Mention balloons and the average person thinks of a party. In the early days of automobiles, the forerunner of the modern tire was often referred to as a "balloon tire." Similarities still exist between "party balloons" and inflatable tires. Motorists may not realize it, but they drive on a cushion of air. Tires alone do not support a vehicle, the air pressure inside them does!
It is normal for tires to lose a small amount of air pressure over a period of time -- like a balloon. Maintaining correct tire air pressure is one of the most important factors for safety, fuel economy,and tire wear. Yet many drivers are painfully unaware of this simple vehicle maintenance measure. As a vehicle is driven, the tires normally generate a certain amount of internal heat. Driving with low tire pressure results in excessive heat build-up which can cause increased wear and serious tire damage.
Think of popping a party balloon. Extreme cases of low tire pressure may result in a "blow out" or complete tire failure, which can be very dangerous -- particularly at high speeds. If curious about heat generation, touch a vehicle's tires after driving a distance. Typically, a tire is no longer cold to the touch even after a moderate driving trip. Proper tire pressure helps to keep tire temperatures within normal operating limits.
The first step toward maintaining proper tire pressure is buying a good tire pressure gauge. It is not possible to tell if a tire is only a few pounds under-inflated just by looking at it. This small, but useful, tool belongs in every glove box. Service station gauges can be inaccurate due to hard usage or abuse. Usually not much larger than a ball-point pen, a tire pressure gauge easily justifies its cost with fuel and tire wear savings. For passenger cars and light trucks, look for a tire pressure gauge marked 5-50 Pounds per Square Inch (in 1 lb. units). These gauges are generally easy to read and give the accuracy needed for most vehicles. Some tire pressure gauges also have "kPa" markings, usually in red numbers. Kilo-pascals (kPa) and Pounds per Square Inch (PSI) do not share the same numerical values. Be sure to understand the gauge markings on the tire pressure gauge!
Routinely check pressure when tires are cold. Cold tires are usually defined as parked for three hours or more or driven less than one mile. However, if a tire actually looks low, don't delay -- check it now! If a tire checks low, fill it with air now and check it again when it is cold.
It is a good practice to visually inspect tires during each fuel stop. Check tire pressure about once a month, before any long trip, and particularly if the vehicle is to be loaded heavily. Check the spare tire at least every other month to ensure a safe replacement.
For recommended tire inflation pressures, consult the vehicle owner's manual, driver-door placard (sticker), or glove box. If these sources do not provide the necessary information, contact the vehicle or tire manufacturer for proper inflation pressures. Note that some vehicles list separate inflation pressures for front and rear tires due to weight differences. Maximum inflation pressure information is found on the tire sidewall and should not be exceeded. Lightly rubbing chalk on the maximum pressure information can make the small print easier to read.
Inflating and maintaining tires at their proper pressure is not difficult. Remove the valve stem cap and firmly apply the tire pressure gauge to record pressure. If you have never checked tire pressure or inflated a tire, ask an automotive technician to demonstrate the technique. The procedure is quick and easy to master with a few minutes of instruction. Be careful not to over inflate the tires, as more air is not necessarily better in the case of tires. Don't burst those balloons!
