One aspect of car maintenance that hasn’t changed since the Model T is finally getting a breath of fresh air.A handful of area tire shops now inflate car and truck tires with nitrogen instead of compressed air.It keeps tires inflated longer, makes them last longer and promotes fuel efficiency, says Jerry Haynes, owner of City Tire & Auto Repair in Logan and Williamson. “With nitrogen, you get more consistent air pressure because of nitrogen’s larger molecules,” says Haynes, whose tire shops have been selling nitrogen for tires for about a year. Because it’s bigger, nitrogen seeps through tires and any other permeable surface about four times more slowly than compressed air, he said.“More consistent air pressure means the tires don’t wear as much, they roll easier and save fuel,” he said. Fuel efficiency comes into play because cars and trucks get the best gas mileage when tires are fully inflated. According to the U.S. Department of Energy, under-inflated tires can lower gas mileage by 0.4 percent for every drop of 1 pound per square inch in pressure in all four tires. Nitrogen is a colorless, odorless gas that makes up about 78 percent of the air we breathe. It’s just as safe to use for inflating tires as compressed air; in fact, it’s safer, Haynes says.Using nitrogen guards against tire belt separation, which has been blamed for countless tire recalls over the past few years, by helping prevent the corrosion caused by airborne moisture, Haynes said.“When you pump in regular air, you’re also pumping in humidity,” he said. “The moisture deposits on steel belts and leads to corrosion.”Drivers are hearing more and more about inflating with nitrogen because NASCAR racers and commercial airlines now use it, as does Russell Corp., maker of the Spalding Never Flat basketball. News source: WV Gazette “We’ve been seeing quite a lot of cars and light trucks, but it’s mostly car enthusiasts,” says Ron Thomas, co-owner of Thomas Tire Service in (fittingly enough) Nitro. “We see a lot of Corvettes and sports cars.”Thomas Tire has been dispensing nitrogen for about 10 months, and the shop gets about five to 10 fill-up customers a week. Each of Haynes’ City Tire shops draws 30 to 40 customers a month asking to have all four of their vehicle’s tires filled, Haynes said. A nitrogen fill-up is much the same as air fill-ups, except air-filled tires must be completely deflated first to purge all the air.Both Haynes’ shops and Thomas’ charge $5 per tire, and both dispense from nitrogen generators costing about $6,000. Suppliers can also buy nitrogen ready to pump from distributors like Airgas Inc.Some new cars and trucks – including Chevrolet’s Tahoe sport utility vehicle – are shipping from the factory with nitrogen-filled tires, Thomas said. And most new models now come equipped with tire-air-pressure sensors that light up on the dashboard, he said. The annoyance of the sensors may well get many drivers to switch to nitrogen too, Thomas said.“I think you’ll see a lot more of it,” he said.