Self-healing "DuraSeal" tires, which instantly seal themselves with little or no loss of air pressure, are now available from Goodyear Tire & Rubber. The "revolutionary" feature seals punctures up to ¼ inch in diameter and avoids flats, the company's executives said.
Sealant imbedded in the tire structure under the tread area immediately swarms into a void caused by a penetration, explained Steve McClellan, vice president of commercial tire systems. The sticky gel-like polymer compound surrounds the nail or screw if it stays in the tire, or fills the hole if the object flies out. Drivers won't know it's working because tires remain fully inflated and just continue rolling.
A tire can survive multiple punctures and keep running as long as one does not occur at the exact spot as a previous puncture. As many as 50 punctures were inflicted in a tire in a test lab and it still retained air, said Bina Patel Botts, a materials engineer. One-quarter inch, the largest nail diameter tested, is about the girth of a gutter spike. DuraSeal can probably handle larger objects, though effectiveness might diminish as punctures get larger.
Some punctures might allow a bit of the compound to ooze out and its yellow color would be obvious in an inspection. A resin mixed into the compound provides the color; yellow was chosen because it stands out against black rubber and it's one of the hues in Goodyear's logo, said Al Cohn, commercial tire marketing manager.
DuraSeal compound remains in the tire structure even after retreading and, unlike aftermarket sealants blown into a tire, is non-flammable and leaves no mess to clean up when the tire's serviced. For now the compound is built only into the tire's tread area; engineers are working to incorporate it into sidewalls but believe that will be much more difficult to accomplish.
DuraSeal has been proven in fleet testing from minus 40 degrees to plus 100 degrees Fahrenheit, and will probably be fully functional at much higher temperatures, Botts said. Tires with the product run no hotter than those without.
DuraSeal adds 20 to 25 percent to a tire's price, or about $60 to $300 a tire, McClellan said. That upcharge will pay for itself the first time a puncture is healed on the run because the owner will probably have avoided an expensive road service call.
Testing by a trash-hauling fleet in Dallas, Texas, showed a dramatic reduction in expenses due to puncture damage, Botts said. Monthly tire repair costs for a 75-truck fleet running into a landfill were $90,000, but DuraSeal tires cut that to $35,000.
Construction trucks need puncture-sealing tires almost as much as trash haulers, Cohn asserted. "It's huge," he said of tire damage suffered at jobsites. "You can spend 80 to 90 percent of your time running on the road, but it's that 10 percent off-road that screws you, no pun intended."
DuraSeal is initially available in Goodyear's new G287 and G288 on/off-highway tires, and will be available later in other commercial truck models. Cohn said it probably won't expand to consumer tires because "there it's price, price, price, and they (most motorists) wouldn't pay for it."