Radical tyres

[Ciro Pabón]

From Gizmag:

The tweel (tyre-wheel) http://www.gizmag.co.uk/go/3603/



The hollow electric wheel http://www.gizmag.co.uk/go/4506/



The orbital wheel http://www.gizmag.co.uk/go/3544/



I wonder: are they F-1 legal? And, would they bring any advantage, specially the suspension related benefits alleged for the orbital one?

Note: I edited this thing to show the pictures (they moved)

[Scuderia_Russ]

[IMG:377:426]http://img.photobucket.com/albums/v284/ ... erie13.jpg[/img]

Is the orbital wheel what is used on the Nike car in GT4?

[DaveKillens]

It's a wonderful stylng exercise, but it's basically just a very large roller bearing. It has advantages and disavantages. Canging a whel can be difficult, as well as keeping thebearings clean and free of debris. And if any part is damaged, it would ease to rotate.
Very pretty and eye catching, but fragile.

[ginsu]

I checked out the orbital website and this seems to be more of a styling revolution rather than an engineering revolution. They don't publish any numbers, only very rough percentages, so you don't really know what designs they're comparing the orbital to.

Also, I simply don't see how this wheel can be stiffer than a typical wheel. After all, it has nothing in the center, there's no way that you can hollow out a circle and expect it to be as strong as a solid circle. It's like an I-beam. You can't just remove the webbing, there has to be a little bit of webbing.

I do believe the braking would be significantly better, but it would not reduce unsprung mass to have a 26-inch solid steel brake "ring", that would be ridiculously heavy. Not to mention, it puts all the weight on the rim, which would increase the rotational inertia as well.

[i70q7m7ghw]

Orbital wheel would provide a lower center of gravity, the strength of the wheel would not be a huge issue as all the wieght would be going straight down through the part of the wheel which is in contact with the ground, not from the middle like on a conventional wheel.

[ginsu]

Orbital wheel would provide a lower center of gravity, the strength of the wheel would not be a huge issue as all the wieght would be going straight down through the part of the wheel which is in contact with the ground, not from the middle like on a conventional wheel.

That is true on most of the designs, but if you go to the website, they have
a Toyota 'Rover' concept that somehow changes where the hub engages the wheel to the top. Also, on the bicycle the hub is on top of the front wheel.

Also, Lower CofG compared to what? Compared to a forged magnesium F1 wheel? Those wheels are probably 8lbs or less. I can't imagine that the orbital wheel is less than 8lbs, especially not with the braking 'ring'. I did make a mistake there, because it would likely be a cast iron, which would be even heavier. Just hollowing out the wheel does little to the CofG but greatly effects the rotational inertia.

I'm really into Mountain biking and the trend there in the past 10 years is to move to disc brakes instead of rim brakes. I don't know why you would go to rim brakes on a vehicle, they don't have any advantages besides increased brake torque which is completely offset by the weight of the brake ring. It is far more important to decrease unsprung weight.

Strangely, they say their design decreases unsprung weight, but then they
have no actual numbers to back it up. I just don't like these 'design houses' where they make something that looks great, but then they have no real engineering info to back it up.

[ackzsel]

I don't think this "tweel" as they call it can handle a lot of torque.

http://www.gizmag.co.uk/picture.php?s=14&p=3603_01.jpg

[DaveKillens]

The mechanism to house the ring is basically a very large roller bearing. To work effectively and be reliable, it would have to be robust. So that "ring" would be fairly heavy, it sure could not be super lightweight. And it would definitely be fragile. It definitely could not be used on a dirt bike, because just one serious ding to the rim would lock the whole thing up, and render it into useless junk.
When you add up the factors of actual unsprung weight, reliability and resistance to damage, cost, and mexhanical complexity, I would have to say the traditional center bearing wheel still holds the advantages in the real world. Pretty styling exercise, but it has limitations.

[CFar]

Also, I simply don't see how this wheel can be stiffer than a typical wheel. After all, it has nothing in the center, there's no way that you can hollow out a circle and expect it to be as strong as a solid circle. It's like an I-beam. You can't just remove the webbing, there has to be a little bit of webbing.

Sure it is. It may in fact be stiffer. A spoked wheel doesn't use the spokes for support, in fact your weight on a typical bicycle is actually hanging from the hub, not pushing in on it. The spoked design has spokes coming from outside, into the wheel connecting to the hub. When you put another spoke on the other side and more all around, the hub is locked in, but only by being pulled, not pushed. Its difficult to articulate in writing and is easier to understand if you see it.

[ginsu]

I know what you're talking about because all the spokes are in tension and can't handle any compressive loads due to the way they are attached to the hubs. That fact is that a bicycle wheel distributes the load over 2 or 3 eyelets i.e. when the spokes are double-crossed or triple-crossed, so it can be quite stiff.

I had a wheel handbuilt by a local bicycle mechanic who's been doing it for years, and that wheel has never had to be trued, not even once in 5 years. And I weigh over 200lbs and hit the trails pretty hard.

I know the orbital wheel's stiffness would be just fine with the 'hub' at the lowermost position, but if you move it to the top, or beyond horizontal then I think you're going to have some problems with this design.

I'd love to see some Carbon NanoTube Spokes or something really innovative like that. As they say, you dont just reinvent the wheel.