What's in a Number? (What Tire Numbers Mean)
August 15, 2021
You've probably never paid much attention to the writing on the sides of your tires, but they contain a wealth of information. There's a long combination of letters and numbers that can tell you a whole lot about what tires your vehicle was designed to be riding on. Let's check out this example found on an SUV: P245/70R17 108T.
The first letter, P, means it's intended for passenger vehicles. If there's no letter, it means it's a metric tire. If there's an LT at the beginning or end that means a tire designed for light trucks.
Moving on to our example, the 245 shows how wide the tire is in millimeters from sidewall to sidewall. The number that follows in our example, 70, means the height of the tire is 70% of its width. The letter after that in our example, R, describes the type of tire (on this vehicle, radial). Following that is the diameter in inches, in our SUV example, 17 inches.
How much load the tires' sidewalls are designed to take is what that next number is all about (108 in our example). The higher the load index, the more weight the sidewalls can take. And the last letter is the speed rating of the tire, in our example, T. The further along in the alphabet that letter is, the higher its speed rating. So now you know what those letters and numbers mean. But why are they important?
When you are getting ready to replace those tires, those numbers are telling you what the original equipment was when your vehicle was new. Sticking with the same rated tires is always a good idea. If you don't know what you're doing, trying different sized tires and wheels can cause real issues when it comes to performance and safety, considering all the computerized systems now found on vehicles. When in doubt, consult your service advisor when it comes to buying new tires. He or she knows what those tire numbers and letters mean… and a whole lot more.
Charlie's Fast Lube Sikeston
2017 E. Malone
Sikeston, Missouri 63801
573-472-1139
http://www.charliesfastlubesikeston.com
Need Service?
More articles from Charlie's Fast Lube Sikeston
It's (Not) Complicated (Engine Air Filter)
January 19, 2025
While many components of your vehicle are complex and composed of lots of mechanical and electrical parts, there's one that isn't complicated but still important. It's your engine air filter. (And, we should point out, the engine air filter isn't to be confused with the cabin air filter. The ca... More
The Light Many Drivers Fear (Check Engine Light)
January 12, 2025
Ask just about any driver about one thing they fear seeing inside their vehicle and they'll say it's the Check Engine light coming on. You know, that little light on your instrument panel that is in the shape of a vehicle engine, often accompanied by the words Check, Check Engine, Check Engine Se... More
Stuck! (Vehicle Door Issues)
January 5, 2025
This may have happened to you. You drive somewhere and get out of your vehicle only to try closing the door and it just won't stay closed! What a helpless feeling. You can't lock it; you can't leave it like it is. Or, let's say you head down to your vehicle to head out to work in the morning a... More