If you are planning on replacing the tires on your truck, you will first need to find out what size tires you need. Putting the wrong type of tires on your truck can cause it to wear unevenly or burst under the weight of your vehicle. Most people only change their tires when they have a flat, but you should actually purchase new truck tires every few years or when you notice the treads wearing down. A lot of people like to replace the original tires with something bigger, and this is where math becomes important.
Normally, you would find your truck tire size in the owner’s manual, but you might not have access to it. Another scenario is that you are looking for tires to fit a bigger or smaller wheel. You might want to increase your rim size, but first you have to make sure the tires will fit on your truck. If you get the wrong size for the wheel, problems will arise. There are a couple of different ways you can find out what size tires your truck needs:
A. First Method: Find Tire Size Label
1. Open up the door on the driver’s side of the truck.
2. Look for a sticker label on the door frame. There should be a section on it called “Tires.”
3. Write down the type of tires it recommends on the label. “P” stands for “Passenger Truck” and “LT” stands for “Light Truck.” The number listed after “P” or “LT” is the width of the tire in millimeters. The number listed after the “R” is the sidewall aspect ratio. The very last two numbers are the rim size. For example, the label might look like: “P202/70R15.”
4. Purchase the type of tires you need for your vehicle. Be sure to type the numbers accurately so you will get the right size tires.
B. Second Method: Look at the Tires for the Size
1. Look at the tires already on your truck.
2. Find the tire size printed on the outer wall of the tires.
3. Write down the tire size exactly as it reads and then purchase the tires online.
C. Third Method: Find the Tire Size for a Wheel
1. Find out what size tires you need to fit a bigger or smaller wheel. First, multiply the width of the tire by the sidewall aspect ratio as percentages. Using the example in the first section, the width of the tire is 202 x 70 = 141.40 millimeters.
2. Multiply the number you got in the step above by 0.04 to convert it to inches. The answer is the height of the sidewall. For example, 141.40 x 0.04 = 5.656. The sidewall height is a little over five and a half inches.
3. Multiply the height of the sidewall by two and add the rim size. The answer is your overall tire diameter in inches. For example, 5.656 x 2 + 15 = 26.312 inches.
4. Keep the diameter the same if you want to increase your rim size. If you go too big or too small, you will run into problems as far as mileage, power, transmission, and speed.
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References
Imperial Club: Wheel Size
Hogan Tire: How to Read a Tire Size
- What are the Best Tires for My Car?
- What Size Tires will Fit my Truck?
- What Size Tires Does My Car Need?
- How to Choose Tires?
- How to Buy Tires?
