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Michelin, that's who.

http://www.michelinman.com/difference/r ... 2005a.html

interesting...

I'll pass. I like my women hot, and my tires full of air.

I was wondering when someone was going to improve on the dated design that is air inflated tires.

Article about this in Road&Track, or maybe it was Automobile, I don't remember.
Could be handy for evil rocks on gravel roads.

Would make adjusting tire pressures at autocross. . . . kinda hard. . . .

Yeah, wonder how they would do for performance situations.

apparently the near lack of lateral deflection (ie: sidewall flex) makes them handle really well.... don't know how they take to excessive camber however

http://www.gizmo.com.au/go/3603/

Or dive and squat.

Steve

Yea, what about wrapping them under hard acceleration? How would they hold up to load, and high power?

I'd think they would just sort of flex around to much to be good for performance.

What about smaller bumps only contacting part of the wheel. To keep a similar "spring rate" the wider the "tire" the less spring each spoke would have, so a tiny rock would sink deeply into the "tire"

Or at least that's what I'd imagine.

BAC5.2 wrote:I'd think they would just sort of flex around to much to be good for performance.

Have you seen what a piece of rubber full of air does . That's really funny because that's exactly what a pneumatic tire does. Adjusting the pressures of the tires is to control sidewall flex (aka lateral deflection), which they can make quite stiff on these. Adjusting lateral stiffness relative to the other tires will be a problem. But typically in a performance driving situation you would just want the rear tires to be either a little looser or tighter in lateral stiffness in relation to the front.

I'm not a proponent of these things or anything. But its funny that people attribute pneumatic tire weakness to them... if anything that would make them equal.

lol, exactly brat. What i wonder about is sidewalling. You can run on the sidewall a little bit with a pneumatic tire, but what happens with these?

I'd imagine it's not that big of a deal since the twheel will hold the contact patch better than air, I would guess it would be one of those situations where if you were to the point where you needed a sidewall you were already too late. If that makes any sense. I do think there is a lil bit of sidewall on them though. Look at the picture.

I'm not one to put looks over functionality, but those things are too ugly to make me even consider them...

William - But the spoke length handles all kinds of loads. To short, and the wheel may be to stiff to be able to absorb shock (thus, cracking).

So unlike a low profile tire, there is more potential for squirm, espically with uneven loads produced by cornering and camber. With a lower profile tire, there's less "sidewall" to flex, espically if properly inflated.

Look at the picture, and see how much deflection there is.

Subyluvr is right though, those look fucking retarded. I'll pass.

BAC5.2 wrote:William - But the spoke length handles all kinds of loads. To short, and the wheel may be to stiff to be able to absorb shock (thus, cracking).

So unlike a low profile tire, there is more potential for squirm, espically with uneven loads produced by cornering and camber. With a lower profile tire, there's less "sidewall" to flex, espically if properly inflated.

Michelin press release wrote: Michelin has also found that it can tune Tweel performances independently of each other, which is a significant change from conventional tires. This means that vertical stiffness (which primarily affects ride comfort) and lateral stiffness (which affects handling and cornering) can both be optimized, pushing the performance envelope in these applications and enabling new performances not possible for current inflated tires. The Tweel prototype, demonstrated on the Audi A4, is within five percent of the rolling resistance and mass levels of current pneumatic tires. That translates to within one percent of the fuel economy of the OE fitment. Additionally, Michelin has increased the lateral stiffness by a factor of five, making the prototype unusually responsive in its handling.

Lateral stiffness is one thing, and if body roll was absolutely a non-issue, then that would solve all potential problems I have with the system.

I guess increased lateral stiffness would be good for turn-in. But what about when you roll over, and vertically load part of the tweel more than the other?

Still, I'd be worried about wrapping the spokes under a hard, high-grip, AWD or RWD launch. Will they ever have the all-out straight line ability of a Mickey-T drag slick bolted to drag wheels? Will they ever have the sheer corner grip of a Hoosier R-Compound?

Maybe, maybe not. I don't see much advantage of the tweel over a pneumatic tire. Pneumatic tires are easy, relatively cheap, and you can do so much fine tuning, with relatively low risk (blowout risk). Sure, you have to give up things to trade off for performance (tire life, which the tweel may not increase, and ride comfort, which the tweel may not increase for a high performance tweel), but that's how it is with everything.

And you need to replace the whole wheelset when you burn through a set of tires?

I think you're thinking of it as too much of a tire filled with air. If the lateral stiffness is 5 times as much as an air tire, it'd be very hard to roll the tweel. How would you wrap the spokes? Reread the part where it says ride comfort and handling/cornering can both be optimized. I'm sure there were people asking these same kinds of questions when the tires we currently use today were just being offered.

The spokes could wrap under hard launch in the manner of a leaf spring winding up - I think that's what he was bringing up. Camber also changes with suspension travel (and road surface some), regardless of sidewall, so uneven loads on the tire tread width are unavoidable in the real world.

Steve

BAC5.2 wrote:And you need to replace the whole wheelset when you burn through a set of tires?

They can be retreaded, rather than replaced, since the tread is bonded on in the manufacturing process.

As with low profile tires, i'm sure they can have low profile tweels with shorter spokes... i'm sure that would do away with tire wrapping issues. Also the way the spokes are angled is seems as though for each pair of spokes one may be able to rotate facilitating "wheel wrap" but the "paired" spoke must stretch to allow this to happen... i dunno how much these spokes will like to stretch

I don't think the paired spoke would need to stretch - that would be the spoke it pivots oin while the other spoke would just collapse inwards.

Steve

Yea, wrap much like a leaf spring.

In the real world, like steve said, tires and wheels see lots of stresses, and alignment causes lots of those.

I think this is a cool idea, and surely something will come of all of the research, but I don't think it's the next best thing to the wonder bra.

It might keep tire manufacturers on the ball, and that would be more than enough for me.

Maybe if the spokes didn't go completely across laterally, but were split into multiple spokes so they could react better to part-tire width surface changes.

Steve

hence currently why they initially targeted at lowspeed applications.I dont know what the quarter mile is of a bobcat - but i cant assume that it would be enough to warp tyres......

What the hell are you talking about? Lol. What about a bobcat?

If they put them on an A4, and are speaking about the "performance enhancement qualities", that doesn't sound like low-speed to me...

I dunno, until I see this idea taken to a performance aspect, it sounds kind of "iffy" to me.