How to tell how old your tires are
Tread depth is the thing most people check, but tires also age. Rubber changes over time whether the tire is driven every day or sits in a trunk, so it is worth knowing when your tires were made. The good news is that the date is printed on every tire; you just need to know where to look.
Finding the DOT code
Look on the sidewall for the letters DOT followed by a string of letters and numbers. That string identifies where and when the tire was made. The date is the very end of it: the last four digits. On some tires the full code is only on one side, so if you cannot find it, look at the side facing under the vehicle. A flashlight helps.
Reading the four digits
The first two digits are the week of manufacture and the last two are the year. For example, 2419 means the tire was made in week 24 of 2019. Write down the code for each tire; they are not always the same, especially if tires were replaced one at a time.
Why age matters
As tires age, the rubber can harden and lose some of its grip and flexibility, even if the tread looks deep. Many vehicle and tire makers advise having tires inspected as they get older and replacing them after about ten years regardless of tread, a commonly cited guideline. Heat, sunlight and long periods sitting still can all speed up aging, so a tire that has been parked for a long time is not automatically in good shape just because it has not been driven much.
Do not forget the spare
Age matters even for a spare that has never touched the road. A spare can look brand new and still be old enough that it should not be relied on. When you check your tires, check the spare too, and include it when you think about replacements.
Keep a record of the dates
Once you have found the codes, write them down somewhere you will find them again, such as a note on your phone along with the date you bought the tires. That makes it easy to see later how old each tire is without crawling under the car with a flashlight.
This is especially useful after buying a used vehicle. The tires on it may be older than the mileage suggests, particularly if the vehicle sat unused for a long stretch, and the date code is the only reliable way to know. When new tires are installed, you can also ask to see the code on each one so your record starts out complete.
Warning signs to look for
Whatever the date code says, have a tire inspected if you see:
- Cracking in the sidewall or between the tread blocks
- Hardening, where the rubber feels stiff rather than slightly flexible
- Sidewall checking, a pattern of fine surface cracks
These are signs the rubber is breaking down. If you are not sure whether what you see is normal, bring the tire in and ask, or call with the DOT code and a description.