In the days before full-service gas stations went the way of the dodo, in addition to filling ‘er up, the attendant would sometimes check the tire pressure. These days that task, along with actually pumping the fuel, has totally fallen back on the driver, but it’s a job that is easily overlooked. This leaves many people driving around on tires at less than optimal pressure resulting in reduced performance and fuel economy. For the past year, Goodyear has been developing its self-inflating tire technology that's designed to keep tires inflated at the optimum pressure and the company is now set to debut the technology in Germany.
Goodyear's Air Maintenance Technology (AMT) system automatically keeps tires inflated to the optimum pressure without the need for any external pumps or electronics. Rather, all the system’s components are contained within the tire itself. The heart of the system is an internal regulator that detects when the air pressure drops below a pre-specified psi and then opens up to allow air from outside the tire into the pumping tube. Air is pushed through this tube to the inlet valve and ultimately into the tire cavity by the deformation of the tire as it rolls over the road.
Goodyear is initially aiming its AMT system at commercial vehicle fleet operators, citing 2008 figures from the American Trucking Association that more than half of all truck and trailer breakdowns for such operators involve a tire in some way, making tire-related costs the single largest maintenance item for fleet owners. The simple act of keeping tires properly inflated can cut costs by improving fuel economy and prolonging tread life.
Goodyear estimates that every 10 psi loss of tire inflation equates to a one percent loss in miles per gallon. Additionally, tires underinflated by 10 percent is estimated to decrease tread life by nine to 16 percent.
So, although Goodyear hasn’t announced pricing details of AMT tires, it will no doubt be claiming the potential savings for fleet operators over the life of the tire will more than offset the initial up front cost.
Goodyear will debut its self-inflating technology for commercial tires at the 2012 Internationale Automobil-Ausstellung (IAA) Commercial Vehicle Show currently running in Hanover, Germany, until September 27.
Source: Goodyear
On road commercial tires, and car tires are designed to provide a flat rolling surface when the tire is at the specified pressure whether the vehicle is loaded or not. Unless you are overloading the tire, need to increase the ground contact area to increase floatation (you forgot about the on road specification), or need to lower the top of your vehicle to clear a low overhead keep the tire pressure at the manufacturer's specified pressure.
re; KushSmoka420
The H1 Hummers have central tire pressure regulation allowing the driver to adjust the tire pressure without stopping allowing him to maintain optimal tire pressure for the terrain in the specially designed tires.
This would be easy to make adjustable, by putting the pressure regulator on the inlet, which still looks a lot like a tire inflation stem, because it sticks out of the rim.