December 2008

Improve Your Mileage Where the Rubber Meets The Road

Discounting engine and other losses, tire rolling resistance accounts for about 20 percent of the energy needed to power a car. Industry data suggests that tires account for about three to five percent of the nation's carbon dioxide emissions and about nine percent of U.S. oil consumption.

The energy losses associated with driving are staggering! According to the National Academy of Sciences, 80 to 88 percent of the energy in your car’s fuel tank is wasted in various thermal, frictional and standby losses in the engine and exhaust systems. This leaves 12 to 20 percent of the potential energy for conversion to vehicle motion. One of the most effective ways to improve this remaining energy’s efficient use is to reduce the rolling resistance of your car’s tires.

Rolling resistance is not a measure of a tire’s traction or grip on the road surface, but rather an indicator of how easily a tire moves down the road, minimizing the energy wasted as heat between the tire and the road, within the tire sidewall and between the tire and the wheel rim.

While the basic rule is “harder tires = lower rolling resistance,” there’s a lot more to the equation than that. You can make your tires “harder” by over-inflating them, but that’s not a safe practice. Make the tire too hard by over-inflating and where the rubbers meets the road becomes smaller. A smaller contact may mean skid or wheel spin.


A tire’s tread design also affects rolling resistance and, more importantly, grip. The more intricate the tread design, the more likely it will grip the road well. The pockets in the tread can also amke you pay a mileage penalty as the engine may have to work harder to compress the treat and grip the road.


Every tire company is working overtime to improve the energy efficiency of their products. Today, there isn’t really a happy medium. If you are an aggressive driver, you are going to be happier with softer tires that “stick” to the road. If you are committed to squeezing every last mile out of a gallon of gas, the harder, low rolling resistance tire is your choice.


Presently, the biggest problem in shopping for low rolling resistance tires is identifying them! You won’t find any indication of this trait on the sidewall where you can note just about everything else of importance about the tire. How can you purchase low rolling resistance tires right now?


Ask us! As your factory authorized service provider, we maintain information on the OEM tires sold with your car. We also stock “aftermarket” tires including the energy saving, low rolling resistance type. We look forward to consulting with you on the best tires for your car.

Schedule Service at Boston Volvo