How to Figure Out What Tire Numbers and Letters Mean – Lexington, KY

Winter is upon us here in Lexington and with it comes the rain, sleet and snow. Don’t take a chance with the one piece of equipment that makes contact with the road. Upon first glance, the letters and numbers on your tire’s sidewall seem intimidating. Thanks to this brief tire sidewall guide, you’ll become a tire expert in under 10 minutes without even needing to make a call to your Lexington Nissan service center!

The numbers are indicators of the size, type, and performance of the tire.






P: Tire Type

The letter ‘P’ at the beginning of the “Tire Size” tells us the tire is a P-Metric tire, referring to tires made to certain standards within the United States, intended for passenger vehicles. As stated on

“A metric tire has a slightly greater load index and higher load-carrying capacity reserve than its P-metric counterpart.”

225: Tire Width

This is the width of the tire measured in millimeters from sidewall to sidewall. The first three-digit number in the tire size refers to the tire width. For instance, in a size P215/65 R15 tire, the width is 215 millimeters.

55: Aspect Ratio

This represents the ratio of the height of the tire’s cross-section to its width. The two-digit number after the slash mark in a tire size is the aspect ratio. For example, in a size P215/65 R15 tire, the 65 means that the height is equal to 65% of the tire’s width. The bigger the aspect ratio, the bigger the tire’s sidewall will be.

R: Construction

The letter ‘R’ in a tire size stands for Radial, which means the layers run in the direction of the radius across the tire.

18: Wheel Diameter

This is simply the size of the wheel measured from one end to the other. It tells us the size of the wheel that the tire is intended to fit. For example, the Yokohama Avid Touring-S size P215/60R16 94T tire is made for 2015 Nissan Altima wheels with a 16″ diameter.

97: Load Index

Load Index indicates the maximum load that the tire can support when properly inflated. You’ll also find the maximum load on the tire sidewall, in both pounds and kilograms.

T: Speed Rating

This tells you the maximum speed capability of a tire. Often speed ratings are matched to the top speed capability of the vehicle. For example, a tire with an H-speed rating has a maximum speed capability of 130 MPH or 210 km/h. This isn’t, however, an endorsement to exceed legally posted speed limits.

All together it looks like this: P225/55R18  97T

Now run outside and rejoice! You now know what the what tire numbers and letters mean!


Time for new tires? Visit the Glenn Nissan online tire center to enter the information that you now know how to get to find the best fitting winter tires for you. For a limited time, Glenn Nissan has a special tire promotion in Lexington available on top-shelf Goodyear, Michelin, BFGoodrich tires, as well as many more. There’s nothing quite like putting quality new tires on your car, but don’t trust anyone but the #1 Nissan dealership in Lexington with your tire care.