Decoding the Date Code on a Tire: Understanding Tire Date Codes

Every tire on the road has a hidden timestamp — a code that tells you exactly when it was manufactured. This tire date code, part of the DOT (Department of Transportation) code stamped on the sidewall, is critical information for your safety. Tires degrade with age regardless of tread depth or use, and knowing how to read this code helps you make informed decisions about when to replace your tires.

Understanding the DOT Code

The DOT code is a series of alphanumeric characters embossed on the sidewall of every tire sold in North America. The full DOT code contains information about the manufacturer, plant, tire size, and — most importantly — the manufacture date.

A typical DOT code looks like this: DOT ABCD EFGH 2519

Here's what each section means:

The last four digits are what you're looking for: 2519 means the tire was manufactured in the 25th week of 2019 (late June 2019).

How to Read the Tire Date Code

The date code is simple once you know the format:

• First two digits = Week of manufacture (01–52)
• Last two digits = Year of manufacture

Examples:

Tires Made Before 2000

Tires manufactured before the year 2000 used a three-digit date code — the first two digits for the week and the last digit for the year. For example, 259 means week 25 of 1999 (or 1989 — there's no way to distinguish the decade). If you encounter a three-digit code, the tire is at least 25 years old and should be replaced immediately.

Why Tire Age Matters

Rubber Degrades Over Time

Tire rubber is a complex polymer compound that deteriorates through a process called oxidation — exposure to oxygen, UV light, heat, and ozone causes the rubber to harden, crack, and lose elasticity. This happens whether the tire is driven on regularly, sitting in storage, or even brand new on a shelf.

What Happens to Old Tires:

• Reduced grip — Hardened rubber provides less traction, especially in wet conditions
• Sidewall cracking — Visible cracks in the sidewall and tread grooves (called "dry rot" or "weather checking")
• Increased blowout risk — The internal structure weakens, increasing the chance of sudden tire failure at highway speeds
• Tread separation — The tread can literally separate from the tire body — one of the most dangerous failure modes
• Degraded performance — Longer braking distances, reduced cornering ability, less responsive handling

The 6-Year Rule

Most tire manufacturers and safety organizations recommend:

• 6 years: Have tires inspected annually by a professional, regardless of tread depth
• 10 years: Replace tires regardless of condition or tread remaining — this is the absolute maximum lifespan

When to Replace Tires Based on Age

Spare Tires Too

Don't forget your spare tire! Spare tires age just like the ones on the road — often faster because they're stored in hot trunk compartments or exposed under the vehicle. Check the date code on your spare and replace it if it's over 10 years old.

How to Check Your Tire's Date Code

1. Find the DOT code — Look on the sidewall near the rim. You'll see "DOT" followed by a series of characters.
2. Locate the last 4 digits — These are the date code. They may be slightly recessed or raised from the sidewall surface.
3. Check both sidewalls — The complete DOT code (including date) may only appear on one side.
4. Check all four tires — They may not all be the same age, especially if they've been replaced at different times.
5. Check the spare — Most people forget this one.

Tire Date Code and Warranty

Most tire manufacturers base their warranty on the date of manufacture, not the date of purchase. Common warranty terms:

• Tread life warranty: Typically 4-6 years from date of manufacture or when tread wears to 2/32", whichever comes first
• Workmanship warranty: Usually 5-6 years from manufacture date
• Road hazard warranty: Often 1-3 years from purchase date

This means buying "old stock" tires — tires that have been sitting in a warehouse for 2+ years — reduces your effective warranty period. When purchasing new tires, check the date code and avoid tires that are more than 18-24 months old.

Tips for Maximizing Tire Life

While you can't stop the aging process, you can slow it down:

1. Store tires properly — Cool, dry, dark location. Away from electric motors (which produce ozone), solvents, and direct sunlight
2. Use tire covers — If tires are stored outdoors or on a vehicle parked outside long-term
3. Maintain proper inflation — Underinflation causes excessive heat buildup, accelerating degradation
4. Rotate regularly — Even wear extends usable life
5. Clean tires — Remove brake dust and chemicals regularly
6. Avoid tire shine products — Many contain petroleum solvents that accelerate rubber degradation
7. Drive regularly — Tires on a frequently driven vehicle last longer than those sitting idle (the flexing action helps distribute protective chemicals within the rubber)

Frequently Asked Questions

Where is the date code on a tire?

The date code is the last four digits of the DOT code, found on the tire's sidewall. Look for the letters "DOT" followed by a series of numbers and letters. The complete DOT code (including the date) may only appear on one side of the tire — check the inner sidewall if you don't see it on the outside.

How old is too old for tires?

Most manufacturers recommend replacing tires at 6-10 years regardless of tread remaining. At 6 years, annual professional inspection is recommended. At 10 years, replacement is mandatory regardless of appearance. Never drive on tires older than 10 years.

Can I tell tire age from the receipt?

No — the receipt shows when you bought the tire, not when it was manufactured. A tire could sit in a warehouse or store for months or years before being sold. Always check the DOT date code on the sidewall.

Do tires expire on the shelf?

Yes. Tires degrade even when never used. A tire that's been in storage for 5 years has the same age-related concerns as one that's been on a car for 5 years. When buying new tires, check the date code — avoid tires manufactured more than 18-24 months ago.

Is it safe to buy tires that are 2 years old?

Generally yes, as long as they were stored properly. However, you're losing 2 years of usable life and warranty coverage. Ideally, buy tires manufactured within the last 12 months for maximum value and longevity.

My tires have good tread but are 8 years old — should I replace them?

Yes. At 8 years old, the rubber compound has degraded significantly regardless of tread depth. The tire may look fine but has reduced grip, increased blowout risk, and compromised structural integrity. The cost of new tires is far less than the cost of a blowout-related accident.

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Checking your tire date codes takes 30 seconds per tire and could save your life. Make it part of your regular vehicle inspection, especially on used vehicles, seasonal tires, and spare tires that are easy to forget about.

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