Testing Rolling Resistance: Fuel Efficieny The tyre is loaded on to a specially deisgned drum and then rotated with a preset load and pressure. The engineers calculate the level of torque required to rotate the drum before the tyre was fitted and so by working out the torque required after it has been fitted they can work out the tyres resistance. The difference before the tyre was fitted and after it was fitted provides the test engineers with the Rolling Resistance Coefficient, and they can then use this to work out the required grading for the new tyres label. The Resistance impacts heavily on the tyres fuel efficiency so it's important to consider this when purchasing your new tyres. Wet Grip Testing The engineers conduct two tests to work out the wet grip rating of the tyre. They then use the results to create the Wet Grip Index and measure the result against a benchmark tyre to see the improvement and thus the tyres overall wet grip efficiency. The First test involves wet braking and measures how the tyre performs braking on a wet surface. They record the distance it takes for the car to slow from 50mph to 12mph. The second test is known as the skid trailer test which calculates the level of fricition between the tyre and road surfaces. The test is conducted when the vehicle is travelling above 40mph and in temperatures between 2c and 20c for winter tyres and 3c and 35c for summer tyres. Noise Emission Testing. The aim of this test is to see the levels of noise emitted by the tyre measured in decibels.