Looking on the sidewall of a tyre will give you its size.
The image to the right, shows the mixture of letters and numbers:
"205 55 R16 91 W" on a tyre.
Below is a table explaining what the different numbers mean:
Tyre sidewalls give the speed rating. This is represented by a letter - in the following example the tyre speed rating is "W".
Once you know your tyre speed rating, you can work out what is the maximum speed your tyre is capable of maintaining.
For example, the "W" rating tells us that a tyre can reach speeds of up to 168mph.
Speed ratings tests involve engineers running the tyre at 6.2 mph steps, in 10 minute increments, until reaching the required speed.
Important: check your speed rating before buying tyres. A low rating not compatible with your car can invalidate your insurance.
Load capacity = what weight each tyre is able to carry.
To avoid your insurance becoming invalid please check what capacity is required with your manufacturer.
Between the diameter reading and the speed rating you will find the load rating.
Provides information on how well the tyre will perform in
wet conditions. 'A' giving you the best grip and 'G' being the lowest.
The difference between each of the grades is approx. 3m.
Therefore the difference between 'A' and 'G' on the scale is
approx. 18m. The length of 4 cars!
When a tyre is rolling it loses energy this is known as
rolling resistance. This resistance has an impact on both
the vehicles fuel consumption and the co2 emissions.
Choosing an a grade tyre will improve your fuel consumption
and lower your co2. The difference from 'A' to 'G' can be up to 7.5% in fuel
The noise created by a tyre is measured in decibels. The diagram shows 3 waves. A tyre with 3 black waves generates the most noise in use. While at the other end of the spectrum the tyre would be a quieter and more environmentally friendly.
Please call Milesmore Tyres if you have any worries about the tyres you are using, our experts can help.