Markings and What they mean

If you have ever looked at the sidewall of a tyre you will have noticed, along with the manufacturers name and brand, a dizzying array of numbers and letters. Understanding this code is vital if you are to choose a tyre that is suitable for you. Before I explain what each number is I will first explain a few simple terms.

Here's how it works. The first two numbers are the tyre width in millimetres and the aspect ratio. They are followed by a letter denoting tyre type (however pretty much all tyres are radial now, so this will invariably be an R). The next number is the rim diameter in inches and that is followed by the load index. The last letter is then the speed rating.

As an example, the tyres on my 1990 roadster have the following mark.

195/50 R 15 82 V

This means that my tyres are 195mm Wide and have an aspect ratio of 50% (ie the sidewall height is 97.5mm). They are radial tyres fitted to 15" rims. They have a load index of 82 (475 kgs) and are V rated (Max. speed 149 mph/240kph)

All tyres for the European market should also have an E mark on them. In my case it is

E9 02 2059