How to Read Tire Numbers
With tire size, you just have to know a few things and how to decode. Best of all, it doesn’t take much work to do it. Let’s break down some of the things to look for on the tire.
Lettering. Most tires will have a letter beginning the sequence of letters and numbers on the tire. If you see the letter “P” it’s short for “P-metric,” which is for an everyday passenger vehicle like a sedan, minivan or SUV. The designation of “LT” means “light truck,” which is for vehicles that carry heavier cargo or trailers. The letter “T” stands for “temporary,” otherwise known as the spare tire.
Tire width. This is the first number found in the sequence. It’s the width, in millimeters, of the tires that should be on your vehicle. Therefore, if the car says “P225” it means it’s a passenger vehicle, and the tires have a width of 225 millimeters.
Speed rating. The final number on the tire is the speed rating, which is a single letter. The letter “S” means the tires are rated up to 112 mph, and “R” is up to 106 mph. Of course, follow all speed limit signs on the road while driving. Higher speed ratings often mean increased handling performance, not the need to drive the car over 100 mph!