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Kingsong 16X Death wobble crash


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I think some of you guys are getting a little bit overly sure of your abilities. Wobble can and does happen to most of us. If you think that its quite simple to avoid and its always easy counter them,

I heard self-oscillating will make you go blind..

After reading this extremely interesting debate, and as a rookie with only about 800kms on an EUC, I think that you all have hit the mark: its all relative to the day's physical condition, syrong/weak

1 hour ago, 5Cauac said:

I'm a new rider and I've been riding every weekend since January of this year. I considered myself a newbie but as @ShanesPlanet stated, I might have graduated to Wanabe status.

Anyway,  just like @RockyTop, I too wobble on occasion and goes unnoticed or corrected instinctually.

This was due to me practicing inducing wobbles. Yes, you read that right, I purposely would create wobbles and try to come out of them. (low speeds of course) Also practicing weaving in and out of bike path divider lines starting off slow and progressing speed getting as close to the lines as possible. This has tremendously helped out in dealing with unexpected wobbles.

 

@5CauacI did exactly the same thing!!! Inducing wobbles is one of the smart things to do, once you start getting the 6th sense to them you instinctively find a way to get out of them. 

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1 hour ago, ShanesPlanet said:

I think some of you guys are getting a little bit overly sure of your abilities. Wobble can and does happen to most of us. If you think that its quite simple to avoid and its always easy counter them, you may be a little inaccurate.  The stakes go up when the speeds go up. I have seen too many excellent riders succomb to wobbles, to think that its something that won't happen to me. So far I have escaped crash from a wobble, but I also havent been unlucky at 40mph. Holding 9' selfie sticks, carrying extra weight, being too tired, excessive cold, poor machine maintenance and probably Murphy's law, can all cause wobbles. Emergency braking, unexpected road deviations, changing traffic, can all cause a person to upset the balance and wobble. Im no pro at all, but after 1200miles, I still enounter them from time to time. I have grown to not panic and ride the little wobbles out, but i have also found myself at the brink of uncontrollable from them. Wobbles, tank slappers, same basic premise.

Its always a bad idea to assume that someone who has vast amounts of riding, is simply doing it wrong, when it comes to a fall. I chalk it up to unforseen factors and the old creedo 'it aint if you'll crash, its when". My typical course of action is to NOT panic, not overcompensate and make minute adjustments to minimize the wobble from crossing into the point of no return. Even so, its only a matter of time before the inevitable happens to me as well. I would say to be careful out there, but careful would mean NOT riding at all. So, don't be too careful, but also don't assume you will be able to manage ANY problems w/o incident. False confidence is a VERY real stage of the game. I do think I've heard a few cases of it in this very thread. :shock2:

I havent bothered to statically balance any of my wheels. I've dynamically balanced thousands of rims and tires but Im just not finding any real need to bother on the euc. Maybe I'm just lucky.

So true. I always start my rides testing the wobble possibilities, and I know that it can happen any time, even if I rarely go over 30km/h. I get a bit more control, but that doesn't mean that it won't happen to me just around the corner. Over confidence has given me a few frights already and I only am with about 500kms on my legs. Hopefully Ill be able to deal with most of them. If not... I'll surely be kissing Mr. Asphalt! 😁😁😁

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Speaking of wobbles...  It definitely helps to not panic. So far so good but can easily imagine wobble situation throwing me out of the wheel and know a colleague wobble crashing 16X  at ~40 km/h

 

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I know a method that I’m sure would kill any wobble with a 100% success rate. But I’m just as confident that no-one will ever even try it.

 The wobble is supported and made possible by the round tire that steers as it tilts in relation to the ground, while rolling on the ground, right?

Let’s remove the ground! The wheel can not wobble in mid air, can it? With the exception of minor wavyness from a badly balanced tire, no it can’t!

 You naturally need jump pads for this, and nerves of steel. Actually, even steel might not cut it, so let’s say nerves of diamond: When you get the wobbles, jump up in the air with the wheel!

I can see Fantomas trying this, but that’s pretty much it. If there are any Fantomas wannabe’s around, please let me know how perfectly the theory works! 😄

Edited by mrelwood
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SOunds like fun, but wouldnt centrifugal forces still be present? I agree that the wobble BEGINS with how the tire tracks the ground, but doesnt it quickly also include dynamics unrelated to the tire itself? Maybe the gyroscopic force would be perfectly stable and centered, i really dont know. Once you remove the ground in an immdiate fashion, it may be likely you would wobble in an entirely new format. Sounds like a challenge!

