It's a well known fact that keeping your tires properly inflated has numerous benefits. But sometimes it's just inconvenient to stop and check and re-pressurize. A new self-inflating tire design from Coda Development can fix that and you don't even have to stop.
Actually, all you have to do is drive to make sure your tires are properly inflated. Now before the comments start rolling in about how self-inflating tires are nothing new, let me explain how they work.
Normally, a compressed air tank is used to inflate tires that are too low. This new system uses something called a peristaltic pump to regulate air flow. A peristaltic pump is the same kind of pump used in hospitals to deliver medication through an I-V.
The system uses a rotating wheel that, as it turns, pushes the tube's contents through one end. The movement causes a low pressure area which pulls more "whatever" into the other end. In Coda's case, the car's wheel is the rotating wheel and your air-filled tire plays the part of the tube. A pressure sensitive valve ensures that your tire stays at a constant pressure.
Since the system doesn't require nearly as many parts and is not powered by an outside source, it should be much more reliable and cost less. Coda plans to show off the new technology at the 2008 SAE World Congress in mid April.
From : HowStuffWorks , SIT Homepage