Upgrade to 16" or better 18"?

[LanghamP]

1 hour ago, EU GUY said:

Right. The batteries isn't that far of from the center, but it's got more to do with the centrifugal force than anything else I guess. Might be the tall body and large wheel that makes it so stable and controllable. Or everything combined as a heavy wheel that requires more force to be disturbed 

You were right the first time; you need to stop caving in to peer pressure when someone says something contradictory, and let them convince you why you're wrong, with the caveat that you can switch positions without emotion (that's what she said ).

Placing the battery well away from the center of gravity makes the wheel more stable.

A very simple demonstration can support or refute @ir_fuel argument; simply take a collapsible umbrellas and try balancing it in its extended versus collapsed position.

When is the umbrellas easier to balance? Report back, and there's your answer to which wheel design elements make it more or less stable.

[eddiemoy]

23 minutes ago, LanghamP said:

You were right the first time; you need to stop caving in to peer pressure when someone says something contradictory, and let them convince you why you're wrong, with the caveat that you can switch positions without emotion (that's what she said ).

Placing the battery well away from the center of gravity makes the wheel more stable.

A very simple demonstration can support or refute @ir_fuel argument; simply take a collapsible umbrellas and try balancing it in its extended versus collapsed position.

When is the umbrellas easier to balance? Report back, and there's your answer to which wheel design elements make it more or less stable.

If this is anything like a car, the center of mass need to be as low to the ground as possible for it to be more stable.  

[ir_fuel]

2 hours ago, LanghamP said:

Placing the battery well away from the center of gravity makes the wheel more stable.

So you are telling me that something top heavy is more stable than something bottom heavy? 

This makes no sense at all.

Something top heavy will be heaps easier to push over than something bottom heavy. 

Your umbrella test makes no sense since you are stabilising it by moving the bottom of the umbrella. This is the complete opposite of what one wants to do with a euc, which is basically "fixed" to the road and you balance by moving the top around.

[stevedig]

8 hours ago, eddiemoy said:

I agree the 18" wheel feels more planted at higher speeds.  That is why I love the 18S.  Even with the taller body of the 18S, Not top heavy,  it doesn't feel as weird as the Msuper.  I got to try both and I don't like the Msuper.  Maybe if you try the KS18S, you might think how bad the Msuper is too...  LOL  If you are able to grip the KS18S with the whole bottom of your leg you will feel even more confident on the trails.  who know...  But for me, that is how I feel and it is my opinion after owning and riding them both.

I own both the MSuper V3S+ and the KS18S. I really like both wheels... a lot. They are very different animals tho, to spite the wheel size.

First, I have to raise my eyes at the grip the wheel better with your legs statement. Unless I'm airborne, there is always a gap between my legs and the body of the wheel. Unless I'm using my leg to brace the wheel, inside or out, in a turn. I do this more with the MSuper than the KS tho because of the height of the KS making it a little uncomfortable where it hits my knees.

I find the KS makes me ride with better stance and posture because of it's height. Better balance/positioning/form is required. You can cheat in a turn with the MSuper,  locking out a knee and varying the pressure on the other pedal. Can't do this with the KS because the high wheel hits your knee and prevents the wheel from leaning further into the turn. You bump you knees a lot until you learn not to cheat. i expect coming from any smaller wheel would result in the same lesson.

Also, the height of the weight on the KS means you need a better stance at speed or your going to get speed wobbles. First time I broke 35 kph on it I got a nice wobble. It worked up to a nice oscillation relatively quickly and my first instinct was to squeeze the wheel with my knees to stop it but that was ineffective. Slowed to stabilize the wheel, adjusted my feet a little more squarely on the pedals and off I went with no wobble. The MSuper is more forgiving as the weight isn't as high to amplify the wobble. 

The MSuper is a little easier to ride because you can take shortcuts in your stance and posture. Once you work out synergy with the KS18S tho it's a magnificent ride. I absolutely love it. I do like the ability to sit on the KS18S too. It's fun to sit on it and roll along. Adds to the bug eyed looks we often get.

