If you have ever looked at the sidewall on any of your car tires then you most likely have been completely confused with all the letters and numbers that are on there. What does it all mean? Well, here’s a quick look at some of the most important information you will see on the tire, and what it means.
Let’s start off with the most common set of numbers you see on any type of tire. It will look like this – P275/R50-18, or something similar to that. All tires have their own numbers, and you may have a different size.
“P” – This letter means that this is a passenger tire. It is designed to fit on cars, light trucks, minivans, etc. Tires designed for SUV’s and trucks can come with “LT” at the beginning. This stands for light truck.
“275” – This lets you know the section width of any particular tire in millimeters.
“R” – This simply stands for a radial tire.
“50” – This number is used for determining the sidewall height of the tire. The lower the number the lower the height.
“18” – The tire size for the rim you need for it to fit on. It’s important for you to match up the tire size with the same rim size. You never want to try and fit on an 18 inch tire on a 17 inch rim.
Other numbers and letters are also found all around your tires and each has different meanings as well. Some are just to identify the manufacturer and they also add some codes for their own use.
A couple of other ones of interest though include the tire speed rating for the particular tire. It can be a letter such as an “S”, which means it is designed to be driven at speeds up to 112 mph. We have a speed rating list on another page on this site to help you better understand all of the ratings and what they mean.
You can also discover exactly when your tires were manufactured as well. You will find a set of digits between 1-52 that tell you the week of the year in which the tire was made. Next to this number will be another number such as 09, 10, etc. This tells you the year they were made. So, if you see something like 12-09, you know that the tire was made in the 12th week of 2009. It’s nice to know when your tires were made for warranty purposes.
Other numbers will give you the tire’s traction, temperature, load and treadwear ratings as well.