Check Tire Pressure With a Digital Gauge and Get Better Gas Mileage

Check your tire pressure with a digital gauge regularly to improve your gas mileage. Digital tire gauges are the easiest and most accurate way to maintain the right pressure and get better mpg.

| August/September 2007

Check your tire pressure when your tires are cold, or after less than a mile of driving. Aim to check your pressure once a month and you’ll stay on top of fluctuations than would otherwise lower your gas mileage.

Check your tire pressure when your tires are cold, or after less than a mile of driving. Aim to check your pressure once a month and you’ll stay on top of fluctuations than would otherwise lower your gas mileage.

Photo by Istockphoto/Marek Tihelka

Check your tire pressure with a digital gauge, digital tire pressure gauges are the best way to check tire pressure, which can improve your mpg.

Check Tire Pressure With a Digital Gauge

Most of us don’t get excited about tire pressure, or the gauges used to measure it. Yet according to the U.S. Department of Energy, under-inflated tires are responsible for nearly 3.3 million gallons of wasted gasoline each and every day. Add in the benefits of safety and tread longevity from maintaining proper tire pressure, and these practical gizmos start looking downright cool.

However, not all tire pressure gauges are created equal. The worn-out public gauge at the gas station is free to use, but don’t bet on it giving an accurate reading. Then there’s the kind your father used: the sliding-stick “pencil-style” pressure gauge that only costs a few bucks at your local auto parts store. Unfortunately, several experts say the latter lack sufficient accuracy and get increasingly worse over time. Analog dial gauges are more accurate, but can be cumbersome and sensitive to rugged use. Digital gauges, on the other hand, are accurate, easy to use, pay for themselves in a short period of time and, best of all, will help you keep your car safe and improve its fuel economy.

According to experts, tires naturally lose about 1 to 2 pounds of pressure, measured in pounds per square inch (psi), every month. Each pound below the recommended psi lowers your mpg by about 0.4 percent. Low tire pressure affects fuel economy by increasing the tires’ rolling resistance, which makes the engine work harder to move the car.

Ask yourself how long ago you last checked your tires, and don’t fib. Three months? Six months? Longer? With today’s high gas prices, that inefficiency can add up to significant money. At $3 a gallon for gas, a 25 mpg vehicle with neglected tire pressure will require an extra $60 of gas each year compared to a car with properly maintained tires. At those prices, it’s easy to justify the purchase of a quality digital gauge. Keep one in your car and aim to check your tires with every other fill-up, or at least once a month. You’ll find the correct pressure for your tires on a sticker that’s usually located around the driver’s doorframe; if it’s not there, check the glove box or owner’s manual. (Don’t use the psi number on the sidewall of your tires, that’s the “maximum permissible” pressure for those tires.) Finally, because “cold” tires are used to define proper pressure levels, check it before your trip or before driving more than a mile.

Most digital gauges cost between $10 and $40, depending on the specific model’s bells and whistles. Some of those features are handy, such as backlit screens, LED flashlights and programmable memories that retain your car’s recommended front and rear tire pressures.

6/10/2016 9:48:23 AM

Spending 21 years in the tire business i managed to learn a couple things about tires and tire gauges. All gauges have mechanical parts. All gauges wear out. The best practice is to use the same gauge every time and periodically check its accuracy against your backup gauge. I prefer the pencil gauge that has the stick that stays out so you can read it. Also the vehicle manufacturer is more concerned with you thinking your car is the best ride you ever felt. So his tire pressure recommendation is on the low side for "cush" factor. The pressure on the sidewall is for "max load" pressure, not max tire pressure. I now average just over 100K miles a year on my fully loaded van and trailer, i run 40psi in all my 35psi tires. I just looked at the wear on my 65K mile tires and they are wearing perfectly and after measuring tread i probably have another 10 to 20K miles on them, after 86K miles. Other than running over a bath tub and truck bumper late at night i have never had a tire failure. Probably due more to grace of God than my tire expertise though.

6/9/2016 7:41:24 AM

One additional complaint about (some?) digital gauges--my main experience is with one my son bought: It cannot save a reading--in other words, you have to bend over and get your head in a position to see the pressure reading while the gauge is "on" the tire valve. (You may also have to adjust your position or shade the readout with your hand to avoid glare from the sun.) The mechanical pencil type is much more convenient because you press it against the tire valve to take a reading and you can then raise / move the gauge to a convenient position to read it. A related concern is that, assuming the gauge is the kind that you have to press against the tire valve to get a reading is that, in fiddling around to view the reading, you may release more air than you might with a mechanical pencil gauge that you typically can get a reading with one "good" press on the tire valve.

6/8/2016 8:46:51 AM

Totally agree with the other 2 comments, mechanical gauge is a must, I replaced my digital one a few months ago, I was so fed up with replacing batteries, I bought an AUTO-TEC one from Amazon, it is accurate, easy to use and very sturdy, a long hose so its easy to fit and saves on the knees and has a 2 inch dial, so easy to read. I wish I had found this long ago. I won't be changing back to digital.

john & virginia ledoux
4/6/2013 10:39:34 PM

Dittos to Jan's comment, buy a high-quality mechanical gauge.

jan steinman
11/26/2010 1:36:54 PM

First off, I find it difficult to believe that one or two pound accuracy is really necessary. If so, then you should go to the trouble of changing your pressure when you add a passenger, or come home with a hundred pounds of groceries! The "correct" tire pressure has as much to do with the load carried as it does an arbitrary number! But more important, those digital gauges are generally of low quality and take batteries. You're buying something that will be in the landfill in a few years, something that will consume several toxic batteries before then. I have a high-quality metal dial mechanical gauge that I bought over 20 years ago. I think it cost about $20 then, so it might be double now. It has markings every pound. I'm sure someone will be using it after I'm dead -- if they still have tyres then. Please, rather than telling people to buy some whiz-bang high-tech plastic crap that they'll have to feed batteries to, advise them to get a high-quality mechanical gauge that will work forever WITHOUT batteries!

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