Edited November 4, 2017 by stevedig

[LanghamP]

5 hours ago, ir_fuel said:

So you are telling me that something top heavy is more stable than something bottom heavy? 

This makes no sense at all.

Something top heavy will be heaps easier to push over than something bottom heavy. 

Your umbrella test makes no sense since you are stabilising it by moving the bottom of the umbrella. This is the complete opposite of what one wants to do with a euc, which is basically "fixed" to the road and you balance by moving the top around.

I though EUCs balanced by moving their wheels to and fro. I didn't realize that it is actually me balancing the EUC by moving on top of it.

Your intellect and logical thinking is truly dizzying, thank you for setting me straight.

[steve454]

5 hours ago, ir_fuel said:

So you are telling me that something top heavy is more stable than something bottom heavy? 

This makes no sense at all.

Something top heavy will be heaps easier to push over than something bottom heavy. 

Your umbrella test makes no sense since you are stabilising it by moving the bottom of the umbrella. This is the complete opposite of what one wants to do with a euc, which is basically "fixed" to the road and you balance by moving the top around.

Me being 6 foot 3 and 210 pounds makes me more careful when riding my wheel with the puny battery and motor.  If I could get back down to my natural weight of 185. it would probably feel a lot stronger.  I would like something stronger to compensate for being heavy.

And now for something completely different.

 

 

[LanghamP]

1 hour ago, steve454 said:

Me being 6 foot 3 and 210 pounds makes me more careful when riding my wheel with the puny battery and motor.  If I could get back down to my natural weight of 185. it would probably feel a lot stronger.  I would like something stronger to compensate for being heavy

 

No no you got it completely backwards, all wrong. Don't you know having all the weight up high, beer belly and all, makes it easier for the wheel to move you around?

[ir_fuel]

2 hours ago, LanghamP said:

I though EUCs balanced by moving their wheels to and fro. I didn't realize that it is actually me balancing the EUC by moving on top of it.

Your intellect and logical thinking is truly dizzying, thank you for setting me straight.

I thought that when we talked about stability it's left-right stability. Front-back stability would be really weird as that would mean your euc is bust.

[ir_fuel]

It's all basic physics, this stuff.

http://www.schoolphysics.co.uk/age11-14/Mechanics/Statics/text/Stability_/index.html

But then again, they never tried balancing a car upside down, so what do they know.

 

[eddiemoy]

5 hours ago, stevedig said:

I own both the MSuper V3S+ and the KS18S. I really like both wheels... a lot. They are very different animals tho, to spite the wheel size.

First, I have to raise my eyes at the grip the wheel better with your legs statement. Unless I'm airborne, there is always a gap between my legs and the body of the wheel. Unless I'm using my leg to brace the wheel, inside or out, in a turn. I do this more with the MSuper than the KS tho because of the height of the KS making it a little uncomfortable where it hits my knees.

I find the KS makes me ride with better stance and posture because of it's height. Better balance/positioning/form is required. You can cheat in a turn with the MSuper,  locking out a knee and varying the pressure on the other pedal. Can't do this with the KS because the high wheel hits your knee and prevents the wheel from leaning further into the turn. You bump you knees a lot until you learn not to cheat. i expect coming from any smaller wheel would result in the same lesson.

Also, the height of the weight on the KS means you need a better stance at speed or your going to get speed wobbles. First time I broke 35 kph on it I got a nice wobble. It worked up to a nice oscillation relatively quickly and my first instinct was to squeeze the wheel with my knees to stop it but that was ineffective. Slowed to stabilize the wheel, adjusted my feet a little more squarely on the pedals and off I went with no wobble. The MSuper is more forgiving as the weight isn't as high to amplify the wobble. 

