The DOT code is a legal ID that shows plant, size, maker info, and a four-digit week-and-year date; colored dots guide precise mounting.
Dot Marking On Tires: Meaning And Uses
Two marks share similar names. One is the molded “DOT” followed by letters and numbers; that’s the TIN. The other is a painted red or yellow dot, or a temporary tag; that’s a mounting cue. Both matter for safety, warranty, and ride quality. Here’s a quick map of the molded code so you can read it at a glance.
DOT Tire Code (TIN) At A Glance
| Segment On Sidewall | What It Identifies | Tips To Read It |
|---|---|---|
| DOT | Meets U.S. Department of Transportation rules | Appears before the code; confirms compliance |
| Plant Code | Factory that built the tire | Two or three symbols assigned by NHTSA |
| Size Code | Size family or type | Links the tire to a size specification |
| Optional Code | Brand or batch tracking | Used by the maker for internal trace |
| Date Code | Production week and year | Four digits: WWYY, such as 2323 = week 23 of 2023 |
| Side Location | Full code may be on one side only | Check both sides; the other face may show a partial |
That layout is set in 49 CFR 574.5. For age guidance, see NHTSA’s TireWise page. For the red and yellow paint marks used during install, Tire Rack’s tech note on match-mounting is a handy reference you can share with your shop; here’s the colored dots explainer.
What The DOT Marking On A Tyre Means In Practice
Think of the molded code as a passport. It links a specific tire to its maker and build batch, and it gives you a clear stamp of when that casing left the mold. That date helps you plan replacements and lets shops rotate stock so the youngest pairs land on your car.
Where To Find The Code
Scan both faces of the sidewall. Many tires show the full code on only one side, while the other face shows a shortened string. If you’re checking a car with the wheels on, turn the steering to view the inner face or use a light and mirror. On directional or asymmetric tread, note which side must face out before flipping a tire just to read it.
How The Date Digits Work
The last four digits carry the week and the year. A code ending in 1222 was built in week 12 of 2022. Before 2000, some tires used three digits; those are past service life. Makers and safety groups often advise replacement based on age range even if tread looks fine, since rubber ages with heat and time.
Reading The DOT Tire Code, Step By Step
Step 1: Spot “DOT” And The String
Clean the sidewall and find the start of the string. “DOT” confirms the tire follows U.S. rules and kicks off the code you need.
Step 2: Note The Plant And Size Segments
The early symbols tell you the plant and size family. That piece matters during a recall and can help match sets on multi-owner cars.
Step 3: Capture The Maker’s Optional Characters
These characters differ by brand. They support batch tracking and internal audits. Snap a photo so you don’t mix digits.
Step 4: Read The Week And Year
Finish with the four digits that show WWYY. Write it on your service record so rotations and aging checks stay on track.
What The Red Or Yellow Dot Means During Mounting
Fresh tires may show a small red dot, a yellow dot, a paint circle, or a temporary tag. Those marks are shop aids. The yellow mark points to the light spot of the tire for static balance. The red mark points to the high point for radial force. When a wheel has a dimple or mark showing its low point, a red mark on the tire is lined up there. If there’s no wheel mark, the yellow mark is aligned with the valve stem, which is usually the wheel’s heavy spot.
Red Dot Versus Yellow Dot
If a wheel shows a low-point dimple, align red to the dimple. If the wheel has no dimple, align yellow to the valve stem. Some brands use tags in place of paint, and some OE wheels carry their own marks. If a shop ignores both marks, you may need more weights to balance the set.
Key Differences Between Codes And Paint Dots
The molded TIN is permanent and tied to law, recalls, and warranty. The paint dots are temporary shop cues. The TIN follows a fixed order. The dots don’t carry a universal color by brand, which is why a tech sheet on the wall is common in tire bays.
How Tire Age Affects Service
A tire’s build date isn’t a timer by itself, yet age matters. Heat, sunlight, storage, and under-inflation speed up aging. Many makers set service advice in the 6–10 year range based on use and inspection. If you buy a used set, check that the dates match across the axle and that none of the tires are past your risk comfort.
Size Line, Load Index, And Speed Rating
Near the size you’ll see a service description such as 91V or 104H. The number is the load index; the letter is the speed symbol. That pair sets the rated load at the tire’s test pressure and the top speed the tire is built to carry that load. Cars, SUVs, and light trucks each have typical ranges. Match or exceed the door-jamb placard when you replace tires.
Quick Load And Speed Pairs
| Marking | What It Means | Quick Note |
|---|---|---|
| 91V | 615 kg per tire; tested to V speed | Common on compact sport sedans |
| 94H | 670 kg per tire; tested to H speed | Typical midsize fitment |
| 99T | 775 kg per tire; tested to T speed | Seen on crossovers |
| 104H | 900 kg per tire; tested to H speed | XL or LT sizes may differ |
| 110S | 1060 kg per tire; tested to S speed | Light-truck single fitment |
| 121/118R | Dual-rated load; R speed | Single/dual marking for LT |
| 88W | 560 kg per tire; W speed | Performance fitment |
| 86H | 530 kg per tire; H speed | Small hatch and sedan |
Common Misreads And Easy Fixes
O Versus 0, I Versus 1
Sidewall fonts can be tight. If a plant code looks odd, cross-check with a maker list or a recall notice. Photos help prevent typos during registration.
Only Three Digits At The End
If the final group shows three digits, the tire predates 2000 and should be retired. Those casings lack the four-digit WWYY readout and have aged out of regular road use.
Short String On One Side
Don’t stop at the first face you see. Many tires show the full date only on one side. If the wheel hides it, ask the shop to check while the car is on a lift.
When The Code Matters Most
Buying Used Tires
Match size, load, speed symbol, and age. Avoid mixing dates across an axle. Closely check for repairs, bubble spots, and deep cuts. A cheap tire that shakes or runs hot can cost far more down the road.
Registering For Recalls
That TIN lets a maker reach you fast. Many shops submit it for you at purchase, and you can also register online with the brand so notices arrive without delay.
Fleet And Ride-share Use
High-mileage service benefits from tight records. Log the date digits at install and watch rotation windows, alignment, and pressures so the set wears as a team.
Quick Checks Before You Drive
- Read the date on each tire during seasonal swaps.
- Confirm load index and speed symbol meet the placard.
- Ask the shop to follow the red and yellow marks during install.
- Rotate on schedule; note the TIN in your records.
- Store sets cool, clean, and away from sunlight.
Pro Tips From The Bay
Take A Clear Photo
Phones grab the code cleanly. Turn on the light, shoot square to the sidewall, and zoom in to read the digits without guesswork.
Swap Front To Rear, Not Side To Side
Directional and asymmetric tread can limit side swaps. Keep pairs matched and follow rotation guides from your maker and service manual.
Watch Valve Stem Caps
The valve stem marks the heavy side of most wheels. If caps keep loosening, balance may be off or the valve stem core may need a quick check.
Bottom Line For Drivers
Read the molded “DOT” string for who, where, and when. Read the paint dots for a smart install. Match your load and speed marks to the door placard. Keep photos of the code in your service file. With those habits, you’ll buy better, mount better, and ride smoother.