Putting air in tires on a car, truck, or even a bicycle can mean the difference between excellent performance and extremely poor performance. The level of air in tires affects the handling of the vehicle as well as the fuel efficiency in cars, trucks, and motorcycles, so properly inflating tires is a crucial step toward making a vehicle run as it should. When putting air in tires, it is important to first check how much air pressure should be in that particular tire, as over-inflating the tire can lead to separation from the rim, and under-inflation can lead to poor performance and punctures.
Before putting air in tires, the user must first remove the valve stem cap. It is important to put this cap somewhere safe and replace it as soon as the user is finished filling the tire; the valve stem cap keeps dirt and grit out of the valve itself, which in turn prevents clogging or slow leaks. Plastic caps are the most commonly used caps on cars and trucks because the plastic will not seize or rust to the valve, which could prevent the user from removing the cap in the future.
When putting air in tires, one should consider how much pressure to put in the tires. Each tire is stamped with its air requirements. Many gas stations have air pumps for use by the general consumer, but few of them come with accurate gauges for measuring the air pressure. It is a good idea to keep a small pressure gauge in the car to measure how much air is being forced into the tire both to prevent blowing the tire off the rim and to prevent under-inflation, which can lead to flat tires, uneven wearing of the tire, sluggish steering, and poor fuel efficiency.
If the user puts air in tires that go flat quickly — generally within a few hours — a thorough inspection of the tire is necessary. A puncture may be causing a leak, which must be repaired immediately. A tire with a leak can cause inconsistent steering, which may lead to an accident. While tire repair kits are available at auto parts stores, most motorists bring their vehicle to an auto shop to get the leak repaired. Such a repair is generally inexpensive and quick, but if the puncture is in the sidewall of the tire, repair costs and time can be more significant.