Measuring Tyre Quality
There are three aspects to the new EU tyre labelling laws that tyre manufacturers and retailers are required to display on all car tyres from November. These are the things that manufacturers are required to measure for all their tyres. These are:
Rolling resistance – effectively this is the fuel efficiency of your tyres. The lower the rolling resistance, the better the fuel efficiency.
Wet braking – this is the most important bit from a safety angle as it gives you an idea of how long it will take to stop your car on a wet road compared to other tyres. Shorter stopping distances are better!
External noise level – this one impacts on other road users and the local environment.
Each manufacturer is responsible for testing their tyres according to a common standard set down by the EU. Each country is responsible for ensuring that the grading system is respected by the manufacturers.
Rolling resistance is the energy consumed by your tyres over whatever distance you travel. A specialised machine is used to test it by simulating driving at 50mph with a load that is equivalent to 80% of that tyre’s load index (i.e. the amount of weight it can safely carry). The better the tyre performs on this test, the less fuel you will use if you fit it to your car.
Braking on wet roads is tested on a track under standardised conditions. The temperature, state of road surface, water depth and speed are all specified by European legislation. In order to give a standard result, each tyre is tested alongside a standard reference tyre that they have already decided a grade for.
External noise level is the easiest to test as it simply involves a car driving past a microphone on a track. Again, the temperature, speed and track are standardised, and the results are measured in decibels.
While these labels will give consumers a snapshot of the tyres, testing doesn’t stop there. All the major tyre manufacturers test their car tyres in a variety of ways to ensure they perform as well as possible in many different situations. So while the labels are a start, it is still worth looking a little deeper into your choice of car tyres as safety is also affected by road handling and dry braking, while the cost will be affected by how long the tyres will last.