Edited by ShanesPlanet
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5 hours ago, ShanesPlanet said:

wouldnt centrifugal forces still be present?

Now that I’m thinking about it more, a separate tire (only a tire) that rolls down a hill does also wobble when it bounces up in the air every now and then. I can’t quite wrap my head around the forces involved just yet though.

Dang. And here I thought I had invented something big! And that when people notice their fellow EUCists wobbling, they would shout “Do the mrelwoods!”. And everybody would know what they meant right away.

Edited by mrelwood
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41 minutes ago, mrelwood said:

Now that I’m thinking about it more, a separate tire (only a tire) that rolls down a hill does also wobble when it bounces up in the air every now and then. I can’t quite wrap my head around the forces involved just yet though.

Dang. And here I thought I had invented something big! And that when people notice their fellow EUCists wobbling, they would shout “Do the mrelwoods!”. And everybody would know what they meant right away.

The wobbles you see for a tire bouncing in the air are a much simpler phenomenon than the wobbles appearing when riding EUCs or other contraptions. The free tire movement is mostly rotation with precession plus a bit of oscillations from elastic deformation (where it deforms periodically). Forget about deformations for a moment and consider a solid rotationally symmetric object (wheel, coin etc). Spin it fast and throw it in the air. Typically, the coin will not stay parallel to a constant plane, instead the orientation of its axis of symmetry will rotate itself (called precession). I suspect that this is what you interpret as wobbles. However, this precession is constant -- it does not amplify or decay while the tire or coin is airborne. This is basic rigid body mechanics (a separate tire complicates thing by deforming, but not that much). 

Regarding the idea to jump-lift an EUC to stop wobbles - it might actually help. Wobbles are a textbook example of self-oscillation (see ,e.g. "speed wobble" and "self-oscillation" on wikipedia). [Sorry if this has already been discussed extensively]. Wobbles appear in certain parametric regimes (certain range of velocity, acceleration, stance, mass-geometry). Loosing ground contact will certainly put you out of that dangerous configuration so you have time to align and calm the wheel while airborne. Still, once you land, you are probably within danger again since you are at roughly the same speed and wobbles may restart.

 

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On 4/5/2021 at 7:28 AM, mrelwood said:

I know a method that I’m sure would kill any wobble with a 100% success rate. But I’m just as confident that no-one will ever even try it.

 The wobble is supported and made possible by the round tire that steers as it tilts in relation to the ground, while rolling on the ground, right?

Nice theory but... I’d love to see someone attempting to jump the EUC from the point of wobbling...XD 

In order to properly jump and land safely you need the wheel to be perpendicular to the ground which is hard to achieve in the wobbling situation as EUC is tilting from left to right slightly.
You also need to to grab the shell with your heels which might reinforce the wobbling just before the jump...

 

Edited by Arek Gryglicki
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20 hours ago, mrelwood said:

“Do the mrelwoods!”. And everybody would know what they meant right away.

Oh those of us in the KNOW, already do. We also know not to tell you about it...:P

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22 hours ago, ShanesPlanet said:

Oh those of us in the KNOW, already do. We also know not to tell you about it...:P

I can’t stop thinking though that it probably has a very different meaning for you guys than what I was talking about... 😆

Edited by mrelwood
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On the topic of "Self-Oscillation" and hairy hand pads, I read that a deep carve will tame the beast.  So when I feel one coming on I will initiate a deep carve that leans the wheel against the opposite leg, one turn possibly two and its gone.  Magic.

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2 hours ago, Rich Sam said:

On the topic of "Self-Oscillation" and hairy hand pads, I read that a deep carve will tame the beast.  So when I feel one coming on I will initiate a deep carve that leans the wheel against the opposite leg, one turn possibly two and its gone.  Magic.

Yes indeed, it breaks the cycle. Light version of the same concept would be to shift weight to one foot.

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@Rich Sam and @null, in my very short experience I believe you are 100% correct. To feel safe, and because I read somewhere summit similar, I'm training myself to ride... carving the entire time. Which with the small and tortuous Portuguese roads it's actually something quite easy to do.

However, I understand that my mates here in the forum that ride those fabulous 100 mile long and straight roads in the USA, might want to just ride in a straight line. 

BTW, I also carve a lot because it great for my sciatica and hips... 😁

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I was witness to a death wobble (non-fatal) crash of a motorcycle a few years ago. I was behind the bike that was passing another car. He initiated an aggressive lean to go around, and as he shifted from left to right doing probably 60-65 mph, the wobble came on fast and bucked him right off. Ended up in the ditch. He was stunned, but not too stunned to say “no ambulance, no cops”. Called someone to come “git me”.  I looked his bike over and noticed a strange wear pattern on the front tire. If you took out a cross section, it was a pronounced V shape. Well worn towards the sides. I told him he needed a new front tire. 
 

