Understanding Tire Sizing

Many mechanics often get questions regarding wheel and tire sizing. This is one of the most common concerns of car owners when choosing for the right tires and wheels for their vehicle. Tread wear, traction, and temperature resistance are also some of the factors that you need to consider.

Let us discuss about tire sizing by using the metric tire, “P205 65 R16”, as an example.

The first letter tell you the class of a car tire. Thus, the letter “P” in our example stands for passenger tire. For tires labeled with “LT”, this means it’s a light truck. For tires with no letter found in the beginning, it’s a European metric tire.

The section width of a metric tire is measured from one sidewall to the other using millimeter. So, a “P205 65 R16” will have a 215mm section width.

The aspect ratio is a certain percentage (85%) of the section width of a metric tire. This denotes the height of the sidewall. Hence, our tire example above means that the height of the sidewall is 182.75 which is the 85% of our section width of 215 mm.

The letter “R” on our example means that the tire has radial construction.

The number “16” on our tire example refers to the wheel diameter measured in inches.

To cap it all, the tire “P205 65 R16” simply means that it is a passenger tire with radial construction and is 215mm wide.

Choosing the right wheels for your tires

Every car owner should understand that every tire should have the right wheels for it. One should not be larger or smaller than the other. Your tire and wheel should be right for each other to ensure safe driving. 

To make sure that you do not regret buying tires and wheels that do not work well for your vehicle, it is highly recommended that you seek advice from an expert such as mechanics. Most tire shops also have personnel who can help you choose the right tires and wheels for your vehicle.


Photo by Steve Garner