Tyre Markings - Reading your Tyre Sidewall
The sidewall of a tyre shows lots of information about that particular tyre. Take a look at our helpful tyre codes guide below to find out what the numbers and symbols on your car tyres mean, and how important they are to you as a driver...
What do the numbers on tyres mean?
Understanding how to check tyre size, what tyre numbers mean and how to read the tyre sidewall markings is important – especially when it comes to replacing your tyres. On a tyre, you can typically find:
Tyre Pattern Name
Each manufacturer has its own range of tyre tread patterns – you’ll find the name of the tyre (aka the tread pattern) on the sidewall, and often the range the tyre has come from, too.
Tyre Wear Indicator
Some manufacturers add tread wear indicators to their tyres. The indicator is set at 1.6mm. When your tyre tread wears and reaches the indicator, legally it’s time to have the tyre replaced.
Tyre Construction
If you are wondering how to identify radial tyres, look at the method of construction identified on the tyre sidewall. Modern tyres are made via the ‘Radial’ method, which has replaced the cross-ply tyre. This means that the cords which construct the tyre run perpendicular to the direction of travel. So if you view the tyre from the side, the cords will run radially.
Maximum Load and Pressure
This indicates the maximum load carrying capacity of the tyre, at the maximum tyre pressure. Check your vehicle handbook for recommended tyre pressures, suitable for everyday driving.
Tyre Brand
The tyre's manufacturer will be identified on the sidewall.
Tyre Size
To understand tyre markings more easily, we’ve broken them down by the tyre size. The size of a tyre is clearly printed on the sidewall and looks something like this... 205/55/R18 105V
This string of numbers indicates the sizes and dimensions of the tyre.
- 205 is the tyre width in millimetres
- 55 indicates the tyres sidewall height as a percentage e.g. 55% of the tyre width
- R identifies that the tyre is of radial construction
- 18 the wheel rim diameter measured in inches
Load Index
The load index is identified at the end of the tyre size string 205/55/R18 105V – it is the number that appears before the letter. This code indicates the maximum load a tyre can carry. The number relates to the below table – so in this example the tyre can carry 925kg.
| Load Index | Kilograms | Load Index | Kilograms | Load Index | Kilograms |
|---|---|---|---|---|---|
| 65 | 290 | 80 | 450 | 95 | 690 |
| 66 | 300 | 81 | 462 | 96 | 710 |
| 67 | 307 | 82 | 475 | 97 | 730 |
| 68 | 315 | 83 | 487 | 98 | 750 |
| 69 | 325 | 84 | 500 | 99 | 775 |
| 70 | 335 | 85 | 515 | 100 | 800 |
| 71 | 345 | 86 | 530 | 101 | 825 |
| 72 | 355 | 87 | 545 | 102 | 850 |
| 73 | 365 | 88 | 560 | 103 | 875 |
| 74 | 375 | 89 | 580 | 104 | 900 |
| 75 | 387 | 90 | 600 | 105 | 925 |
| 76 | 400 | 91 | 615 | 106 | 950 |
| 77 | 412 | 92 | 630 | 107 | 975 |
| 78 | 425 | 93 | 650 | 108 | 1000 |
| 79 | 437 | 94 | 670 |
Speed Index
The speed index, is the letter that follows the load index next to the tyre size 205/55/R18 105V
This indicates the maximum speed the tyre can service. The following table identifies the speeds in relation to the Letter.
| Speed Symbol | Approx MPH |
|---|---|
| Q | 99 |
| R | 106 |
| S | 112 |
| T | 118 |
| H | 131 |
| V | 149 |
| VR | 131 |
| W | 168 |
| Y | 186 |
| ZR | 149 |
Mounting Direction
On an asymmetric tyre the indicator shows which side of the tyre must face outwards. Directional tyres have markings to show which direction of rotation is required.
Now you know what tyre sidewall markings mean. If you are looking to buy tyres online simply browse through our range and then arrange a fitting at your nearest branch at a time and place to suit you.
For more information on tyre codes, contact your local PTA Garage Services branch where one of our tyre specialists will be able to provide further guidance.
