Tire Numbers – Say What?


Have you ever looked at all those numbers on the side of your tires and wonder; “What the heck am I looking at?” If it looks like Greek, we get it. These numbers are baffling until you know what they mean, and they are actually quite helpful. These numbers serve as an identification of sorts, and, a way for companies to remain compliant with government regulations. At A’s Legitimate New and Used Tires, we don’t just change tires out; we try to explain the method behind our madness. Let’s take a moment and break it all down. (You’re going to need this one day when you’re playing Trivial Pursuit!) We have even provided a diagram to make this even easier to learn. 

  1. The first number in the series means how big the tire is and, most notably, at its widest spot. 
  2. This is the aspect ratio (percentage) number and defines the profile of the tire. Still, confused? It’s the height of your sidewall. 
  3. The “R” stands for radial construction (rarer bias-ply and belted tires are denoted by a D and B, respectively).
  4. The next number is the size wheel the tire fits on the following letter refers to the type of vehicle the tire should go on. P=metric/passenger car. LT = light truck. T= Temporary spare. Others include Z or F that reference a service number. 
  5. The next number is alphanumeric and tells us two things. a. how much weight it carries and how fast it’s intended to run. There are charts online that can flush this out for you if needed.
  6. This number gives you the treadwear number, which reveals how long the tire is intended to last. The higher the number, the more chance of longevity you’ll have with it. 
  7. The letter that follows the word “traction” is the result of what you can expect from the grip of the tire.
  8. If you see an M+S on your tire, that means it is rated for snow and mud. This doesn’t mean they are winter tires, but that they can handle adverse conditions. 
  9. OE marks on a tire designate the tire as original equipment. Work with your tire professional (like us) to ensure you’re not getting too radical with OE tires that might look the same but perform differently. 
  10. Lists tire features and materials, which likely means more to us then it does to you. We are kind of tire nerds like that. 
  11. The DOT label is mandatory by the department of transportation. 
  12. The first two characters = factory of manufacture. The next five or six characters = manufacturer-specific jargon. The last four numbers = date of production, which let you know how old your tires are with the first two digits indicating the week and the latter two the year. 


And just like that, you are now an expert. Okay, we might be taking that too far. But, you now have a good idea of what you’re looking at. We pay close attention to these numbers at our Indianapolis used tire shop. We know what rides on these tires, and our priority is to give you the best tire we can. 


If you need help finding a particular set of tires… you can start by giving us the alphanumeric numbers, and you can send us a message with those right to our Facebook page. We are very accomodating and respond quickly to your inquiries. We look forward to helping you.