Different Tyre Markings Explained

For those unfamiliar with their markings, buying a new set of car tyres can feel like trying to crack a code. Luckily for you, here at LK Performance we know our ‘Run Flat’ from our radial, and we can help you find the right car tyres and winter tyres for your ride with our handy guide to different tyre markings. 

EU Tyre Labels

When car tyres are purchased new, they should have a familiar-looking label stuck to them, rather like the ones you now find on a fridge or washing machine. These labels, required by EU legislation, offer information on the individual properties of the tyre and will help you to compare it to other types. 

The information you will see on car tyre labels includes:

Fuel economy

An ‘A’ rated tyre offers better fuel efficiency than a ‘G’ rated one, to the sum of 80 litres of fuel over the life of the tyres.

Braking efficiency in wet conditions

Here’s a pretty sobering fact: an ‘A’ rated tyre will stop a full 18metres shorter than a ‘G’ rated one, when travelling at 50mph. 

External noise levels

This is offered at three levels, with three waves being the noisiest. This is louder than future limits will allow, but is ok for the time being.

Two waves will remain within future sound limits and one wave is obviously the quietest.

It’s also worth considering tyre longevity, road handling and dry braking capabilities, all of which will be on the label, before deciding on a purchase.

Tyre Codes

Apart from brand and model, the letters and numbers embossed on the side of the actual tyres establish their fitting, age, dimensions, composition and capabilities. However, the numbers are not as straightforward as they may first appear, so you would be forgiven for being a little confused. 

If we were to use the tyre code P185 65 R15 88 H as an example, it would break down as follows:

P denotes that it’s for a passenger-bearing vehicle.

185 is the tyre width expressed in mm.

65 is the tyre sidewall height or profile, but as a percentage of its width, rather than an actual measurement.

R denotes a ‘radial’ tyre structure, as opposed to cross-ply. It’s important not to mix these two up on a car and have all of them the same.

15 is the diameter of the wheel rim, or ‘rim size’, but in inches as opposed to mm, confusingly.

H is the speed rating, which must at least match or exceed the top speed of the vehicle.

All of this may seem impossibly convoluted, but this info is in your car handbook and can also be found very easily by tapping your car make and model into LK Performance’s handy car tyre search function. 

Standard car tyre speed ratings tend to fall into eight given categories:- 

S up to 112mph

T up to 118mph

U up to 125mph

H up to 130mph

V up to 149mph

W up to 168mph

Y up to 186mph

ZR over 149mph

Again, the higher the rating, the more your car tyres will cost. Tyres for a Bugatti Veyron for example, are around £5000 each.

Other Markings You Should Be Aware Of

There’s one other set of numbers it’s worth knowing about: the manufacturers date stamp. You may be buying new-looking, unworn tyres that are in fact quite old, having sat in a warehouse for any number of years.

In addition there are another set of markings which are relatively new, and these are the letters indicating ‘Run Flat’ tyres. This means that should you get a puncture, the tyre is safe to run flat for a full 50 miles, without shredding and allowing the wheel itself to sustain damage - depending on the kind of blow-out you suffered in the first place, of course.

These letters are ROF, RunFL, DSST and RFT.

As with cross-ply, it’s important that Run Flat tyres are not added as individual tyres, but as a whole set, as they could adversely affect the car’s handling. 

It’s also advisable that some sort of tyre pressure monitoring system is utilized in conjunction with these tyres, just to ensure you’re aware if you do get a loss of pressure for any reason.

Finally, it’s quite common these days that tyres are asymmetric in their construction and need to be fitted a certain way around, with one side on the outside of the car. 

This is particularly important when you consider the front steered wheels, which take substantially different loads under stress, so be absolutely sure they are fitted the correctly before you take them for a spin,