Finding the exact manufacturing age of your Yokohama tires takes less than a minute once you know where to look. You just need to locate the DOT code stamped on the tire sidewall and read the final four digits, where the first two numbers show the production week and the last two show the manufacturing year.
Tire rubber degrades naturally over time from heat, sunlight, and environmental exposure, even if the tread looks deep and the tire was never driven on. Knowing how to read these codes protects you from buying stale warehouse stock or driving on aged rubber that has lost its structural integrity.
Locating and Reading the DOT Tire Identification Number
Every legal tire sold for highway use features a Department of Transportation (DOT) identification code molded into at least one sidewall. On many modern passenger and light truck tires, you might see a partial DOT code on one side and the full code—complete with the date stamp—on the inner sidewall, meaning you may need to look closely or jack up the vehicle to inspect both sides.
The DOT code starts with the letters "DOT" followed by a combination of manufacturer and plant codes, culminating in a 3-digit or 4-digit sequence at the very end.
- The Plant Code: The first two characters following "DOT" identify the exact factory where the tire was built (for example, Yokohama operates plants in the US, Japan, the Philippines, and elsewhere).
- The Size and Type Code: The middle characters represent the tire size and manufacturer specific product lines.
- The Date Code: The final digits at the end of the string indicate when the tire left the production mold.
If you don't find a 4-digit number at the end of the code, you're likely looking at an older tire manufactured prior to the year 2000. Those legacy tires used a 3-digit format, where the first two digits indicated the week and the final single digit represented the year within that decade (such as "348" for the 34th week of 1998). Because those tires are well past safe operating age, any tire you purchase or inspect today should feature the modern 4-digit standard.
Step-by-Step Breakdown of the 4-Digit Date Stamp
Reading a modern Yokohama date code is simple once you separate the numbers into two distinct pairs.
- Find the 4-digit block: Scan the end of the long DOT alphanumeric sequence for a standalone box or group of four numbers (for example, DOT ABC1234 2423).
- Read the first two digits: These represent the week of the year, running from 01 through 53. Keep in mind that week 01 starts in early January and week 52 or 53 lands in late December.
- Read the last two digits: These represent the calendar year of production. A code ending in "23" means the tire was built in 2023, while "25" indicates 2025.
If a Yokohama tire displays the code 1524, it was manufactured during the 15th week of 2024 (roughly mid-April 2024). If the code reads 0826, it rolled out of the factory during the 8th week of 2026 (late February 2026).
According to guidelines from the National Highway Traffic Safety Administration, consumers should pay close attention to these timestamps when purchasing replacement rubber or evaluating tires that have spent time sitting in home garages.
Real-World Examples and Common Variations
Not all tire molds look identical, and stamp placements can vary slightly depending on the tire model, whether it's an Advan performance tire, a Geolandar all-terrain tire, or an Avid touring tire. Here is how different date codes translate in practice:
- Example A (Recent Production): You inspect a set of Yokohama Geolandar tires on a light truck and find the stamp ...1125. The first two digits (11) mean early March, and the last two (25) mean 2025. These tires are fresh and well within their optimal service window.
- Example B (Mid-Range Age): A set of passenger car tires shows the code ...4022. Week 40 falls in early October, and 22 represents 2022. While these tires may still have plenty of tread remaining, they are entering their fourth year of aging.
- Example C (Raised Border Box): Yokohama often stamps the 4-digit date code inside a shallow, raised rectangular box on the sidewall, making it stand out slightly from the rest of the lengthy DOT string.
If you're buying new tires from a local shop or an online distributor like Tire Rack, it's entirely normal for tires to be a few months to a year old due to shipping and warehouse storage timelines. However, if a retailer tries to sell you tires that are three or four years old as "brand new," you should request a fresher batch.
When Should You Replace Aged Tires?
Tire longevity depends on more than just tread depth. Rubber compounds contain anti-aging chemical agents that migrate to the surface as the tire flexes during driving, but these compounds eventually deplete. Heat exposure, UV rays from the sun, and parking on asphalt all accelerate the breakdown of the rubber matrix.
Most automotive manufacturers and safety agencies recommend a strict inspection regime once tires reach five years of age, with a general consensus to replace all tires that reach 10 years from their manufacturing date, regardless of how much tread is left. If you live in an arid, high-heat climate like Arizona or inland Australia, rubber degradation happens much faster, and mechanics often recommend replacement at the 6-to-8-year mark.
Look closely at the sidewalls and tread grooves for physical warning signs of age:
- Micro-cracking (Crazing): Fine spiderweb cracks appearing in the black rubber of the sidewall or between the tread blocks.
- Bulges or Blisters: Localized deformations indicating internal fabric separation, which can lead to a sudden blowout.
- Stiffness: Rubber that feels hard, brittle, or lacks pliability when pressed with a fingernail.
Frequently Asked Questions
Does the Yokohama warranty start from the purchase date or the manufacturing date?
Yokohama's limited warranty typically covers tires for up to five years from the date of purchase (with original purchase receipt) or for the specified treadwear mileage warranty, whichever comes first. If you cannot provide proof of purchase, the warranty period is calculated based on the DOT manufacturing date stamped on the sidewall.
Can tires stored in a warehouse age even if they aren't mounted on a car?
Yes. Unmounted tires stored in a warehouse still experience chemical aging, though at a slower rate than tires exposed to outdoor weather and UV light on a vehicle. Proper indoor storage away from direct sunlight, ozone-producing electric motors, and extreme temperature swings helps preserve the rubber, but age still accumulates from day one.
What should I do if my tire has a 3-digit code instead of 4 digits?
If your tire displays a 3-digit code at the end of the DOT string, it was manufactured prior to the year 2000. These tires are over two decades old and are dangerously unsafe for highway driving due to severe rubber degradation. You should replace them immediately, regardless of how deep the tread appears.
Are tires bought online older than tires bought at a physical shop?
Not necessarily. Major online tire distributors move high volumes of inventory and often ship tires directly from regional distribution hubs with recent production dates. Always check the manufacturing date upon delivery, and ensure you purchase from reputable sellers with transparent return policies in case you receive older stock.
