What Do Tire Numbers Mean?

Maybe you’ve never noticed, but in all likelihood, if you’re reading this you have — tire sidewalls are marked by a combination of numbers and letters that look something like “P215/65R15 95H”. Each of these alphanumeric series has a specific denotation. What do each of these tire numbers mean? Read on or contact our service experts at (423) 424-4040 to find out more!

What Do the Numbers on Tires Mean? Explained

A tire’s code aka series of “tire numbers” is a combination of letters and numbers you’ll find on your tires’ sidewalls that tells you about things like its:

• Size
• Load index
• Speed rating
• Type of tire 

Example: P215/65R15 95H

Each piece of the above number series means something unique, and together, they tell a story about the tire. Here’s what tire numbers like the above mean, explained:

“P”, Explained

The “P” stands for “P-Metric tire,” meaning that it is used for passenger vehicles. Do your tires read “LT,” instead? That stands for “light truck”. If the tire does not have a letter preceding the code, it is a European style tire, or Euro-Metric tire.

“215”, Explained

Following the “P” is the “215” number, which stands for tire width in millimeters from sidewall to sidewall.

“65”, Explained

The aspect ratio code comes next, indicated in this example by the number “65.” A tire’s aspect ratio is simply how high the cross-section is related to its width. This tire’s height, then, is equal to 65% of its width. The bigger the aspect ratio, the beefier the sidewalls of the tires will be.

“R”, Explained

The “R” indicates the tire’s construction, with “R” representing that it’s a radial tire.

Decoding “15”

“15” tells you the size of the wheel diameter, in inches.

“95H”, Explained

At the end of the code is “95H,” which is the load index and speed rating for the tire. The load index (“95” in this instance) tells you about how much weight the tire can support when it’s properly inflated. This can range from 75-105 for passenger vehicles. 

“H” represents the speed rating, which is how fast the tire can safely go based on its load capacity. This rating is ranked from A-Z, and with our example, a tire with an “H” rating can reach a maximum speed of 130 mph.

How Often to Rotate Tires

Now that you know more about tire number meaning in context, you may be wondering about some other tire-related questions, such as “How often should I rotate my tires?” Thankfully, most car’s tires can be rotated every time an oil change is done, or roughly every 5,000 miles.

Turn to INFINITI of Chattanooga for All Your Maintenance Needs

Ready to get more up to date information on how to maintain your vehicle and its tires in Chattanooga? INFINITI of Chattanooga is here to help with all your car service & maintenance needs! Need to order new tires? Our tire store is here to help!