Hollow bore motor bearing failure Thread

[Flying W]

I wonder if the fix for this from gotway is really going to work out well or we should just plan on buying higher quality bearings and replacing them.

[EUChristian]

5 hours ago, Flying W said:

I wonder if the fix for this from gotway is really going to work out well or we should just plan on buying higher quality bearings and replacing them.

Same problem we are having with V11. People are getting new motors but no one has enough wheel time yet to know if the new bearings are indeed better. 

[Flying W]

I'm hoping they are just as good as the old way, but looking at prices of quality bearings I don't think EUC companies are spending that kind of money, even if buying in bulk. 

If I replace mine my self I'm going to stay in the $60 to $80 range a piece. I'm hoping that would be good enough. There this size bearings out there hundreds a piece though! 

@EUChristian, inmotion went with a larger bearing too right? I think I saw that somewhere, but between work and a baby it all runs together haha

[Scottie888]

58 minutes ago, Flying W said:

I'm hoping they are just as good as the old way, but looking at prices of quality bearings I don't think EUC companies are spending that kind of money, even if buying in bulk. 

Funny enough, at the wholesale pricing that mfgr's can purchase quality sealed bearings for, its likely only a $50 increase (if that) even if costs were passed on to consumers. Unlike engineers, bean counters will almost always win to bring production costs down to the lowest common denominator. Maybe if we start to NOT purchase their products, things might change for the better.

[Flying W]

@Scottie888, I would not mind at all paying extra for better parts.....but I also can't resist giving them my darn 💰. 

I swear wheels are the only thing I buy knowing I'll have to fix things, and reroute wires....and being completely fine with that!

I wish I could resist, but I'm powerless. The only thing that kept from getting a new for a while was all the new wheels coming out so close together. Trying to decide between them all was difficult. 

[tumbla.jr]

20 hours ago, Planemo said:

I'm staggered that there can be rust in bearings that have never seen water, and even more surprised given there is grease present.

What do these manufacturers do? Soak them in salt water before assembling the wheel?

One can only imagine. I was riding the wheel in Miami and at no point did it even hint that a failure was imminent. Took the wheel home and tossed it on the charger like I always do. I went for a ride the next day and I immediately knew something was wrong. 😑 

[Ben Kim]

16 hours ago, Flying W said:

@Scottie888, I would not mind at all paying extra for better parts.....but I also can't resist giving them my darn 💰. 

I swear wheels are the only thing I buy knowing I'll have to fix things, and reroute wires....and being completely fine with that!

I wish I could resist, but I'm powerless. The only thing that kept from getting a new for a while was all the new wheels coming out so close together. Trying to decide between them all was difficult. 

Wheels are rock solid reliable compared to scooters.  Before hollow bore motors existed, you rarely heard of any issues with them aside from board failures.  

[tumbla.jr]

Cringe...

 

 

[Flying W]

@tumbla.jr Cringe indeed....I hope you get it back up and running as quickly as possible. Did they say how long it will take, amd are they sending you a while motor or just bearings?

[tumbla.jr]

13 minutes ago, Flying W said:

@tumbla.jr Cringe indeed....I hope you get it back up and running as quickly as possible. Did they say how long it will take, amd are they sending you a while motor or just bearings?

Just Bearings. The wheel is already apart. Just need the new bits. The parts just cleared customs so maybe another week or so. 

[EUChristian]

5 hours ago, tumbla.jr said:

Cringe...

 

 

Oh my that sounds horrible.

[pontoonpete]

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 there is a gap between the bearing and the housing. Any water that gets in that gap has no way to get out other than going into the bearing. If you add centrifugal force to the equation any water that gets in there is basically forced into the bearing. In my opinion any moisture that gets in there and collects will be forced into the bearing no matter how good the bearing is. If you have a good look you'll see what I mean.

https://www.instagram.com/p/CJm8sIbDt9B/?utm_source=ig_web_copy_link

Second, a friend of mine got the RS and it began to click. I've heard other people have this problem as well. I've been a heavy duty mechanic for a very long time and the clicking sound is the sound of a bearing moving where it is pressed into the motor housing (misalignment). I've installed thousands of bearings and that clicking sound as a common sound you hear when pressing a bearing into place. An engineer could probably describe this better than me but the fact that the hollow bearings are so much bigger makes it susceptible to exponentially higher side loading (twisting force) which I think is forcing the bearings out of alignment during moments of high side loading like a crash or hitting a curb or something. I fixed the clicking in my friends RS. I confirmed it was a misalignment by loosening the ring bolts around the motor and gently rotating the motor which eliminated the clicking because the black housing was able to move slightly so that the bearing was not moving within the pressfit. I tightened the ring bolts following a cross pattern. I did the same thing with the other side and the clicking was gone. I was lucky that loosening and re-tightening provided enough of an adjustment that it realigned the bearings. Keep in mind the movement that makes the clicking sound is very small. We are talking about a movement that is not able to be seen.

https://www.instagram.com/p/CJm8uC7D5e7/?utm_source=ig_web_copy_link

https://www.facebook.com/100156965192353/videos/357474182243894

Anyway I think the hollow motor idea has potential but has not been thought through as well as it should have been.

