Airless Michelin Tires

This has been discussed some before. But in watching the video about Michelin’s airless tires I can’t help wondering about several things:

  • Wear on the outer edges of the tread and how that will affect performance and handling.
  • Rocks and other road debris getting lodged in the open baffles and how that might effect the tire.
  • Wondering what the already known pros and cons are from using airless tires on military vehicles and heavy equipment.
  • Cost compared to tires with air.
  • Typical life of airless tires in miles and age.
    Etc. etc. etc.

If you can’t trust Michelin, who can you trust.

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You can trust your car , to the man who wears the star.


Here are my comments as a retired tire engineer.

The idea of a tire that doesn’t go flat, but has the same cushioning powers as a pneumatic tire (one that uses air) has been around at least 50 years. It took the development of new materials to bring it close, but Michelin’s Tweel has some severe shortcomings, among them speed limitations.

Can the Tweel or its imitators get the same wear as regular tires? Sure! There is nothing preventing the use of the same tread rubber.

What about the edges of the tread? That can also be solved by making the wear surface more narrow and contoured. Details matter.

What about stuff getting caught in the spokes? Then we should have the same problem with spoked wheels - and we don’t. Besides we can always use a cover - like a wheel disc.

Summary, I don’t see any reason why this concept can’t make it into the mainstream. It’s just going to take some time to figure out how to do it. We’ve been waiting at least 50 years - what’s a few decades more going to matter?


@CapriRacer Thanks for addressing my curiosity. I was hoping you’d share your expertise. :slightly_smiling_face: Looks like we’ll all still be filling our car tires with air for awhile more. :grin:

Guess it"s time then to go ahead and change the air in my tires to “premium winter air” along with changing the blinker fluid and flushing the tailpipe. :wink::rofl:


My biggest concern is for failure from repeated stress at the flex points and adhesion of the “spokes” to the wheel and tread donuts where maximum stress occurs.

I’d like to see a picture of that construction under hard launch. How far out of phase will the outer donut be with maximum torque on the hub? Do the spokes/vanes fully collapse?

Since they are stressed all 360 degrees, unlikely anything would collapse, but YES, some kind of flex/twist stress will be present.

IMHO this will be quite a self-centering/self-reinforced construction, where “spokes” will stretch under heavy load, but only to hold the center stronger under stress.

And for the failure… Eager new technology adopters will probably give us some statistics few years down the road from the public launch :slight_smile:

Unlike a spoked bicycle tire, these spokes are designed to flex. Just like the picture above. The 360 degree stress you mention works well when static. Since they can flex, when the driven hub begins to rotate, the tread ring will lag behind a bit. How much is what I’m asking. If it lags far enough, the spokes will lay against each other. This is what I meant by collapse. That probably can’t happen if the outer ring is stiff enough but seeing it flex over the rock has me wondering.

Yes, I’ve got what you mean by “collapse”, and the “lag” will definitely be on the higher scale to compare to traditional “aired” tire.
Still, the whole construction is naturally self-centering and self-supporting, so even if that “collapse” happen (which I doubt), it will not have impact on the overall shape of the wheel.
What I would like to know is how this flex/lag will affect the vehicle stability.

As far as rocks in the spokes, I’m assuming there will be a flexible sidewall cover to make it look more like a regular tire and the one pictured is just to show how the tire works, although I could be wrong. Otherwise, I see dirt and snow getting in those spokes. Plus, they’d make the tire pretty tough to clean and make look decent after a trip down a dusty road.

Not necessarily. They’re already in use on lawn equipment. I saw a commercial lawn service running a zero-turn riding mower with tweels for the drive tires. No cover or anything.

I just don’t see how’d they survive without some kind of cover. Rock gets stuck in there, would tear it up.

Unless there’s a quantum leap in material science (along the lines of transparent aluminum) airless tires will never come close to the performance of pneumatic tires.
First, compressed air makes an excellent, near ideal spring that’s nearly weightless.
Almost no hysteresis or internal friction, which add to rolling resistance and heat.
Second, all the air in the tire works against the contact patch, whereas with an airless tire only the material (foam, spokes etc.) in the immediate area of the patch is working at any given instant.
Basically about 90% dead weight.

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Air works against all 360 degrees of the tire, but happen to push against a contact patch too.
I do not see how it is different for air-less.
Also, “spokes” seem to work by pulling there, not by pushing, so all 360 degrees are at work pulling and centering the hub, while the contact area actually releases the pull tension and “floats”.

Hard to tell.
Do they publish the weight of airless vs. weight of conventional?
I would not expect too much difference as regular tire sidewalls are quite heavy.

Maybe… But you don’t generally mow in snow, rocks, or mud, or above 5 miles per hour. I dunno. Maybe I’m missing something. I surely can’t envision those tires used as a mud tire (or a snow tire I assume, but I’m out of my arena of expertise commenting on snow) as they’ll pack with mud and become unbalanced in about 30 seconds. Reminds me of that line from My Cousin Vinnie. “I’ve got mud…in my tires…?”

Now I have run similar tires (or at least with voids through the sidewall) on a skid steer with no real issue. But tire balancing isn’t a concern.

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I’m going to suggest that the spokes in the Tweel are no more susceptible to debris being trapped than the spokes in wheels.

Second, I am going to suggest that the Tweel operates very similarly to a pneumatic tire - in that the torque and deflection due to the road is felt throughout the tire - which is contrary to what circuitsmith points out - BUT - he is right that air is an excellent spring.

??? The spokes in the Tweel are constantly flexing, moving relative to each other, and changing the gap between each other. Put a rock in there, and something is going to break. And it won’t be the rock.

None of this is true for a spoked conventional wheel.

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I believe the tweel spokes are going to be a lot more prone to catching and holding debris than the spokes of a wheel due to the facts that they’re closer to the ground and have a whole lot more surface area to trap stuff.

Rubber seems to degrade somewhat quickly here in OK with the sunshine and high heat. I wonder about problems due to dry rot which could lead to the tire shredding itself in a heartbeat.

Excellent thoughts . . .

If you’re right, the southwest would be a poor climate for the tweel