This question comes up a lot, usually right after someone blows a tire out and also removes their trailer fender.
To find out tire age, on one sidewall is an oval (5/8" x 3/4") with 4 numbers in it (pre 2000 is 3 digits).
First 2 digits are week of the year, second 2 are the year.
Good info...
https://www.checktire.com/?lang=en
A code of 2212 is, 22nd week of 2012, thus about 11 years old.
Tires up to 3 years old can be sold as new.
Tires over 5 years old "should" be replaced.
When getting new tires, have them mount them so the date code is to the outside so you can read the date.
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