How to Read a Tyre Sidewall: What All Those Numbers Mean
The sidewall of your tyre tells you everything you need to know about it — if you know how to read it. Here's your complete guide to decoding tyre markings.
Every tyre has a string of numbers and letters on its sidewall that contains a wealth of information about its size, type, and performance ratings. Understanding these markings helps you buy the right replacement tyres and ensures you know exactly what is fitted to your car. Let us walk through a typical tyre marking: 205/55 R16 91V.
The first number, 205, is the tyre's width in millimetres measured across the tread. The second number, 55, is the aspect ratio — the height of the tyre's sidewall as a percentage of its width. So a 205/55 tyre has a sidewall height that is 55% of 205mm, which is roughly 113mm. Lower aspect ratio numbers mean a lower-profile tyre. The R indicates radial construction, which is standard on all modern car tyres.
The number 16 is the rim diameter in inches — this must match your wheel exactly. The number 91 is the load index, which tells you the maximum weight the tyre can carry. A load index of 91 means the tyre can support 615kg. Finally, the V is the speed rating — V-rated tyres are approved for speeds up to 240 km/h. Always replace tyres with the same or higher speed rating than the original fitment.
When booking mobile tyre fitting with Bristol Mobile Tyre Guys, you can simply give us your vehicle registration and we will look up the correct tyre specifications for your car. However, understanding these markings yourself helps you make informed decisions and ensures you always get the right tyres for your vehicle and driving style.
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