What Do Tire Markings Mean? | Read Every Number Right

Tire markings show size, load, speed, build date, and grip grades, so you can match the right tire and spot old stock.

Those letters and numbers on a tire are not random. They tell you what fits your wheel, how much weight it can carry, its speed class, build date, and extra labels for snow or extra load.

Once you know the pattern, the sidewall stops feeling like shop-only code. You can check a used set, catch a bad online listing, and make sure a replacement tire matches your car.

What Do Tire Markings Mean? Start With The Size Code

A common passenger-tire code looks like this: P225/60R17 99H. Read it from left to right. Each piece answers one plain question about fit.

The First Half Of The Code

• P tells you it is a passenger tire. You may also see LT for light-truck or no prefix on some passenger tires.
• 225 is the section width in millimeters.
• 60 is the aspect ratio. The sidewall height is 60% of the tire’s width.
• R means radial construction, which is the norm on modern road vehicles.
• 17 is the wheel diameter in inches.

A tire can share the same wheel diameter and still be the wrong overall height or load class. A 225/60R17 and a 225/65R17 both fit a 17-inch wheel, yet the second tire stands taller and can change clearance and speedometer reading.

The Service Description After The Size

The last part of the main code is the service description. In 99H, the number is the load index and the letter is the speed rating. Together they tell you how much weight one tire can carry and the speed class tied to that load.

Many buying mistakes start here. Drivers often match size and stop there. Size alone is not enough.

Marks People Often Read The Wrong Way

Sidewalls also show Max Load and Max Press. Those values are not your daily inflation target. Use the cold-pressure figure on the door-jamb sticker or in the owner’s manual instead.

Some marks describe fit. Others show legal labeling, weather use, or tread grades. Sort them into groups and the whole wall becomes easier to read.

Reading Tire Markings For Load, Speed, And Age

The DOT code near the bead is worth checking any time you buy tires. The final four digits show the week and year of manufacture. A tire ending in 0825 was made in the eighth week of 2025.

On passenger tires sold in the United States, treadwear, traction, and temperature grades may also appear under the Uniform Tire Quality Grading System. For a clean visual of size codes, date marks, winter symbols, and load ratings on one sidewall, Michelin’s page on tire sidewall markings is handy.

UTQG grades help when you compare passenger tires in the same broad class. A higher treadwear number is not a promise of a set mileage life in your car.

Winter And All-Season Labels

M+S and 3PMSF are easy to mix up. M+S means the tread design meets the maker’s mud-and-snow labeling standard. The three-peak mountain snowflake goes further. It marks a tire that passed a snow-traction test. If you live where roads stay icy or packed with snow, that little mountain-and-snowflake symbol says more than M+S alone.

Load Range And Extra Load Marks

Truck and van tires may carry a load range letter such as C, D, or E. Passenger tires may show XL, which means Extra Load. Two tires can share a size code and still carry different load labels.

Original-Equipment Tags

You may also see small OE marks tied to a car maker. Those tags show the tire was tuned for that vehicle line at the factory.

Marking	What It Means	Why You Should Care
P / LT / ST	Passenger, light-truck, or trailer tire type	Shows the tire’s duty class and where it belongs
225	Section width in millimeters	Affects fitment, footprint, and clearance
60	Aspect ratio, or sidewall height as a share of width	Changes ride, overall tire height, and wheel-gap feel
R	Radial construction	Part of the tire’s build type
17	Wheel diameter in inches	Must match your rim size
99H	Load index and speed rating	Shows the tire’s working limit under load
DOT 0825	Date code ending in week 08 of 2025	Helps you spot older stock before buying
UTQG	Treadwear, traction, and temperature grades on many U.S. passenger tires	Useful for same-class comparisons
M+S	Mud-and-snow marking set by the tire maker	Common on all-season tires, but not a severe-snow test mark
3PMSF	Three-Peak Mountain Snowflake symbol	Shows the tire passed a snow-traction test
XL / Extra Load	Tire built to carry more load at higher pressure	Needs correct fitment and inflation for that vehicle

How To Check A Tire Before You Buy

If you are shopping online, standing in a warehouse aisle, or sorting through used tires, run through the same short check each time.

1. Match the size to the vehicle placard. Start with the driver’s door sticker or the manual, not the old tire alone. A past owner may have fitted the wrong size.
2. Match or exceed the load index and speed rating. A correct width does not cancel out a weak service description.
3. Read the DOT date code. Fresh stock is not the only thing that matters, but age still belongs on the checklist.
4. Check weather marks. M+S and 3PMSF tell different stories.
5. Read all four tires if the car already has a mixed set. Small code changes across an axle can change how the car feels and wears.

Also check the tire type before you pay. A passenger tire, light-truck tire, trailer tire, and temporary spare can share a few familiar-looking numbers while being built for very different jobs. The sidewall tells you that story right away if you read the prefix and service marks first.

When you are replacing one damaged tire, also check tread depth across the axle. On AWD vehicles, one new tire beside a worn one can create a diameter gap that is larger than it looks.

Sample Code	Plain-English Read	Quick Take
P215/55R17 94V	Passenger tire, 215 mm wide, 55 profile, radial, fits 17-inch wheel, load index 94, speed rating V	Common sedan or hatchback fitment
LT265/70R18 124/121R	Light-truck tire, 265 mm wide, 70 profile, radial, 18-inch wheel, dual load indexes, speed rating R	Built for heavier truck duty
235/45R18 98Y XL	Passenger-style tire, 235 mm wide, 45 profile, radial, 18-inch wheel, higher load index, speed rating Y, extra-load build	Seen on sport sedans and heavier EV fitments
225/65R17 102H M+S	225 mm wide, 65 profile, radial, 17-inch wheel, load index 102, speed rating H, mud-and-snow marked	Typical crossover all-season setup
DOT XX XX 4724	Tire made in week 47 of 2024	Useful when checking age at the shop

The Most Common Reading Mistakes

The first mistake is reading only the wheel diameter and ignoring the rest. A tire that says 17 on the sidewall is not enough by itself.

The second mistake is using the sidewall’s max-pressure figure as the daily fill target. The third is missing the date code when buying “new” tires made years earlier.

Read the sidewall left to right, group the marks by job, and the whole code starts making sense.