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Tire width - Is wider better?


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I unfortunately don't have the time to write all I want. I'm guessing my words are betraying me and conveying a message I didn't mean.

So you push a bike down a hill and it will actually keep itself upright. This is what I meant by self corrective steering, it's a finely tuned and balanced tested process that is not just a natural phenomena. This can't really be compared to a electric powered self balancing device, especially one that only has one wheel.

You push a hula hoop or car tire down a hill it will stay upright with enough forward momentum. This is only because of the angular momentum that essentially turns it into a crude gyroscope (gyroscopic effect is a thing there are tons of papers written on it). That single wheel is not steering itself since it's only one wheel....steering isn't a thing like it is with a bike or motorcycle. The tire profile or size won't have nearly as much effect as the weight of the wheel and it's speed. Now if you make a tire so wide it's essentially a cylinder, well that's a whole different matter and has nothing to do with what we are talking about (not to mention unfeasible for an EUC)

A massive point to remember is that not all gyroscopes are made equal, not by a country mile. I can easily alter a kids gyroscope or fidget spinner with almost no effort. But in doing so I will feel the very obvious and very real gyroscopic effect (just as I do with a EUC). But you spin a NASA grade space age metal gyroscope up to 5000 rpm and have me try and move it I won't be able to, but a force strong enough can alter it's trajectory and it will stabilize along a new orientation.

A motorcycle has side to side inverted pendulum characteristics at speed, an EUC has front to back inverted pendulum characteristics (again though it's self-balancing, not user balanced). These two system couldn't be more different than comparing a moped to a car.

Edited by tenofnine
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Anyone at any discussion forum may be struggling with a language barrier, culture differences, difficulty conveying thoughts into words, etc. I hope my attempts to take this into account will prevent my posts from sounding too attacking. We’re all here to discuss and ponder upon these amazing vehicles, and in good spirit I hope!

I absolutely agree that the force that tries to keep the spinning wheel of the EUC from being turned exists. No doubt about that. I even made the test with my MSX. Pretty much impossible to turn with one hand when the tire is spinning at 70km/h! My point is that the force that people call the gyro-effect on some tires, is a different force.

After you have finally gotten the EUC to make the turn and start riding straight, do you have to lean to the opposite direction to get the gyroscope back running upright? No, you don’t. The gyro effect should make it fight back just as much as before the turn, but it doesn’t. The wheel has the tendency to stay upright, not in the tilt angle it has at any given moment, which is what a gyroscope (and the finger spinner) does.

The hula hoop was a great example. The ring is extremely light. The forces in continuation of angular rotation are calculated by mass, distance from the axle, and speed. A hula hoop tends to stay upright when rolling down the hill despite being extremely light, and having only very little speed. Even there, there are many forces and mechanics involved, not just the ”gyroscopic force”, which by itself is unable to automatically steer. Or to get the ring back towards vertical once it starts to fall on it’s side.

3 hours ago, tenofnine said:

This can't really be compared to a electric powered self balancing device, especially one that only has one wheel.

When pushing both downhill without a rider, and both keep themselves upright by turning to the direction of the fall, why not? As you wrote, just a single tire is able to keep itself upright. The mechanics are not all that different.

Take this video for example, that some jerk made just to prove a point...:

The (16x2.5”) tire doesn’t even need more than a walking speed and it already takes a steep turn in the direction of the fall. Now imagine a few strings for spokes, and let the wheel spin at that same speed. Would it be hard to turn? Not really. Not much gyroscopic effect present. Still, it attempts to get back upright by pretty drastic steering motions, which is what the gyroscopic force alone is unable to do at any speed.

What happens is that when a tubular tire gets tilted towards it’s side, the point of contact moves from the centre line of the tire to the side. This creates the cone effect, where the smaller radius of the edge makes the tire turn. The point of contact is now also closer to the CoG, which slows down the fall. The wider the tire, the more the point of contact is displaced, and the more it tries to get itself upright.

That’s why tilt-steering works, even below walking speeds, where the gyro-effect doesn’t seem to yet to be doing anything at all. Even on a MSX with it’s heavy motor and tire. It takes roughly 20km/h to even feel the gyroscopic resistance by hand. At those speeds the Z10 already felt impossible to tilt when riding. I’m pretty sure that a lift test on the Z10 wouldn’t be all that different from the MSX. Hence, different force at play here.

