Tire Sizes – Everything You Need to Know

When it comes to tires, size matters. That’s why it’s important to know about the different tire sizes out there before you go shopping for new ones.

In this blog post, we will discuss the most common tire sizes and what they mean for your car. We will also provide a guide on how to choose the right size for your vehicle. So, whether you’re in the market for a new set of tires or just curious about the topic, read on!

Everything You Need to Know About Tire Sizes

All tires come with a set of numbers and letters that tell you important information about them. These markings tell you the tires size, amongst other details, and they can be found on the sidewall of every tire.

Where to find your tires size?

The size of your tires is usually located on the sidewall of your tire, and it should look something like this: P215/65R15. These numbers will determine the size of the tire and next we will have a look at what they all mean.

Tire Size Meaning

Vehicle Tire type

The first thing you’ll notice when comparing tire sizes is a letter, which indicates what kind of vehicle the tire has been designed for. Here are the most common letters you’ll see:

P: Passenger Car

T: Temporary Spare Tire

LT: Light Truck

C: Commercial Truck

ST: Special Trailer

Now that we know what the letters mean, let’s take a closer look at the numbers.

Tire Width

The width of your tire is the first number in the series and it is measured in millimeters. This measurement is taken from the widest point of the tire, from sidewall to sidewall.

For example, in a size P215/65R15 tire, the width would be 215 mm.

Wider tire sizes provide better stability and handling and are found on larger and more high end vehicles. They also come at a greater cost and may not be necessary for all vehicles.

Narrower tires are more fuel-efficient and easier to control, but they may not provide as much grip on the road. They are also more susceptible to damage from potholes and other objects on the road.

Aspect Ratio

The next number is the aspect ratio, and this tells you the height of the sidewall. Sometimes it is also called the tire Profile.

In our example P215/65R15 tire, the aspect ratio is 65, which means that the sidewall is 65% as tall as the width of the tire. This means that tires with the same aspect ratio will not always be the same height, as the height of each tire will depend on the width of the tire.

It is simple to work out the height of a tire in mm. Start off by finding out the width of the tire and then multiplying it by the aspect ratio percentage. For example, for a tire size P215/65R15, we do 215 x 65% which gives us a mm height of 139.75mm.

While it is not necessary to work out the height of a tire in mm, this measurement is important because it affects the overall height and size of a tire. This is important to be aware of as not knowing that the aspect ratio alone does not represent the height and size of a tires sidewall can lead you to purchasing tires that may not be suitable for your vehicle.

A tires height will affect the ride of your vehicle, and how well it handles. A taller sidewall will give you a softer ride, while a shorter sidewall will give you a firmer ride.

Rim Diameter

The last number in the series is the rim diameter, and this is measured in inches. This is the diameter of the wheel that the tire will be mounted on. In our example, the rim diameter is 15 inches.

If you are purchasing new tires, the diameter of your rim will be exactly the same as your old tires if you are not changing wheels. This information can also be found printed on the inside of your rim, on the inside of the drivers door jamb, or in your owner’s manual.

Other tire markings

Alongside the tire size markings on every tires sidewall, you will also find other important markings. These include:

Load Index: This is a number that tells you how much weight your tire can carry. The load index is always followed by a letter, with the letter ‘P’ meaning passenger car tire, and ‘T’ meaning temporary spare.

Speed Rating: The speed rating is the last letter in the series of numbers and letters on your tire sidewall. The speed rating tells you the maximum speed your tire can handle. The speed rating is not the same as your vehicle’s top speed, but rather the maximum speed that the tire can handle when it is carrying the load index.

Now that you know how to read a tire size, let’s take a look at how to choose the right size for your vehicle.

How to choose the right tires

When it comes to choosing tires, there are a few things you need to keep in mind.

Check your current tires size

First, you need to make sure that the tire sizes you choose will fit on your vehicle. This means checking that the size of the tires will fit the same size rims that are currently on your vehicle. The easiest way to check this is to look at the rim diameter on your tire and ensuring it matches up with the rim diameter printed on the inside of your rim.

