Guides
How old is my tire?
Find the letters DOT on the sidewall and read the last four digits of the code after them. The first two are the week, the last two are the year, so 3419 means week 34 of 2019. Manufacturers commonly advise a yearly inspection from six years and replacement by ten.
Finding the code
Every tire sold in the United States carries a Tire Identification Number moulded into the sidewall, starting with the letters DOT. It runs to eleven or twelve characters and most of it identifies the plant and the specification. Only the last four matter to you.
Two digits for the week and two for the year. 3419 is week 34 of 2019, which is late August. 0125 is the first week of 2025.
It is often stamped in full on one side of the tire only, with a shortened version on the other, so if the code you find ends before the four digits, look at the other face. On a fitted wheel that can mean looking at the inboard side, which is easier with the wheel turned to full lock.
What the number means
A tire ages whether it is used or not, because rubber is a compound that changes over time. Oils leach out, the compound hardens, and it grips less and cracks more. None of that shows in the tread depth.
Tire manufacturers commonly advise having a tire inspected once a year from six years old, and replacing it by ten regardless of how much tread is left. Those are the figures to work with. They are guidance from manufacturers rather than a legal limit, and the vehicle maker sometimes gives its own figure in the owner's manual.
The practical version: under six years, age is not the thing to worry about on that tire. Over ten, it is the only thing that matters.
Why this is worse in Central Texas
Heat and ultraviolet light are what age a tire, and Austin supplies both. A car parked outside through a run of hundred degree afternoons is doing to its tires what a decade in a cool garage would do more slowly.
You can see it before you can measure it. Fine cracking in the grooves between the tread blocks, or on the sidewall where it flexes, is the compound giving up. A tire with plenty of tread and visible crazing across the sidewall is not a tire to take on I-35 in July.
The spare is the one this catches. It sits under the boot floor untouched for a decade, looks perfect, and is well past the point where anyone should trust it at seventy in the heat.
When age beats tread
Tread depth and age are two separate tests and a tire has to pass both.
- Deep tread, ten years old: replace it. The rubber is the problem, not the pattern.
- Shallow tread, two years old: replace it, and ask why it wore that fast. Usually pressure or alignment.
- A used tire being sold to you: check the date code before the tread. A used tire with good tread and a twelve year old code is not a bargain.
- A spare that has never been used: check the date code, because nothing else about it will tell you anything.
- Visible cracking at any age: replace it, whatever the code says.
Checking yours
The decoder on this site reads the code for you: type the four digits into the tire size tool and it returns the week, the year, the age and where that sits against the six and ten year marks.
If you would rather not, the arithmetic is easy enough by hand. The reason to bother is that the answer changes what you should do next, and it is the one thing about a tire that no amount of looking at it will tell you.
Questions about this service
Where exactly is the DOT code on the tire?
On the sidewall, starting with the letters DOT in raised characters. The full code with the four date digits at the end is often on one side only, so if the one you find stops short, check the other face of the tire. Turning the wheel to full lock makes the inboard side reachable.
My tire has plenty of tread but it is nine years old. Is it safe?
It is at the point where it should be inspected rather than assumed good. Manufacturers commonly advise annual inspection from six years and replacement by ten. Look for fine cracking in the tread grooves and on the sidewall. In Austin heat, a nine year old tire with visible crazing should be replaced now.
Does an unused spare age too?
Yes, and the spare is where this catches most people. It sits under the boot floor for a decade untouched, looks perfect, and is well past the age anyone should trust at highway speed. Check its date code the next time you have the boot empty, not the next time you need it.
What if the code has only three digits?
Then the tire was made before 2000, when the format changed from three digits to four. Whatever the third digit says, a tire that old should be replaced without further investigation. That includes spares, which is the only place a code that old normally turns up.
Is there a law about tire age in Texas?
Not one that sets a maximum age for a passenger car tire. The six and ten year figures are manufacturer guidance rather than regulation, which means the judgement is yours. The vehicle maker sometimes states its own figure in the owner's manual, and that one is worth following.
Should I buy used tires given all this?
They can be sound value if you check the date code before the tread, and a good seller will show it to you without being asked. An inspected used tire a few years old with solid tread is a reasonable buy. One with deep tread and a ten year old code is not, whatever the price.
Tell us where you are.
Call or text (512) 573-0135. Give us the cross street or a dropped pin and we will tell you what it costs before anyone drives.
(512) 573-0135