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The military has a unique requirement to operate in different terrains throughout the world. The ability to travel in as much varying terrain as possible provides the military greater tactical options. This requirement/need is for the tire to provide a variable footprint to allow for different ground pressure. Much of the current run-flat technology utilized by the military severely limits mobility and adds significant weight to the unsprung mass. This technology gap has allowed for the development of new run-flat tire technology. New tire technology (fig 1) has been developed that substantially increases survivability, eliminates the need for heavy run-flat inserts, significantly reduces air pressure requirements and provides full (or near full) speed capability in degraded/damaged mode (punctured tire). This run-flat technology is built directly into the tire, yet maintains the normal variable footprint of a normal pneumatic tire. This makes the tire/wheel assembly much lighter and far more survivable than normal military run-flat technology. Safety, logistics, economics, and fuel economy are additional benefits this tire technology provides over current military tires with run-flat inserts. INTRODUCTION The current state of the art tire technology utilizes a run-flat insert sometimes weighing over 100lbs. Fig 2 shows a cut-away showing the run-flat for a military tire/wheel. The stability of the vehicle running on a run-flat is significantly reduced and the operator is limited to a maximum speed of 30 mph, and sometimes less depending on stability. The distance that a vehicle can travel with a run-flat tire is also limited to typically 30 miles. This is also very similar to the NATO standard of 50 km [1]. The purpose of the run-flat is to allow the vehicle to have limp home capability and that’s it. Logistically the run-flat has further drawbacks. Unless you buy the wheel, run-flat, and tire as a package, you have to get the run-flat into the tire. This requires Unclassified/Distribution A Approved for Public Release Unclassified/Distribution A Approved for Public Release Figure 2. Military Run-flat Tire with Insert [1] a special tool to compress the run-flat and get it into the tire [2]. One such tool used on a HMMWV tire is shown in Figure 3 [2]. The larger the run-flat the more difficult this becomes. This process further adds to the maintenance burden on the military that has limited resources. Although run flat technology has been around for a while, very little improvement has been made over the past 25-30 years. The current requirement of the run-flat tire for the HMMWV is the same as it has ever been. To make a run-flat insert better than what is currently produced is extremely difficult. The commercial application for run-flat inserts is limited because of cost and performance. The systems typically costs a lot more because of the additional hardware of the insert and the wheel needs to be specially designed for the run-flat insert. Still, the premise of the run-flat insert is running on a small solid tire. The insert can only be so large or it will act as a bump stop for the tire and the width of the run-flat is going to be significantly less than the width of the tire. This limits the surface area that the load can be distributed over. Also, the flat tire must either flop along or degrade due to the heat buildup of running directly on the tire and run-flat insert. This could lead to stability issues, smoke and possible flammability issues. There is a way to sum up the difficulty in making the run-flat performance significantly better, physics. Aside from physics, another reason the development will be slow for the run-flat insert is that the commercial market has different requirements. Most military vehicles need to have the capacity to change the tire pressure for the different terrain profile encountered for different missions and theaters, plus run-flat capability. New military wheeled vehicles systems such as the Stryker or MATV have on-board CTIS systems to enable these vehicles to quickly transition from highway mode to off-road, or vice versa, within the safety of the vehicle [3]. Most of the commercial market needs only one tire pressure setting for highway usage. Automobiles benefit the most from proper tire inflation pressure, resulting in premium fuel economy, extended tire life and proper handling. This has lead to the development of stiff sidewall tires that provide similar handling and perform with or without air. However, the tire reliability and durability are significantly worse without air pressure. Consumers of these tires have actually complained that when the tire lost air pressure they had no degradation of performance so they kept running the tires until they were damaged beyond repair. This problem is the reason why some cars have tire pressure monitors to notify the driver of a flat tire. This is a far different experience of riding on a tire with a run-flat insert. The stiff sidewall tire requires a very low aspect ratio so the tire can be supported properly by the sidewalls. “The sidewalls can't be very tall, so most are low-profile designs. Because of this, they are typically used on sports, though they're also available for regular passenger cars and even minivans. ”[4] The drawback with this tire is that the stiff sidewalls tend to put more energy into the vehicles suspension system and ultimately the vehicle. For new car designs, this can be designed up front. However, the military has vehicles that are in inventory for extensive periods of time and cost to swap out suspension systems along with the tires can be a cost that is hard to justify. Since the runflat is built into a stiff sidewall, how much can the footprint can changed to provide different ground pressure for different terrain may be an issue that prevents this technology from being used for the military. Figure 4. Comparison of Conventional Tire to a Stiff Sidewall Tire [4] Figure 3. HMMWV Run-flat Insert Special Tool and