I currently have a tire on my Volvo wagon that has a slow leak. Every week or so, my dashboard lights up with the “low tire pressure” warning. When I get tired of looking at it, I drag the air hose over and fill it up. It’s a super slow leak, and I know I should either find the leaky hole and plug it or replace the tire. But it’s a snow tire, and I kept telling myself that winter was almost over and I’d be swapping my snow tires for my comfy summer tires sometime soon, so I just kept filling it a little at a time when the light told me to.


Sadly we are stuck in the winter that will not end, so here I am, two months later, still stopping once a week to bend over my right front snow tire. 
Picture this: A world without air pumps, without leaky tires, without "low tire pressure" warning lights! No, I'm not suggesting we all make the trip to work on a Big Wheel (TM?). I'm poking at some new technology that has been in the works for some time. It's called an airless tire, and the name is about as self-explanatory as it can get. It's a tire, that has no air inside. The technology is actually so far along that you can already buy airless tires for things like forklifts and construction equipment. Car tires should be just around the corner, right? Maybe not quite so close. The physics of keeping a car on the road are much more challenging than the basic load a forklift places on its tires. Cornering, accelerating to speed, stopping -- these are all things that airless tires will have to do really well before the make their way onto a passenger car.

 
Airless tires work like this. In a traditional, aka pneumatic, tire, you have what is basically a sealed rubber tube full of pressurized air. These days they are reinforced with steel belts and have tread patterns with development histories rivaled only by NASA probes. But at the end of the day they are still rubber tubes filled with air. The air not only supports the car, it provides a crucial element that was not part of the design of early solid rubber car tires, or wagon wheels for that matter. The air provides comfort via the cushioning effect of compressed air inside flexible rubber. No matter how hard tire thinkers have tried, it's been very hard to come up with a new technology that provides the same level of ride safety and comfort of a traditional air filled tire. The difference in the airless tire, obviously, is the lack of pressurized air. In fact, most of the current airless tire designs aren't even sealed, the inside of the tire is open to the elements. A fabulous series of rubber ribs, or ribbons supports the tire from the top and lifts it from the bottom. These ribs radiate from the center of the tire like spokes. It's amazing to watch these tires work, and as the technology becomes available to the public, it will be downright freaky to see a car driving down the street wearing them. Airless tires promise to be better in other ways, too. They will be more fuel efficient because they will be taking advantage of new developments in rubber technology and will lose less energy to rolling resistance. Even better, you'll never have a flat or find yourself worshipping that quarter-eating air pump at the local quickie mart. Hallelujah.