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5 hours ago, mrelwood said:

1)Anyone at any discussion forum may be struggling with a language barrier, culture differences, difficulty conveying thoughts into words, etc. [....]

2)The wider the tire, the more the point of contact is displaced, and the more it tries to get itself upright.[...]

 

1) It's terribly right, I always have to "struggle" with the language barrier when I need to communicate (to read and even more writing or talking) in english. And at least in  my case what it lacks usually it's also the time to follow all, translating and checking your reply, with the constant fear of possible misunderstandings.

 

2) I've selected only this remark but I read all your observations also in the previous posts.   What I would find interesting and maybe potentially very useful to know/discover is if it's possible to calculate and/or to guesstimate (even, with experience, while riding) the "point of collapse" of a self-balancing Euc in use (with the same rider in the same riding-context) before a displacement(/loss of balance while riding) turns irreversible.  

I'm not a physicist but I think it should remain essential the relationship between weight (Euc +rider) and tire's width. Of course keeping still the other variables (included environment). 

That determining relationship should affect more than anything else the chances to recover balance in a critical riding situation (like after hitting a bump or a bad hole or after avoiding fast a sudden obstacle). 

I'd like to know what you think about it....

Edited by Eko
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I'd caution against losing sight of the forest for the trees. Irrelevant of whether the phenomenon in question is "gyroscopic" in nature, the fact remains that wider tires are harder to turn/less nimble [edit: at medium-to-higher speeds], and distinctly try to 'right' themselves/like they don't want to turn/like they want to be upright.

I think this phenomenon itself needs a name other than "gyroscopic" simply because every time it comes up people get distracted by debating what the cause is/whether it is actually "gyroscopic" or not. As far as I'm concerned, the cause is simply the tire width itself. Wide tires cause less maneuverable EUCs [at medium to higher speeds], period.

As much as people try to argue why this happens, the cause is secondary to the effect itself which we /know/ is true--and the fact remains that I have never ridden an EUC with a 3" or wider tire that turned anywhere close to as well as any 2.5" or narrower tire [edit: at medium to higher speeds]. Even the best 3" tire everyone says is better ("oh this one is way better/way less bad than the other ones") is still fundamentally worse than even the worst/cheapest 2.5" or smaller width tire, without exception. Which means none of the other things people argue about--the shape, the tread, the rubber, the tire pressure, whatever--matters anywhere near as much as the width itself.

Until someone can show me a 3+" tire that doesn't exhibit this behavior (without having to slow way down), or a 2.5" or less tire that does exhibit this behavior, none of the rest of this matters.

Edited by AtlasP
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31 minutes ago, AtlasP said:

I'd caution against losing sight of the forest for the trees. Irrelevant of whether the phenomenon in question is "gyroscopic" in nature, the fact remains that wider tires are harder to turn/less nimble, and distinctly try to 'right' themselves/like they don't want to turn/like they want to be upright.

I think this phenomenon itself needs a name other than "gyroscopic" simply because every time it comes up people get distracted by debating what the cause is/whether it is actually "gyroscopic" or not. As far as I'm concerned, the cause is simply the tire width itself. Wide tires cause less maneuverable EUCs, period.

As much as people try to argue why this happens, the fact remains that I have never ridden an EUC with a 3" or wider tire that turned anywhere close to as well as any 2.5" or narrower tire. Even the best 3" tire everyone says is better ("oh this one is way better/way less bad than the other ones") is still fundamentally worse than even the worst/cheapest 2.5" or smaller width tire, without exception. Which means none of the other things people argue about--the shape, the tread, the rubber, the tire pressure, whatever--matters anywhere near as much as the width.

Until someone can show me a 3+" tire that doesn't exhibit this behavior, or a 2.5" or less tire that does exhibit this behavior, none of the rest of this matters.

If you ever get a chance to ride a Z6 or Z10 your mind will change on this, and if you have ridden on one then I'd be shocked you still have this opinion.

 

A Z10 18" x 4.1" rounded motorcycle tire with the right PSI is probably the most comfy and maneuverable tires to ride at low speeds, feels like you are floating on a ball and you can almost turn on a dime (very fun like the Mten). But the tire and hub motor are so heavy and large in proportion to the chassis that at medium to higher speeds the gyroscopic force makes it one of the hardest EUCs to turn, and it has a mind of it's own. This pretty much proves the points I've been talking about.

Contact patch really is the limiting factor on EUC tires. Since it's only one wheel the tread, profile, etc matter a lot in terms of agility.

