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Car and truck parts & accessories shipped to your door Wheels & Tires for your car or truck
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Since the early development of the automobile, tires have played an important role in determining a vehicle's overall comfort and safety. However, there are few products that are placed in harms way more often than the our tires. During their life they will face extremes in temperature, exposure to the elements, and attacks by debris on the road. And while the tire manufacturers' continuous improvements to their products have improved durability and longevity, only recently have they developed tires which help maintain vehicle mobility using standard Original Equipment and aftermarket wheels. These tires allow the driver to be better able to decide when and where tire repairs are made.
Tires don't typically carry the weight of our vehicles, the air inside them does. There are three basic elements which determine the load capacity of a tire...the size of the air chamber formed between the tire and wheel...the strength provided by the tire's construction to hold air pressure...and the amount of air pressure actually in the tire.
Most flat tires (and tire "blowouts") are the result of slow leaks which go unnoticed and allow the tire's air pressure to escape over time. If we had a way to conveniently monitor our tires air pressure, we'd be half way there. If we had tires which could maintain vehicle mobility even after air loss, we'd be just about invincible.
Today there are three technologies being developed to help maintain vehicle mobility as a tire is punctured and after. Of the three, self-sealing and self-supporting tires are available today, while auxiliary supported systems are on the drawing boards for use as Original Equipment in the future.
Self-Sealing
Self-sealing tires are to designed fix most punctures instantly and permanently. These tires feature standard tire construction with the exception of an extra lining inside the tire under the tread area that's coated with a puncture sealant which can permanently seal most punctures from nails, bolts or screws up to 3/16 of an inch in diameter. These tires first provide a seal around the object when the tire is first punctured and then fill in the hole in the tread when the object is removed. Because these tires are designed to seal the tire immediately upon being punctured, most drivers will never even know that they just had a puncture. Also because these tires feature standard tire constructions, the traditional loss-of-air symptoms which accompany a flat tire remain to warn the driver if the tire is damaged beyond repair. Therefore, self-sealing tires do not require a low air pressure warning system. Example: Continental ContiSeal.
Self-Supporting
Self-supporting tires feature a stiffer internal construction which is capable of actually temporarily carrying the weight of the vehicle, even after the tire has lost all air pressure. These tires typically sandwich rubber between layers of heat resistant cord in the sidewall to help prevent the sidewalls from folding over on themselves and "pinching" their sidewalls in the event of loss of air pressure to give the tires "self-supporting" capability. They also feature specialized beads which allow the tire to firmly grip current Original Equipment and aftermarket wheels even in the event of air loss. Because self-supporting tires are so good at masking the traditional loss-of-air symptoms which accompany a flat tire, they require a tire pressure monitoring system to alert the driver that they have lost air pressure. Without such a system, the driver may not notice underinflation and may inadvertently cause additional tire damage by failing to inflate or repair the tire at the first opportunity. Typically, self-supporting tires maintain vehicle mobility for 50 miles at speeds up to 55 mph. The BFGoodrich SSS (Self-Supporting Structure), Bridgestone RFT (Run Flat Tire), Dunlop DSST (Dunlop Self-Supporting Technology), Firestone RFT (Run Flat Tire), Goodyear EMT (Extended Mobility Technology), Kumho XRP, Michelin ZP (Zero Pressure), Pirelli RFT (Run Flat Technology) and Yokohama Run Flat are all self-supporting run flat tires.
Auxiliary Supported Run Flat Systems
Auxiliary supported systems combine unique wheels and tires and are currently under development for use on future Original Equipment vehicle applications. In these systems, when the tire loses pressure, it rests on a support ring attached to the wheel. The advantage to this type of system is that it will place most of the task of providing run-flat capability on the wheel (which doesn't wear out or need to be replaced), and minimizes the responsibility of the tire (which does wear out and requires replacement). Additionally, auxiliary supported systems promise better ride quality because their sidewall's stiffness can be equivalent to today's standard tires. Currently only the Honda Odyssey Touring and Rolls-Royce Phantom use Michelin's PAX System in the United States. Goodyear and Pirelli have announced that they will also develop run flat tires based on the PAX System, while Bridgestone and Continental are currently developing alternate designs. The disadvantage to auxiliary supported systems is that their unique wheels will not accept standard tires and that their lower volume will make this type of system more expensive. It is too early to confirm which system, if either will be widely accepted by vehicle manufacturers and consumers in the future.
