How To Tell If Your Tires Are New Or Old

Believe it or not, a tire shop could equip your car with tires manufactured some time ago and sell them to you as if they were brand new. Technically, those tires would be new, as they've never been used, but it's also true that if several months have passed since they were properly made, the correct term would be 'unused aged tires.' Today, we'll explain how to tell if a tire is new or old, as this information is found on the tire sidewall and only requires a bit of interpretation.

Understanding Tire Sidewall Markings

You've likely noticed the multitude of numbers and symbols on tire sidewalls. One of the most important pieces of information you can find here are the tire measurements, which tell you if those wheels are compatible with your car's rims and, more importantly, if they match the homologated tire sizes listed in your vehicle's documentation.

Decoding The DOT Code

But what we're really interested in is how to determine the tire's manufacturing date. To do this, simply look at the tire sidewall and find the so-called DOT code. This is a sequence of letters and numbers engraved on the sidewalls that indicates information such as the manufacturer, the production plant, and the exact date of manufacture. This is the data we want to find, and the last four digits of the DOT code will tell us. The four-digit sequence indicates both the week and the year of tire manufacture. Let's illustrate with an example. Using the code 4025 as a reference, this tire was manufactured during the 40th week of 2025. The first two numbers correspond to the week, and the last two to the year. Another example could be 1321, or in other words, the 13th week of 2021.

This is one of the most useful pieces of information you'll find when buying new tires, as it allows you to check their age even if they've never been used. This is because tire shops often purchase large quantities of the most common tire sizes to offer availability to customers, which means they store them until a buyer appears. The same thing happens in tire factories. Production is diverted to distribution centers where tires can be stored for months before ending up on a car. And these timeframes are what cause wheels that appear to be new and are purchased as such to have actually been manufactured over a year ago.

Additional Information on Tire Sidewalls

Besides the manufacturing date, you'll find other interesting information on the tire sidewalls once you learn how to interpret it. Taking as an example one of the most common tire sizes, 205/55 R16 91V, we'll explain.