How to Read a Tire Size
Posted On12.05.2020What’s On Your Tire’s Sidewall?
Tire Type
The letter “P” at the beginning of the “Tire Size” tells us the tire is a P-Metric tire, referring to tires made to certain standards within the United States, intended for Passenger vehicles.
If a tire size has no letters at the beginning, this indicates a Euro metric tire. P-Metric and Euro-Metric tires may have different load capacities.
The letters “LT,” either at the beginning or at the end of the tire size indicate the tire was designed for light trucks. Vehicle manufacturers equip some light trucks with “LT” type tires. These tires generally require higher inflation pressures than passenger tires.
Consult your owner’s manual or tire placard for the recommended tire size and inflation pressure for your vehicle.
Tire Width
Aspect Ratio
Construction
Wheel Diameter
Load Index
Speed Rating
DOT Symbol
Tire Identification Number
UTQG
Stands for Uniform Tire Quality Grading, a rating system developed by the U.S. Department of Transportation to provide consumers with information to help them purchase tires based on their relative treadwear, traction and temperature capabilities.
Traction grades indicate the wet traction of a tire under a controlled test. A tire with an “AA” rating offers outstanding traction in wet conditions.
| Traction Grades |
|---|
| AA |
| A |
| B |
| C |
Temperature grades indicate the ability of the tire to withstand and dissipate destructive heat. A tire with a higher temperature grade is able to operate at higher speeds.
| Temperature Grades | Speeds in mph |
|---|---|
| A | Over 115 |
| B | Between 100 and 115 |
| C | Between 85 and 100 |
Treadwear grades are based on standardized government tests to help predict the expected treadwear of a tire. For example, a tire with a treadwear grade of 200 should last twice as long as a tire with a treadwear grade of 100.
Source : Good Year
