Tire Marking Decoder
Fast, accurate, and free online Tire Marking Decoder tool that runs directly in your browser.
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Tire marking decoder
Enter oznaczenie z boku opony, e.g. 205/55 R16 91Vand we can read the width, profile, diameter and load and speed indexes.
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Other tools you may find usefulHow to read the markings on car tires - a guide to symbols and numbers
Car tires are the only element of the vehicle that has direct contact with the road surface. The safety of the driver, passengers and other road users depends on their technical condition, quality and correct selection. On the side of each tire there is a string of characters, numbers and letters (e.g. **205/55 R16 91V**), which for many drivers sounds like a mysterious code. These markings contain a set of key information about the tire: its width, profile, rim diameter, type of internal structure, load index and speed index. Additionally, the tire has the production date (DOT code) and winter approval symbols.
Our interactive online tire marking decoder allows you to instantly decipher the parameters of any tire, which is an invaluable help when purchasing new or used car tires.
Deciphering the basic tire size using the example: 205/55 R16 91V
Here is a detailed breakdown of the parameters that make up the standard tire size designation:
- 205 (Width):The first three-digit number determines the width of the tire's cross-section expressed in millimeters (in this case, the tire is 205 mm wide from the side to the side).
- 55 (Tire profile):The second two-digit number is the tire profile, i.e. the height of the tire sidewall expressed as a percentage of its width. Here the side height is 55% of 205 mm, which gives approximately 112.75 mm. The lower the value, the lower the profile of the tire (it looks flatter).
- R (Construction):The letter representing the construction of the tire. The vast majority of modern tires are radial tires (R), in which the cord layers are arranged radially relative to the tire axis.
- 16 (Diameter):A two-digit number specifying the diameter of the rim on which the tire should be mounted, expressed in inches (here: 16 inches).
- 91 (Load Index):Code specifying the maximum permissible load per tire at maximum speed (91 indicates a limit of 615 kg per tire).
- V (Speed Index):A letter specifying the maximum safe speed at which the vehicle can travel with a given tire (V stands for a limit of 240 km/h).
Table: Tire speed ratings and their maximum values in km/h
The tire speed rating must always be adapted to the maximum design performance of the vehicle. The table below shows the most common speed indexes for passenger tires:
| Speed index symbol | Maximum permissible speed (km/h) | Typical use / Vehicle class |
|---|---|---|
| Q | 160 km/h | Some winter tires, 4x4 off-road vehicles. |
| T | 190 km/h | Small city cars, budget winter/summer tires. |
| H | 210 km/h | Compact cars, SUVs with standard engine power. |
| V | 240 km/h | Middle and upper class cars, popular diesels and petrols. |
| W | 270 km/h | Sports cars, powerful premium limousines. |
| Y | 300 km/h | Super sports cars, high-performance versions of passenger cars. |
How to check the year and week of tire production? DOT code
Tire age is crucial to safety because rubber ages and hardens over time, losing traction. The tire production date is read from the so-calledof the DOT codeplaced on its side. Look for an oval box with four digits (e.g.1224):
- The first two digits represent theweek of productionin a given year (12 is the 12th week, i.e. March).
- The last two digits indicateyear of production(24 is 2024).
- The tire with DOT code 1224 was manufactured in March 2024. According to the standards, tires older than 5-6 years from the date of production lose some of their properties, and 10-year-old tires absolutely qualify for replacement, even if they have high tread.
Frequently asked questions (FAQ)
What do the M+S and Alpine (3PMSF) symbols on the tire mean?
The M+S marking (Mud and Snow) is the manufacturer's declaration of better properties on mud and snow, but it is not a full winter approval. Real winter and all-season tires have the so-calledalpine symbol (3PMSF)– three mountain peaks with a snowflake in the middle. It means that the tire has passed rigorous snow grip tests.
Is it possible to use tires with a lower load index than recommended by the manufacturer?
No, it is absolutely forbidden to use tires with a load index lower than that approved by the vehicle manufacturer. This may result in overheating and bursting of the tire when driving fast, as well as problems with payment of compensation from AC insurance in the event of an accident.
What is an XL (Extra Load) tire?
The XL (or RF - Reinforced) marking on a tire means that it has a reinforced internal structure and a higher load index than a standard tire in this size. XL tires are used in heavier upper-class cars, SUVs, electric cars and delivery vans.
What is the minimum allowable tire tread wear in Poland?
According to Polish road traffic law, the minimum tread height is 1.6 mm. However, safety experts recommend replacing summer tires when the tread is less than 3 mm, and winter tires when the tread is below 4 mm - below these values, wet grip drops dramatically.
What do tubeless (TL) and tube type (TT) mean?
The inscription "Tubeless" (TL) means a tubeless tire that maintains pressure thanks to the tightness of the tire and rim (standard in modern cars). The inscription "Tube Type" (TT) means a tire that requires the use of an inner tube (used in older vehicles, some motorcycles or bicycles).