If you’ve ever looked at the side of your tires and saw a string of letters and numbers, you’ve already found your tire’s identity code. It isn’t just a random jumble, either. It’s a detailed breakdown of your tire’s dimensions, construction, load capacity, and speed rating. And knowing how to read your tire size (and more) can help you make informed decisions when it’s time for new tires.

Understanding tire identity codes

Tire codes typically follow a format like P215/65R16 98H. Each part of that info string has a specific meaning, read from left to right.

P = tire type
The first letter identifies the tire class. “P” stands for passenger vehicle, which includes most cars, minivans, and small SUVs. “LT” means light truck, for vehicles that carry heavier loads. If there’s no letter, the tire likely follows Euro-metric standards used for some passenger vehicles.

215 = tire width (millimeters)
This number tells you the width from sidewall to sidewall. Here, it’s 215 mm.

65 = aspect ratio
This number is the sidewall height given as a percentage of the tire’s width. In this case, the sidewall height is 65% of 215 mm, which gives you a general idea of how tall the tire is.

R = construction type
“R” means radial, which refers to the tire’s internal layers. Nearly all modern passenger tires are radial.

16 = wheel diameter (inches)
This number is the size of the wheel the tire will fit. A tire marked with “16” fits a 16-inch wheel.

98 = load index
This number refers to how much weight the tire can safely support at proper inflation. A load index of 98 translates to roughly 1,653 pounds per tire. Many manufacturers and retailers publish load index charts for looking up specific weight ratings.

H = speed rating
This letter indicates the maximum sustained speed the tire can handle. “H” typically means up to 130 mph, while other letters like “T” or “V” are classifications for different limits. All speed ratings assume proper inflation. Again, it’s easy to find tire speed ratings online if you know the letter.

A note: While you’ll find your tire’s size code on its sidewall, most vehicles list the recommended tire size on the sticker inside the driver’s door, along with the inflation pressure guidelines.

Some bonus codes to know

While a tire’s size code is the most important spec when shopping for new tires, you may notice a few other markings on your old (or replacement) tires:

• DOT code: A longer sequence that includes production details. The last four digits reveal when the tire was made. For example, 1322 means the tire was manufactured in the 13th week of 2022.

• XL, HL, or Reinforced: These tags tell you when a tire has a higher load capacity than a standard version in the same size

• M+S or M&S: Indicates mud and snow capability, which is common for all-season tires

• 3PMSF: Similar to M+S, but was put through actual traction tests in snowy environments

Is tire replacement the right move?

Getting four new tires can sometimes top $1,000. Before making that kind of investment, be sure to check your vehicle’s current market value through a site like Kelley Blue Book or Edmunds.

If you’re in danger of being upside down in your car after conducting necessary maintenance, Credit Acceptance works with over 15,000 dealerships nationwide. So, if you’re leaning towards replacing your vehicle vs. its tires, you can pre-qualify for auto financing through our website.