How to Measure Tire Size

Importance of tires should never be taken for granted. A question would definitely arise in your mind regarding how a tire size is determined. There are some tips regarding the measurement of tires. Tires are not available in uniform sizes and they are very much dependent on the type of vehicle one drives. Without having improper information and detail, there is a lot of chance that you will end up installing incorrect sizing that will have a negative effect on the overall performance of the vehicle. This is the reason that one must know how the tire size is measured.

Here are some different ways to measure tire in a correct way.

1. A measuring tool has to be used which is actually a very simple. A vinyl tape measure is needed, it is that type which the dressmaking shop use. As an added information, tires are measured in millimeters, so there is no need to use inches as a unit of length.

Tire Size

2. Now, the tire has to be inspected. Look at the sidewall of the vehicle’s tires. The brand of the tire is the first thing which will be seen. Dunlop, Michelin and Firestone are some examples. There will also be a labeled series of numbers and letter that signifies the load capacity, heat resistance, durability, dimensions and so on. This is also an indication that whether the tires were built for regular roads, rough/smooth terrain and wet/icy roads.

3. The letters have to be given attention because you don’t want to remiss thinking that tires are measured with numbers. That is correct but tire sizes are also determined using letters. Here is an example for clarity.

P – Passenger Vehicles

C – Commercial

T – Temporary Spare

ST – Special Trailer Service

LT – Light-Truck Metric Vehicles

4. When the tires are identified by letters that specify their purpose, a series of numerical data can be seen after the letter that reads like this;

  • P255 – The number 255 in this case represents the section width of the tire in millimeter as an international standard unit of length.
  • P255/60 – In this case, the number 60 is the aspect ratio or the size of the tire from the rim to the tread. It is also known as the sidewall height.
  • 8, 10, and 12 – These represent the wheel and tire diameters, they always match for the vehicle to run properly. To be sure that you are reading the tire and wheel diameter details of the tire, the letter ‘R’ has to be checked which is preceding it. This letter stands for Radial construction which is still the most trendy internal construction used in the tires.

In the end, properly inflated tires are very important to come up with the accurate results. The suggestions shared here are basically ideas to measure size of a vehicle’s tires. Although it is complicated but it will take some time to get perfect. However, you will learn more about doing this with the help of a good car mechanic.