 

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Wobbles during a high speed corner is my worst fear - have not found a good way to solve this problem yet. I stay loose w/ no leg contact in turns and use pedal pressure/leaning instead to maintain the turn. This allows me to absorb bumps without the wheel hitting me and throwing my balance, but the problem is a series of small bumps in combination of uneven pedal pressure (kind of unavoidable in a turn) can also generate wobbles and when this happens choices are so limited in what can be done.

Pinching the wheel and doing a deeper carve while braking has worked so far but still feel a little sketchy because it doesn't stop the wobbles as fast as when doing the same while going straight (wobbles eliminated almost instantly). I think it's because of the uneven pedal pressure when in a turn, and maybe this is just unavoidable due to the physics of riding one wheel?

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Every day, at the end of my ride, and as I always do, I clear the roundabout at the beginning of my road and exit on a a very short and steep dead end road just before my roundabout exit. It's real fun to speed up on the roundabout and speed even more up that short and steep dead end. and then turn 180º and come down slowly relaxing my legs.

But today I was going really fast and when I curved to go up fast the KS16X wobbled quite a bit (and I was holding tight and strong) I immediately decelerated while curving upward and got control of the wheel. 

Curious about it (and worried) I went around the block again and did the exact same maneuver at (I think) the same speed, same feet stance...and no wobbles...

Go figure it... a total mystery.

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I've never had a wobble-crash. I've had a bit of wobbling in hard braking situations, and a bit while learning to do hard accelerations on the EX but nothing too scary. I ride with a very uneven stance, one foot quite a bit forward of the other, so the right foot is for acceleration, the left for braking. Also a very wide stance where one leg is only lightly contacting the wheel and the other is disengaged entirely from the side of the wheel.

On the few occasions where I've tried to ride with a narrow stance -- both legs pressed against the side of the wheel -- that has felt very wobble prone to me, it feels like I don't have any way to counteract the wheel action if it did decide to become wobbly. With that bit of spacing available I can just press in with one leg or the other and dampen it out. I also don't use power pads in case that's seen as relevant.

 

 

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6 hours ago, winterwheel said:

I've never had a wobble-crash. I've had a bit of wobbling in hard braking situations, and a bit while learning to do hard accelerations on the EX but nothing too scary. I ride with a very uneven stance, one foot quite a bit forward of the other, so the right foot is for acceleration, the left for braking. Also a very wide stance where one leg is only lightly contacting the wheel and the other is disengaged entirely from the side of the wheel.

On the few occasions where I've tried to ride with a narrow stance -- both legs pressed against the side of the wheel -- that has felt very wobble prone to me, it feels like I don't have any way to counteract the wheel action if it did decide to become wobbly. With that bit of spacing available I can just press in with one leg or the other and dampen it out. I also don't use power pads in case that's seen as relevant.

 

 

Very interesting. From what I've been reading your idea makes all the sense to me. Btw how misaligned are you feet from each other? One inch? more? 

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Normally my right foot is about an inch forward of my left I would say. With the EX it might even be closer to two, I like getting off the line quickly and that allows me to really put pressure on the front of the wheel. Also I opted for big pedals on the EX so there's lots of room for custom foot positioning. 

I'd also say this is after five years of riding though, and I got here gradually. I'd caution everyone to be very careful about trying anything too extreme to start out with.

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6 hours ago, winterwheel said:

Normally my right foot is about an inch forward of my left I would say. With the EX it might even be closer to two, I like getting off the line quickly and that allows me to really put pressure on the front of the wheel. Also I opted for big pedals on the EX so there's lots of room for custom foot positioning. 

I'd also say this is after five years of riding though, and I got here gradually. I'd caution everyone to be very careful about trying anything too extreme to start out with.

I've ridden with one foot one inch in front of the other on occasion, and it was quite comfortable. But wouldn't dare a bigger distance. 

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7 hours ago, Paulo Mesquita said:

I've ridden with one foot one inch in front of the other on occasion, and it was quite comfortable. But wouldn't dare a bigger distance. 

If you are riding with one foot forward and one back. As a learning tool try to accelerate with the forward foot and brake with the rear. Be careful if you haven’t done this before. It can be useful on very long trips or extremely hilly areas. It also teaches either foot to drive rather than a joint effort of both feet. :D

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