393.75B

393.75B Violation: Front Tire Tread Below 4/32 Inch

A tire on the front wheels of a bus, truck, or truck tractor was recorded below the 4/32-inch tread-depth requirement.

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Plain-English answer

What does violation code 393.75B mean?

A tire on the front wheels of a bus, truck, or truck tractor was recorded below the 4/32-inch tread-depth requirement.

Why carriers pay attention

How 393.75B can affect a trucking safety record

Front-tire tread requirements are stricter than the general 2/32-inch standard. The tire position and the exact groove measured are central to reviewing this violation.

FMCSA inspection data can flow into the Safety Measurement System used to organize carrier performance into Behavior Analysis and Safety Improvement Categories, commonly called FMCSA SMS BASICs. The carrier should verify the inspection, the assigned BASIC, and whether the violation is included in the official calculation.

How it gets cited

Common 393.75B inspection situations

  • A steer tire measures below 4/32 of an inch in a major tread groove.

  • The inspection report incorrectly treats a non-steering tire as a front-wheel tire.

DataQ review

When a 393.75B violation may deserve a closer look

A DataQ challenge should identify a specific factual or legal error in the inspection data. These are review questions—not assumptions that the violation should be removed.

Potential review angles

  • The cited tire was not installed on a front wheel covered by the 4/32-inch standard.
  • The measurement was taken outside a qualifying major tread groove.
  • Contemporaneous tread measurements show the cited threshold was not met.

Evidence to collect

  • Photographs establishing axle position and measured tread depth
  • Pre-trip inspection and tire-maintenance records
  • Technician statement identifying the tire and calibrated gauge reading
Compliance expert review

Not sure whether 393.75B belongs on your record?

We'll review the violation details, identify evidence gaps, and explain whether the facts may support a DataQ challenge.

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DataQs changes in 2026

A stronger review process still requires a stronger record.

FMCSA’s 2026 DataQs overhaul adds independent review stages, decision deadlines, and more detailed explanations. Carriers still carry the burden of identifying the error and supporting the requested correction.

See the 2026 DataQs changes
Frequently asked questions

393.75B violation FAQ

What does a 393.75B violation mean?

A tire on the front wheels of a bus, truck, or truck tractor was recorded below the 4/32-inch tread-depth requirement.

Which FMCSA SMS BASIC is associated with 393.75B?

Code 393.75B is commonly associated with the Vehicle Maintenance BASIC in the FMCSA Safety Measurement System. Inclusion and weighting should be confirmed on the carrier’s official record.

Can a trucking company challenge a 393.75B violation?

A carrier may submit an FMCSA DataQs Request for Data Review when the underlying inspection data is incomplete or incorrect. A repair made after the inspection does not by itself prove the original 393.75B finding was wrong.

What evidence helps review a 393.75B violation?

Useful evidence may include photographs establishing axle position and measured tread depth, pre-trip inspection and tire-maintenance records, technician statement identifying the tire and calibrated gauge reading. The best evidence is tied to the cited vehicle, driver, location, and inspection time.

Keep reviewing

Related DOT violation codes

View all violation guides
393.75A3Flat Tire or Audible Air LeakTires and wheels393.75CTire Tread Depth Below 2/32 InchTires and wheels393.9Inoperable Required LampLighting396.17CNo Proof of Periodic InspectionInspection and maintenance

Source references: 49 CFR 393.75 and FMCSA roadside inspection data. This guide is general information and does not guarantee a DataQs outcome or replace legal advice.