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Gotway Msuper V3s+ 84v (1300wh) failed. Loose axle nut.


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21 minutes ago, Hunka Hunka Burning Love said:

That's very strange why a loose axle nut could cause the wheel to ultimately burn MOSFETs out.  How old is the wheel / how many kilometres are on it?  Maybe check with your dealer to see what they think.

Only about 60 kilometers.  My thought was the axle drift starts to misalign the hall sensors until the wheel and the control board loose coherence (the violent shakes begin) and the resulting output current spikes overheat the MOSFETs.  Just a theory.

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60 km?  Oh man that's a bummer.  :(  That's a pretty pricey wheel to go kaput that quickly.   Which dealer did you buy from?  Jason?  You would think there's got to be a better method to secure a bolt?  Even with my Ninebot, hammering small pieces of metal into the aluminum housing to wedge the bolt seems a little weird as removing them and reinstalling them wrecks up the aluminum a bit.  Maybe a castle nut?

https://engineerdog.com/2015/01/11/10-tricks-engineers-need-to-know-about-fasteners/

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1 hour ago, n2eus said:

Today, my new Gotway Msuper V3s+ 84v (1300wh) failed.  It had performed fine on this route previously.  Started with 91% charge on the battery, rode 7.6 miles on relatively level bikeways, then while creeping slowly along the walkway, the MSuper began quivering violently (approximately 1 inch oscillations in the top end).  The indicating lights remained illuminated even after pressing the button.  Within a couple seconds, I heard a "pop" sound and saw a puff of smoke as the burnt smell hit my nostrils.  It appeared to be off after I placed it on the left side.

When I got home, I took a look (didn't touch internals) and found a loose axle nut and a couple burnt MOSFETs.  See attached photo.  This wheel has never dropped off a curb and has always been driven gently (no sudden changes in torque demands).

My takeaway is that if the wheel begins quivering/grumbling, or is otherwise not as smooth as normal, it may be warning of a loosening axle nut.  Maybe others have experienced violent feedback from your wheel and found a loose axle nut?

Wow, that really sucks. I may be wrong but I don't recall hearing about a loose axle nut on any other MSuper's so hopefully that's a fluke that won't affect the rest of us.

Now you're going to have a quandary as to the replacement board. How do you get one that's assured not to have the bad firmware? It's going to be possible of course but it may take an unusually long time.

I'll be interested in seeing what's involved in tightening the nut so that it doesn't loosen again.

Did you have earlier signs that something wasn't right with the wheel, or did the nut loosen and cause the failure all within a handful of seconds?

BTW, did you post any pictures because I don't see any.

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1 hour ago, Hunka Hunka Burning Love said:

60 km?  Oh man that's a bummer.  :(  That's a pretty pricey wheel to go kaput that quickly.   Which dealer did you buy from?  Jason?  You would think there's got to be a better method to secure a bolt?  Even with my Ninebot, hammering small pieces of metal into the aluminum housing to wedge the bolt seems a little weird as removing them and reinstalling them wrecks up the aluminum a bit.  Maybe a castle nut?

https://engineerdog.com/2015/01/11/10-tricks-engineers-need-to-know-about-fasteners/

I'll let Dion restore it.  I don't want to mess anything up.

1 hour ago, Marty Backe said:

Wow, that really sucks. I may be wrong but I don't recall hearing about a loose axle nut on any other MSuper's so hopefully that's a fluke that won't affect the rest of us.

Now you're going to have a quandary as to the replacement board. How do you get one that's assured not to have the bad firmware? It's going to be possible of course but it may take an unusually long time.

I'll be interested in seeing what's involved in tightening the nut so that it doesn't loosen again.

Did you have earlier signs that something wasn't right with the wheel, or did the nut loosen and cause the failure all within a handful of seconds?

BTW, did you post any pictures because I don't see any.

That's a good question.  I'll see what Dion knows.

The wheel seemed to vibrate (as if complaining) during minor torque transitions.  Over a half hour minor occasional vibrating until the amplitude ramped up and the right end of the axle appears totally free, moving independently of the left end of the axle, which is secured solid.  Does this mean the axle is broke also?

Untitled.jpg

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I doubt the axle is broken as there usually is scraping of the pedal support against the motor.  The bolt might be loose on one side though?  Yikes :blink: it looks like there was a small explosion in there judging by the blackened wiring and MOSFETS area.  I wonder if there was a wiring short somewhere along the motor power wiring.

How much do you weigh if you don't mind me asking?  Did you do any climbing of hills during those 60 kms?