Secondly, you also need to make sure that the width and height of the tires will not cause any clearance issues. Fitting larger tires without checking this beforehand can lead to your tires rubbing against the your vehicle’s wheel arch when turning which is dangerous and will cause damage to both your tires and your vehicle.

The easiest way to ensure you buy the right size tires for your vehicle is to purchase the same size tires you currently have on your vehicle. Your vehicles handbook will also list the specific sizes and type of tires that are recommended for your vehicle.

If you want to purchase a different tire sizes, it is best to consult with a professional who will be able to advise you on what size is best suited for your vehicle.

Another thing to keep in mind is that changing the size of your tires will also change the speedometer reading on your vehicle. This is because larger tires cover more ground per revolution than smaller tires.

This means that if you fitted larger tires without calibrating your speedometer, you would be exceeding the speed limit without realizing it. To avoid this, you should have your speedometer calibrated.

Deciding what kind of tire you need

Choosing the right kind of tires for your vehicle is just as important as choosing the right tire sizes. There are many different types of tires available on the market, each suited for a different purpose. The most common types of tires are all-season, summer, and winter tires.

All-season tires are designed to provide good traction and handling in a variety of weather conditions including rain, snow, and dry conditions. They are a good comprimise between the higher performance summer tires and winter tires, making them very versatile.

They also provide a comfortable ride and are the most common type of tire found on passenger vehicles.

Summer tires are designed to provide good traction and handling in warm weather conditions. They are made from a softer rubber compound which means they wear out faster than all-season tires. They also provide some of the smoothest and quietest rides and are more suitable for high performance vehicles with their need for increased grip and handling.

Winter tires are designed to provide good traction and handling in cold weather conditions including rain, snow, and ice. They are made from a harder rubber compound which means they last longer than summer tires. They also have deeper treads which helps to disperse water and prevent hydroplaning.

It is important to note that you should not mix different types of tires on your vehicle. For example, if you have winter tires on the front and all-season tires on the back, it can cause your vehicle to handle poorly.

Can I put different size tires on my wheels?

It is generally not recommended to put different size tires on your vehicle. This is because it can cause a number of issues such as throwing off the speedometer readings, making your vehicle handle poorly, and causing premature wear and tear on your tires and suspension.

However there are situation where putting different size tires on your car may be beneficial. Some vehicles come as standard with different size wheels on the front and the back of the vehicle. This is because depending on which wheels are the driven wheels of your vehicle, wider tires may be fitted to aid with traction,

Stretched tires

Stretching tires is when you put a tire on a rim that is too small for the rim. This gives the tire a stretched and lowered look which is popular in some car communities. It is dangerous to drive on overly stretched tires due to the reduced contact patch which reduces your vehicles grip and handling.

However, it is important to note that stretched tires are more susceptible to punctures and can cause your rims to become damaged from the tire rubbing on them.

If you decide to stretch your tires, it is important to consult with a professional who will be able to advise you on what size rim is best suited for the size of tire you want to use. They will also be able to help you install the tires correctly so that you do not damage your rims or tires.

Plus sizing

Plus sizing is when you put a tire on a rim that is larger than the factory size. This can be beneficial as it can increase your vehicles grip and handling as well as improve the look of your vehicle.

It is possible to put a wider tire or a taller tire on your rim. However you will not be able to put a tire with a larger rim diameter on your vehicle as it will not fit.

If you decide to plus size your tires, it is important to consult with a professional who will be able to advise you on what size tire is best suited for your rims and vehicle. They will also be able to help ensure that the tires fit on your vehicle without causing any fitment issues.

Conclusion

Now that you know all about tire sizes and how to choose the right ones for your vehicle, you’ll be able to make an informed decision next time you need to purchase tires. Keep these things in mind, and you’ll be able to choose the right tires for your vehicle.

We hope you enjoyed this article and found it informative. If you have any questions then please leave a comment below or get in touch via email or through social media and we will read and respond to every comment, email or question. Thanks for reading!