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Much of the technology that is used on modern cars, though it has been incrementally improved over the decades, is still built on the same basic concepts that were used on history’s first automobiles. Windshield wipers, for example, have not seen much improvement at all. Another aspect of modern automobilery which is little more than a polished up version of the original design is the classic wheel-and-tire combination.
In 1901, the Oldsmobile “Curved Dash Olds” became the world’s first high-volume mass-produced automobile, and it was a contraption which looked very different from cars today. It resembled a carriage more than it did a car; it was started with a seat-side crank, steered with a “tiller” lever, and when the four-horsepower engine started pinging, the driver simply used a hand-operated dispenser to feed the it more oil. But one thing it did have in common with modern cars is that it came with a set of metal rims wrapped with rubber tires. They were narrower and flimsier back then, but in principle, they’re not so different from what you’d find on an automobile today. Now, over one hundred years later, Michelin is developing what looks to be the next evolutionary step in tire/wheel technology. They call it the Tweel.
The word “Tweel” is a portmanteau of “tire” and “wheel.” Michelin’s prototypes integrate the tire and wheel into one component, and the use polyurethane spokes in place of the air in a traditional tire. This design completely eliminates the problem of flat tires and blowouts, and allows the tire to deform locally in a way which very effectively absorbs shock.
A tweel’s vertical stiffness (which primarily affects ride comfort) and lateral stiffness (which affects handling and cornering) can both be exactingly optimized for a particular application. A tweel’s design also seems to be more conducive to “capping,” where the tread of the tire is replaced rather than the entire unit. This would reduce tire maintenance costs for vehicle owners, and sharply reduce the amount of waste rubber generated by discarded automobile tires.
One aspect of tweels that seems conspicuously left out of the available information is its braking performance. The same property which allows the Tweel to absorb shock so effectively might also make it lousy during hard braking, causing the tire’s leading edge to flatten and deform in undesirable ways. The Tweel’s construction may also cause slightly more drag during normal driving, reducing fuel efficiency and tread life. Another overlooked data point is the shear strength of the polyurethane spokes in a tweel; it would be interesting to learn whether they can withstand hard steering at high speeds without tearing.
Tweels are already being produced for use in some lightweight applications such as the iBOT mobility system, a wheelchair-like device which can navigate stairs and uneven terrain. But tweels for heavier applications such as cars are still in the early prototype phase. Initial tests show excellent performance, but some vibration problems must be overcome to eliminate excessive noise. But once tweels are ready for heavier applications, the military may be Michelin’s first customer; flat-proof tires which effectively absorb bumps would be extremely advantageous to vehicles moving in difficult or dangerous areas.
Further info:
Press release from Michelin
CBS News segment on the Tweel (Windows Media)
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I read about this about a year ago in either Popular Science/Mechanics. Back then, they had the same problem with excessive noise. I see they’re coming along nicely…
Hmmm, doesn’t this look suspiciously similar to the design used by the Lunar Rover on the Apollo missions?
The wheels look incredibly ugly. No person in thier right mind would ever put them on a car.
This sounds almost exactly like the first press release I read over a year ago, you would think it there would be more progress since then, by the way I beleive the picture is of a cut away version with the sidewall removed to show the internal struture, it can me made to look like any standard tire wheel assembly.
The cynic in me thinks that they are really trying to work out how to make them last long enough to be desirable, but not so long that they aren’t profitable.
Well the rappers are going to be pissed
If they can make that look like a normal tyre then its okay, they aren’t so ugly anymore. Then it would make them a really good piece of engineering. But what guarantee that the spokes wont break?
alipardiwala said: “If they can make that look like a normal tyre then its okay, they aren’t so ugly anymore. Then it would make them a really good piece of engineering. But what guarantee that the spokes wont break?”
The spokes might break, but if at all, it would happen one at a time, and gradually. The tweel would still be decently operational, unlike pneumatic tires, which when popped or slashed fail entirely and potentially catastrophically. That’s probably one of the selling points of this design.
Berkana, I don’t know that I agree. Polyurethane has a bad tendency to become dry, brittle, and fragile over time. I think that they are going to have to do a heckuva a lot more work before this is truly a signifigant improvement over current tire technology.
Ugly? I don’t think they’re ugly at all. They look pretty cool when rolling. Almost like the car is floating above the road. http://video.google.com/videoplay?docid=-2602309358284516882&q=tweel
The picture is not of a cutaway – that’s how the tweel looks. I would imagine, though, if these do go into the public realm, Michelin would probably add some sort of a sidewall for aesthetic purposes.
I think we have a loser! … at least for this application. Maybe it would be better suited for a moon rover vehicle.
I think they must have a cover. Fill all those gaps with mud, water or peebles seems a very bad idea.
Technology like this will one day change the face of all racing and i can’t wait
stox said: “Hmmm, doesn’t this look suspiciously similar to the design used by the Lunar Rover on the Apollo missions?”
Ummm….not at all.
http://www.hq.nasa.gov/alsj/a15/a15mr059.jpg
i’m sure they can make spinning tweels ;-)
I guess they didn’t make as much progress as they expected. A search of the Michelin Website for the word Tweel resulted in zero. They’ve obviously given up on this one…
Update: They released an industrial version for use on small tractors. Still no commercial use, but they are getting there.
http://www.michelintweel.com/