Tyre labelling: How is tyre performance compared?

Energy efficiency: Indicates the tyre’s contribution to fuel consumption and CO2 emissions  

Tyres are responsible for approximately 20% of a vehicle’s fuel consumption. Indeed, when rolling, the energy loss due to tyre deformation creates a force known as the rolling resistance. A higher rolling resistance means the vehicle consumes more fuel to overcome the force and will produce more CO2 emissions.

The tyre label indicates its rolling resistance class. There is a significant difference between an A and a G class tyre.

• Fuel consumption: The difference between an A and a G class tyre represents 0.5 litres per 100 km, i.e 17.6 gallons of fuel per year (based on 10,000 miles / year).

• CO2 emissions: The difference between an A and a G class tyre represents 12 g /km i.e. 0.18 tonnes of CO2 per year. For info, a malus is applied to vehicles in the form of a carbon tax starting from 141 g/km of C02.

Fuel efficiency rating for passenger cars

Rolling Resistance coefficient (RR), in kg/t (kilograms of resistance per tonne)	Labelling category
RR ≤ 6,5	A
6,6 ≤ RR ≤ 7,7	B
7,8 ≤ RR ≤ 9	C
Not used	D
9,1 ≤ RR ≤ 10,5	E
10,6 ≤ RR ≤ 12	F
RR ≥ 12,1	G

Braking efficiency: The tyre’s wet grip performance

Wet grip is an essential parameter for road safety. It is the second criteria taken into account for European tyre labels.  Measurements are taken during a test conducted using a protocol defined by the European regulation (speed, track characteristics, water depth, temperature, etc.).

The class is determined by comparing the test results with those obtained with a reference tyre. Again, there is a significant difference between an A and an F class tyre (G class is not used).

• Braking: The difference between A and G class tyres represents a distance of 18 metres, i.e. the equivalent of 4 car lengths.

Wet grip rating for passenger cars

Grip coefficient (G is the reference index)	Labelling category
1,55 ≤ G	A
1,40 ≤ G ≤ 1,54	B
1,25 ≤ G ≤ 1,39	C
Not used	D
1,10 ≤ G ≤ 1,24	E
G ≤ 1,09	F
Not used	G

Noise efficiency: Tyre external rolling noise

External rolling noise generated by tyres is an element that influences the tyre’s environmental impact, particularly in urban areas.  The result measured during the test is compared with a maximum limit (this regulation will see further reductions come into force by 2016).

• External noise: The performance difference between two noise classes is 3 dB, i.e. the noise level is increased or decreased by half.

1 black bar: Good performance.  The level of tyre external rolling noise is 3 dB below the future limit.

2 black bars: Satisfactory performance.  The level of tyre external rolling noise is in line with the future limit.

3 black bars: Poor performance. The level of tyre external rolling noise is above the limit set by the future standard but below the current maximum authorised limit.