Every tyre carries numerous numbers and codes. The most important numbers and their meanings are:
Tyre size: Take 205/55 R16 as an example. “205” is the tyre width in millimetres. “55” is the aspect ratio, meaning sidewall height as a percentage of width, here 55% of 205 mm. “R16” indicates radial construction and a 16 inch rim diameter. These numbers describe the tyre’s size and format.
Load index: A number often follows the tyre size, for example 91. This code indicates the maximum load capacity per tyre. For example, 91 corresponds to a load capacity of 615 kg. Other common indices are 88 (560 kg) and 94 (670 kg). A table maps each index to its value in kg.
Speed rating: A letter also appears after the size, sometimes as part of a combination such as “91V”, where 91 is the load index and V the speed rating. The letter indicates the tyre’s maximum permitted speed. Examples: T = 190 km/h, H = 210 km/h, V = 240 km/h, W = 270 km/h, Y = 300 km/h. Older markings such as ZR generally mean speeds above 240 km/h, but are now specified more precisely with W/Y.
DOT number: Another important group of characters starts with DOT. The final four digits indicate the production date: for example, DOT ... 4319 means week 43 of 2019. Factory and type codes precede them.
Tyre pressure markings: Maximum pressure values in PSI or bar are often printed on the tyre, for example MAX 44 PSI. This number indicates the maximum pressure the tyre can withstand and must not be confused with the operating pressure recommended for the vehicle.
Approval numbers: Additional combinations of numbers and letters may appear, such as ECE approval marks, for example a number in a circle or e4, indicating that the tyre has type approval.
Other markings: M+S or the snowflake symbol identify tyres with winter characteristics (Mud & Snow). XL means Extra Load, indicating reinforcement. Some tyres also have manufacturer-specific codes, such as AO for Audi Original or ★ for BMW. These are less relevant to everyday users but indicate manufacturer recommendations.
In brief, the numbers on a tyre tell you its size, load capacity, production date and more. Understanding these codes helps you determine whether a tyre suits your vehicle. At Reifenshop Landshut, we will be happy to explain your vehicle’s tyre markings in detail.