Find Your Tire Manufacturing Year Information Guide

Understanding Tire Manufacturing Dates and DOT Codes

Every tire sold in the United States contains a Department of Transportation (DOT) code that identifies when and where the tire was manufactured. This code appears on the sidewall of the tire and provides crucial information about the tire's age. The DOT code is a series of characters that includes the manufacturing date as its final component. Understanding how to read this code helps you determine whether a tire is new, recently manufactured, or older. The manufacturing date matters because tires can degrade over time even when stored properly and never used on a vehicle.

The DOT code format typically begins with the letters "DOT" followed by plant code, size code, and ends with the week and year of manufacture. For example, a code ending in "3219" means the tire was made in week 32 of 2019. The first two digits represent the week of the year (ranging from 01 to 53), and the final two digits represent the year. This system has been standard since 2000, making it consistent across all tire manufacturers including Michelin, Goodyear, Bridgestone, Continental, and Pirelli.

Locating the DOT code on your tire requires checking the sidewall, which is the outer surface of the tire. On some vehicles, you may need to look at both the inner and outer sidewalls, as manufacturers sometimes print the code on both sides. The code is printed in small characters and may be harder to read on older tires or those exposed to significant sun damage. Using a flashlight and rubbing your finger across the sidewall can help you locate and read the numbers more clearly.

Practical takeaway: Before purchasing a tire, ask the retailer to show you the DOT code on the sidewall. Record the last four digits to verify the manufacturing date. Tires older than five to six years may have experienced degradation, even if they appear to have significant tread remaining.

How to Read the DOT Code Correctly

Reading the DOT code requires understanding the specific position and meaning of each character. The code always ends with four digits that represent the manufacturing date. To avoid confusion, look for the longest string of numbers and letters on the sidewall – this is your DOT code. The manufacturing date is always the last four digits of this entire code. For tires manufactured after January 1, 2000, this format is consistent and standardized across all manufacturers worldwide.

Breaking down the date format: the first two digits of the final four represent the week of manufacture, and the last two digits represent the year. If you see "2817," this means week 28 of 2017. Week numbers run from 01 through 53, with week 01 being the first full week of January and week 53 appearing only in years where January 1st falls on a Thursday or later. To convert the week number to a calendar month, use this general guide: weeks 1-4 are January-February, weeks 5-8 are February-March, weeks 9-13 are March-April, weeks 14-17 are April-May, weeks 18-22 are May-June, weeks 23-26 are June-July, weeks 27-30 are July-August, weeks 31-35 are August-September, weeks 36-39 are September-October, weeks 40-43 are October-November, and weeks 44-48 are November-December.

For tires manufactured before January 1, 2000, the date code format differs. Older tires use a different system where the final characters may include letters or use a different numerical arrangement. If you encounter a tire with only three digits at the end of the DOT code, it was manufactured before 2000. These tires are now nearly 25 years old and should not be used on vehicles, regardless of tread depth, due to rubber degradation over time.

Practical takeaway: Write down the DOT code from your tires and practice reading several examples. Keep a record of the dates when you purchase new tires. This documentation helps you track tire age over time and make informed decisions about replacement or rotation.

Tire Age and Safety Considerations

Tire age affects safety even when tread depth appears adequate. Rubber is a material that degrades over time due to exposure to sunlight, heat, oxygen, and ozone. This oxidation process causes the rubber to become brittle and lose elasticity. The National Highway Traffic Safety Administration (NHTSA) and tire manufacturers recommend replacing tires when they reach six years of age, even if the tread depth remains acceptable. For tires stored in vehicles that are not driven regularly, many manufacturers recommend replacement at ten years of age maximum, with inspection by a professional at the five-year mark.

Research has documented that tires older than six years experience increased rates of blowouts and failures. A study examining tire failures found that tires manufactured more than five years before the failure date were significantly more likely to have failed compared to newer tires. Environmental factors accelerate aging: tires subjected to intense heat, direct sunlight, high humidity, or salty air environments degrade faster than those in moderate climates. Underinflation also accelerates tire degradation because it causes excessive flexing and heat buildup within the tire structure.

Different driving conditions place different demands on tires. Tires used in stop-and-go city driving experience more stress than tires used primarily on highways. Commercial vehicles and those used for towing tend to degrade tires faster than personal vehicles used for commuting. Additionally, tires that have been repaired, especially repairs involving the sidewall, may have compromised structural integrity that could worsen with age. Even a properly repaired tread puncture can become problematic as the surrounding rubber ages and loses flexibility.

Practical takeaway: Check the manufacturing date on all four tires on your vehicle, including the spare tire. If any tire is six years old or older, schedule a professional inspection to assess overall condition. Document the manufacturing dates of your current tires and set a reminder to check them annually after the five-year mark.

Finding Manufacturing Dates on Different Tire Types

The DOT code location remains consistent across all tire categories, but certain tire types may present challenges when locating the code. Summer tires, all-season tires, winter tires, and performance tires all carry the same DOT code on the sidewall. However, the sidewall location can vary slightly depending on the tire's design and size. On some tires, the DOT code appears on the outer sidewall facing outward from the vehicle, making it easy to read. On other tires, particularly some European brands, the code may appear on the inner sidewall facing toward the wheel or vehicle interior.

For vehicles where the inner sidewall is difficult to access, you may need to remove the wheel to read the complete DOT code on that side. Many tire shops will help you locate and read the DOT code at no charge. They can also photograph the code for your records. Specialty tires, including truck tires, motorcycle tires, and trailer tires, all contain DOT codes following the same format. Pickup truck tires and SUV tires use the identical system as standard passenger vehicle tires, making the reading process straightforward.

Run-flat tires, which are designed to function temporarily even after puncture, display their DOT codes in the standard location. Low-profile tires on high-performance vehicles have DOT codes in the same position as standard tires, though the smaller sidewall surface area may make the code slightly smaller and potentially harder to read. All-terrain tires and mud-terrain tires used on trucks and off-road vehicles follow the same DOT coding system. Regardless of tire brand – whether Bridgestone, Michelin, Goodyear, Continental, Pirelli, Dunlop, Cooper, Yokohama, Hankook, or others – the DOT code format and location remain identical.

Practical takeaway: When purchasing replacement tires, request that the retailer show you the DOT code on all four tires before installation. Take photographs of the codes from multiple angles to maintain clear records. This practice ensures you know the exact manufacturing dates of your new tires from the moment of purchase.

Storage and Degradation Factors That Affect Tire Lifespan

How tires are stored significantly impacts how quickly they age. Tires stored indoors in a climate-controlled environment degrade much more slowly than those exposed to outdoor conditions. Outdoor storage exposes tires to temperature fluctuations, ultraviolet radiation, and humidity changes that accelerate the