You can identify the age of your tyre by an imprinted coded date that indicate when that tyre was manufactured. The four-digit tyre code is usually located on the tyre sidewall. However the best way to determine the age of the tyre is by looking at the serial number. This is sometimes called the DOT Code. This code has information on who manufactured the tire, where it was made, as well as other tracking information. TIt also shows that the tyre has passed the legal manufacturer requirements. For example of a tyre manufacture DOT code is 3817. In this code the first 2 digits are the week while the last 2 digits are the year. In this example, the tire was made in the 38th week of 2017.
If your tyre has a 3-digit number in the serial number, it was manufactured before the year 2000, and you should replace it regardless of tread depth. Tyres are considered to be “new” and suitable for retail sale for up to 5 years from the original date of production with proper storage. To check for the serial number of your tire to determine its age, you can remove the tire or ask your service professional or tire shop.