Obviously, a car cannot drive on bare wheels. A car tire is a construction of hard rubber that fits on a wheel and covers a pocket of air to provide a partial cushion for shocks, plus some level of adhesion to the road surface. Car tires require regular maintenance and care to keep you safely on the road. Understanding how your tires work and how to care for them is vital to your car's performance and your safety. You need to know about tread, tire pressure, balance, and alignment.
The tire tread is the zigzag design of grooves you see when you inspect a car tire closely. Its main purpose is to allow water (or other liquids) to flow away from the tire, ensuring that the rubber keeps a tight grip on the road. This provides traction and control. Without the groove, you would be prone to hydroplaning: gliding on a sheet of water. Over time, tire tread wears down and reduces traction. Tire tread should never drop below 1/8 of an inch. If it does, the tire is considered unsafe.
Tire pressure is another thing to check regularly, especially before a long trip. Some suggest doing it every other time you stop for gas, just try to do it when the tires are "cold." Tire pressure is measured in pounds per square inch. The specific psi measurement for your tires will be in your owner's manual or on the placard near your door or fuel tank. You can check tire pressure by removing the cap on the tire and inserting the pressure gauge. All tires-including your spare-need to be kept at the same pressure.
Tire balance and suspension alignment -- which can affect tire wear -- are usually checked at a car service station. Both are part of the normal wear and tear of driving.
If you notice your tires leaking more than usual, you should change them as soon as possible. Products such as tire sealant can help in the short term, but they are temporary. They will not fully reinflate a tire and will wear off over time.
A high-performance vehicle, such as a racecar is different from a garden-variety passenger vehicle. A racecar tire is filled with a nitrogen mixture instead of air, so there's less heat to expand the tires.
When you purchase a new car tire, you need to match the old tires as closely as possible. If you are preparing for winter, there are special snow tires with deeper tread or studs to help your car maintain control on slippery roads. Checking your tires regularly, keeping them properly filled, and balancing them can save you thousands of dollars in repair costs over the long term.