Making Sense of Tirewall Symbols
Posted on March 15, 2021
What are the Symbols on the Side of My Tires?
When it’s time to buy a new set of tires, it’s important to know a few things that are specific to your car to ensure that you purchase the correct car tires. Before making a purchase decision, it is best to familiarize yourself with the meaning of all of those tire symbols on the side of the tire, such as tire width, aspect ratio and load rating. You can check out our in-depth video detailing the meaning of all of those symbols here.
There are a lot of symbols on the side of your tire, but an especially important one is the alphanumeric code listed that will be stylized as something like, ‘245/40R18’. This code will tell you everything that you need to know about the sizing of your tire.
Let’s dig into this code a little more.
Tire Size
The first numbers on the side of the tire are important. They’re going to tell you how big your tires are. For instance, if this first number reads ‘245’, that means that it’s 245 millimetres at its widest point when it’s mounted on a wheel. When you’re looking for a new set of tires, you’re going to want to match the size of your new ones with the ones that you currently own.
Aspect Ratio
The second number in this series, the one after the slash, is your tire’s aspect ratio, or profile. It indicates your tire’s height. This is an important feature to be aware of when choosing your next set of tires.
Construction type
Next in line is a letter, usually an ‘R’. This stands for ‘radial construction’. The vast majority of tires these days will feature an ‘R’ in this spot but it is possible to see a D or B, instead. These stand for bias-ply and belted tires, so if you have either of these and you’re looking for the perfect match in your new set, it’s something to consider.
Wheel Size
The next number in this series indicates the size of the wheel that this tire will fit on. For instance, if the number is ‘18’, this means that this tire fits an 18-inch wheel. If a letter precedes this number it is a part of a coding system. A P means that it’s p-metric, which is usually on passenger cars. A T means that it’s a temporary tire or a spare. An F or Z means that it’s a run-flat tire, which is a specific type that will let you get to a shop in a hurry if you have a puncture in your tire.
This gives you a sense of the maximum load that can be carried on your tires and the maximum tire pressure needed to support that load. Now, for most passenger vehicles, the max load shouldn’t be much of an issue for you. You will want to know your tire pressure though, to be as safe as possible on your tires.
Please note that you should always fill your tires according to your tire fill placard, which is usually located on your driver door frame or in your owner’s manual.
Alphanumeric Code
Next, you’ll find an alphanumeric code. It may be a little bit confusing at first but it’s pretty simple. It gives two key insights into the intended performance level of your car: how much weight it can carry and how fast it can safely go. It’s always best to make sure that you have tires on your car that are intended for the performance of your vehicle. The letters range from L - which would be 75mph - and Y - which would be 186mph. You may need to consult your owner’s manual for this one as well but it makes sense to do it right. Your car’s performance will be greatly affected if you put the wrong tires on!
Treadwear Symbol
Next, we come to treadwear. This number will give you an indication of how long your tire is slated to last. The higher the number, the longer you’ll likely have your tires on the road. For example, a'80’ will mean that you’re likely to get 80k km out of your tires. Be aware though, this is an estimate, not an exact amount!
Leave it to a Pro
You don’t have to go on the tire buying journey alone! A CarHub service professional is here to give you all of the info and tips that a person could want when it comes to tires.
You can book an appointment to speak to a CarHub Product Advisor today, to get you on the road with a new set of tires today!