The MSuper is a little easier to ride because you can take shortcuts in your stance and posture. Once you work out synergy with the KS18S tho it's a magnificent ride. I absolutely love it. I do like the ability to sit on the KS18S too. It's fun to sit on it and roll along. Adds to the bug eyed looks we often get.

I have the opposite, I find the 18S is a lot easier to ride.  I don't have the knee issue you are describing.  I can let the unit drop with lots of space between my legs if i wanted to play around with it.  Wobbles have to do with fatigue and uneven weight applied to peddles.  

[stevedig]

Just now, eddiemoy said:

I have the opposite, I find the 18S is a lot easier to ride.  I don't have the knee issue you are describing.  I can let the unit drop with lots of space between my legs if i wanted to play around with it.  Wobbles have to do with fatigue and uneven weight applied to peddles.  

Sounds like we're saying the same thing to me... you have to place your feet more carefully on the KS and you have to open up your stance and flex both knees in pretty much every turn. 

I can get the MSuper to wobble as well but I generally ride it with my feet offset, one a little more forward than the other. To introduce the wobble, I have to increase that offset rather significantly. It was my MSuper riding style that led to the wobble on the KS and the higher cg that amplified it so quickly on me.

The KS made me square my stance and add more flex to my knees. No more locking one knee and flexing the ankle on the other side to vary a turn. If I'd started on the KS I probably never would have had to make an adjustment.

Neither one is harder or easier to ride. They are just different. 

[LanghamP]

31 minutes ago, ir_fuel said:

It's all basic physics, this stuff.

http://www.schoolphysics.co.uk/age11-14/Mechanics/Statics/text/Stability_/index.html

But then again, they never tried balancing a car upside down, so what do they know.

 

You have it right; try balancing the car on a single point.

Or try balancing any of those objects on a single point. When doing so, which of those objects will be easier to do so? Can you take a guess?

[steve454]

Turn the umbrella upside down,  then open it.  That's what he meant to say.

[ir_fuel]

6 hours ago, LanghamP said:

You have it right; try balancing the car on a single point.

Or try balancing any of those objects on a single point. When doing so, which of those objects will be easier to do so? Can you take a guess?

I'm not even going to continue about this.

This is getting ridiculous

6 hours ago, steve454 said:

Turn the umbrella upside down,  then open it.  That's what he meant to say.

If I try that I'll probably get hit in the face, knowing how clumsy I am  

[LanghamP]

4 hours ago, ir_fuel said:

I'm not even going to continue about this.

This is getting ridiculous

If I try that I'll probably get hit in the face, knowing how clumsy I am  

Have you ever slacklined? If so, do you think having your arms up and out makes it easier than having your arms by your side? Perhaps it would be easier when most of your mass is down low? Or perhaps not. Not that it matters one iota, but notice this is a left and right balance.

 

[ir_fuel]

You should go work in a MotoGP team. Guess you could make them win the world championship with a few simple tips.

[eddiemoy]

18 hours ago, stevedig said:

Sounds like we're saying the same thing to me... you have to place your feet more carefully on the KS and you have to open up your stance and flex both knees in pretty much every turn. 

I can get the MSuper to wobble as well but I generally ride it with my feet offset, one a little more forward than the other. To introduce the wobble, I have to increase that offset rather significantly. It was my MSuper riding style that led to the wobble on the KS and the higher cg that amplified it so quickly on me.

The KS made me square my stance and add more flex to my knees. No more locking one knee and flexing the ankle on the other side to vary a turn. If I'd started on the KS I probably never would have had to make an adjustment.

Neither one is harder or easier to ride. They are just different. 

