How to Read a Tire Date Code

Note what prompted the check

Start by writing down why the tire's age matters right now. Common triggers include fine cracks in the sidewall or between tread blocks, rubber that looks dull or feels hard, a slow leak, a vibration that developed gradually, or a bulge. Often there is no symptom at all. You may have bought a used vehicle, a shop may have installed tires that looked new, or an RV, trailer, motorcycle or classic car may have been parked for months.

Record when each sign appears and on which tires. Examples include low pressure after cold nights or vibration only above a certain speed. Also note recent changes such as new tires, a rotation, a pothole strike or long storage in the sun. Include the spare, because it ages even when it is never used. These notes help you avoid blaming an old date code for a problem that has a different cause.

Age or something else?

Rubber begins to age from the day it is cured, whether the tire is driven or stored. Some signs support age as the cause: fine, crazed cracking spread across the sidewalls of several tires with similar dates, especially tires that sat outdoors or were rarely driven. Age becomes a weaker explanation when only one tire is affected or when that tire is much newer than the rest.

Other causes produce similar signs. Running below the inflation pressure on the vehicle placard overheats the sidewall and can crack the shoulders, usually along with wear on both outer edges of the tread. A bulge in one spot after an impact points to internal cord damage rather than age. Vibration can come from wheel balance, a bent wheel or a separating belt, and only an inspection tells these apart. Many confusing readings are simply misread codes, because the plant and size characters printed before the date are not part of it.

Finding and reading the date code

Look on the sidewall near the rim for the letters DOT followed by a string of letters and numbers. This is the Tire Identification Number. The full number, including the date, may appear on only one side, so if you find a short code, check the other sidewall. On many vehicles that side faces inward, so turn the steering to full lock or shine a flashlight from below. The date is the last four digits, often set slightly apart in an oval. The first two digits give the week and the last two give the year. For example, 3319 means the 33rd week of 2019, and 0124 means the first week of 2024. The format is the same on Michelin, Goodyear, Bridgestone, Continental, Cooper, Pirelli, Toyo, Hankook, Yokohama and other DOT-marked passenger, light truck, semi truck, trailer and motorcycle tires.

Tires built before 2000 used a three-digit code: two digits for the week and one for the year. A code of 258, for example, means the 25th week of a year ending in 8. Some 1990s tires added a small triangle after the code to mark that decade. Any tire with a three-digit date code is now more than 25 years old. If you cannot find a date code, check both sidewalls before drawing conclusions. The code may be worn, painted over or ground off. Some off-road, racing and ATV tires, as well as tires built for other markets, are not marked in the DOT format. Treat an unknown date as unknown, not as new.

After reading the date, continue with checks you can safely do in a driveway. Compare the codes on every tire and the spare. Measure tread depth with a gauge in several grooves. Check inflation pressure when the tires are cold and compare it with the vehicle placard on the driver's door jamb, not the maximum printed on the sidewall. Look for cracks, bulges and cuts on the visible sidewall. Leave some checks to a qualified technician: the inboard sidewall on a lifted vehicle, the inside of the tire, and any suspected belt separation. A technician can dismount the tire if needed.

What the result establishes

The date code proves only when the tire was manufactured. It does not show when the tire was installed or how it was stored, and it says nothing about internal condition. A tire sold as new may have spent time in inventory, so its date can be older than your purchase receipt. No US federal law sets a tire expiration date. Common industry guidance calls for a yearly professional inspection once a tire is about five years old and replacement no later than ten years from manufacture. Some vehicle makers call for earlier replacement, often at six years. Follow the owner's manual and the tire maker's guidance for your specific tires.

Interpret the age together with your other findings. An old tire with fine cracking on all sidewalls supports age as the main issue. A young tire with cracks points back to underinflation, overloading or storage exposure, and those causes must be corrected or a new set will crack too. An old tire that looks fine still needs an inspection, because aging inside the casing is not always visible. Confirm the cause before buying replacements.

Urgency and next action

Stop driving on a tire if you see any of these signs: a sidewall bulge, exposed cords or steel, cracks deep enough to reach the cords, tread separating or missing chunks, repeated air loss, or a vibration that keeps getting worse. Fit the spare only if its own date code and condition are acceptable; otherwise have the vehicle towed. Neither the date code nor a visual check can tell you how many miles a tire has left, so do not rely on any estimate.

Bring the shop the following information: the full DOT code and date for each tire, the tire size, load index and speed rating from the sidewall, the placard pressures, your tread depth readings and your symptom notes. Replacements should match the placard size and meet or exceed its load and speed ratings. On all-wheel and four-wheel drive vehicles, ask about drivetrain compatibility, because the vehicle maker may require matched tire diameter or tread depth across the axles. Trailer tires need trailer-rated construction with enough load capacity for the trailer.