Edited January 4, 2021 by pontoonpete
Trying to add pictures

[Scottie888]

@pontoonpete I mostly agree with all your points but damn if reading it made me dizzy. Far be it for me to be a grammar monitor & definitely no offence intended here but it would be super helpful to me (& I assume some others) if you can break up the paragraph into multi's. It would be of mucho assistance to read & get all your points across. IMO ofcos

[pontoonpete]

8 minutes ago, Scottie888 said:

@pontoonpete I mostly agree with all your points but damn if reading it made me dizzy. Far be it for me to be a grammar monitor & definitely no offence intended here but it would be super helpful to me (& I assume some others) if you can break up the paragraph into multi's. It would be of mucho assistance to read & get all your points across. IMO ofcos

How do I edit my post? LOL

[Scottie888]

4 minutes ago, pontoonpete said:

How do I edit my post? LOL

heheh no worries bud. There's a 3dot button on the top right corner of your post. Click on it & thou shalt see an edit option. Slam that & you can edit you post to your hearts content👍

[Planemo]

5 hours ago, pontoonpete said:

 the fact that the hollow bearings are so much bigger makes it susceptible to exponentially higher side loading (twisting force)

I am struggling to follow you on this. Surely the larger the diameter of the bearing, the less side loading it has, due to less leverage (being further from the fulcrum - centre of the wheel in our case).

[pontoonpete]

16 hours ago, Planemo said:

I am struggling to follow you on this. Surely the larger the diameter of the bearing, the less side loading it has, due to less leverage (being further from the fulcrum - centre of the wheel in our case).

I struggled trying to explain this to my friend also. If you look at the second picture in my post, the cross-sectional view of the bearing area. Imagine you stomp on one pedal and imagine how those bearings want to move. The old small bearings would basically just try to shift up and down not left to right. The new larger hollow bearings are much closer together proportionally compared to the smaller bearings. If you stomp on the pedal with the larger hollow bearings they not only try to move up and down but they also are forced left and right to a much larger degree then with the small bearings.

My friend is a house framer and I use the example of someone standing on a 2 x 4 laying on the ground and you try to twist it. Do the same thing with a 4 x 4 piece of lumber. You will see it is much easier to rotate a 4x4 with someone standing on it than a 2 x 4.

Another way to visualize it. Imagine the hollow motor with bearings the diameter of the rim and the space between the bearings is the same as the space between the small bearings. Now which way will the bearings want to move if you stomped on one pedal? All of the force would be trying to move the bearings to the left and right and twist them out of place. 

[Planemo]

OK I think I know where this is going wrong now, and may be what you are trying to explain. I'm not sure.

The 'old' bearings are linked by a common axle, which takes the majority of the load (riders weight) and very little sideways (axial) load as these loads will be transferred along the axle to the 'top' of the other bearing.

The 'new' hollow bearing do not have this common axle, so all axial loads do not have the axle to help support the inside race of the bearing.

Thus, in the new bearings, the riders weight is literally trying to 'twist' the inner race out of the bearing.

Hence, serious axial loading for a bearing that is not designed to have any large axial loads.

The problem is not so much the bearing (it's size is fine, if not overkill for the radial loads). The problem is that without an axle to support the inner race, there will always be a fundamental problem with axial loads.

Not having an axle is actually the problem here.

Thats the way I am seeing it, although I stand to be corrected as I am not 100% sure what the design is with regards to the hollow motors, and I don't have Instagram so can't see your pics.

The only way around the current problem, as far as I can see, would be to employ some sort of additional, dedicated thrust bearing to deal with the axial loads, leaving the current bearing to deal with the radial loads only. Or, do away with the current bearing and additional thrust bearing, and use a bearing like a stub axle on a car - conical roller thrust bearing which kinda deals with both problems.

[NordEstEuc]

On 1/4/2021 at 12:53 AM, pontoonpete said:

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 there is a gap between the bearing and the housing. Any water that gets in that gap has no way to get out other than going into the bearing. If you add centrifugal force to the equation any water that gets in there is basically forced into the bearing. In my opinion any moisture that gets in there and collects will be forced into the bearing no matter how good the bearing is. If you have a good look you'll see what I mean.