 

Edited by tenofnine
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5 hours ago, AtlasP said:

the fact remains that wider tires are harder to turn/less nimble

Unfortunately even this is debatable. Since they indeed do try to stay upright, they require a different technique to turn at speed. But at slow speeds a wider tire allows for much more precise control and, as @tenofnine wrote, can turn in a dime. But it requires a technique that can utilize this behaviour.

Despite being slightly misleading, I’m fine by people calling the phenomena a ”gyro effect” for example. But when people try to explain the cause by saying something like:

4 hours ago, tenofnine said:

But the tire and hub motor are so heavy and large in proportion to the chassis that at medium to higher speeds the gyroscopic force makes it one of the hardest EUCs to turn, and it has a mind of it's own.

... that just isn’t correct, it should be corrected. Why leave false information to be spread when we already know the right one?

4 hours ago, tenofnine said:

This pretty much proves the points I've been talking about.

Until you read what I’ve replied. Maybe I need to figure out a way to explain this in a shorter way for it to be understandable.

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22 hours ago, tenofnine said:

If you ever get a chance to ride a Z6 or Z10 your mind will change on this, and if you have ridden on one then I'd be shocked you still have this opinion.

A Z10 18" x 4.1" rounded motorcycle tire with the right PSI is probably the most comfy and maneuverable tires to ride at low speeds, feels like you are floating on a ball and you can almost turn on a dime (very fun like the Mten). But the tire and hub motor are so heavy and large in proportion to the chassis that at medium to higher speeds the gyroscopic force makes it one of the hardest EUCs to turn, and it has a mind of it's own. This pretty much proves the points I've been talking about.

I forgot to specify turning at normal, higher riding speeds. Yes a Z10 or Nikola can turn tightly at slow speeds, but you have to slow way down to do it.

(Which is kinda weird/borderline dangerous I think. Oftentimes on my Nikola in the beginning I'd be trying to turn at higher speeds and just not turning tight enough so I'd have to slow down, only to have it suddenly then turn much tighter. It's a weird sensation [and again, borderline dangerous] to have such drastic differences in responsiveness at different speeds--and seemingly not just on a smooth curve which would be one thing, but there's like a distinct point when slowing down that it suddenly 'bites' and turns much more sharply then it would just a few mph faster. It's not great.)

Edited by AtlasP
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28 minutes ago, AtlasP said:

Oftentimes on my Nikola in the beginning

It definitely is a different kind of behaviour compared to a narrow tire, and requires a different technique. If you had learned to ride on a Nikola and then switched to a narrow tired EUC, the situation would be similiar: It would feel dangerous as the wheel was falling into the turn, and you would need to learn a new technique.

When I got to try the Nikola for a short while, I’d been riding thousands of kms on the MSX. Therefore I didn’t notice the behaviour to change drastically at a certain speed, I had already learned an appropriate technique for a 3” tire.

The Z10 absolutely does that though, at exactly 15km/h. Under that speed it’s a precise and stable turner, above that I couldn’t get it to tilt no matter what I did. It absolutely requires it’s own technique, more than any other wheel.

I actually remember a video from when Marty started with the Z10. During the video, he failed to turn in time twice and had to bail as the wheel continued to the bushes.

Another interesting video was one where some guys raced on a track painted on pavement. The rider with the Z10 (I think he was RoberAce) had to take corners much slower than the ones with MSXs, V10s etc, and he was still leaning much more than the wheel was tilting. The others had a much more natural posture in turns, and much more speed.

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On 2/3/2020 at 6:35 PM, mrelwood said:

 

If I were you, I’d consider trying a different tire. Two down already is a very fast wear! For me 5000km is common from a single tire.

ChaoYang H-666 should be available as a 16x3.0, and at least as a 18x3.0 it’s the most beautifully handling tire I’ve ridden on. Carves just right, and lets me go much faster in tight corners than any other tire.

I appreciate the advice and may try on my 4th tire change as I already have the replacement.  I really like the feel of the CST-1488 and have 3k miles on the current tire. It's lasting much better than the first which only got 1600 miles. I ride a lot :)  

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My 2 favorite wheels, the 16X and the Mten3, both have 3" tires - I love the feel.  I love how comfortable it is on the 16X with the wide tire, and the Mten3 is very maneuverable and yet easier to go slow and do tricks.  It seems the 3" tire is great for roads and increased stability - I am for the wider tire.

