How to Do a Tire PSI Chalk Test

Check Proper Tire Inflation for Your Jeep

Running the right tire pressure is critical for both safety and performance, especially if you’ve upgraded to larger tires. Over-inflated tires wear unevenly in the center, while under-inflated tires wear on the edges. So how can you tell if your Jeep’s tires are properly inflated? One simple and effective way is the tire PSI chalk test.

Why Proper Tire Inflation Matters

Tire pressure affects ride quality, traction, and tread life. Running the correct PSI ensures even wear, maximizes performance on and off-road, and reduces the risk of tire failure. With bigger tires, like my 35” Duratracs LT 315/70R/18, getting your PSI dialed in becomes even more important.

Tools You’ll Need

Performing a chalk test requires just a few basic items:

• Chalk

• Tire pressure gauge

• A flat, smooth surface (like a driveway or paved road)

These simple tools help you see how much of your tire tread actually contacts the ground.

Tools for chalk test: chalk and tire pressure guage

Step-by-Step Tire PSI Chalk Test

Step 1: Check Your Current Tire Pressure

Use a tire gauge to measure the PSI of all four tires. On my Jeep, three of my tires read 31 PSI, and the rear driver-side tire was 29 PSI. This baseline lets you know where your tires are before making adjustments.

using the tire pressure guage to measure pressure

Step 2: Apply Chalk to the Tread

Draw a thick line of chalk across the width of each tire tread. Make sure the chalk line is even so you can clearly see which parts of the tread contact the ground.

putting chalk on tire 

Step 3: Drive on a Flat Surface

Drive back and forth over a flat surface, like your repaved driveway. Avoid cracks, potholes, or steep inclines so your results aren’t skewed. This helps transfer the chalk from the tire to the pavement.

chalk on tire before measuring

Step 4: Inspect the Chalk

Check where the chalk made contact with the ground. Here’s what to look for:

• Over-inflated tire: Only the center of the tread touches the ground; the chalk line will show a gap on the edges.

• Under-inflated tire: Only the sides of the tread touch the ground; the middle of the chalk line will be missing.

• Properly inflated tire: The chalk line is even across the tread, indicating full contact.

Knowing the true edges of your tread makes it easier to see if your tires are hitting the pavement correctly. After testing, I found my tires were spot-on, running around 30–32 PSI on asphalt.

Before with chalk

After when the Jeep has been driven

Showing the edge of the tire

Step 5: Adjust as Needed

If your chalk test shows uneven contact, adjust your PSI accordingly and re-test. Remember that tire width, vehicle load, and terrain can all affect your ideal PSI.

Tips & Considerations

• Tire width: Wider tires spread the weight differently, so PSI might need slight adjustments.

• Temperature: Cold weather lowers PSI; hot weather raises it. Always check tires when they’re cold.

• Tire type: Different tread patterns and off-road tires may behave differently in a chalk test.

The Nexen Tires have so far been my favorite tires both on and off-road. 

Troubleshooting Common Tire PSI Issues

Even after performing a chalk test, your Jeep’s tires may not behave exactly as expected. Here’s how to troubleshoot common problems:

1. Chalk Line Shows Only Center Contact (Over-Inflated)

• Cause: PSI is too high, causing the middle of the tread to bear most of the weight.

• Fix: Slowly reduce tire pressure in 1–2 PSI increments, then re-test with chalk until the tread contacts the ground evenly.

2. Chalk Line Shows Only Edge Contact (Under-Inflated)

• Cause: PSI is too low, causing the sides of the tread to flex more than the center.

• Fix: Gradually increase tire pressure, checking after each adjustment, until the chalk line is even.

3. Uneven Chalk Transfer Between Tires

• Cause: Uneven driveway, soft pavement, or different tire wear patterns.

• Fix: Use the flattest surface possible and check for tire irregularities. Rotating tires or checking alignment may help.

4. Tires Lose Pressure Quickly After Adjustment

• Cause: Small leaks, valve stem issues, or bead seating problems.

• Fix: Inspect tires for punctures, tighten valve stems, or consult a tire shop if the problem persists.

5. Chalk Wears Off Too Quickly

• Cause: Tires may be too dirty or wet, or chalk applied too lightly.

• Fix: Clean tires and apply a thicker line of chalk for better visibility.

Pro Tip:

Check tire pressure regularly, especially with larger off-road tires. Environmental factors like temperature changes and off-road adventures can affect PSI, so make the chalk test part of your routine maintenance.

FAQs: Tire PSI Chalk Test

Q1: What is a tire PSI chalk test?
A simple method to check if your tires are properly inflated by marking the tread with chalk and seeing which parts contact the ground after driving a short distance.

Q2: How often should I check tire PSI?
At least once a month or before long trips. After off-roading or heavy hauling, check PSI again.

Q3: Can I rely only on a chalk test to set tire pressure?
It’s a great visual guide, but factors like tire size, load, and road type mean you should also reference the manufacturer’s recommended PSI.

Q4: What happens if my tires are over- or under-inflated?
Over-inflation wears the center of the tread; under-inflation wears the edges. Both can affect handling, traction, and safety.

Q5: Does tire temperature affect the chalk test?
Yes, always check tires when cold. Driving heats them up, temporarily increasing PSI and potentially skewing results.