What Do The Number On The Car Tires Mean?

What Do The Number On The Car Tires Mean

A tire is a circular component of a road vehicle that helps in protecting the rim of the wheel and also helps in delivering better performance of the vehicle. When you go for a drive on your vehicle, it is very much essential to balance your car tire as an imbalance can cause fatal accidents.

Along with the balance between the tires, it is also necessary to keep changing the tires of the vehicle so that the vehicle never fails in delivering good performance. So, the owners or the drivers have to know in detail about the best time to replace your car tire.

When you have a careful look at the tire of your car, you will notice that there are certain numbers across the side wall of the tire. These numbers indicate important information regarding the tire such as the size of the tire, how much load can the tire bare and so on. In the blog below, there is a complete description about what the numbers on the car tire means.

What is the Meaning of Numbers on the Tire of a Car?

read number on car tires

Photo Credit: http://www.continentaltire.com/news/how-read-tire-sidewall

When you have a look at the tire of the car, you will notice that the numbers are written in the following pattern:

P215/50R17

What is the Meaning of the First Letter?

The first alphabet on the tire can be P, LT, ST or T. Sometimes there is the absence of the first alphabet. The first alphabet denotes:

  • P: P stands for Passenger car, and it indicates that the tire is the P-metric type. The vehicles that are perfectly suitable for such tires are either lightweight trucks or cabs. These types of tires are widely in use.
  • LT: Light Truck types of tires are usually recommendable for heavy weight vehicles like sports utility vehicles or heavy-duty pickup trucks. The design of these tires enables them to easily bear all type of additional weight that is put on them.
  • ST: Special Trailer types of tires are only for special vehicles like boats or aircraft. It is highly advisable not to use these tires for small and light weight vehicles.
  • T: Temporary types of tires are especially for spare tires only. You can make use of these tires when you need to replace the car tire.

When there is an absence of an alphabet before the three digit numbers, then it indicates that the tire is of metric type.

What does the Three-Digit Number Indicate?

read number on car tires

Photo Credit: https://en.wikipedia.org/wiki/Tire_code

The three-digit number after the first alphabet indicates the cross section width of the tire. The unit of the quantity is usually in millimeter.

For instance, the first three digits are 247 then it is appropriate to say that the cross section width of the tire is 247 millimeter.

What does the Two-Digit Number Indicate?

The two-digit number after the three-digit number, separated by an oblique, indicates the aspect ratio of the tire. The aspect ratio is regarding from the rim of the tire to the head of the tire.

For instance, if the two-digit number after the three-digit number is 60, then it is much appropriate to say that the side wall of the tire of the car is 60% of the cross section width of the tire. It also denotes that the higher the aspect ratio, the taller will be the sidewall of the tire.

In some tires, there might be an absence of the two-digit number. In such cases, you can consider the aspect ratio to be 82%.

What does the Next Letter Indicate?

The alphabet after the two-digit number provides an indication of the internal construction of the tire. The alphabets are R, B or D.

  • R: R indicates the radical design of the tire that is highly common nowadays.
  • B: If the next alphabet is B, then it means that there is a presence of belt beneath the strand vicinity of the tire. These designs are now out of fashion and no longer in use.
  • D: If the alphabet is D then it means that the tire is moving internally in a diagonal manner. This type of design is mostly for either lightweight trucks or spare tires.

What does the Two-Digit Number Indicate?

car tire number

Photo Credit: http://www.wheels.ca/guides/torque-mean-gearhead-terms-explained-2/

The two-digit number that is after the alphabet in the tire is for referring to the diameter of the rim of the tire. The measurement of the diameter of the rim of the tire is in inches. The different size diameters that are highly in use are 8, 12, 13, 14, 15, 17, 188, 19, 20, 22, 23, 24, 26 and 28. These types of rims involve all type of vehicles ranging from lightweight trucks to sport utility cars.

For instance, if the two-digit number is 22 then you can appropriately say that the diameter of the rim of the tire is 22 inches.

What does the Combination of Two Digit Number and Alphabet Indicate?

The combination of the two-digit number and the alphabet indicates the service of the tire. This combination also helps in recognizing the load index and the speed rating of the tire of the car.

It is very important to know in detail about the numbers that are present on the tire of the car. It is important that you buy the perfect tire for your vehicle by inspecting various factors like the speed index of the tire, the diameter of the rim of the tire, aspect ratio and many more factors.

In the above blog, there is a mention of a complete guide that will help you know what different numbers on tire indicate. Now you can not only buy a tire without even consulting any expert but also be a pro and explain the importance of different numbers on the car. Now you know that something written on the tire is not sheer design but is essential information.