Have you ever wondered what all those numbers and letters stamped on the tyre sidewall mean? Find out how to easily decipher them: tyre sizes, speed rating, load index and other markings will no longer hold any secrets for you!
How to read your tyre size?
Here are 3 ways to find approved tyre sizes for your vehicle:
- Check the size on the tyre sidewall of your original fit tyres
- Check on the inside of the driver’s door
- Select the model of your vehicle on the rezulteo website to view available sizes
Tyre size
The brand, model and size of a tyre are always indicated on its sidewall. Take the example of this winter tyre, the Bridgestone Blizzak, on which you can see the following marking: 205 55 R 16 91 T Here’s the breakdown:
| 205 | tyre width in millimetres |
| 55 | ratio between the sidewall height and the tyre width as a % |
| R | tyre structure (most tyres available have R for radial) |
| 16 | rim diameter in inches |
| 91 | load index |
| T | speed rating |
Load index
The Load Index indicates the maximum weight a tyre can carry at its maximum speed. In the following table, you will find the maximum weight per tyre in kilograms for each load index.
| Tyre load index | Maximum load in kg | Tyre load index | Maximum load in kg |
| 75 | 387 | 101 | 825 |
| 76 | 400 | 102 | 850 |
| 77 | 412 | 103 | 875 |
| 78 | 425 | 104 | 900 |
| 79 | 437 | 105 | 925 |
| 80 | 450 | 106 | 950 |
| 81 | 462 | 107 | 975 |
| 82 | 475 | 108 | 1000 |
| 83 | 487 | 109 | 1030 |
| 84 | 500 | 110 | 1060 |
| 85 | 515 | 111 | 1090 |
| 86 | 530 | 112 | 1120 |
| 87 | 545 | 113 | 1150 |
| 88 | 560 | 114 | 1180 |
| 89 | 580 | 115 | 1215 |
| 90 | 600 | 116 | 1250 |
| 91 | 615 | 117 | 1285 |
| 92 | 630 | 118 | 1320 |
| 93 | 650 | 119 | 1360 |
| 94 | 670 | 120 | 1400 |
| 95 | 690 | 121 | 1450 |
| 96 | 710 | 122 | 1500 |
| 97 | 730 | 123 | 1550 |
| 98 | 750 | 124 | 1600 |
| 99 | 775 | 125 | 1650 |
| 100 | 800 | 126 | 1700 |
Speed rating
The Speed Rating indicates the maximum speed the tyre is capable of reaching. The following table shows the maximum speed in miles per hour and kilometres per hour for each speed rating.
| Tyre speed rating | Maximum speed in mph | Maximum speed in km/h |
| Q | 99 | 160 |
| R | 106 | 170 |
| S | 112 | 180 |
| T | 118 | 190 |
| U | 124 | 200 |
| H | 130 | 210 |
| V | 149 | 240 |
| ZR | >149 | >240 |
| W | 168 | 270 |
| Y | 186 | 300 |
You can also refer to the following load index and speed rating tables
Technical markings
On the tyre’s sidewall, you can also find some technical information. For example on winter tyres you will usually see the M+S marking (Mud and Snow) which is mandatory for snow tyres in some countries. You might also see the 3PMSF marking (3 Peak Mountain Snow Flake) represented by a snowflake inside 3 mountain peaks. This label provides a guarantee of high winter performance.
Markings can also be found on some high performance tyres specially developed for top of the range models from car manufacturers such as Porsche or Mercedes. In this case, a marking on the sidewall indicates the manufacturer’s approval or ‘homologation’.
Some technical markings apply to all tyre brands, others are manufacturer specific.
| M + S |  |
Mud + Snow marking, specific to winter, 4×4 and all season tyres, indicating good grip performance on soft ground (snow, mud) |
| 3PMSF |  |
Symbol stamped on tyres that are specially designed for driving in snow and difficult winter conditions, it comprises a snow flake and a three peak mountain (“Three Peak Mountain Snow Flake”) |
| RF or Reinforced(XL, Extraload or Reinforced) | Tyre with a higher load index, suitable for heavy vehicles such as people carriers, estate cars, large saloons or vans. | |
| TL or Tubeless |  |
Tyre with an inner liner integrated inside the tyre, which therefore does not require an air chamber. |
| TT or Tube Type | Tyre requiring the use of an air chamber | |
| TWI | Tread Wear Indicator | |
| MO | Mercedes fitment | |
| N0/N1/N2… | Porsche fitment | |
| M3 | BMW M3 | |
| R01 | Audi | |
| * |  |
BMW Approval |
| J | Jaguar | |
| G1 | Original equipment on certain vehicles (C6, Laguna 2, Espace 4…) | |
| B | Bentley or Audi | |
| C1 | Chrysler Viper | |
| F or K1 | Ferrari | |
| S8 | Lexus RX300 | |
| AMS | Aston Martin | |
| OWL | Outline White Letter | |
| ULW | Ultra light weight tyre construction | |
| MFS | Max Flange Shield | |
| RBL | Recessed Black Letter | |
| WLT | White Letter | |
| RWL | Raised white lettering | |
| FR | Flange rim protection | |
| ML | Sidewall flange protection | |
| FP | Rim protection | |
| WW | White wall | |
| RB | Black lettering | |
| RW | White lettering |
Markings common to all tyre brands
Some manufacturer specific markings
| RFT | Runflat tyre |
| RW | Runflat tyre for Mercedes |
| SSR | Self-Supporting Runflat tyre |
| Vmax | Tyre designed for ultra-high performance saloon cars |
| ContiSeal | Technique that prevents air escaping from the tyre by means of a sealant layer that provides a seal around the object that caused the puncture. |
| ContiSilent | Technology that uses polyurethane foam to reduce the effects of tyre noise |
| FL | Front left tyre |
| FR | Front right tyre |
| Runonflat | Runflat tyre |
| Noise Shield | Technology using polyurethane foam to reduce interior vehicle noise |
| EMT or ROF | Runflat tyre |
| SoundComfort | Technology using polyurethane foam to reduce interior vehicle noise |
| Zp | Zero pressure runflat tyre |
| Green X | Green tyre offering a high level of energy efficiency in terms of fuel consumption, wear and wet grip. |
| Run flat | Runflat tyre |
| Allroad | Audi allroad |
| Seal Inside | Tyre structure that allows you to drive without losing air pressure even after a puncture. |
Regulation markings: DOT, UTQG…
Finally, in some countries specific markings are required by law.
In Europe, passenger car tyres are subject to a noise regulation. An approval number stamped on the tyre (e.g: E2 02-03 527) certifies compliance with this regulation.
The United States requires the following two markings:
The DOT code (Department of Transportation)
The DOT code means that the tyre complies with the safety standards set by the American Department of Transportation. In particular, it indicates where the tyre was produced and its date of manufacture.
UTQG (Uniform Tire Quality Grading) marking
When buying tyres, the UTQG marking aims to help consumers assess the performance of various models on the basis of 3 criteria:
- Treadwear: Tread wear grade (score between 60 and 620)
- Traction: Traction grade on wet roads (grade from A to C, where A is the highest grade and C the minimum acceptable)
- Temperature : Temperature grade (grade from A to C, where C is the legal minimum)
UTQG ratings are based on each manufacturer’s own assessment. Therefore they do not allow tyres from different brands to be compared with each other. If you want to assess the performance of a tyre, it is best to refer to the tyre label and our rezulteo ratings, which are based on test results conducted by tyre industry experts.
