Tire measurements are crucial for replacing your current set of tires or determining if it’s time for new ones. From tire size, tread depth, to aspect ratios, understanding these measurements will help ensure safety and performance. Follow these 13 steps to measure your tires accurately.

1. Gather necessary tools: To begin, you’ll need a tire tread depth gauge, a ruler or tape measure, and pen and paper to jot down notes.

2. Find the tire code: On the sidewall of your tires, look for a series of letters and numbers (e.g., P215/65R15). This code is important to identify your tire size accurately.

3. Record the tire type: The first letter in the code indicates the type of vehicle. ‘P’ – Passenger car, ‘LT’ – Light truck, ‘ST’ – Special trailer, and ‘T’ – Temporary spare.

4. Measure section width: Identify the three-digit number after the tire type (e.g., 215). This represents the tire’s width in millimeters from sidewall to sidewall.

5. Determine aspect ratio: After the slash (/), note the two-digit number (e.g., 65). This is the aspect ratio, representing the tire’s height as a percentage of its width.

6. Observe construction type: The letter following the aspect ratio signals how a tire is constructed; ‘R’ – Radial or ‘D’ – Diagonal (bias-ply).

7. Note wheel diameter: The final two-digit number (e.g., 15) indicates the wheel’s diameter in inches that fits this specific tire.

8. Check manufacturing date: It’s essential to know your tire age, as well. Locate a four-digit code within an oval and read it as WWYY (Week-Year); for instance, “2120” means it was manufactured on the 21st week of 2020.

9. Measure tread depth: For an accurate reading, use a tire tread depth gauge. First, locate the central tread groove and insert the gauge’s probe into the groove until it stops. Record the measurement in 32nds of an inch.

10. Examine wear bars: In between the tire’s grooves, you’ll notice raised bars called wear indicators. If these indicators are flush with the tread, it’s time for new tires.

11. Perform a penny test: Insert a penny into your tire’s groove with Lincoln’s head facing down. If his head is still visible, this indicates insufficient tire tread.

12. Inspect sidewalls for signs of damage: Check for any bulges, cracks, or punctures to avoid dangerous blowouts while driving.

13. Compare measurements to manufacturer’s recommendations: Refer to your vehicle’s owner manual or placard on the driver-side doorjamb for correct tire dimensions and pressure guidelines.

Following these steps will ensure you accurately measure your tires and make informed decisions about maintenance, replacement, and optimal performance for a safer driving experience.