How to check tire size in my car?

2 weeks ago by Maverik

No matter, what car or vehicle you are driving, it is always important to get the right tire size. This is needed for your safety and also to improve the overall performance of your vehicle.

When it comes to reading tire sizes, many of you are not equipped with knowledge. Unless you learn to read tire sizes, you will have a hard time finding the right tires. The good news is checking tire size is easy. Because all the information you need is present within the vehicle or in the user manual. In this guide, we will give you all the details you need to know.

Finding the Tire Size

Many of you must be wondering where to find the tire size. You should start searching the user manual because that’s where you find all the details of your vehicle. In case, you are unable to find the tire details in the manual, look for these locations:

  • Within the gas tank hatch
  • Inside the glove box door
  • The driver’s side doorjamb

You can also find tire size data on your current tires. If the current tires are of the right size, you can buy the same again.

How to Read Tire Size?

Just finding the tire size details is not enough if you cannot read them. You need to understand what each letter or number stands for. In this case, we will use the example: P255/70R15 90S

1. Letters P & LT
The number sequence of a tire in most vehicles starts with the letter P which means “passenger car” tire type. This signifies that the tire is designed for passenger vehicles only. This includes SUVs, cars, minivans, and other light duty pickup trucks.  If the sequence starts with the letters “LT” it means “light truck” type tire. These tires are designed for vehicles that are capable of carrying heavy loads. The letter “T” stands for “temporary” and it means spare tire. If it has “ST,” then it means “special trailer.”

2. Width
The first number that you see in your tire size information is the width in millimeters. For example P255. This means the size “P225” is for a passenger vehicle that has a width of 225 millimeters.

3. Aspect ratio
The next number after the slash mark is the aspect ratio of the tire. This tells you how tall your tire’s profile is. For example, 70. This means your tire has an aspect ratio of 70. This indicates that the tire’s height is 70% of its width. 

4. Construction
After the aspect number, you will see a letter that indicates the type of internal construction of your tire. There are two types of construction:
R – Radial
D – Diagonal or Bias Ply

5. Rim diameter
The next number in the sequence is the rim diameter code, in inches. For example, a tire with 15 fit a rim with a 15-inch diameter.

6. Load index
The next number in the sequence is the load index. It tells you how much weight your tire can support.

7. Speed rating
The last number in the sequence is the speed rating of your tire. Tires that come with higher speed ratings, give you better performance. You have to make sure that you get tires of the same or higher speed rating to maintain the vehicle’s performance.

Once you go through each part of the tire number sequence, you will figure out what type and size of tire you need. By following this step-by-step explanation, you should be able to read the tire size of your car easily.

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