My Gotway Monster 100v committed suicide today and it was all my lack of maintenance fault.

[chulander]

TLDR:

1. Don't be lazy on maintenance

2. Axle nut and gyroscope are somehow dependent on each other

 

Wheel History

I've been riding the Monster 100v ever weekend since late May of 2019 with about 800 miles clocked. There were no major accidents other than the wheel tipping over onto its heavy side two/three times.

Event:

Today as I was leaving a NYC Kickstarter PEV demo event, I powered on the wheel in disbelief as it took on a life of its own and bolted toward the the bench it was previously leaning against. The wheel did a cool backflip onto its handle bar, breaking it, then cartwheeled a few times before cutting off.

This video demonstrated what happened minus the backflipping

WTF??? 4 Gotway wheels in 2 years and what did I just see?

Diagnosis

As my EUC world crumbles, I resort to crying to @Jason McNeil for parts and messaging @houseofjob on how to fix it and what tools are required. Luckily, I went to the event with Chris so really only had to cry to Jason.

Chris inspected the wheel's right side where all the electronics are and said appears fine, no burnt smell and the wiring was not only secure but isolated. To make matters worse, the 6/8 screws holding the pedal arms was also tight and the axle nut was a-okay.

Quote

The day can't get any better than this, having a known problem is fixable but not knowing what to fix is....

As Chris proceeded towards the left side, I wondered what could possible be there that's related to the gyroscope? Isn't it just batteries on that side?

Demoralized, as I heard there was nothing new and that the wires and 6 (or 8?) screws holding the pedal arms were secured but this time Chris suddenly blurted out "the axle is loose" in a surprised tone.

He turns it and says "1 rotation?", "2 rotation??", 3 rotation???" in an escalating alarmed tone.

Success

I didn't think much of it but here's @houseofjob holding up the wheel (securely) and powering on the wheel

 

Lesson to those that are really lazy and uninformed (like me)

Lesson be learned, I didn't think I needed to tighten the axle because "that can't happen to me, it's still new right?".

Wrong!!!

If you are torquing the Monster and riding it hard (because you can!), save yourself the money and learn from my costly ignorance

 

It's still my personal favorite wheel despite not fully understanding how an axle nut can make the wheel possessed. Even better, after a 6 mile ride ,albeit cautiously for the first 0.5 miles, the wheel rides more responsively now that both axles are equally tighten.

Nothing beats balance..... and that will include maintenance from now on.

 

 

 

 

 

Edited December 9, 2019 by chulander

[alcatraz]

Do you mean the giant nut with the motor wire coming out of it, but the opposite side?

Even with tire changes that nut never needs to be touched. That was loose?

[chulander]

yes that gian

Just now, alcatraz said:

Do you mean the giant nut with the motor wire coming out of it, but the opposite side?

Even with tire changes that nut never needs to be touched. That was loose?

Yes, that giant 24mm nut. The side with the wiring requires a slightly altered tool

[Joker10]

I better check the axle nut on my 18l.  It has about 2000 miles on it now.  

[Rywokast]

23 minutes ago, Joker10 said:

I better check the axle nut on my 18l.  It has about 2000 miles on it now.  

there is no need, this is only an issue with gotway wheels.. it is absolutely ludicrous that anyone should be expected to do any maintenance sub 1000 miles.. I have many thousands of km on many wheels and the most I've ever had on one was around 10,000 km.. in perfect condition as the day I got it never any maintenance.. this is something that gotway absolutely needs to address with next year's EUC lineup it's unacceptable for something that cost that much

Edited December 9, 2019 by Rywokast

[Ben Kim]

53 minutes ago, alcatraz said:

Do you mean the giant nut with the motor wire coming out of it, but the opposite side?

Even with tire changes that nut never needs to be touched. That was loose?

Oh they definitely need to be touched, with red loctite for a longer maintenance interval. On Monsters it’s a 99.9% certainty it will need to be done eventually, MSX it’s far less frequent but it does happen, Nikola so far so good. 

