Knowing how to read tires can give you important information about the type of tire for your car, recreational vehicle (RV), trailer, or motorcycle. This can be useful when buying new tires, opting for a tire upgrade, or changing seasonal tires if you live in a place with harsh winters. By knowing how to interpret the numbers and letters printed on the surface of a car tire, you can find out the speed rating, temperature resistance, maximum load index, tire width and rim diameter.
Step
Step 1. Read the tire brand and manufacturer
This text is usually printed in large letters on the outside of the tire. It usually includes a company brand name, such as Hankook, or Michelin, or Goodyear.
Tire brands can consist of letters only or a combination of letters and numbers, for example Goodyear Eagle F1 GS-D3, Hankook Ventus R-S2 Z212, or Kumho Ecsta MX
Step 2. Look at the tire usage description
While not all tires display a usage description, this information is usually printed right next to the manufacturer's name. It's usually a "P," "LT," "ST," or "T."
- "P" stands for passenger car (passenger car).
- "LT" stands for light truck (small truck).
- "ST" stands for special trailer.
- "T" stands for temporary, and is printed on the spare tire.
- "BP" stands for cosmetically blemished passenger (tyres for passenger cars with minor visual defects).
Step 3. Find the width and aspect ratio of the tire
This text contains a row of numbers right next to the usage description. The series of numbers and letters are separated by slashes in the general format www/aaCrr.
- The first row of three numbers is the tire tread width in millimeters. The tread width ranges from 155 to 315 millimeters.
- The two numbers after the slash indicate the aspect ratio of the tire. Aspect ratio is the percentage of tire tread with tire thickness whose value is equal to the height of the outside of the tire. Passenger vehicles generally have an average aspect ratio range of between 55 to 75 percent.
Step 4. Get to know the tire's internal construction
It's almost certain that the "R" symbol is right next to the aspect ratio. The "R" stands for radial construction, an industry standard for passenger cars. Certain trucks may bear the symbol "B," which stands for bias-ply (bias layer). This “B” symbol has largely been discontinued due to difficult handling issues.
Step 5. Identify the rim diameter
Usually after the internal construction is immediately followed by a suitable rim size for the tire. For example, if you have a rim diameter of 55.9 cm, your tires will have the same rim diameter, which is 55.9 cm.
The letters in position SC or C describe the speed rating (pre-1991) or tire construction. "R" means the tire has a radial construction. If it says "HR," the tire is a high-speed radial tire
Step 6. Find the tire's maximum load index
This figure is very important because the maximum load index describes the relative load carrying capacity of the tire size. The greater the value of the maximum load index, the greater the load carrying capacity.
- The load index is not a complicated number; just a kind of symbol. To determine how many pounds a tire can carry (1 pound = approx. 453,592 grams), look at the Load Per Tire chart.
- To find out how much your car can carry without overloading the tires, multiply the number you find in the Carrying Capacity Per Tire chart by four. Because the car has four tires.
- Never replace your tires with tires that have a maximum load index lower than the original tires. You should buy tires with the same or greater load index. This means that if your first tire's maximum load index was 92, buy new tires with a load index of 92 or more.
Step 7. Find the tire speed rating
The speed rating indicates that the tire can carry a specified load up to a certain speed. The speed ratings commonly used are S, T, U, H, V, Z, W, Y, and (Y).
- S means the tire can move at 180 km/h for a long time.
- T means the tire can move at 190 km/h for a long time.
- U means the tire can move at 200 km/h for a long time.
- H means the tire can move at a speed of 210 km/h for a long time.
- V means the tire can move at a speed of 240 km/h for a long time.
- Z means the tire can move at a speed of more than 240 km/h for a long time.
- W means the tire can move at a speed of 270 km/h for a long time.
- Y means the tire can move at a speed of 299 km/h for a long time.
- (Y) means the tire can move at a speed of more than 299 km/h for a long time.
Step 8. Find the temperature resistance of the tire
This text describes the tire's resistance to heat generated on the inside of the tire when the car is traveling at high speed. This endurance consists of endurance A, B, or C. Endurance A is the highest, while C is the lowest.
Step 9. Identify the Department of Transportation code by finding the acronym DOT followed by a series of numbers
Step 10. Find the cold (before walking) tire pressure reading near the inner end of the tire
This figure tells you the ideal air pressure to optimize tire performance.
