Tires will become more important in the next few years, as automotive manufacturers struggle with new federal Corporate Average Fuel Economy standards designed to make the average vehicle go farther on a gallon of gas.

The new national standard is 35 miles per gallon by 2020 for all vehicles.

Vehicle weight causes tires to compress, creating rolling resistance and resulting in a negative impact on fuel economy.

You can see the effect with a vehicle at rest. The part of the tire on the ground is flatter than the rest of the tire but returns to normal shape once the tire begins to rotate.

In the past, durability and speed performance were major concerns for tire manufacturers, but now rolling resistance, which must be overcome to get the vehicle moving, has their attention as a way to increase fuel economy.

Thinner Tread?
One solution is to decrease the thickness of the tire’s tread, resulting in greater flexibility, but this shortens the tire’s life requiring replacement more often.

Another by-product of decreased tread depth is a 10 percent loss of stopping ability and less precise performance.

Tire manufacturers may introduce energy efficient tires with lower rolling resistance and market them as “Green” tires, citing due improved fuel economy.

Tire manufacturers hope to avoid government controls and accumulate data to rebut any tire standards they feel are unreasonable.

Green” tires will come with warnings of shortened tire life, along with a description of the tires’ ability to stop and handle slippery or wet conditions.

Consumers need to be aware of these considerations when buying tires, along with tread life and speed performance ratings.

Nitrogen-Filled Tire
Nitrogen-filled tires have been promoted as one way to increase fuel efficiency.

Nitrogen is a non-corrosive gas that doesn’t expand or retract with temperature variations the same as atmospheric air. It maintains air pressure better than atmospheric air because it does not leak through the tire as quickly as atmospheric air, thus maintaining air pressure longer.

This may be a major plus for a tractor-trailer driven hundreds of thousands of miles per year because better tire pressure will minimize fuel consumption.

A motorist driving 12,000 miles per year will not realize great savings from nitrogen-inflated tires. The same result can be achieved with atmospheric air if the tire pressure is regularly check and maintained at the proper air pressure. At $3 a gallon for gas, the savings for a vehicle getting 20 mpg and maintaining constant air pressure whether nitrogen or atmospheric air would be about $60 a year savings, according to the EPA. Filling all four tires would cost about $8 each.

The EPA says proper tire inflation can improve fuel consumption 3.3 percent.

No tire manufacturer currently endorses nitrogen for passenger tires; instead they comment on the benefits maintaining properly inflated tires.

Tire Monitoring
Most modern car’s computer systems today monitor tire inflation and display individual tire pressure.

However, severe changes in tire pressure (a flat) or tire rotation can confuse computers, which must be reset for accuracy.

Proper equipment is needed to recalibrate the computer.

Garages without this equipment can mislead consumers by stating computer readouts are accurate without resetting the computer.

Be sure to ask your mechanic when they rotate tires if they have the proper equipment to reset the computer.

All AAA Car Care Center locations and most AAA Approved facilities offer this service free when rotating tires.