Hollow bore motor bearing failure Thread

[Rawnei]

2 hours ago, Silver said:

True, but it will still take much longer for them to go bad.

No its random, luck of the draw, I rode 4 times in good weather and got busted bearings, others ride 1000km in wet weather before it happens.

[Ben Kim]

On 3/17/2021 at 6:52 AM, EMA said:

yes, the cover also has direct contact to the external ring of the bearing. basically the bearing seal the hole, i suppose if the sealing is good we will not have problems in the future.
 

Generally speaking I am seeing far less bearing failure complaints these days so I believe Gotway has fixed the problem, or at least significantly reduced it. 

[Waulnut]

Batch 1 RS here. No issues at 1000 miles, mostly pavement and some light off roading. 🤞

[EMA]

5 hours ago, Ben Kim said:

Generally speaking I am seeing far less bearing failure complaints these days so I believe Gotway has fixed the problem, or at least significantly reduced it. 

Agree

[Darren0128]

9 hours ago, Waulnut said:

Batch 1 RS here. No issues at 1000 miles, mostly pavement and some light off roading. 🤞

Same boat. approaching 1000 miles, no issues yet.  Looking at replacing the tire already, while I am in there, I am thinking of installing a set of EMA's bearing spacers just as a precautionary measure.

[EMA]

47 minutes ago, Darren0128 said:

Same boat. approaching 1000 miles, no issues yet.  Looking at replacing the tire already, while I am in there, I am thinking of installing a set of EMA's bearing spacers just as a precautionary measure.

your motor probably has good tolerances, if it works don't touch it

the tire should last at least another 1000 miles but if you want to change go for it, it's super easy 

[Flying W]

I'm at 600 miles on my RS, about half off road. I don't get a lot of rain so the off road is dry and dusty. No issues yet. I avoid wet roads and have only caught once in the rain, which was a light rain but enough to wet the streets. 

This is my second RS, the first one must have had an alignment problem. It developed the knocking in the first 10 miles. eWheels swapped it out for a new one.

I know a lot of people have been on the fence with the bearing issues but if it's fixed, and especially if you live in a dry area, pick one up. The wheel is fantastic! 

[Rawnei]

On 3/21/2021 at 8:43 PM, Yo_Yo said:

RS has been protected.Now we r testing EXN .600km was gone in all weather condition already

EXN protection is a 3D printed seal?

[EMA]

4 hours ago, Rawnei said:

EXN protection is a 3D printed seal?

EXN already has the improved motor covers, it should run fine without any mod.

i've designed one btw if someone want it

[Rawnei]

52 minutes ago, EMA said:

EXN already has the improved motor covers, it should run fine without any mod.

i've designed one btw if someone want it

So the EXN bearing is safe from water and dirt ingress without additional protection?

[EMA]

4 minutes ago, Rawnei said:

So the EXN bearing is safe from water and dirt ingress without additional protection?

right now all new c30 and c38 motors have been upgraded and, from what i know, no one has reported problems.

(all hollow motors exactly)

time will tell...

Edited April 13, 2021 by EMA

[Rawnei]

19 hours ago, EMA said:

right now all new c30 and c38 motors have been upgraded and, from what i know, no one has reported problems.

(all hollow motors exactly)

time will tell...

Hmm look at evX review of the EXN and you will see the problem exists even with new motor cover: https://youtu.be/XKozR0OMu2M

My conclusion is that you still need 3D printed seal even on "newer" covers since the bearing is still exposed, but with new motor cover it would require a new design for the seal as well if it's at all possible now.

[EMA]

1 hour ago, Rawnei said:

Hmm look at evX review of the EXN and you will see the problem exists even with new motor cover: https://youtu.be/XKozR0OMu2M

My conclusion is that you still need 3D printed seal even on "newer" covers since the bearing is still exposed, but with new motor cover it would require a new design for the seal as well if it's at all possible now.

are you sure he has the newest motors ? becouse i remember he got the wheel a long time ago and faced the issue like 2 days after

[Rawnei]

1 hour ago, EMA said:

are you sure he has the newest motors ? becouse i remember he got the wheel a long time ago and faced the issue like 2 days after

Looks like it from the workshop footage.

[Boogieman]

On 11/18/2020 at 3:51 PM, null said:

Good consideration indeed, a counter point is that the more balls, the less weight pressure per ball.

