Face it: your tires are important. As in, critically important. You've heard this a thousand times before, but it always bears repeating: The tires are only part of your car or truck that actually make contact with the pavement. Keeping them properly inflated is vital on multiple levels.
Obviously, safety is paramount. Underinflated tires are much more likely to fail, and the effect can range from being merely annoying and inconvenient, such as as finding a flat when you walk out of the supermarket, to something more scary and dangerous, such as experiencing a blowout on the highway. Properly inflated tires also help ensure that your car handles as its engineers meant it to, and they help you achieve better fuel economy. Experts say that to ensure proper inflation, you should check your tire pressure monthly. For that, you'll need a tire pressure gauge, and some kinds are better than others.
If you have a 2008 model-year vehicle or newer, an integrated tire pressure monitoring system (TPMS) is part of its standard equipment list. At the very least, that system will alert you when one or more of your tires falls below a specific pressure level with a warning light on the instrument cluster. Some systems are more detailed, and have a readout that displays the exact tire pressure at each wheel. If you have an older car, however, it may not be equipped with TPMS, and even if you have TPMS, you'lll still need to check your tire pressure when it throws up a warning.
Pencils are for your kids' homework, not checking tire pressure
Tom and Ray Magliozzi, nationally syndicated columnists and the affable hosts of NPR's Car Talk, mince no words on their website, saying, "We recommend that you never use one of those cheap, pencil-type tire gauges. They're notoriously inaccurate." You've likely seen these before. Heck, you might even have one in your glovebox. As the fellas say, it looks like a pen or pencil -- most even have a pocket clip -- and when you use it to check your car's tire inflation, a stick marked with numbers and hashes pops out, indicating the supposed pressure.Tom and Ray also warn not to put too much faith in the pressure gauge built into the air hose at your local filling station either (if the hose is even so equipped). They say they're also not accurate, and in our experience, those built-in gauges often use the same basic setup as the cheap pencil gauges, so the Magliozzi's skepticism isn't all that surprising.
The only good thing about pencil-style tire gauges is that they're dirt cheap, ranging from around $5 to $8, and widely available -- chances are, you can pick one up in your local supermarket or drugstore's car care aisle. We'd be willing to bet the car wash down the street has them hanging near the cash register as a cheap impulse buy, too. Resist the urge. After all, you've spent hundreds of dollars on your tires -- don't cheap out on the most important tool you'll use to maintain them.
Besides, the dirty little secret is that you don't need to spend a whole lot more to get something a whole lot better.
Digital tire gauges: Easiest to read
For a little more than the cost of a junky pencil-style gauge, you can get yourself a basic digital gauge. Digital gauges are popular for an obvious reason: they're very easy to read. At present, the Accutire MS-4021B (*Est. $8) is the second-bestselling item overall in Amazon.com's automotive department. Over 100 reviewers give it an average rating of 4 stars out of five, with the majority saying that the device is accurate, shows the tire pressure in half-PSI increments, and is usable at night thanks to its LED display. Of the total number of reviewers, however, some have a poor opinion of the gauge, rating it one or two stars, complaining that it's cheaply made, unreliable, inaccurate, and in many cases, doesn't make a good seal on the valve stem, causing air to escape the tire. The battery in this gauge is not user-replaceable, either -- it has to be sent to the manufacturer. A number of the users posting negative reviews conclude that, for all practical purposes, the Accutire MS-4021B is a disposable item.
Another Accutire digital gauge, the MS-4350B (*Est. $10) is also an Amazon.com bestseller (#4 overall in the automotive category when we checked), and in addition to reading tire pressure in .5 PSI increments, it features a backlit digital display. Plus, it's programmable (it can remember what your car's factory-recommended pressure settings are for your car), and it has an integrated LED light in the tip to make finding your valve stem in the dark easier. With over 150 user reviews on record, it's averaging 3.5 out of 5 stars. The majority of reviews for this digital tire gauge are indeed positive, but even owners giving it high marks note that it was tough to get a good seal, and that many modified the gauge with an additional o-ring that resolved the problem. Newer reviews indicate that the issue was eventually addressed by Accutire itself, and that the homebrew mods are no longer required. Reviewers who give it a low rating say that it's difficult to get a proper seal, complain of short battery life and expensive replacement batteries, and in some cases, say that their units were defective right out of the box.
