You can find you car’s tyre size on the tyres’ sidewall, in car’s manual as well as on a sticker inside the driver’s door. The tyre size might read like this: 205/55 R16 91 V. Hardly user friendly but, when you know what it all means, you’ll realise it tells you useful information about the tyre’s construction, size and type.
1. Cross section width
The first three numbers, in this case 205, refer to the section width of the tyre. This is the measurement, in millimetres, from the tyre’s inner sidewall to its outer sidewall.
2. Aspect ratio
The aspect ratio, or profile, refers to the height of the sidewall as a % of the section width. In our example, 55 means the height is equal to 55% of the 205mm width. The bigger the aspect ratio, the bigger the sidewall will be.
3. Construction type
The letter R means the tyre is a radial construction. Almost all new car tyres are radials.
The number to the right of the construction type is the rim diameter, measured in inches. In this case, it’s a 16” wheel.
5. Load index
The final number is the load index i.e. the maximum load (in kg) that the tyre can carry. See chart below:
6. Speed symbol
The final character (in this case V) relates to the maximum speed of use. Again, the following table will clarify what your tyre’s symbol means.