I thought OPs board failed given the sudden nature of his wheel going nuts, but I was wrong. @chulander make sure you red loctite both those axle nuts before riding it again. 

[Rywokast]

3 minutes ago, Ben Kim said:

Oh they definitely need to be touched, with red loctite for a longer maintenance interval. On Monsters it’s a 99.9% certainty it will need to be done eventually, MSX it’s far less frequent but it does happen, Nikola so far so good. 

I thought OPs board failed given the sudden nature of his wheel going nuts, but I was wrong. @chulander make sure you red loctite both those axle nuts before riding it again. 

just weld it on lol

[Ben Kim]

Just now, Rywokast said:

just weld it on lol

Honestly, no reason why not. those nuts don’t need to come off on tire changes. you’d need new pedal hangers if you ever needed to swap your motor out, but that’s pretty unlikely. 

[Rywokast]

9 minutes ago, Ben Kim said:

Honestly, no reason why not. those nuts don’t need to come off on tire changes. you’d need new pedal hangers if you ever needed to swap your motor out, but that’s pretty unlikely. 

they should do it from factory.. motor would be the last thing to go and hangers are cheap,, actually, they should just find a non idiotic way to connect the hangers like every other euc manufacturer but that would be too easy lmao

[houseofjob]

1 hour ago, Joker10 said:

I better check the axle nut on my 18l.  It has about 2000 miles on it now.  

King Song doesn't employ an axle nut, it's 2 hex screws on top that secure the top piece to the KS pedal arm, and they *usually* blue loctite these screws.

KS pedal arm system:

Gotway pedal arm system:

 

42 minutes ago, Rywokast said:

just weld it on lol

40 minutes ago, Ben Kim said:

Honestly, no reason why not. those nuts don’t need to come off on tire changes. you’d need new pedal hangers if you ever needed to swap your motor out, but that’s pretty unlikely. 

If Gotway ever changes their mounting standard, like KS has done twice now for the XL & 16X pedals, you're screwed if you weld the nut.

 

1 hour ago, alcatraz said:

Even with tire changes that nut never needs to be touched. That was loose?

Sounds like you've never owned a Gotway Monster 

This is just a known issue, esp w/ v2 & v3 Monsters, since the increased size of the 22" wheel increases all the torque forces going on. Really screams for a multi-bolting system for the bigger Monster, ala how a car bolts on their rims.

[Rywokast]

15 minutes ago, houseofjob said:

King Song doesn't employ an axle nut, it's 2 hex screws on top that secure the top piece to the KS pedal arm, and they *usually* blue loctite these screws.

KS pedal arm system:

Gotway pedal arm system:

yup I've done it more than once :-) the gotway system is ridiculous, hence why no one else does it

[chulander]

19 minutes ago, houseofjob said:

King Song doesn't employ an axle nut, it's 2 hex screws on top that secure the top piece to the KS pedal arm, and they *usually* blue loctite these screws.

KS pedal arm system:

Gotway pedal arm system:

 

If Gotway ever changes their mounting standard, like KS has done twice now for the XL & 16X pedals, you're screwed if you weld the nut.

 

Sounds like you've never owned a Gotway Monster 

This is just a known issue, esp w/ v2 & v3 Monsters, since the increased size of the 22" wheel increases all the torque forces going on. Really screams for a multi-bolting system for the bigger Monster, ala how a car bolts on their rims.

imagine if tires were bolted on with 1 nut..... 

[houseofjob]

4 minutes ago, chulander said:

imagine if tires were bolted on with 1 nut..... 

yeah, when you get this big, you really need like 2 more nuts that's what she said, to make a small tight circle.

Edited December 9, 2019 by houseofjob

[Ben Kim]

1 hour ago, houseofjob said:

yeah, when you get this big, you really need like 2 more nuts that's what she said, to make a small tight circle.

