Are Car Tire Sizes Greek To You?

Nobody wants to learn the language of tires, except mechanics. That’s what we pay them to do, get their fingers greasy and fix our cars. When I say we, I mean, your average person. But, could it be that there is something that anybody can learn that would really help them out when they’re looking for tires?

Maybe there is a bit of knowledge that can be gleaned from something we look at all the time. I know I learned something. Normal people, it seems, or at least people like me, just look at the label on the side of the tires already on their cars when they need new tires.

I always did so anyway. Then you can compare this name with other tires in the price range and make your choice. It seems simple. But is it wise? If you really know nothing about tires, don’t understand what the label on the side of your existing tires says, then you would never know, would you?

I didn’t. In fact, a whole array of available choices in tires is out there, and it’s up to you to pick the right one. If you look at an average tire label, it will read something like this “P175/50R 14 80Z”. This little series of letters packs quite a lot of information, if you know what you need to do to unpack it.

But if you’re clueless, like I was, then it is useless to you. If you are without a clue with regards to understanding tire sizes, then the information that follows will help you. On any tire label, the first letter tells what sort of vehicle should be using the tire.

In our label above, the tire is intended for a passenger car. It breaks down as follows. P is for passenger cars, LT is for light trucks, and T is used to designate your spare, or temporary, tire.

The number that immediately follows the first letter is the width of the tire in millimeters. 175, then, means that our example tire is 175 millimeters wide. After the first number in the label comes a slash and then a second number.

This second number tells us the ratio of the height and the width. Our tire has a height which is 50% of the width. It is a general rule of thumb that tires with a lower ratio of height to width are performance tires.

The letter following the ratio of height to width tells us the type of the tire. In our example, the R stands for radial. Following the type indicator comes the number telling you how much a tire can carry, its load index.

In our tire, it is 80. Consulting the Maximum Load-Carrying Capacity chart for this number, as it is indicated on your tire, will tell you exactly how much four tires of the same capacity can safely carry.

The last sign on the label tells you how fast the tire is rated for. Our example tire has a rating of Z, which means that it is rated for speeds of over 150 mph. It’s quite a speedster! The other ratings are S, for up to 112 mph, H, for up to 130, and V, for up to 150 mph.

It is imperative that your follow these guidelines and not go faster than your tires are rated, because as you increase your speed, you increase friction. Friction heats up your tires, and as you tires get over heated, their treads can come unglued from their belts, which is never a good position to find yourself in.

Speed ratings let you know exactly how fast you can go and not risk your life. These signs are the most basic things that you need to know about what tires will fit on your car.

And see, even you, a normal person, could pick them up. So put them to use! There are other things to consider when you are choosing tires, such as mileage and weather conditions.

Don’t hesitate to ask your dealer about anything in particular you need of your tires, or come across a label sign you don’t understand. They will inform you of what you can get or teach you the new term.