Tire Size Guide


A tire size guide is essential for new vehicle owners. By knowing how to read the information on tires, you will know not just the tire dimensions but other important information as well. For example, you will learn the load ratings and the speed too. 

The Tire Code

The information can be found on the side of the tires. The code will look like the following: 205/55 R 16 68 V. In some vehicles, there will be an LT or P at the start of the tire code. The LT stands for light truck while the P is for passenger cars. 

Aspect Ratio and Width

In the 205/55 R 16 68 V code, the 205 refers to the width of the tire. It is expressed in millimeters. The 55 is the aspect ratio or profile. The profile is equivalent to the tire’s sidewall high. This is in percentage multiplied using the width. The 55 is a percentage; 55% of 205 mm, resulting in 112.75 mm high sidewall. 

Some people may find the measurement confusing since it is in mm. To convert to inches, divide the width of the section by 25.4. The result will be the section width in inches. 

Dimensions and Construction 

To read a tire size guide, you must also be aware of the size and construction. In the 205/55 R 16 68 V example, the R is indicative of radial. This is the belt setup utilized for the tire. 

In some cases you may see a B instead.B is for bias ply. These are very rare on cars however. The 16 on the 205/55 R 16 68 V code refers to the tire hole diameter. This is used to determine the rim dimensions that can fit. The size is expressed in inches (i.e., 16 inches).

Speed Rating and Load 

The last two numbers (in this example, 68) refer to the load rating of the tire. This will match with a pounds load rating chart. The final letter is the speed rating of the tire. The further the letter is into the alphabet, the faster it will be. The letter V in this example means the tire is very fast. 

As this tire size guide shows, it is actually quite easy to decipher the size and specs of a tire. By knowing what those numbers and letters mean you will never make mistakes when buying a pair for the car. 

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