Editor's Note: In this limited series Under the Hood, we'll share do-it-yourself tips for drivers who want to wrench their own cars, no matter their skill level. Whether you\u2019re in the middle of a road trip or on your way to work, there\u2019s never a convenient time to get a flat tire. But flats happen, so it pays to be prepared. Here\u2019s what you need to know. Regularly Check for Tire Wear Checking for tire wear is essential for avoiding flats. Start with the tread (the grooved part of the tire that touches the road), which over time wears down. Most tires have wear indicators\u2014small bars of rubber embedded within the grooves of the tread. When the tread wears down to the level of those indicators, the tire should be replaced. You can also use a penny to check tire wear. Stick a penny upside down inside the tread. If there is enough tread left, Lincoln's head should be at least partially covered. If the top of Lincoln's head is visible above the tread when you look at it directly from the side, the tire should be replaced. In addition, if you see any cracks, bulges, or gouges on the sidewall of a tire (the smooth, vertical sides that face outward), the tire should be replaced. Inflate Your Tires (Purchase the supplies and tools mentioned below from eBay Motors or your retailer of choice.) Keeping your tires (including your spare) properly inflated will also increase their longevity and ensure your vehicle performs at its best. The manufacturer's recommended tire pressure will be listed in your owner\u2019s manual and possibly on a sticker on the driver\u2019s door sill\u2013but these numbers apply only to the exact tires originally installed from the factory. The best place to look for recommended tire pressure\u2013especially if your tires have ever been replaced\u2013is on the tire's sidewall. There, you'll see a bunch of information (tire pressure, tire size, etc.) molded into the rubber itself. Tire pressure will be indicated either in pounds or psi (meaning pounds per square inch). If only a maximum pressure is indicated (e.g., "max pressure 45 pounds"), try filling to a few pounds below it. Grab a tire pressure gauge, check the pressure on all your tires, and inflate them with an air compressor or manual pump if they\u2019re low. Most gas stations have air compressors available for a dollar. Changing a Tire If you get a flat while driving, stay calm and focus on controlling the vehicle, as it may become unstable and difficult to steer. Brake gently to slow your vehicle, as hard braking could worsen the problem. When it's safe to do so, pull over as far onto the shoulder as possible, or turn off the road into a parking lot. Try to stop on a flat, paved surface\u2014changing a tire on soft or slanted ground is dangerous. Lift Your Car Once stopped, set the parking brake and put on your hazards. Locate the spare tire and grab a jack and a lug wrench. Many vehicles are sold with these tools stored alongside the spare tire; if not, buy them and keep them in your car. (Make sure you buy a jack that\u2019s rated to handle slightly more than the weight of your vehicle). \u200b\u200bCrack open your car\u2019s owner\u2019s manual to see how to remove the spare (likely, it's clamped in with a simple screw-down tool) and where to set up the jack. Only lift your vehicle at its dedicated jack points as indicated in the manual; otherwise, you may cause damage or, worse yet, the car will fall off the jack. It's also worth noting that not all cars come with spare tires; this is most common in small vehicles like sports cars. If this is your situation and you get a flat, after you've pulled over and popped on your hazards, you're gonna need to call a tow truck. Remove the Wheel First, remove any hubcap or wheel cover connected to the wheel in question. Before lifting the car with the jack, grab your lug wrench and loosen the lug nuts but don't remove them. It's common for lug nuts to be VERY tight due to road build-up, slight rusting, or over-tightening\u2013so (carefully) put your back into it. Once the lugnuts are loose, align the jack at the lift point closest to the flat tire and raise the jack according to the manufacturer\u2019s instructions. Keep raising it until the flat tire is off the ground by a few inches, and finish loosening and removing all the lug nuts. Put on the Spare Pull off the wheel, and set it aside. (Pro tip: set your tire face down and use it as a tray to keep track of your lug nuts.) Mounting the spare tire works in the reverse order of removing the wheel. Lift the spare onto the wheel studs and at first tighten the lug nuts by hand. Refer to your owner\u2019s manual for the correct order to tighten the lugs\u2014this ensures the wheel is mounted straight. When in doubt, tighten the lugnuts in a "star pattern" rather than around in a clockwise or counterclockwise direction. Use the lug wrench to get the lug nuts a little more, but still not very tight (again, following the proper order). Now, carefully lower the jack until the tire touches the ground with the car's full weight. Remove the jack, then fully tighten the lug nuts using the same tightening pattern. Once the jack is out of the way, and the spare tire is fully back on the ground, tighten the lug nuts one final time until they feel snug. Put away your tools, stow the flat tire in the trunk, and you\u2019re ready to roll.