Run-Flat Tires: Self-Sealing, Self-Supporting, Auxiliary supported

Run-Flat Tires: Self-Sealing, Self-Supporting, Auxiliary supported

For many many years tires have played a very important role in determining how well a vehicle performs. Whether we’re talking about high performance, comfort or overall safety, tires are a major part of the equation.  Tires are constantly subjected to the worst and most extreme parts of driving, extreme temperatures, varying road surfaces, potholes and other debris and constant load changes. Tire manufacturers have worked hard over the years to provide the public with tires that could perform well and also deal with things like punctures and other holes or loss of air. It wasn’t until the invention of the Run-Flat tire that this was actually achieved. And the inflated performance of these Run-Flat tires has gotten remarkably better over the years.

Ill bet you never thought about this…..Tires don’t carry the load of our vehicles!!!! Then what does? The air in the tires is what carries the load. The amount of load that a tire is allowed to carry is determined by three main factors. 1) The size of the air chamber between the tire and wheel. 2) How much air pressure the tire can hold based on its construction. 3) The air pressure in the tire.

So let’s look at the different methods used to support tires should they have a blowout or other form of flat.

Self-Sealing

These tires are designed the same as standard tires with one exception. They have an extra liner in the tread area on the inside of the tire that is coated with a puncture sealant. Any object that punctures the treat area, up to about 3/16 of an inch is instantly and permanently sealed.  The sealant will seal around whatever punctured the tire i.e. nail, screw etc. And then, if the object is removed it will fill and seal the hole. Because these tires work so quickly and permanently, most drivers never know it happened.

Self-Supporting

Self-supporting tires are capable of supporting the weight of a vehicle even after the tire has lost all air pressure. This is achieved by adding heat-resistant cords in the sidewall construction as well as special beads that secure themselves to the wheel. These tires do such a good job of masking a tire that has lost all air pressure, it is recommended that they only be used if your vehicle has a TPMS (Tire Pressure Monitoring System). If these tires lose all air pressure they are typically rated to last for around 50 miles at speeds around 50mph.

Auxiliary Supported System

These systems are not quite as widely used in the general public, in large part due to their cost. These systems require special wheels and therefor normal tires will not fit. One of the best examples of an auxiliary System is Michelin’s PAX system.

These auxiliary systems are more common on military and protection vehicles. For example, the presidential limousine has an auxiliary run-flat system.