Look at the sidewall of your tyre and you'll notice different markings and codes. One of them represents your tyre's size.
Various numbers and letters are joined together to show the tyre size. For example - 205/55 R16 82 H.
What does it mean?
This is all the basic information for an educated tyre purchase. If you want to delve deeper into the "writings on the wall", do refer to the information below.
Aspect ratio, or profile helps us determine what percentage of tyre's width goes into the height of its sidewall. The bigger the percentage, the bigger the driving comfort but at the expense of handling properties. It's usual for buses and trucks to have high aspect ratios (up to 95% of tyre's width!). Sports vehicles, on the other hand, have extremely low aspect ratios. You must have heard about the low-profile tyres before. Their sidewalls are rather short (up to 30% of tyre's width), which brings about sport-grade handling at the expense of driving comfort. Much of the vibrations gets passed on to the suspension. One of the reason race cars have upgraded suspension systems.
Every tyre has its speed limit, depicted by a certain letter. For the most part, the higher up the alphabet scale the letter is, the faster your tyre can run, with two exceptions to the rule. Consult the table to see what we mean.
Max speed mph
Max. speed km/h
*ZR marking was used before 1990s to mark the high-performace tyres.
The last two-digit number denotes the tyre's maximum load capacity when reaching its speed rating limit.
If you're asking yourself "how old are my tyres?", look for either a three-digit number or a four-digit number on the tyre sidewall. Three-digit numbers represent tyres made before 2000, four-digit ones the tyres made after 2000. If you're on the south side of 2000, you definitely need a tyre change. And not only then. Generally, if the tyre is older than ten years, it should be replaced, even if the tread depth is within bounds. Production year of your tyre is represented by the last two digits. The first two digits represent the production week.