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Tire Pressure: Inflating Your Car’s Efficiency
To learn more about why the included tire-pressure check is so important—and why a pro can enhance even this simple task—read on.
There are many things that you need to do regularly to keep a vehicle running smoothly—change the oil, check the fluids, and occasionally open a garage door instead of just plowing through it. Tire pressure can be the easiest of these tasks to overlook: it takes a lot of extra pressure to damage a tire, and only a seriously under-filled tire will look visibly flat.
The small range in the middle can make a substantial difference in performance, though. The Department of Energy estimates that properly inflated tires can boost fuel economy by about 3%, largely because underinflated tires create extra drag. That doesn’t mean that going overboard with the air pump will increase the benefits—pressure that is too high means less tire surface in contact with the street, making the vehicle less stable and harder to handle.
Some manufacturers are beginning to craft tires with built-in RFID chips that help track and regulate tire pressure. For now, though, most drivers still have to find the optimal tire pressure in their owner’s manual or on a sticker that may be found in the doorjamb or glove box. (The number printed on the sidewall of the tire is simply a maximum beyond which the vehicle is unsafe, and shouldn’t be used as a guideline.) That number will often be different for each wheel, since weight is distributed differently across the frame of a car.
Professional mechanics have access to digital pressure gauges and a database of proper inflation levels, which help vehicles run safely and efficiently when you’re on long road trips or entertaining a child by driving through a car wash all day. Pros will also be able to better take into account another quirk of calculating tire pressure: manufacturers’ recommended pressure levels assume that the tire is “cold,” meaning that it hasn’t been driven on in at least three hours. So if you’ve recently been on the road, you’ll need to factor in the extra pressure that builds up from the heating and expansion of the air inside a tire in motion.