EU tyre ratings could be misleading

Preliminary tests held by Emissions Analytics have shown that the current tyre rating system in the EU may be misleading.

Two contrasting sets of 175/70 R14 tyres were tested on the road; one rated B for fuel economy and the other F. The results revealed that at mid-range speeds, an F-rated tyre performs as well as a "more economical" B-rated tyre.

The B or 'eco' rated tyre was indeed superior in the 40-70 mph range by an average of 3.8% mpg and 3.4% less CO2. However, at a mid-range speed there is very little in it.

This means for urban and city driving a consumer will notice barely any difference in fuel economy between the two tyres.

For drivers who regularly use motorways and consistently hit speeds of 70mph a B rated tyre would give a 12.9% improvement in fuel economy. Yet, under the current tyre labeling system, which the EU made mandatory in November 2012, this distinction is not clear.

These basic tests highlight that the relationship between rolling resistance and fuel economy is not linear.

Emissions Analytics suggest that a better system must be adopted. Manufacturers, they say, require improved testing models that can help translate rolling resistance information into monetary quantification; in turn, this would help consumers make better tyre choices.

Emissions Analytics

Edward Wirgman

Author:Edward Wirgman
Date Updated:3rd Jun 2014

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