These are tyre markings, numbers and letters that are printed on the side of a tyre. They tell you information about the size, type, and performance of the tyre. The markings usually look something like this: 205/55 R16 91V. The first number (205) tells you the width of the tyre in millimetres. The second number (55) tells you the height of the tyre as a percentage of the width. The letter (R) stands for “Radial” which is the type of tyre. The number (16) tells you the size of the wheel rim in inches. The last two numbers (91) tell you the load index rating and the letter (V) tells you the speed rating. Here they are labelled and broken down further:
The width of your tyre, in millimetres, measured from sidewall to sidewall.
This is the ratio of the tyre’s cross-section to its width, expressed as a percentage. An aspect ratio of 65, for example, indicates that the tyre’s height is 65% of its width.
The diameter (height) of the wheel in inches.
Your tyre’s load index relates to its maximum carrying capacity (in kg). You’ll find the load rating of your tyre on the sidewall, just to the right of the diameter.
For example, a tyre with a load index of 91 can carry 615kg of weight.
Load ratings and speed ratings should be looked at together when you buy a new tyre. Also remember to check your manufacturer’s recommendations.
The speed rating is the maximum speed for a tyre when it is correctly inflated and being used under load. The speed rating is the letter at the end of the sidewall, after the load index number. A tyre with a speed rating of V, for example, has a maximum speed of 240 km/h.
When buying new tyres, make sure you match their speed rating with the speed capabilities of your vehicle.