https://www.instagram.com/p/CJm8sIbDt9B/?utm_source=ig_web_copy_link

Second, a friend of mine got the RS and it began to click. I've heard other people have this problem as well. I've been a heavy duty mechanic for a very long time and the clicking sound is the sound of a bearing moving where it is pressed into the motor housing (misalignment). I've installed thousands of bearings and that clicking sound as a common sound you hear when pressing a bearing into place. An engineer could probably describe this better than me but the fact that the hollow bearings are so much bigger makes it susceptible to exponentially higher side loading (twisting force) which I think is forcing the bearings out of alignment during moments of high side loading like a crash or hitting a curb or something. I fixed the clicking in my friends RS. I confirmed it was a misalignment by loosening the ring bolts around the motor and gently rotating the motor which eliminated the clicking because the black housing was able to move slightly so that the bearing was not moving within the pressfit. I tightened the ring bolts following a cross pattern. I did the same thing with the other side and the clicking was gone. I was lucky that loosening and re-tightening provided enough of an adjustment that it realigned the bearings. Keep in mind the movement that makes the clicking sound is very small. We are talking about a movement that is not able to be seen.

https://www.instagram.com/p/CJm8uC7D5e7/?utm_source=ig_web_copy_link

https://www.facebook.com/100156965192353/videos/357474182243894

Anyway I think the hollow motor idea has potential but has not been thought through as well as it should have been.

It's happen also to my RS! the CLICK comes and go sometime..... 

[NordEstEuc]

At the beginning I was very happy with the behavior of my RS! Thinking I have a wheel that will almost certainly cause problems makes me angry. It would be interesting to read some statistics on how many RS cycling fail, Spedyfeet in England traveled 650km in the typical English climate (very wet) without problems. The Click I have on my RS has disappeared by itself, at first I thought it was a problem with the outgoing motor cable, Gotway assistance just sent me two spare bearings that look different from the ones I saw in the picture.

[JirkaMak]

Hi guys,

count my RS bearings as well.

And I think Planemo might be right about the axial forces. My bearing are not only rusted, but also slightly warped in the housing causing the stator to scratch the magnets array at the closest point. I'm on a bit heavier side hitting about 105kg (230 pounds) fully geared, but the wheel is supposed to handle it. I found some 61824-RS2 bearings for about $300 for a pair from a local dealer, a bit higher than I thought, but the price for the bearing of different brands spikes at about $800 for a pair so I may be actually around the middle.

To be honest, I consider buying the RS to be a $2k disaster, dealing with different issues from day one.

[Planemo]

Whilst a higher quality bearing may well provide better durability, its not the real answer if its the axial loads that are indeed the problem. Even high quality bearings could still suffer. Not now, but how long...?

Million dollar question.

[Scottie888]

All theory ofcos but in this case, I'd leaned alot towards the hypothesis postulated by @pontoonpete. Normally, most load bearing axles are firmly locked in place through the main motor bearings thereby insuring there is mainly radial loading. In the case of hollow bore motors & how it is implemented, axial shearing forces introduces an unknown quantity in that age old equation.

That & plus the extra diameter of hollow bore motors can be a large factor in failures. IMO ofcos

Edited January 5, 2021 by Scottie888

[StealthPhoenix]

On 1/3/2021 at 6:53 PM, pontoonpete said:

I fixed the clicking in my friends RS. I confirmed it was a misalignment by loosening the ring bolts around the motor and gently rotating the motor which eliminated the clicking because the black housing was able to move slightly so that the bearing was not moving within the pressfit. I tightened the ring bolts following a cross pattern. I did the same thing with the other side and the clicking was gone. I was lucky that loosening and re-tightening provided enough of an adjustment that it realigned the bearings.

for me, this is proof it is NOT the bearing. everytime you open the motor cover even slightly, the motor cover will spin freely round and round. because the bearings ARE good. there is just broken debris (plastic and iron from the coils of the stator)that is being shifted around in the enclosed stator/rotor assembly. when you open this compact situation up, you detach a working component (bearing) from the problem area (rotor/stator assembly beneath the motor cover/bearing), so the bearing spins freely again, if someone had a clear motor cover to see the balance of the stator when the coils are energized, you could see the imbalance of coils and any debris inside. ive seen cracked pieces in my own euc and still ride it with intermittent noise.

[Planemo]

4 minutes ago, StealthPhoenix said:

for me, this is proof it is NOT the bearing. everytime you open the motor cover even slightly, the motor cover will spin freely round and round. because the bearings ARE good. there is just broken debris (plastic and iron from the coils of the stator)that is being shifted around in the enclosed stator/rotor assembly. when you open this compact situation up, you detach a working component (bearing) from the problem area (rotor/stator assembly beneath the motor cover/bearing), so the bearing spins freely again

Yes, many motors could have a bit of debris floating about. And theres tight tolerances between magnets and stators in all wheels. This includes the RS, MSP and MSX.

The point is that any intolerance due to bearings shows up this issue. The real issue isnt debris, its bearing slop.

If the problem goes away without loads being applied to the bearing (as you suggest) then the problem absolutely points to the bearing being the problem. I am unsure how you say it isnt.