Why does my tire only have 3 numbers for the DOT code?

Before the year 2000, manufacturers assumed tires would never last a full 10 years in service. Therefore, they only used one digit for the year (e.g., '8' for 1988). When the year 1998 rolled around, the code repeated itself, causing mass confusion and forcing the switch to 4 digits.

Are tires from before 2000 safe to drive on?

No, absolutely not. A tire from 1999 is over 25 years old. The internal chemical bonds of the rubber have completely degraded. If driven at highway speeds, it is almost guaranteed to suffer a catastrophic tread separation.

What does the triangle after a 3-digit DOT code mean?

In the 1990s, manufacturers realized the 3-digit system was flawed because a code ending in '2' could mean 1982 or 1992. To fix this, they added a small triangle symbol after the numbers to specifically denote the 1990s decade.

Do trailer tires use the 3-digit code?

Modern trailer tires use the 4-digit code. However, it is incredibly common to find neglected boat or utility trailers sitting in yards that still have original 3-digit tires from the 1990s bolted to them.

Can I use vintage tires for a classic car show?

Yes, many classic car restorers keep original 3-digit DOT tires for judging at concours car shows. However, these cars should be trailered to the event; the tires should never be driven on public roads.

Pre-2000 3-Digit Tire Date Decoder

Decode the obsolete 3-digit date codes found on classic cars, trailers, and vintage tires manufactured before 2000.

Quick Answer

If you enter the 3-digit code "328", the calculator reveals an inherent ambiguity: the tire was manufactured in the 32nd week of the 8th year of a decade. Because it lacks a fourth digit, this tire was either made in August 1988 or August 1998. Regardless of the decade, the tool flags the tire as over 25 years old and critically dangerous to drive on.

Enter DOT date code

Look on the tire sidewall for DOT … XXYY — enter the last 4 digits (week + year)

How to Read 3-Digit vs 4-Digit Codes

Era	Example Code	Code Breakdown	Example Meaning
Pre-1990	258	2 Digits (Week) + 1 Digit (Year)	Week 25 of 1978 or 1988
1990–1999	258◄	3 Digits + Triangle Symbol	Week 25 of exactly 1998
2000–Present	2508	2 Digits (Week) + 2 Digits (Year)	Week 25 of exactly 2008

Formula

Week = First two digits | Year = 1980 + Last digit OR 1990 + Last digit

Triangle symbol (◄) after the 3 digits = definitively from the 1990s
No triangle = ambiguous (could be 1980s or 1990s) — assume worst case (oldest)
Example: "419" = Week 41 of 1989 or 1999 — either way, 25+ years old
Any 3-digit code = remove from road use immediately regardless of tread depth

Frequently Asked Questions

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