Should You Use Nitrogen in Your Car Tires? This common pitch is compelling: Filling your car’s tires with nitrogen will reduce air loss, boost fuel economy, reduce rolling resistance, and improve safety. Some cars are even sold with the telltale green caps on valve stems, signaling the tires have already been filled with nitrogen. Consumer Report’s tests show that using nitrogen is not worth the money or inconvenience. There is a stronger case to be made for nitrogen for high-tire-pressure, heavy-duty applications, ranging from large commercial trucks to airplanes. But based on Consumer Report’s experience with passenger cars and these test results, consumers would be better served—and would save their money—by just using air in their tires and checking them monthly. There is nothing wrong with using nitrogen in passenger cars and trucks, but it does take commitment and potentially cost. Nitrogen users should be diligent about only topping off with nitrogen to ensure they are getting the intended benefits. There are a limited number of places, like Costco, that will top off tires with nitrogen gas. When Cars of Hope donates a car to a Deserving Family, tires are topped off with regular air so they have many convenient places to check and add air to their tires. Please consider donating your car to Cars of Hope so that we can help more families who have fallen on hard times get back on their feet financially.