And it's as simple as what you put in your tires.
If you bought your tires from Costco lately, you already have the secret ingredient.
If you got them at Discount Tires, you might have it.
Those are the two major tire retailers in our region who will fill your tires with something other than compressed air.
They're using nitrogen.
Nitrogen molecules are bigger than oxygen molecules, so they don't leak out of your tires as quickly.
"As long as your air pressure is maintained, you're going to have better gas mileage," said Chris Stone with Discount Tire Company.
Stone estimates 4 out of every 5 cars on the road have low tire pressure. So just about all of us are driving around with low tire pressure. And all it takes is being 5 pounds under, and you're losing one mile per gallon of gas.
Eventually, Discount Tires will exclusively use nitrogen. Right now, it's request only.
And who's asking for it? For one, race car drivers. They use it on the track, so why not use it to drive to the grocery store?
"They actually do that too," Stone said. "Because they know the benefits of it. They're already keen on the benefits of nitrogen."
Benefits like your tires last longer and your car handles better when you have the right tire pressure.
Costco's been using nitrogen exclusively for more than a year.
"I think we're a little bit ahead of the game trying to get it out there," said Mike Anderson with Costco. "We know it's the right thing to do, the safe thing to do. It's something we try to teach our members as they walk in, why we're doing it."
It's no gimmick. And it's free. With the right tire pressure and nitrogen in your tires, and you really can get an extra mile per gallon out of your gas.
If you stick with plain old air, you can get the same benefits. You have to make sure your tires have the right air pressure. But you'll have to check the pressure more often, since regular air leaks out faster than nitrogen.