Tires: Roll out the rolling resistance

Did you know that Consumer Reports provides ratings on tire rolling resistance? What's rolling resistance, you ask? Rolling resistance is the force required to keep a tire rotating. Or, simply put, lower the rolling resistance, the less energy needed to keep it in motion. Industry figures vary, but typically a 10 percent reduction in rolling resistance means about one to two percent reduction in fuel consumption. That might not seem like a lot at first, but it can save you a couple of tanks of fuel a year.   

CR measures this tire attribute through a standard protocol known as the SAE J1269 test for steady-state rolling resistance measurement.  It's one of the few tests that we purchase from an independent tire testing laboratory, which precisely measures the force to rotate our test tires loaded against a steel drum and run at 50 mph. For good measure, we test three tires of the same model and average the rolling loss, and then statistically apply ratings to the results. The ratings become part of the weighted average of all the performance tests that make up the overall score for tire model. Rolling resistance is not weighted much and, frankly, we recommend using the rolling resistance rating as a tie-breaker when narrowing down your tire choice between models.

The federal government and some states (led by California) are looking at either providing consumers with tire fuel efficiency information or requiring that replacement tires be at least as fuel efficient as the original equipment tires that came on your car. But until that happens, CR is the only independent source providing consumers with such information. 

Some industry insiders suggest that forcing reductions in rolling resistance could have a negative impact on tire grip and tread life. There is some validity to that based on what we had seen as a trend up to a few years ago from our testing, but tire manufactures are developing technologies to break that trend. Our latest results show some very good tire choices having impressive all-season performance, long wear, and low rolling resistance, too.  So before tire shopping check out our tire ratings.

--Gene Petersen