Analog tire pressure gauges: Traditional, reliable
For all the convenience digital tire pressure gauges offer, traditional analog mechanical tire gauges are lauded for their simplicity and accuracy. Some, but not all, will retain the tire pressure reading after you remove the gauge until you release the pressure. Most have a bleed-off valve that you can use to let air out from the tire while the gauge is attached, in case you find that you've overfilled. Another reason some drivers prefer traditional gauges centers on reliability: Since there's no battery to worry about, the device will always be ready to go. In a discussion thread at NorthAmericanMotoring.com, a forum for Mini enthusiasts, one poster notes, "I'm sure there are some really nice digital gauges out there, but I still prefer analog. Digital implies the need for a battery, and I don't like that. I consider a tire gauge to be a piece of safety gear."
Chances are, you'll pay more for a good basic analog gauge than for a comparable digital unit. The Auto Meter 2343 Autogage (*Est. $22) averages 4.5 out of 5 stars in over 10 Amazon.com user reviews. Owners say it makes a good seal on the tire's valve stem, is easy to read, and they like that it will hang onto the last pressure reading until they manually clear the gauge. The Auto Meter 2343 is also compact enough to be easily stored in a car's center console or glove compartment. Over 40 owners weigh in on the Moroso 89560 Tire Pressure Gauge (*Est. $40), and they almost universally rave about the device, which uses a flexible hose to connect to the tire, giving users a little more leeway in how they're able to view the gauge. It doesn't retain the last pressure reading, but that barely registers as a concern, as users say it has such a solid, airtight seal while attached to the tire, it's easy to just bleed off excess air. The one possible drawback to consider is that a tire gauge like this Moroso, with its flexible hose, is going to be more cumbersome to store in your glovebox than one of the aforementioned digital gauges or the Auto Meter we just discussed. It may be a better fit for the tool kit you keep in your garage.
For vehicles without factory TPMS installed, you can pick up an aftermarket setup such as the Hopkins 30100VA nVision for around $300. The Hopkins system can remember tire setups for multiple cars and configurations, so, for example, if you want to monitor the tires for your truck and trailer, it affords that level of flexibility. The smattering of reviews posted at Amazon.com are mixed, however, and using an aftermarket TPMS seems like it could get expensive. Additional sensors run about $75 per pair, and signal repeaters (recommended for vehicles over 38 feet long, such as RVs) cost around $170.
A much cheaper and interesting solution can be found in screw-on Tire Safety Monitors (*Est. $20). These monitors replace your tires' existing valve caps and are calibrated to a specific tire pressure. When the pressure's at the proper level, the cap has a green indicator. If it falls below, the indicator turns red, letting you know you need to check that particular tire. About.com's auto repair guide, Matthew Wright, was skeptical when he saw these so he picked up a set. Much to his surprise, they worked just as advertised: "I have to say that I was impressed with the simplicity and low cost of these useful accessories. Tire pressure is one of the most neglected maintenance items, and something like this can turn a chore into a no-brainer." The sole drawback? In Wright's opinion, the tire pressure monitoring caps are ugly. (Note: About.com owns ConsumerSearch, but the two share no editorial affiliation.)
Remember to check those tires monthly!
Regardless of what kind of tire gauge you buy, it'll do you no good unless you actually use it. Check your tires monthly when they're cold -- do not drive on them first, as that can alter pressure and give you a misleading reading. And don't trust your eyes, either -- a visual inspection isn't enough to determine whether a tire is under or overinflated. Hook up that gauge, get a proper reading and fill your tires to their proper levels. Your car's manufacturer will have a placard in the driver's doorsill showing what the proper levels are supposed to be. For more information on tire safety in general, SaferCar.gov has extensive resources on the topic, including discussions on tire pressure, TPMS, and other related issues.