Edited by Hunka Hunka Burning Love
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3 hours ago, n2eus said:

Today, my new Gotway Msuper V3s+ 84v (1300wh) failed.  It had performed fine on this route previously.  Started with 91% charge on the battery, rode 7.6 miles on relatively level bikeways, then while creeping slowly along the walkway, the MSuper began quivering violently (approximately 1 inch oscillations in the top end).  The indicating lights remained illuminated even after pressing the button.  Within a couple seconds, I heard a "pop" sound and saw a puff of smoke as the burnt smell hit my nostrils.  It appeared to be off after I placed it on the left side.

When I got home, I took a look (didn't touch internals) and found a loose axle nut and a couple burnt MOSFETs.  See attached photo.  This wheel has never dropped off a curb and has always been driven gently (no sudden changes in torque demands).

My takeaway is that if the wheel begins quivering/grumbling, or is otherwise not as smooth as normal, it may be warning of a loosening axle nut.  Maybe others have experienced violent feedback from your wheel and found a loose axle nut?

Man that sucks.Hard to believe that a new wheel could leave the factory with a loose axlenut.Between problems with burning wires/mosfets,shorts,or bad firmware,Gotway needs to be rebranded as "GetoffwayTM"

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7 minutes ago, Hunka Hunka Burning Love said:

I doubt the axle is broken as there usually is scraping of the pedal support against the motor.  The bolt might be loose on one side though?  Yikes :blink: it looks like there was a small explosion in there judging by the blackened wiring and MOSFETS area.  I wonder if there was a wiring short somewhere along the motor power wiring.

How much do you weigh if you don't mind me asking?  Did you do any climbing of hills during those 60 kms?

Yes, the MOSFET debris was everywhere in a flash.  I weigh 82 kilograms 180 lbs.  Only mild riding with this wheel, nothing real steep.

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15 minutes ago, n2eus said:

I'll let Dion restore it.  I don't want to mess anything up.

That's a good question.  I'll see what Dion knows.

The wheel seemed to vibrate (as if complaining) during minor torque transitions.  Over a half hour minor occasional vibrating until the amplitude ramped up and the right end of the axle appears totally free, moving independently of the left end of the axle, which is secured solid.  Does this mean the axle is broke also?

Untitled.jpg

Thanks a lot for the additional symptoms. That's good information and something I won't ignore if I ever feel similar sensations. I guess we all need to become one with our wheels so we can pick up on subtle changes that can occur.

Fortunately you got it from Dion so everything should be covered by warranty. Definitely talk to him so you understand how he's guaranteeing a good firmware board is installed. Hopefully he has one or more spare boards acquired from much earlier in the year.

Let us know how it works out in the end.

Do you have another wheel to use while you wait? Hopefully not a generic ;) 

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12 minutes ago, Marty Backe said:

Thanks a lot for the additional symptoms. That's good information and something I won't ignore if I ever feel similar sensations. I guess we all need to become one with our wheels so we can pick up on subtle changes that can occur.

Fortunately you got it from Dion so everything should be covered by warranty. Definitely talk to him so you understand how he's guaranteeing a good firmware board is installed. Hopefully he has one or more spare boards acquired from much earlier in the year.

Let us know how it works out in the end.

Do you have another wheel to use while you wait? Hopefully not a generic ;) 

I'll pass on what I learn.

I still love my other Msuper V3 820wh 25 miles every day:D

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4 minutes ago, n2eus said:

I'll pass on what I learn.

I still love my other Msuper V3 820wh 25 miles every day:D

Oh cool, I really enjoyed mine too. Had 800 miles on when I sold it. In hindsight I should have kept it as a backup.

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16 hours ago, jrkline said:

Gotway needs to be rebranded as "GetoffwayTM"

I guess there's a reason some people call it "GotProblems"... Most of it seems to stem from them taking the hardware to the limits vs. most of the manufacturers.

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You're all missing the obvious....

"Got way too many problems" (you have to pronounce the part after Gotway really quickly)

Also, stronger wheels aren't the only reason for that, also and probably more importantly: absolutely no QC or testing.

--

My ACM now makes a sliiiiiiiighty uneven sound when riding, so I'm sensitized because it might be the axle being not totally bomb proof. Or the tire a tiny bit uneven. Or whatever.

Thanks for the description of how your failure sounded and felt.

 

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4 minutes ago, Rehab1 said:

Sorry about your wheel! The good news is it sounds like your faulty wheel will be fixed. The bad news is if GW owners would like to check the tightness of the axle nut on the mainboard side they will either need to disassemble the wheel further to gain complete access to the nut or use a 'Pass Through Socket'. 

The axle nut simply does not have enough surface area protruding above the plastic shell to adequately grasp it with an open end wrench. A socket will not work because of the wires protruding out the top of the shaft. A pass through socket works well in these unique situations where there is zero clearance for an end wrench combined with wires ( or a bolt like below ) is protruding out the end.

