How to Check Your Tyre Size?
Tyres come in a whole lot of sizes. And because cars are often compatible with more than one size, choosing the right tyre for your car can be a real challenge.
Knowing your car’s tyre size may come in handy whenever you’re looking to buy new tyres. By knowing your tyre size, you can quickly narrow down your options and find one that falls within your range.
If you ask others about their tyre size, most of them will not know what to answer straight away. Maybe that’s why should to read this guide.
Are you part of the car owners who don’t have any clue on where to check your tyre size? Have you been asking yourself this question: “Where can I locate my car’s tyre size?” If yes, this guide is perfect for you.
Keep reading to learn how to find out more about tyre specifications, including your car’s ideal tyre size.
Method 1: Checking Your Resources
Find your user manual.
Let’s admit it. Checking your tyre size can be quite confusing, but it can be made easy by simply searching for your car’s user manual.
Your car’s user manual contains a detailed list of information about your car’s essentials, including its tyre size. The tyre size does not vary depending on your car’s brand since these measurements have been established to make tyre sizing easier and more convenient, both for manufacturers and car owners.
Most car dealers and tyre manufacturers also have online vehicle registration lookup tools to find out what tyre size is appropriate for your vehicle.
Determine your tyre specification.
Upon checking your tyre size in the user manual, you can compare and reassess whether the tyre size listed on your manual is accurate and correct with the current tyre size you have on your tyre’s sidewall.
Method 2: Assessing Your Current Tyre’s Size Through Its Sidewall
Understand the basics.
There are two types of tyre size measurements: metric and flotation. Metric is more commonly used and is more popular among consumers. The metric tyre is named after how it is measured, through the metric system.
Flotation tyres, on the other hand, are tyres used in agriculture since they’re designed to float over sandy surfaces and loose sediments. Unlike Metric tyres, flotation tyres are measured in inches.
Identify your tyre’s different sections.
Metric tyre size measurements are more difficult to understand. Usually, the metric sizing is divided into 5 sections, but it can span up to 7 different sections. These sections determine the composition, weight capacity, maximum speed capability, and more.
Service Type
The first section designates the service type. This refers to what type of vehicle the tyre is manufactured for. Some tyres are specifically designed for passenger type vehicles, while other tyres are made for larger trucks. Even though service type cannot be classified as a measurement, it helps in making a tyre choice.
To determine the service type of the tyre, check the series of letters and numbers on your sidewall. The first two letters are considered your car tyre’s service type. The letters are represented as follows:
P – Passenger
LT – Light Truck
ST – Special Trailer
T – Temporary
Some tyres don’t have letters indicating their service type. It’s safe to assume that these tyres are for passenger vehicles.
Section Width
This is the three-digit number that comes immediately after the service type. The section width measures the tyre’s overall width when it is mounted on a properly sized wheel.
It measures the widest point of the inner sidewall to the widest part of the outer sidewall. Generally, wider tyres give more traction to the vehicle. However, this could also mean that it will be heavier, causing more fuel consumption.
Aspect Ratio
The aspect ratio represents the height of the sidewall corresponding to the section width.
The higher the number of the aspect ratio, the taller the sidewall. Tyres with a higher aspect ratio gives a more cushioned ride. It also means lesser road-noise. Tyres with a lower aspect ratio is way better it terms of mobility, handling, and cornering
Construction
A letter that identifies the tyre's internal construction follows the two digits used to identify the aspect ratio. There are three types of tyre constructions: Belted Bias, Diagonal, and Radial.
Diagonal (or Bias) ply tyres employ layers of cord, which are formed in a crisscross pattern layered in several plies.
Using cords that stretch from bead to bead, these tyres allow the entire body to flex. When a tyre has added flexibility, it helps in having a smoother and more comfortable ride even in rough terrains.
Belted Bias tyres combine the diagonal ply casing of Bias tyres with belts (usually made of fibreglass) under the tread for increased traction and tread wear.
While these tyres will still have a crisscross layer of coils, they differentiate themselves with a steel stabilising belt that is found underneath the tread.
Radial tyres are the most common type of tyre construction. These tyres are made with layers of fabric cords positioned at a perpendicular angle to the centreline of the tread.
A radial tyre combines the technology of bias and belted bias. The cord construction extends across the tread but is perpendicular to the centreline of the tread.
Rim Diameter
The Rim Diameter can be determined by checking the next digits after the letter. It is one of the most important numbers on your tyre. The wheel or rim diameter plays a significant role in your tyre size. Often measured in inches, this is the wheel’s measurement from one end to the other.
Load Index
Your tyre’s load index identifies your tyre’s maximum load-carrying capacity. These numbers are a representation of the actual pounds or kilogram. That is why you need to check the tyre load index. This helps you know the maximum load your tyre can support when properly inflated.
Speed Rating
The last letter found on the series is called the speed rating. The speed rating tells you the maximum speed your tyre is tested corresponding to your tyre’s load index. The tyre’s speed rating is also an indicator on the tyre’s performance capability, from traction, braking, and handling.
It’s always good to have an idea about your tyre size. Whenever you’re still confused in choosing the tyre that works for your car, it’s best to consult and visit an expert to determine the right tyre for you. Don’t hesitate to visit your local tyre experts and seek for help on your tyre concerns.