Arizona Tire Regulations: Thread Depth & Protrusion Rules 2026

Arizona enforces strict tire tread depth and protrusion rules to ensure road safety and prevent blowouts. The state requires a minimum tread depth of 2/32 of an inch and prohibits any tire protrusion beyond the vehicle’s fender line.

These regulations fall under the Arizona Department of Transportation (ADOT) and the Arizona Department of Public Safety (DPS), governed by Arizona Revised Statutes (ARS) § 28-958 and Arizona Administrative Code (AAC) R17-5-204. Non-compliance risks fines, failed inspections, and liability in accidents.

---

Governing Agencies & Codes

1. Arizona Department of Transportation (ADOT)
• Oversees vehicle safety standards, including tire regulations.
• Enforces ARS § 28-958 (tire safety) and AAC R17-5-204 (inspection requirements).

2. Arizona Department of Public Safety (DPS)
• Conducts roadside inspections and enforces protrusion limits.
• Cites violations under ARS § 28-1091 (unsafe vehicles).

3. Federal Motor Carrier Safety Administration (FMCSA)
• Applies to commercial vehicles (e.g., trucks, buses) under 49 CFR § 393.75.
• Requires 4/32-inch tread depth for steer tires and 2/32-inch for others.

Key Statutes & Rules

---

1. Measure Tread Depth

• Tool Required: Use a tread depth gauge (available at auto parts stores for $5–$15).
• Method:
1. Insert the gauge into the tread grooves at three points: outer, middle, and inner.
2. Record the lowest measurement.
3. Replace tires if any reading is below 2/32-inch (or 4/32-inch for commercial steer tires).

• Alternative: Use the "penny test":
• Insert a penny into the tread with Lincoln’s head upside down.
• If the top of Lincoln’s head is visible, tread depth is below 2/32-inch.

2. Check for Protrusions

• Definition: A protrusion occurs when any part of the tire (including tread or sidewall) extends beyond the vehicle’s fender line.
• Inspection Steps:
1. Park on a flat surface and turn the wheels to full lock (left and right).
2. Visually inspect the tire’s outer edge relative to the fender.
3. Measure any protrusion with a ruler—zero tolerance for protrusion beyond the fender.

• Exceptions:
• Dually trucks (e.g., pickup trucks with dual rear wheels) may have slight protrusion if the outer tire does not exceed the fender by more than 1 inch.
• Off-road vehicles (e.g., Jeeps with lifted suspensions) must comply with ARS § 28-958.1, which allows modifications if they do not pose a hazard.

3. Vehicle Inspection Compliance

• Annual Inspection: Required for all vehicles registered in Arizona (except new vehicles under 2 years old).
• Inspection Locations:
• ADOT Motor Vehicle Division (MVD) offices.
• Authorized third-party providers (list available on ADOT’s website).
• Fees:
• Passenger vehicles: $15–$25.
• Commercial vehicles: $50–$100 (varies by weight class).
• Documents Needed:
• Vehicle registration.
• Proof of insurance.
• Driver’s license.

4. Commercial Vehicle Requirements

• FMCSA Standards:
• Steer tires: Minimum 4/32-inch tread depth.
• Non-steer tires: Minimum 2/32-inch tread depth.
• Protrusion: No part of the tire may extend beyond the vehicle’s width (measured at the widest point).
• Inspection Frequency:
• Annual for most commercial vehicles.
• Every 90 days for vehicles transporting hazardous materials.

---

Compliance Mistakes

1. Ignoring Inner Tread Wear
• Many drivers check only the outer tread, missing uneven wear on the inner grooves.
• Fix: Rotate tires every 5,000–7,500 miles to ensure even wear.

2. Modifying Fenders Without Adjusting Tires
• Lifting or lowering a vehicle can cause tires to protrude.
• Fix: Install fender flares or adjust suspension to maintain compliance.

3. Using Retreaded Tires on Steer Axles
• FMCSA prohibits retreaded tires on steer axles for commercial vehicles.
• Fix: Use new tires on steer axles; retreads are allowed on non-steer positions.

Exceptions

Penalties for Violations

---

Can I drive with 3/32-inch tread in Arizona?

No. Arizona law requires a minimum of 2/32-inch tread depth. While 3/32-inch is close, it fails the legal standard and risks a $100+ fine during inspections.

What happens if my tires protrude 1 inch beyond the fender?

Protrusion of any amount beyond the fender violates ARS § 28-1091. You may receive a $150–$500 fine and be required to modify the vehicle (e.g., install fender flares) before passing inspection.

How long does an Arizona tire inspection take?

Most inspections take 15–30 minutes at ADOT MVD offices or authorized providers. Commercial vehicles may take 45–60 minutes due to additional FMCSA checks.

Are winter tires required in Arizona?

No, but if used, they must meet the 2/32-inch tread depth requirement. Arizona does not mandate winter tires, even in northern regions like Flagstaff.

Can I get a ticket for bald tires during a traffic stop?

Yes. DPS officers can issue a citation for insufficient tread depth (ARS § 28-958) during routine stops, even if no accident occurs. Fines start at $100.

Do trailer tires need to meet the same tread depth rules?

Yes. All tires on trailers registered in Arizona must comply with the 2/32-inch tread depth rule. Commercial trailers must also meet FMCSA standards (4/32-inch for steer tires if applicable).

---

Compliance Checklist

• ✅Measure tread depth at three points on each tire using a gauge or penny test.
• ✅Inspect for protrusions by turning wheels to full lock and checking fender alignment.
• ✅Rotate tires every 5,000–7,500 miles to prevent uneven wear.
• ✅Schedule an inspection at an ADOT MVD office or authorized provider.
• ✅Replace tires if tread is below 2/32-inch (or 4/32-inch for commercial steer tires).
• ✅Install fender flares if modifying suspension to prevent protrusion.

Official Contacts & Resources

• ADOT Motor Vehicle Division (MVD)
• Phone: (602) 255-0072
• Website: www.azdot.gov/mvd
• Arizona Department of Public Safety (DPS)
• Phone: (602) 223-2000
• Website: www.azdps.gov
• FMCSA Arizona Division
• Phone: (602) 379-6851
• Website: www.fmcsa.dot.gov

Disclaimer: This article is for informational and educational purposes only. It does not constitute formal legal advice and does not establish an attorney-client relationship. For specific compliance questions, consult the Arizona Department of Transportation or a licensed attorney.