Tire Compliance: Tread Depths, Conditions, and When You're Out of Service

Tires are the third most common OOS (Out of Service — when an inspector finds a violation severe enough to pull the vehicle off the road) violation. And unlike brakes, tire problems are visible to the naked eye. A driver who does a proper pre-trip should catch every tire issue before it becomes a violation. Should.

Minimum Tread Depths

• Steer tires (front axle tires that control steering): 4/32" in any major groove
• Drive tires (rear axle tires that power the vehicle) and trailer tires: 2/32" in any major groove

Measure with a tread depth gauge — not a penny. Penny tests are fine for your personal car. For commercial vehicles, use the right tool and document it.

Immediate OOS Conditions

Any of these puts you out of service on the spot:

• Flat tire or audibly leaking tire
• Exposed body cords (visible through the rubber)
• Tire tread separation
• Any fabric or cord showing due to a cut or crack
• A tire mounted on a damaged rim
• Regrooved or recapped steer tires (illegal on steer axle)

Recaps and Retreads

Retreaded tires are legal on drive and trailer axles. They are never legal on the steer axle. We still see carriers running retreads on steers because they didn't check when they bought used tires. That's an immediate violation.

Inflation and Load Ratings

A tire that's inflated but underinflated for its load is technically in violation. More practically, underinflated tires run hot, wear unevenly, and blow out. Check inflation cold, before driving. Use a calibrated gauge, not a thump test.

Simple Prevention

Tire violations are the most preventable item on this list. Walk around the truck. Look at every tire. Check the tread with a gauge. Feel for bulges or separations. It takes 3 minutes. Three minutes vs. a $400+ fine and a 4-hour roadside delay. Easy math.