Airless WHAT???

Have we talked about airless tires on cars yet? I know they've been around for machinery, but they're being developed for cars now. Good? Bad? Imagine an airless slick!

What's the scoop on these?

What treadwear rating are they? 

They are forever "just around the corner" for cars.

You can already get them for stuff like mowers. But these have been the "next big thing" for decades.

Seems like a nice idea, just don't drive in gravel, mud, or park when it is snowing?

How do they ride at 20 below?

I guess they have been tested on military vehicles and reports are less than good.

I couldn't imagine what happens to them when they get full of snow, or water that freezes.

The question I always have is, what problem is it supposed to solve, and does solving that problem outweigh the downsides?

All good points above. That makes me wonder if they're more suited for UPS trucks in cities rather than passenger cars. 

There's nothing keeping them from putting sidewalls  on them. I think the open sided ones are just to look cool and attract press. 

In reply to dculberson :

Very true.  

My question however is what are they solving by going to a tweel and how are they mounted/installed?  With a pneumatic tire you can adjust the air pressure for the temperature outside and the load on the tire.  With a tweel you just live with it.

dculberson said:

There's nothing keeping them from putting sidewalls  on them. I think the open sided ones are just to look cool and attract press. 

IIRC, they will overheat if they don't have airflow through them, so they have to stay open.

This also makes them kinda loud, from all the air whooshing in and out.

Granted, the last I paid attention to this sort of thing was 5-10 years ago, but I can't imagine that they could solve the overheating problem very easily.   Or the contact patch issue, where the center of the tread needs to contact and leave the ground first for best stability and roadfeel.

Wheels have all been getting increasingly closed off for aerodynamic reasons in recent years. It's especially noticeable on EVs. Seems like this might be a non starter unless the aero is really good somehow.

In reply to Pete. (l33t FS) :

I also wonder if sidewalls could work the way the ribs deflect. Unless the sidewall is only attached to the bead and tread, although that seems like it would be really hard to mold. 

I presume the goal is a tire that can't be punctured or come off its bead under side loads. I see them a lot on mowers, skid steer loaders, and similar equipment around here, so it would appear they don't have too much trouble with the compartments trapping dirt or stones.

I like them, though true that I have seen them for a while now. There are acoustic problems with something flexible compressing and expanding over and over. It would be trivial to add sidewalls to cover them for aerodynamics and environmental concerns. I suspect that they could be a lot stiffer than they are and still work well, which would help with both of those things.

What does it solve? It uses a small fraction of the rubber of a traditional tire, it cannot get a flat, it is infinitely recyclable by retreading so the waste tire carcasses become much less of a problem, and you no longer need a TPMS system. 

slefain said:

They are forever "just around the corner" for cars.

You can already get them for stuff like mowers. But these have been the "next big thing" for decades.

I've seen pictures of them on a 2000 Audi A6 for testing... when a 2000 Audi A6 was a new car.

I drove on some of these on a Scion FR-S when I was in Michelin in 2014. They were a little louder, and tramlined a little (flat contact patch, anyone?), but were perfectly normal to drive on otherwise. At the time, there were still requirements in Federal guidelines for tires to be "Inflated to xxxPSI" in some words or another, which means federal regulations would have to be altered/updated for any of these to be truly legal for broad sale. They are out there (Tweel by Michelin) on lawn equipment and Bobcats I believe.

They are really cool, they work more by tensioning the upper spokes than by compressing the lower spokes. 

Are they really that much different than something like this?  Not like there is a lot of air in these!

I wonder how they'd work after driving a few miles in yesterday's snow storm, when they're packed full of slush and ice.

Tires are balanced to half an ounce.  Can you imagine if you had three or four of those cavities packed with ice or mud?  Wicked imbalance.

The other problem I foresee is loading.  You can put the same exact tire on 20 different cars and inflate it to the pressure required for THAT CAR.  You can't adjust tweels.  Manufacturers would have to make a dizzying array of tweels with different "pressures" for all the possible cars they could fit.

Air is also very compliant.  I'm told that one of the downsides to a tweel is that it rides very stiff.  Air can move around in a regular tire, and the entirety of the air volume is providing pressure.  With a tweel, all of the tire's suspension ability is centered on just a few spokes at a time.  

Pete. (l33t FS) said:

I couldn't imagine what happens to them when they get full of snow, or water that freezes.

 

The question I always have is, what problem is it supposed to solve, and does solving that problem outweigh the downsides?

My thoughts exactly on the first point.  The problem they're trying to solve is death, dismemberment, and property damage, so that's a pretty big problem solved so I would imagine the downsides could be considered by some to be less scrutinized.

Edit:  Just checked NHTSA.  Approximately 78,000 crashes per year caused by tire blowouts.

I had to double check to see if this was a 10 year old post. Like nuclear fusion and flying cars, tweels have been 10 years away for the last 50 years.

In reply to Curtis73 (Forum Supporter) :

I'd love to know the car-truck-motorcycle spread on blowout statistics.

I can NOT see these using less petrochemicals than a tire.  A tire is a thin veneer of "rubber" over air, reinforced by steel and some fabrics.  These things are a three dimensional mesh of plastic.

As for blowouts, that is generally a self-inflicted issue.  Tires don't just go from "okay" to "completely flat" without either a large impact (that itself will cause other problems like suspension damage) or being neglected for condition or pressure.   Further, TPMS has been mandatory for the past 14 years, longer than the average vehicle age, so there is no excuse for pressure neglect in the majority of cases.

We also have conventional run flat tires...

Tweels make sense for equipment. These machines tend to have much lower operating speeds, don't typically carry a spare onboard, and any downtime costs the owner money. 

Road cars are a different situation.