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I have figured out why Kingsong wobbles at high speed


Cloud
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ok,  i have figured out why several people reported that kingsong shakes and wobbles at higher speed.

I just experienced it. It has turned out to be quite simple - your feet are too much forward on the foot rest. Makes it wobble at higher speed. Bring them back a bit and the wobbling will dissapear.

Please try it and let me know

 

Edited by Cloud
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ok,  i have figured out why several people reported that kingsong shakes and wobbles at higher speed.

I just experienced it. It has turned out to be quite simple - your feet are too much forward on the foot rest. Makes it wobble at higher speed. Bring them back a bit and the wobbling will dissapear.

Please try it and let me know

I think any sort of unbalanced footing can be a cause for the wobbling, especially at higher speed. Usually it seems to go away with most people after the initial training hurdle. Unless the pedals or the tire are warped or deformed.

They also admitted it was a bug in their firmware.  The recent version from about two weeks ago has fixed this issue (so they say).  Unfortuantely, the only way to get latest code (remotely) is by swapping the board since it's not user flash upgradeable.

That's weird, given that there's only one motor and no turn control in an EUC itself, how could the software cause this? In the end, the only control it has over the motion is controlling the motor speed, I'm not sure if I can see how software would cause wobble. Changing speed quickly back and forth to cause the rider to start the wobble?

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They also admitted it was a bug in their firmware.  The recent version from about two weeks ago has fixed this issue (so they say).  Unfortuantely, the only way to get latest code (remotely) is by swapping the board since it's not user flash upgradeable.

Surely you could return you wheel under warranty for something like this.

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KS vibration at high-speed, >25kph (not very significant), due to back-EMF build up at higher RPM. It is better in the Mark II production run than the original.  

There might be a difference in terms used in this topic and how I understand them... I understand wobble as the wheel doing the "squirming" sideways turning motion, like shown here for a motorcycles' front tire: 

wobble.gif

Vee's MCM2s starts "rocking" back and forth when the speed goes around or over 25km/h or so (Gotway app-speed) in level, flat road. It slightly tilts back and forth in somewhat rapid succession. Very scary, as it feels like the wheel could fall forwards or backwards from under you ;)  Doesn't effect turning or cause sideways wobble.

"Vibration" I would understand as, well, vibration, like the wheel shaking at low amplitude and at somewhat high frequency (higher than wobbling)... doesn't really affect your riding, but you can feel it. My Firewheels' tire isn't exactly 100% round, and has very slight vibration that doesn't affect riding or is that noticeable, but it's there.

 

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@esaj
Perhaps Cloud and I are talking about different things.  I was referring to see-saw rocking back and forth.  I have never experienced this phenomenon myself but this was how it was described to me.

Yeah, that sounds like the "rocking" the MCM2s does in high speed. Guess it's over-correcting the pitch-angle both ways rapidly, so probably a motor drive control issue.

Edited by esaj
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@esaj
Perhaps Cloud and I are talking about different things.  I was referring to see-saw rocking back and forth.  I have never experienced this phenomenon myself but this was how it was described to me.

i am talking about the wheel movement perfectly illustrated by the images esaj attached, not the regular vibration.

what i was trying to say is that perhaps due to the kingsong shape, mass distribution and the location of the center of mass in relation to the foot position, kingsong may be susceptible to these movements more than the other wheels when your feet are too forward, and maybe this is why several people have reported this phenomenon. I have never had an issue with this when my feet were placed in the centers of the foot rest and symmetrical, except when i was learning. But when i put them too forward, it does happen at higher speeds and i cannot control the bulk of the wheelsince i am kind of grabbing the front tip of the wheel only... This is what the few others may have experienced.

Edited by Cloud
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I've never experienced it myself, nor has my son Peter (my mad test pilot) even though he went 6miles to visit his friend in a neighbouring town of Keynsham on Sunday.

He used the Bath to Bristol cycle path for about half of the route and was beeping and on tilt back all the way there and back with no wobbles or instability.

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  • 2 months later...

  I'm sorry that I don't know why.  I had the same problem when I started.  I don't know what I changed, but after a while the wobble went away.  I was learning to ride with a 16" 9bot clone.  There isn't any way I know to change that Wheels settings, so it had too be something I was doing.  It might not be where your feet are in as much as where you rest your weight.  At first I was riding with my toes.  Most of the weight was on the balls of my feet. This was making it hard to learn to ride all by itself.   Now most of my weight is on my heals, and I'm leaning to control speed.  

Edited by Colestien
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The first week or two I was learning I had a speed barrier of around 11MPH (17kph) at that point, just as Colestien found, it wobbled every time and I had to back off quickly. I thought it was wheel imbalance or something like that. A week or two later I could reach 15MPH (24kph) with no sign of a wobble. I think Cloud may have put his finger right on it. I'm now wondering if my stance improved?

of course it could have just been that 11MPH was the point fear set in and it was just being caused by my knees knocking!?

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2 hours ago, Keith said:

The first week or two I was learning I had a speed barrier of around 11MPH (17kph) at that point, just as Colestien found, it wobbled every time and I had to back off quickly. I thought it was wheel imbalance or something like that. A week or two later I could reach 15MPH (24kph) with no sign of a wobble. I think Cloud may have put his finger right on it. I'm now wondering if my stance improved?

of course it could have just been that 11MPH was the point fear set in and it was just being caused by my knees knocking!?

Apart from the wobbling that i pointed out below, everyone who learns to ride on a kingsong wheel goes through the wobbling stage, simply due to lack of experience and being uncertain when riding fast. After a few weeks the wobbling disappears. I went thru it as well as some other people i know. This is different from the wobble i was talking about above. 