I actually find my stance wider on the Msuper v3+.  If you measure the two, you will find the Msuper is wider.  Not sure why you feel your stance is wider on the 18S

[stevedig]

because i need to keep my knees spread a little wider. in order to do that i have to open my stance some. in pretty much any turn, you have to move your inside knee out of the way even with the opened stance (toes pointed out some). not so with the msuper. 

i suppose my feet are close to the same width apart really, a little more square on the KS but... i have to open my stance up higher to ride comfortably on the KS. i can't lock out my knees and relax my legs as much on the KS. 

i've only put about 170 miles on the KS so far. It arrived about 3.5 weeks ago. the msuper and i have been pals for about 7 months and about 600 or so miles now. it's been neglected a bit since the KS's arrival. I'm pretty smooth with the KS now. i still fall back to some msuper riding habits from time to time tho and bang a knee, especially in tight corners.

[eddiemoy]

13 hours ago, stevedig said:

because i need to keep my knees spread a little wider. in order to do that i have to open my stance some. in pretty much any turn, you have to move your inside knee out of the way even with the opened stance (toes pointed out some). not so with the msuper. 

i suppose my feet are close to the same width apart really, a little more square on the KS but... i have to open my stance up higher to ride comfortably on the KS. i can't lock out my knees and relax my legs as much on the KS. 

i've only put about 170 miles on the KS so far. It arrived about 3.5 weeks ago. the msuper and i have been pals for about 7 months and about 600 or so miles now. it's been neglected a bit since the KS's arrival. I'm pretty smooth with the KS now. i still fall back to some msuper riding habits from time to time tho and bang a knee, especially in tight corners.

you are doing it wrong.  try to learn to turn with your upper body.  with bigger wheels like the monster, you have to use your upper body to turn.  Also i learned it from manual unicycling, you need to use upper body to turn.  with the smaller wheels, you can lean the unit between your legs, I can do that with the KS too, but the upper body twist works better.  when you learn to go really slow, slower than walking, you need to use your upper body to do that.

i'm very comfortable riding the KS and I can ride with my legs straight on lock out most of the time unless there are bumps then I bend them a little.  when i get tired, i sit.  on the msuper, there is no option but to be bowlegged.  It is too wide.  that is really the thing i hate about the msuper.  plus it is top heavy.  lol

 

[Ruben Jimenez]

On 11/5/2017 at 2:55 PM, LanghamP said:

Have you ever slacklined? If so, do you think having your arms up and out makes it easier than having your arms by your side? Perhaps it would be easier when most of your mass is down low? Or perhaps not. Not that it matters one iota, but notice this is a left and right balance.

 

Hey guys I'm trying to understand this but I'm still not sure.

We can be sure that the axis of rotation (left-right) is always touching the ground (otherwise the wheel should be slipping), so a higher center of mass will increase the moment of inertia. That is, a higher battery makes it harder to rotate the EUC.

However, I don't think that necessarily relates to stability. The wheel might turn faster or slower but still be stable, without wobbles. I think it has more to do with the caster angle of a wheel in a car.

If you take the EUC turned off and move it like a suitcase, dragging it behind you, you will find it very hard to carry it straight. It will turn to the sides like crazy. However, if you push it in front of you, unintuitively, it will ride fine. That's equivalent to the caster angle of a wheel in a car, considering your wrist as the axis of steering.

EUCs by themselves are stable, because if you push them fast enough so that the gyroscopic effect works, they will remain straight without anyone over them, and without wobbles (https://youtu.be/VYDZ6FzUEGY). I have not seen one go fast without rider though.

I think the mechanism is basically this:

but with our body instead of the suspension making the wheel oscillate to the sides. Instead of springs and the mass of the car, we have our legs and the mass of our body naturally pushing the wheel to the center, like a spring.

How the weight distribution on the euc itself affects the stability is another story. I think it might be analogous to how the weight has to be distributed in trailers. If the weight is far back from the wheels, it becomes unstable. The rider would be equivalent to the car, and the trailer to the EUC. The trailer (EUC) becomes unstable when the car (the rider) pulls it to the center (while driving sideways, and putting energy into the oscillations), only if the weight is far from the wheels. I imagine the wheels of the trailer as the axis of a lever where the car is pulling more and more the mass to the sides.

