So gas prices jumped to about $4 per gallon this week. I have a pretty long commute, so that hurts. It also means I stay on top of ways to keep my fuel prices as low as I can.
Dollar cost averaging
Buying gas is like buying stocks. You never know when prices will be up, or down. The general trend for stations around me is for a big price change (usually up) per week, usually on a Wednesday or Thursday, and then lower prices by a penny or two a day until the next big price change happens. That’s how it usually works. But a really big jump can happen on any day, and usually without warning.
In the long run, you’re better off buying gas whenever you have room for it in your tank. Buy gas half-tanks at a time rather than filling up, and you get twice as many chances to be buying on a down day. And when those unexpected jumps happen, it buys you a little time to hope for a drop, if you want to try to time the market.
And when you’re traveling, if you see a price that’s lower than what you’re used to seeing, buy some gas. When I drove to Ohio last summer, I really regretted not doing that. Ohio’s gas prices were lower than anywhere else, and Indiana’s prices were lower than Illinois’. Had I filled up once in Ohio and once in Indiana, I would have saved over filling up twice in Indiana.
It’s also important not to forget your tire pressure. Your tire pressure decreases over time, especially when it starts getting cold. Keeping the proper tire pressure in your tires gets you better gas mileage, and keeps your car safer. Just don’t overinflate in a quest to save more gas. Having too much tire pressure also causes a safety issue. That’s not worth whatever gas you might save.
My mechanic checks my tire pressure at every oil change. I usually also have to top off my tire pressure at least once near the start of winter. Checking it takes five minutes, it saves me money, and it makes my car safer. What’s not to like?
I have a Costco membership. When gas prices jump, Costco is always the last place to raise prices. So if I see a jump as I drive home, I drive to Costco and fill up that evening. I’m not the only one who does that, because the place is always hopping on those evenings. Some people even bring big 5-gallon gas cans and fill those up too. I’ll do that sometimes, if I’m alone and have time to grab my cans. I don’t like having gas cans in my car when my kids are with me. I’d rather not have them breathe the fumes.
It used to be that you got better gas mileage driving 55 MPH than 65 MPH. The optimal speed for today’s cars, with better aerodynamics, is 63 MPH. At least that’s what I heard on the radio last week. I tried that out, along with an old trick, to see what would happen on Monday.
One more thing: Drafting
Earlier this week I drove 120 miles. I set my cruise control for 63 MPH and stayed behind a tractor-trailer for most of the way. I got 40 MPG when I did this. Normally I get 30-32 MPG.
I can’t always find a tractor-trailer to draft behind on my way to and from work, but to get 25% better gas mileage, it probably behooves me to look harder. And if I do find a tractor-trailer, there’s a decent chance it’ll be going close to 63 MPH anyway, since the speed limit for them is usually 60-65 MPH.