So most likely you just feel more confindent now. Your foot position may have i proved also

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  • 3 months later...

Be sure to check the mounting of the tire to the rim. On my machine the tire bead was not even around the rim from the factory. It took two or three attempts at deflating and re-inflating the tire to seat the bead uniformly. Huge wobble before, no wobble now.

 

If the wheel is unbalanced you should feel vibration holding it off the ground and letting it over speed. A poorly mounted tire may be any of these: unbalanced, out of round, and not wanting to track true. 

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12 hours ago, Trucktent said:

Be sure to check the mounting of the tire to the rim. On my machine the tire bead was not even around the rim from the factory. It took two or three attempts at deflating and re-inflating the tire to seat the bead uniformly. Huge wobble before, no wobble now.

 

If the wheel is unbalanced you should feel vibration holding it off the ground and letting it over speed. A poorly mounted tire may be any of these: unbalanced, out of round, and not wanting to track true. 

Yes very true, a different kind of wobble though. I have figured out that many of these wheels have minor vibrations due to the tire issues

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On 28-9-2015 at 5:15 PM, esaj said:

Yeah, that sounds like the "rocking" the MCM2s does in high speed. Guess it's over-correcting the pitch-angle both ways rapidly, so probably a motor drive control issue.

I think I got a unit that has the see-saw rocking. I've captured it on video, can someone confirm?

 

 

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I had far worse wheel wobble than shown in the video above, and after 15 (no exaggeration) or so attempts to reseat the tire I now live with minor wobble, not happy but think the tire it self is out of balance and ,or the tube inside.

It seems the rim is true.

I was thinking that when I need to open it someday I will try to get it in balance.

At first I thought I could not feel it when riding, but now after 2 months of daily sessions I know I feel it at higher speeds, vibration.

We did the lift test with many other EUC, 2 nine bots spin true, new KS18 also and even a super cheap off brand was ok.

If anyone has any other ideas of how to fix this please share. Who wants to drive a car that the tires have not been computer spin balanced therefore causing vibration, I feel the same about my EUC, I do not think it is to much to ask to have a wheel that spins true with little or no wobble, vibration.

I am more than willing to get it close to perfect myself but have run out of ideas?

UKJ

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On 12/20/2015 at 4:56 PM, Cloud said:

Apart from the wobbling that i pointed out below, everyone who learns to ride on a kingsong wheel goes through the wobbling stage, simply due to lack of experience and being uncertain when riding fast. After a few weeks the wobbling disappears. I went thru it as well as some other people i know. This is different from the wobble i was talking about above. 

So most likely you just feel more confindent now. Your foot position may have i proved also

My brother who was just learning said that he experienced wobble when he was riding the ninebot. I rode it fast and didn't experience it. He later experienced wobble when on my kingsong and Gotway too. Again, I had no wobble when I rode them. So the main reason for the wobble is simply riding experience. But this is side-to-side wobble.

The wobble shown in the video above I actually do experience with my kingsong, and it initially made going above 15 mph on the kingsong feel very nerve racking.  However I guess I've gotten used to it and now I'm just more confident and in control at higher speeds on my kingsong even when I feel those little "back-and-forth" wobbles.

My MCM4 and Msuper doesn't do that which makes riding >15mph feel very smooth and doesn't feel as fast.

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2 hours ago, Michael Vu said:

My brother who was just learning said that he experienced wobble when he was riding the ninebot. I rode it fast and didn't experience it. He later experienced wobble when on my kingsong and Gotway too. Again, I had no wobble when I rode them. So the main reason for the wobble is simply riding experience. But this is side-to-side wobble.

The wobble shown in the video above I actually do experience with my kingsong, and it initially made going above 15 mph on the kingsong feel very nerve racking.  However I guess I've gotten used to it and now I'm just more confident and in control at higher speeds on my kingsong even when I feel those little "back-and-forth" wobbles.

My MCM4 and Msuper doesn't do that which makes riding >15mph feel very smooth and doesn't feel as fast.

Thank you Michael Vu. This helps with my decision making. So far GotWay MCM4 is on top of my list. ?

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2 hours ago, Michael Vu said:

My brother who was just learning said that he experienced wobble when he was riding the ninebot. I rode it fast and didn't experience it. He later experienced wobble when on my kingsong and Gotway too. Again, I had no wobble when I rode them. So the main reason for the wobble is simply riding experience. But this is side-to-side wobble.

The wobble shown in the video above I actually do experience with my kingsong, and it initially made going above 15 mph on the kingsong feel very nerve racking.  However I guess I've gotten used to it and now I'm just more confident and in control at higher speeds on my kingsong even when I feel those little "back-and-forth" wobbles.

My MCM4 and Msuper doesn't do that which makes riding >15mph feel very smooth and doesn't feel as fast.

I believe what you are experiencing with the kingsong is caused by the tire not being perfectly round and going out in some spots. Ive tried many kingsong wheels ( manufactured around the same time with the same firmwareinstalled) and Some kingsong units have this phenomenon and some dont, which is best felt at higher speeds above 15kph. But overtime this gets better as the tire smoothes out....The "nodding" of the wheel when freespinning and riding , is there but not causing a noticeable wobble while riding. You can see it nodding/ diving but cant feel it. 

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  • 1 month later...
  • 1 month later...

We tested it in Russia and right-left wobbles on kingsong (apart from tires problem) are caused by legs tension of unexperienced or somehow tired or stressed rider. I havent heard of anyone having the software bug as a reason of such wobbles. 

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