... and you wanted them to make a 26” wheel, which would make this issue even larger 😂

[hyperair]

5 hours ago, Rywokast said:

yup I've done it more than once :-) the gotway system is ridiculous, hence why no one else does it

Inmotion uses the same system as Gotway, and IIRC, so does Ninebot, and this is before we even get into the various off-brand wheels on the market.
The only EUC manufacturers I've seen using the King Song pedal arm clamp system are King Song themselves and the Rockwheel (specifically the GT16).

[EMA]

maybe the system could be improved, but a lot of brand use it and it works, for sure.

the giant tire of the monster needs more accurate check, starting from factory to end users

[Joker10]

Whew glad I bought the kingsong.  Thanks for the info everyone.

[Xoltri]

Personally I am not a fan of the kingsong mounting method though.  On my KS 16b those hangers bend eventually and the pedal hangers scrape the motor.  The only fix I've been able to do is to use a wrench to bend it back outwards, about once a season.

[meepmeepmayer]

May 2019 is brand new. Don't blame yourself. Blame Gotway

[Rywokast]

13 hours ago, hyperair said:

Inmotion uses the same system as Gotway, and IIRC, so does Ninebot, and this is before we even get into the various off-brand wheels on the market.
The only EUC manufacturers I've seen using the King Song pedal arm clamp system are King Song themselves and the Rockwheel (specifically the GT16).

yes you are right but they are doing something different because gotway is the only one i have ever once heard of them coming loose, something perhaps about how they use the shims maybe im not sure but its not a problem with anyone else

[Hunka Hunka Burning Love]

  I wonder why EUC makers don't switch to axle splines?  They could still have a mating part made of a compatible material to the axle for the spline that bolts/fits into the aluminum alloy pedal support block. 

https://viciousoffroad.com/n-31-counting-on-the-spline-why-axle-spline-count-matters.html

[Rehab1]

1 hour ago, Hunka Hunka Burning Love said:

  I wonder why EUC makers don't switch to axle splines?  They could still have a mating part made of a compatible material to the axle for the spline that bolts/fits into the aluminum alloy pedal support block. 

https://viciousoffroad.com/n-31-counting-on-the-spline-why-axle-spline-count-matters.html

Or at a minimum drill tap a hole in the hanger and add a set screw to impale the nut. 

 

 

Edited December 10, 2019 by Rehab1

[Joker10]

Well I must say it was not all you fault.  I don’t think you should have to do this maintenance.  Sounds like a problem that Gotway should address.

[Peter Q]

Can anyone please tell me where I can buy one of that special 24mm socket which can use on the Monster? Or maybe someone can help me to make one, and I will pay you back.

Thanks.

Peter Q

Edited December 10, 2019 by Peter Q

[hyperair]

3 hours ago, Rywokast said:

yes you are right but they are doing something different because gotway is the only one i have ever once heard of them coming loose, something perhaps about how they use the shims maybe im not sure but its not a problem with anyone else

I think Ninebot hammers some metal shims into the gap between the six nut side faces and the cylindrical wall of the pedal hangers, which prevents it from unscrewing. It's a workable system until you want to replace the motor, because it damages the pedal hanger every time you install that shim.

Inmotion seems to just use threadlock as far as I can tell. I suspect that the only difference between Inmotion and Gotway in this regard is how tightly they install the nut (whether they use a torque wrench for repeatable torque, or whether they just use a normal wrench and tighten by feel), and whether or not they use threadlock.

Another thing is that none of the other vendors using the wheel nut system have wheels above 16" in diameter (I think), and the torque requirements on the axle go up linearly with an increasing wheel size. It might simply be that this system fails on wheels with larger torque requirements, or that the wheel nut needs to be installed with more torque on these larger wheels. Also, did Gotway increase their axle size? I suspect that an increase in thread size requires a corresponding increase in nut tightening torque.