When you look at the side of your tire, you’ll see a bunch of letters and numbers. Most people have no idea what they mean — but those markings actually tell you everything about your tire’s size, strength, and how it performs.
In this guide, we’ll explain what it all means in simple terms, so you can feel more confident when it’s time to replace your tires.
First, What Is a Sidewall?
The sidewall is the side part of your tire — the smooth area between the part that touches the road (the tread) and the metal rim (also called the wheel). It’s where all the important info about your tire is printed.
Example Tire Size:
P225/65R17 102H
Let’s break it down, step by step:
1. “P” — What Type of Vehicle the Tire Is For
- P means the tire is made for a passenger vehicle (like a car or SUV).
- You might also see:
- LT = for Light Trucks (like pickups)
- T = for Temporary or spare tires
2. “225” — How Wide the Tire Is
This number tells you how wide the tire is, in millimeters (from side to side).
So, 225 means the tire is 225 mm wide, which is about 8.9 inches.
3. “65” — How Tall the Sidewall Is (Compared to the Width)
This is called the aspect ratio. It’s a percentage that shows how tall the side of the tire is compared to the width.
In this case:
65% of 225 mm = about 146 mm (or 5.7 inches)
- Bigger number = taller sidewall = smoother ride
- Smaller number = shorter sidewall = sportier feel but bumpier
4. “R” — How the Tire Is Built
- “R” stands for Radial, which is the way the tire is built on the inside.
- This is standard for almost all tires today.
5. “17” — The Wheel Size It Fits
This number means the tire fits a 17-inch wheel (that’s the metal rim).
Important: The tire has to match your wheel size.
6. “102” — How Much Weight the Tire Can Handle
This is the load index. It’s a code that tells you how much weight one tire can support.
- 102 means it can hold about 1,874 pounds
Always check your car’s manual or door sticker to know the right load index for your vehicle.
7. “H” — Speed Rating
This letter tells you how fast the tire can safely go.
- H = safe up to 130 mph
- Other common ratings:
- T = 118 mph
- V = 149 mph
You don’t need race tires — but using tires rated too low for your vehicle can be unsafe.
Bonus: How to Check Tire Age
Look for a small code that starts with “DOT” — this tells you when your tire was made.
Example: DOT XXXXX1922
That means the tire was made in the 19th week of 2022.
👉 If your tires are more than 6 years old, it’s usually time to replace them — even if they still look okay.
Not Sure What Tires You Need?
That’s what we’re here for.
At T&T Mobile Tires, we’ll help you choose the right tires for your car, your driving style, and your budget — and we’ll install them right at your home or office.
📍 Serving Boise, Meridian, Nampa & all of the Treasure Valley
📅 Book online at ttmobiletires.com
📞 Or call us at (208) 565-9186
