Which tyre size fits my car?

Finding the tyre size – a piece of cake

What is the easiest way to find out the correct tyre size? Our recommendation: Just take a look at the side of your tyre, on the sidewall. The tyre labelling will be explained below. This is a code consisting of numbers and letters. Its four components provide you with all the important information about the tyre size. For example, the code on your tyre might look like this:
245 / 45 R16 91V

What exactly do the numbers and letters mean? You can use the tyre size table to decipher the code. It tells you at a glance where you can find the tyre size, rim diameter details, etc.

1. The tyre width

The first three numbers describe the tyre width in millimetres. It is measured from the tyre's inside wall to its outside wall.

2. The profile cross-section

The second number after the slash is a percentage. It is the ratio of the tyre height to tyre width. In this example it means that: The height of the tyre flank is 45% of the tyre width of 245 mm.

3. The type of tyre

The letter contained in the code indicates type of tyre (see our expert's advice below). In this case, 'R' stands for Radial tyres. The alternative would be a 'D' for diagonal tyres.

4. The rim

A number follows immediately after the tyre type letter. It indicates the tyre or rim diameter in inches.

5. The load index and speed rating

The last number/letter combination in the code represents the tyre's maximum load-bearing capacity and the maximum permitted speed. The number tells you the maximum load per tyre according to the load index. The letter tells you the maximum speed.

The maximum speed rating tells you the tyre's maximum permitted speed. 32 speed classes are defined here and they are marked with letters. A denotes the lowest and Y the highest speed class for a tyre. The index also tells you something about driving comfort, wear, traction and cornering stability.

An example: tyres with a higher index value have a very good grip and high braking performance. Therefore their wear is greater and they are less suitable for driving in cold climates.

But do the recommended standard tyres always have to be used with the car? No, you can opt for something a bit sportier. So why not choose other tyre sizes for your car?

Which alternative tyre sizes are permitted for your car?

You don't have to choose the recommended tyre size for your car. In Germany, alternative tyre dimensions for your car can be found in the Certificate of Conformity (CoC). This document lists all tyre and rim combinations permitted by the vehicle manufacturer. You will automatically receive the certificate of conformity when you purchase a new vehicle. Alternatively, you can also request the document directly from the car manufacturer. Important information on this topic can also be found in our "Tyre approval" guide.