How to read tyre size

What size tyre is on my car?

Before changing tyres, it is always a good idea to know more about them. To do this, take a look at one of the sidewalls of the tyre. Here you will find the Tyre Size, Speed and Load Rating. If in doubt, we can always check the user manual to find out if they are compatible with our vehicle. 

The obligatory part

The Most Important Numbers & Letters

The first code shows the size and specification of the tyres. The second confirms that the tyre meets European safety standards. The letter ‘E’ or ‘e’ certifies that the tyres comply with European Standard requirements.

  1. Width (205)
    The number 205 is the width in millimetres. For standard tyres, this number varies between 125 and 335 millimetres.
  2. Height (45)
    45 is the height, expressed as a percentage of the width. In this example, the height is 65% of the total width of 195mm, so that is 126.75 mm.

  3. The letter “R” means radial, the type of tyre. All tyres are radial, so this is an optional indicator.
  4. Diameter (17)
    17 is the diameter of the inside edge of the rim. It is always expressed in inches. The number varies from 10 to 12 inches. This is an important factor to bear in mind before changing tyres.

The additional part

Speed & Load Index

  1. Load Index (99)
    99 is an index showing the maximum payload for the tyre at the speed designated by the speed symbol (99 = 615 Kg.)
  2. Speed symbol (W)
    The final letter shows the maximum speed at which the tyre can travel with a full load. W is a maximum speed of 270 km/hr. In general, this symbol is greater than the vehicle's maximum speed. However, there are exceptions for winter tyres and exemptions in some countries. It is important to take care not to fit tyres with a speed symbol or load index lower than those shown (see above). All the information to help change tyres correct is included in the technical data sheet and the manual of each vehicle

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