How to Read a Tire Sidewall
In today’s fast-paced world, understanding your vehicle’s components is essential for maintaining safety and performance. One often-overlooked aspect is the information embedded on the tire sidewall. This article will guide you through reading and understanding the various codes, symbols and text written on a tire sidewall.
1. Brand and Model:
At first glance, you’ll notice the brand and model of the tire. Renowned brands like Bridgestone, Michelin or Goodyear ensure quality products, while the model signifies the specific design and purpose of the tire. Knowing these two factors can help you select the right tire for your vehicle.
2. Tire Size:
The largest alphanumeric sequence on your tire sidewall reveals its size—essential when replacing tires. The numbers indicate width, aspect ratio (height), and rim diameter in inches. For example, 215/60R16 translates to a width of 215mm, an aspect ratio (height) of 60%, and a rim diameter of 16 inches.
3. Load Index and Speed Rating:
Moving further along the tire sidewall, you will find an alphanumeric code representing the load index (LI) and speed rating (SR). LI indicates the maximum carrying capacity available when tires are inflated properly. The SR signals the top speed at which your tires can safely perform under full load conditions.
For instance, a code like ’93V’ means an LI of 93 (carrying capacity of 1,433 lbs per tire) and an SR of V (maximum safe speed up to 149 mph).
4. U.S. DOT Safety Standards:
A string of letters starting with ‘DOT’ indicates that your tire complies with U.S. Department of Transportation safety standards. The letters following ‘DOT’ represent manufacturer codes for specific production facilities.
5. Manufacturing Date:
The last four characters on the DOT code tell you the manufacturing date. The first two numbers represent the week, and the last two signify the year. For example, ‘3721’ translates to the 37th week of 2021.
6. Tire Types and Position:
Some tires are marked with letters indicating their intended use:
– P: passenger car
– LT: light truck
– T: temporary spare
– ST: special trailer
For unidirectional tires, you’ll see ‘rotation’ or an arrow denoting correct rotation direction and ideal performance.
7. Treadwear, Traction, and Temperature Ratings:
Uniform Tire Quality Grading (UTQG) shows a tire’s relative performance in treadwear, traction, and temperature resistance. A number (e.g., 450) indicates treadwear lifespan compared to the reference tire. Traction ratings range from AA (best) to C (minimum). Temperature ratings from A (highest) to C (lowest) measure resistance to heat buildup related to speed.
8. Maximum Inflation Pressure:
Tire sidewalls will also mention the maximum inflation pressure. This detail does not reflect recommended tire pressure but serves as a guideline for safe operating limits.
Now that you can read tire sidewalls properly, you’re equipped to make informed decisions when purchasing or maintaining your vehicle’s tires. Regularly checking tire details ensures road safety, optimum performance, and longevity for your ride.