Tire sidewalls hold crucial information for selecting and maintaining the right tires for your vehicle. Here’s how to read the codes and what they mean:

1. Tire Size

• Example: P235/65R17
• P: Passenger car tire (or LT for light trucks).
• 235: Width of the tire in millimeters.
• 65: Aspect ratio (sidewall height is 65% of the width).
• R: Radial-ply construction.
• 17: Diameter of the wheel (in inches).

2. Load Index

• Number after tire size (e.g., 103 in P235/65R17 103T).
• Indicates the maximum weight the tire can carry.
• 103 = 1,929 lbs.
• Match or exceed the load index specified on your vehicle placard.

3. Speed Rating

• Letter following the load index (e.g., T in 103T).
• Indicates maximum sustainable speed:
  • S: 112 mph
  • T: 118 mph
  • H: 130 mph
  • V: 149 mph
  • W: 168 mph
  • Y: 186 mph
  • ZR: Over 149 mph
• Higher speed ratings often improve handling, even at legal speeds.

4. Treadwear Rating

• A numerical value (e.g., 500–800).
• Theoretically, a tire with a 400 treadwear rating lasts twice as long as one rated 200.
• For a more accurate measure, refer to tread life predictions.

5. Traction and Temperature Scores

• Traction: Wet-stopping ability.
• AA (best) to C (worst).
• Temperature: Heat resistance.
• A (best) to C (lowest).

6. Maximum Pressure

• Listed in PSI (pounds per square inch).
• Do not inflate to this number!
• Follow the manufacturer’s recommended pressure on your car’s placard.

7. Manufacturing Date

• Found in the DOT code (last 4 digits).
• Example: 0424 = 4th week of 2024.
• Avoid tires over 2 years old when purchasing. Replace tires after 6–10 years, even if treadwear is minimal.

Tips for Tire Selection

• Match recommended size, speed, and load ratings from your car’s placard or owner’s manual.
• Check front and rear tire specs, especially on sports cars (they may differ).
• Inspect manufacturing dates to ensure tires are fresh.

Keep your tires in top shape for better safety, performance, and efficiency!

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