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contact patch is what determines your ride as well. For example the Monster has a 2.75” width tire BUT it has a greater contact patch than a Nikola with its 3” wide tire; i would say the contact patch on that wheel is closer to 0.75 inches with load. 

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1 hour ago, fujio001 said:

For those concerned about gyroscopic effect of the wheels, find a way to reduce the rotating mass.I am sure you could optimize the material/weight the rotating components. In cycling rotating weight is preceived to be about 3 times more important that static weight. Cyclists spend thousands of dollars to save grams of weight. Two identical EUCs with a 1lb reduction in rotating weight would probably see a noticable difference in both acceleration and braking with everything else kept the same.

 

30 minutes ago, alcatraz said:

Only the alloy shell with the magnets attached actually rotate. Should be fairly light. 

Fairly light and "only" are imo very relative. It's still the two massive covers plus the rim with the permanent magnets that are rotating.

So there should be potential to save some couple of pounds!

But i don't see that there should be a massive difference between a Z10 and any of the other new wheels (in regard to rotating weight).

And for example GW wheels drive faster than the Z10 and have "no issues" with cornering.

So the main difference has to be the tire width and by this the profile!?

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  • 1 year later...
  • 3 months later...

Wider tires don't lean well, you can see it is the wrong tire when the rider is having o bend his knee and lean to the side of the wheel because the unicycle can't lean enough and is only reaching like 20 degrees of leaning...

I think cornering leaning hard where you are scraping the pedals on a 35 degree and you are accelerating into the corner is the best thing of unicycle riding. The G forces push you down into the wheel and also you overcome the higher friction and ratain momentum.... heaven.

This is not something I've ever managed to do with a big wheel or a wide tire.

I personally downgrade all 2.5" tires and put a 1.95" chao yang, which are super boucy. actually they are so elastic their their width grow to 2.x" (I should measure this)

Thinner tires are easier to lean and turn faster with less lean.

So maybe bigger unicycles should using thinner tires whilst smaller unicycles should be using wider tires..

 

 

Edited by OneLeg
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lean angle is usually a product of profile more than overall width. Leaning body parts out is typically not to overcome a square tire profile or wide tire, its to counteract the g-forces or inertia that are trying to keep you upright. Things in motion wanting to stay in motion and all that jazz. Probably a little gyroscopic forces at play as well. Tbh, I won't pretend to know which exact forces and to what degree. Motorcycles and euc's same basic premise. Accel AFTER/AT the apex is usually preferable than accel prior to. :eff02be2d7:

Edited by ShanesPlanet
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12 hours ago, OneLeg said:

I think cornering leaning hard where you are scraping the pedals on a 35 degree and you are accelerating into the corner is the best thing of unicycle riding. The G forces push you down into the wheel and also you overcome the higher friction and ratain momentum.... heaven.

And then a slight bump in the road grabs your scraping pedal and literally sends you to heaven. No thanks. I’m an atheist. Besides, having to lean sideways that far is an off-road hell. Still an atheist though.

12 hours ago, OneLeg said:

Thinner tires are easier to lean and turn faster with less lean.

This is incorrect though. As you described yourself, a wide tire only needs to be tilted a little bit for the same turn because it turns faster with less sideways lean.

12 hours ago, OneLeg said:

So maybe bigger unicycles should using thinner tires whilst smaller unicycles should be using wider tires..

More than the size of the wheel I think it’s about the speed one likes to ride at. Faster speeds call for thinner tires for the same behavior that wider tires get at slower speeds.

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10 hours ago, mrelwood said:

This is incorrect though. As you described yourself, a wide tire only needs to be tilted a little bit for the same turn because it turns faster with less sideways lean.

According to the vlog 3 posts before ( Titled "Wider tires require more lean angle") its the opposite way round. 

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22 hours ago, ShanesPlanet said:

lean angle is usually a product of profile more than overall width. Leaning body parts out is typically not to overcome a square tire profile or wide tire, its to counteract the g-forces or inertia that are trying to keep you upright. Things in motion wanting to stay in motion and all that jazz. Probably a little gyroscopic forces at play as well. Tbh, I won't pretend to know which exact forces and to what degree. Motorcycles and euc's same basic premise. Accel AFTER/AT the apex is usually preferable than accel prior to. :eff02be2d7:

This is the correct answer. And indeed people who have been riding motorcycles for a long time will know this.

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