Actually not quite right.

The force does not act on all balls in the bearing at any given moment if considering radial forces (the big ones normally).
Rather the force (gravity and acceleration) only acts on one (or a few) balls at any given moment, then the force acts on the next ball and so on.
For one full revolution each ball will have LESS time with force though which is positive.

But a bearing is broken when ONE ball is broken.
More balls = higher likelyhood (especially with cheap bearing)

Then there is lateral forces, where a ball bearing is NOT as strong. I.e. forces from turning, the wheel tumbling hitting a kerb on the side (hard impact = really bad)

[Boogieman]

On 4/13/2021 at 3:53 PM, Rawnei said:

So the EXN bearing is safe from water and dirt ingress without additional protection?

Not if You ask Chooch

 

[Boogieman]

China engineering - my GOOD. They really dont care the least about buyers health.
DO NOT RIDE IN THE WET BEFORE FIXING YOUR EX.N
On the other hand - all rocks and debris will be knocking on the MOS-FET cooler constantly as You ride. Cant be prevented unless You block cooling but then it will likelt over heat. LOL - they probably wanted to make the over heat hill on this designed byt failed miserably on all other points.

Two giant holes into mobo compartment, the worst at 4:30 but the other at 4:20 (allready "fixed" by wrong way)

 

Edited April 18, 2021 by Boogieman

[Killian253]

On 1/29/2021 at 1:25 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

Can you share your .stl file.  What thickness did you use?

[Killian253]

On 1/18/2021 at 2:03 PM, StealthPhoenix said:

for me the noise is gone now for 300 miles

My monster pro just started knocking real bad after only 300 miles. Do we know the problem is for certain just bearing misalignment?

[EMA]

1 hour ago, Killian253 said:

Can you share your .stl file.  What thickness did you use?

which bearing size you need? after fixing some motors i think 1mm is the best, i'll update the files 

1 hour ago, Killian253 said:

My monster pro just started knocking real bad after only 300 miles. Do we know the problem is for certain just bearing misalignment?

yes

 

[Schmudel]

Hi EMA, i am getting my EXN next week and would like to be proactive before i even ride it. Would you be able to share the STL file for that. If you already have, i apologize but i cannot seem to find it on thingiverse.

Thanks in advance.

[EMA]

4 hours ago, Schmudel said:

Hi EMA, i am getting my EXN next week and would like to be proactive before i even ride it. Would you be able to share the STL file for that. If you already have, i apologize but i cannot seem to find it on thingiverse.

Thanks in advance.

EXN already has updated motor, you should be fine, just remember to:

slide the motor out a bit and seal the back of the board
seal the holes under the back light
seal the motor cable hole

for those who need spacers i've updated the files in the shared folder : https://www.dropbox.com/sh/mxui67e2qkdgvff/AAAF5e8MY2qioHy6xacJicrJa?dl=0

i recommend 1mm spacers for knock issue, lock bearings on covers and use one spacer each side, every motor i fixed like this is running fine (RS and EX).
(M24pro has EX motor with RS bearing size, so i don't know)

i've put also some simple cover for both old and new motor version if someone want to try.

[Killian253]

12 minutes ago, EMA said:

EXN already has updated motor, you should be fine, just remember to:

slide the motor out a bit and seal the back of the board
seal the holes under the back light
seal the motor cable hole

for those who need spacers i've updated the files in the shared folder : https://www.dropbox.com/sh/mxui67e2qkdgvff/AAAF5e8MY2qioHy6xacJicrJa?dl=0

i recommend 1mm spacers for knock issue, lock bearings on covers and use one spacer each side, every motor i fixed like this is running fine (RS and EX).
(M24pro has EX motor with RS bearing size, so i don't know)

i've put also some simple cover for both old and new motor version if someone want to try.

So the spacer goes on the motor side, not case side? Or the other way around? And how will I know if its aligned correctly? Thanks for the info in advance! 

[Schmudel]

Thank you very much for the tips and files EMA.

Much appreciated.

[EMA]

10 hours ago, Killian253 said:

So the spacer goes on the motor side, not case side? Or the other way around? And how will I know if its aligned correctly? Thanks for the info in advance! 

spacers should prevent the bearing sliding towards motor hole because covers don't hold them enough, you can find some picture here :

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