Purcell: We'll keep you moving

Are Your Tires Properly Inflated?

When tires are not inflated to the pounds per square inch (PSI) rating recommended by manufacturers, they are less “round” and require more energy to begin moving and to maintain speed. As such, under-inflated tires do indeed contribute to pollution and increase fuel costs.

The majority of cars on U.S. roads are operating on tires inflated to only 80% capacity. According to the website, fueleconomy.gov, inflating tires to their proper pressure can improve mileage by about 3.3 percent, whereas leaving them under-inflated can lower mileage by 0.4 percent for every one PSI drop in pressure of all four tires. That may not sound like much, but it means that the average person who drives 12,000 miles yearly on under-inflated tires uses about 144 extra gallons of gas, at a cost of $300-$500 a year. 

Besides saving fuel and money and minimizing emissions, properly inflated tires are safer and less likely to fail at high speeds. Under-inflated tires make for longer stopping distances and will skid longer on wet surfaces. Analysts point to under-inflated tires as a likely cause of many SUV rollover accidents. Properly inflated tires also wear more evenly and will last longer accordingly.