The tires you choose can affect your vehicle’s fuel economy. That’s because different models have varying degrees of rolling resistance, which is a measurement of how much energy it takes to roll a tire down a road. According to government estimates, a tire’s rolling resistance accounts for about 5 percent of the fuel a vehicle consumes.
Consumer Reports includes rolling resistance in our tire Ratings charts (for subscribers). This year’s tires ranged from very good to poor. All-season tires generally have lower rolling resistance than all-terrain tires.
To show how rolling resistance affects gas mileage, we used our Chevrolet Silverado test truck to measure the highway fuel economy of the tires with the best and worst rolling resistance.
The Silverado got 2.4 mpg better highway mileage with the Goodyear Wrangler SR-A all-season tire than with the General Grabber AT 2 all-terrain tire. That is a difference of about $300 per year, assuming gas cost $4 a gallon and the car is driven 12,000 miles a year.
To help consumers compare rolling resistance, California is adopting a tire-efficiency standard for tires sold in the state. The federal government is scheduled to follow suit in 2009.
But don’t use rolling resistance as your primary consideration in choosing tires. Some compromise wet grip for low rolling resistance, which can affect safety. In our tests, the top tire in rolling resistance, the Wrangler SR-A, rated only fair in wet braking.
We suggest you first look for tire models that provide good overall performance and then use rolling resistance as a tiebreaker.