UK-based Emissions Analytics carried out preliminary tests on two contrasting sets of 175/70 R14 tyres on the road. One set was a standard tyre 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 to 70mph on tarmac in consistent ambient temperatures.

The firm says its research has indicated that ratings on tyre labels are not telling the full story. At mid-range speeds, an F-rated tyre performs as well as a B-rated tyre for fuel economy.

The research found that the B-rated tyre was superior in the 40-70mph (64-113kph) range by an average of 3.8% mpg and 3.4% less CO2. There wasn’t much variance at the mid-range speed but a performance gap opened up at 55mph (89kph) and by 70mph (113mph) the fuel economy had improved by 12.9%.

As a result the firm said that drivers using B-rated tyres are unlikely to notice a fuel economy benefit if the journeys they customarily make are mainly urban, whereas a driver heading up and down the motorway each day should see an improvement.

In response, the firm said it thinks ‘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.’

The research follows a study that found the current tyre 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 tyres, it was found that one year on 93% of tyre retailers said customers never or only occasionally requested information on the label and only 30% knew that tyres affect fuel consumption.