Tyre markings are far from just a random assortment of numbers and letters, rather, they can tell you everything you need to know about a tyre. Here’s a quick guide.
Tyres play a massive role in maintaining your car’s performance, as well as your own safety. But far from being just “those black circles” that keep the car’s body off the ground, there’s actually a lot of information contained in the string of letters and numbers on the sidewall. Here’s what they mean:
Tyre width – Measured in millimetres. All else being equal, a wider tyre will give more grip in the turns, but will also be slightly noisier and less fuel efficient.
Tyre profile – Can also be referred to as the height of the tyre’s sidewall. This is expressed as a percentage of tyre width; so for example, this tyre’s sidewall height is 45% of 225mm. A lower profile helps provide more stability when going round corners, while a higher profile means there’s more rubber to help absorb bumps, making for a softer, more comfortable ride.
Tyre construction – The “R” denotes that the tyre is of a radial construction, which is simply one of the ways tyres are put together. Since virtually all tyres these days are radial ones, this marking can generally be safely ignored.
Wheel rim diameter – Larger wheel sizes usually look nicer, but are generally heavier, which affects ride comfort and increases fuel consumption. Do note that if you are changing your wheels to a larger size, you’ll need to get lower profile tyres at the same time, so as to maintain the overall rolling circumference of the wheel plus tyre. Not doing so will cause your speedometer reading to be inaccurate.
Manufacture date – This code will allow you to easily determine the age of a tyre. Look for a stamped oval shape containing a four-digit number: the first two digits denote the week of production, and the latter two the year. So in this example, the tyre was made in the 3rd week of 2021. As a tyre’s rubber compound ages, it will degrade and harden, which is why even though your tyres might not have covered many miles, it is still advisable to check them regularly for signs of wear such as cracking or bulging.
Load and speed rating – Refers to the maximum weight and speed the tyres are designed to bear. Tyre firms use a special chart whose values correspond to different ratings, so in this case, ’94’ means the tyre is able to support up to 670kg each (for a combined total of 2680kg), while a ‘W’-rated tyre means it is designed to travel at speeds up to 270km/h.