You will first need to disconnect the 3 motor wires at the bullet connector sites.  You can then feed the 3 wires up through the Pass Through Socket, attach the ratchet and then tighten the nut,  reconnect the bullet connectors and you are good go. Important:  Do forget to slide shrink wrap over the motor wires before reconnecting the bullets!

 

Great info. You are now our go-to guy for anything Gotway related :cheers: as you have first hand experience with just about everything.

I was wondering if this idea has any merit. Applying some epoxy along the outside of the nut to keep it from loosening in the first place?

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1 minute ago, Rehab1 said:

If you are certain that the nut is tight you could use a center punch and hammer to really secure the nut. The idea is to punch a small amount of the axle's threads outward into the nut creating a burr that makes it hard for the nut to loosen. I will try to shoot a short video at work tomorrow demonstrating the technique. 

 

Thanks, that looks even better. Even if the nut weren't fully tight this technique would't preclude you from further tightening it later?

I just don't see myself disconnecting the wire and buying the socket & driver, but a little preventive maintenance next time I'm in the shell couldn't hurt.

I've never tried cutting a socket, but i wonder if you could make something like this, so you don't have to disconnect the motor and sensor cables from the control board to tighten the nut?

s-l64.jpg

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On 6/27/2017 at 10:21 PM, myfunwheel said:

Rest assured, I'll take care of any repairs that are needed.  I'll pay for shipping both ways also, it's unfortunate Gotway shipped us faulty boards resulting in all of these problems.  

Is Gotway warrantying these repairs?  I'm curious as I've been planning to buy one.   This information is important to me,  since it feels like it's a critical growth issue, with a company that is pushing like a startup.  But no Public relations.  I haven't even seen there website,  but KingSong seems to be more mature...  though styling is...  meh. 

 

Imo gotway should have a rep in here, just not dealers and resellers having to play spokesperson for their Brand.  Atleast Ninebot got that right.

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5 minutes ago, SeattleAbarth said:

Is Gotway warrantying these repairs?  I'm curious as I've been planning to buy one.   This information is important to me,  since it feels like it's a critical growth issue, with a company that is pushing like a startup.  But no Public relations.  I haven't even seen there website,  but KingSong seems to be more mature...  though styling is...  meh. 

 

Imo gotway should have a rep in here, just not dealers and resellers having to play spokesperson for their Brand.  Atleast Ninebot got that right.

They do have two reps here. Unfortunately they rarely post or interact. It's probably the language barrier and the Chinese firewall. But I agree with you.

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1 hour ago, Marty Backe said:

They do have two reps here. Unfortunately they rarely post or interact. It's probably the language barrier and the Chinese firewall. But I agree with you.

I think @SeattleAbarth means, "here in the US." (like I will be next week).

And if Gotway did, I'm sure things would be quite different!

Now if only we could find a Gotway-fanboy to apply...

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7 hours ago, Marty Backe said:

I've never tried cutting a socket, but i wonder if you could make something like this, so you don't have to disconnect the motor and sensor cables from the control board to tighten the nut?

That is a great suggestion Marty! I have never tried that. You might now get the torque before the socket splits in half but modifying socket in this fashion is definitely worth the time. 

 

7 hours ago, Marty Backe said:

Great info. You are now our go-to guy for anything Gotway related :cheers: as you have first hand experience with just about everything.

I missed this comment. Many thanks but no way!  I'm just a tinkerer trying to stay alive.;)

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11 hours ago, Marty Backe said:

Thanks, that looks even better. Even if the nut weren't fully tight this technique would't preclude you from further tightening it later?

I just don't see myself disconnecting the wire and buying the socket & driver, but a little preventive maintenance next time I'm in the shell couldn't hurt.

I've never tried cutting a socket, but i wonder if you could make something like this, so you don't have to disconnect the motor and sensor cables from the control board to tighten the nut?

s-l64.jpg

That kind of looks like an oxygen sensor socket, except they only have a slot in the side just wide enough to let the wires go through.  If you measure the nut and go to Autozone, you might get lucky and find one the right size.

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12 hours ago, Rehab1 said:

You will first need to disconnect the 3 motor wires at the bullet connector sites.  You can then feed the 3 wires up through the Pass Through Socket, attach the ratchet and then tighten the nut. You then reconnect the bullet connectors, route your wires neatly, and you are good to go. Important:  Do not forget to slide shrink wrap over the motor wires before reconnecting the bullets!

Problem will be that also to the 3 Motor wires there are the sensor wires which are nicely siliconed to the board :-(

 

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