d printed :innocent1:

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3 minutes ago, EMA said:

inside the motor, RS-T, it's like the ring i've 3d printed :innocent1:

I see, they've started making their own spacers. This could essentially remove all potential for bearing knocking in the future. 

Edited by xiiijojjo
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