As a mental model: When the wheel is turned to the left (yaw to the left), the road pushes it laterally (roll to the right). Then the shape of the tyre and the gyroscopic effect make it turn to the right (yaw to the right), and the cycle repeats. Usually this cycle fades away, but the rider is doing something to feed it. Maybe when the wheel is turned left (yaw left), and it's rolling to the right, more weight is being applied on the left pedal, because it's higher up. That momentum pushes the wheel violently to the left (rolls to the left while it moves to the right, pushing the upper mass of the EUC to the left), accelerating the next transition. It's taking energy from the speed, slowing down the wheel, and putting that energy into the oscillations.

Weight at the bottom of the wheel would behave as if it wasn't there, just higher friction forces in the tyre. Weight at the top would cause the wheel to roll more when the road is applying a force to the tyre, and that momentum would last longer, so the wheel would end up rolling to the left further. I don't think weight at the top would be beneficial. At best it would not matter.

Hmm this is complicated. I'm not sure how it could be modeled.

[atdlzpae]

EUC's are stable because your brain learned to counter basically everything the wheel does.
Gyroscopic effect doesn't work AT ALL at low speeds and wheels are stable anyway.

High-speed wobbles that new riders experience are some evidence for it. And gyroscopic effect is just one of the forces you subconsciously learn to counter/use.

Edited June 30, 2021 by atdlzpae

[FerdinandK]

The system wheel+stator (battery, frame) + rider is dynamic system, you can think of masses springs and dampers as a model. Now signals are introduced by the wheel (the driver acts, some stone, a gap, some catch of the wheel from a slightly different direction than it is turning, ....) this signals (they happen all the time) introduce responses in the system typically they will smooth out (fade out), except if you hit an (so called) "eigen-frequency" of this particular system, then for (exactly) state of the system, the response of the system will amplify the introduced signal by its response which in case of the EUC is the "wobble".

Here and example on motorcycle, I also have experienced this myself on motorcycles and trust me, the EUC wobble is a lot less "spectacular".

The only way to escape is to change the system parameter, e.g. add more damping add more stiffness, even reduce the stiffness can work, as it will shift the "eigen-frequency" lower or higher. If you e.g. start to carve this is exactly what happens, you change the system (of masses, springs and dampers) and therefore shift the eigen-frequency. Also when you reduce the energy in the system, there is less available for amplification and to be amplified. The problem with "high-speed" wobble is, that you accelerate, you experience wobble, it takes some time and you still accelerate (so you overshoot the eigenfrequency) then you start to decelerate and you hit the eigen-frequeny again.

Beeing new and unexperienced beeing "afraid" or exhausted does also not help, as it reduces typically the "damping" in your muscles. If you are completely relaxed and experienced and skilled you also shift your "eigen"-spectrum into a completely different area as you have less "tention" and a lot more active corrections.

The more you exercise the better it will get, as your muscles will learn, the will learn how to act properly and how to avoid.

Of course eliminating physical sources to introduce the disturbing signal will help (aligning the tyre, ...) However battery high, battery low will not eliminate wobble, it just gives you a different spectrum (of eigen-values) that does not mean that it has to be beneficial for the wobble. If the CG is close to the center of the wheel, you can better deal with steps or pot-holes

 

 

 

[OldFartRides]

I was doing maybe  25/40 yesterday on the s18 hit a bump, got a wobble. Threw it left,right,left with my knees as I slowed and got it under control fairly quick then backup to speed. Had to pat myself on the back.

That said, I enjoy slow riding better. Reason I was riding faster- on a schedule to go shoot pool. Doh !

 

[Nostris]

On 11/5/2017 at 2:55 PM, LanghamP said:

Have you ever slacklined? If so, do you think having your arms up and out makes it easier than having your arms by your side? Perhaps it would be easier when most of your mass is down low? Or perhaps not. Not that it matters one iota, but notice this is a left and right balance.

 

As an aside…. The old films of tightrope walkers usually showed them carrying a long horizontal bar with a weight at each end to help them balance.