Report: Tire labelling can mislead drivers over fuel-savings

ERJ staff report (TP)

Winchester, UK – According to research by Emission Analytics (EA), preliminary tests have shown that ratings on tire labels are not telling the full story. At mid-range speeds, an F-rated tire performs as well as a B-rated one for fuel economy.

EA tested two different sets of 175/70 R14 tires on the road. One set was standard with B-rating for fuel economy and the other had an F-rating. The test route incorporated a range of steady-state speeds from 40mph (64kph) to 70mph (112kph) on tarmac in consistent ambient temperatures.

The B rated tire was better in the 40-70 mph range by an average of 3.8% mpg and 3.4% less CO2. In the mid-range speed, the results were negligible – but a performance gap opens up at 55mph and at 70mph the fuel economy improves by 12.9%.

This means a consumer buying B rated tires is unlikely to notice a fuel economy benefit if the journeys they usually make are mainly urban. But a consumer using the motorway each day should see an improvement.

EA recognised this was “an unashamedly quick and dirty investigation” but believed it showed the relationship between rolling resistance and fuel economy is not linear and that to bring real improvements to the way tires are bought and sold manufacturers need to adopt more sophisticated models.

In addition, EA thinks the current tire labelling system, made mandatory by the EU in November 2012, is “not working”.

In a report compiled by the National Tyre Distributors Association (NTDA) and Lanxess, the manufacturers of high-tech rubber for tires, it was found that one year 93% of tire retailers said customers never or only occasionally requested information on the label and only 30% knew that tires affect fuel consumption.

As a result of these findings, EA think “manufacturers need better models to translate rolling resistance calculations into fuel economy effects. Improved, independently verified testing and labelling, perhaps with a monetary quantification of the typical benefit would provide a tangible benefit that the consumer would welcome”.