How Do You Know The Expiry Date Of A Car Tyre?

2120 on this tyre means 21st week of 2020. There are 4 weeks in a month. The 21st week of the year should be in May. So the tyre was manufactured in May 2020. It will expire in May 2024.
3119 means 31st week of 2019. The 31st week of the year is in August. So the tyre was manufactured in August 2019 and should expire in Augsut 2023.

According to the Federal Road Safety Corps, your car tyre has a life span of four years from the date of manufacture. Once that four-year period elapses, your tyre is deemed to have expired. If you drive your vehicle with such a tyre, you have broken the law, and there is a penalty for that.
But how do you know when your tyre was manufactured? Look closely at the front side of the tyre (the side that faces the outside when the tyre is mounted on the wheel). You will see a number with four digits as shown in the attached photos here.

When you buy a new tyre that is two years old already, you have been shortchanged by two years already. The road safety agency will not look at the receipt of purchase of the tyre.
Note that sellers of used cars usually wash them to make them look new. Don’t bother about how new a tyre looks and the talk about Grade A or Grade B tyres. Search for its date of manufacture first. If you can’t find it, look for another tyre. It is only when its year of manufacture shows that it has not expired that you can check if the tyre is still in good condition or not.

Knowledge is power.