FMCSR 393.75(c): Tire Tread Depth (Non-Steer Axles) — Driver Q&A

It can, but it's not the most likely outcome. Across 86,013 all-time citations in our inspection records, 7,569 trucks were placed out of service under 393.75(c) — an OOS rate of 8.8%. That means roughly 9 out of every 100 drivers cited for insufficient tread depth on non-steer axles got parked on the spot. The other 78,444 citations resulted in a violation recorded without an immediate OOS order. Whether the inspector pulls you off the road often comes down to how far below the 2/32-inch threshold your tires measure, so there's real stakes here even if the odds favor you staying on the road.

A 393.75(c) citation carries a severity weight of 5 in the FMCSA's CSA scoring system. That base score gets multiplied depending on how recently the inspection occurred — violations within the last 6 months carry a 3× time-weight multiplier, dropping to 2× between 6 and 12 months, and 1× from 12 to 24 months. So a fresh citation effectively hits your Vehicle Maintenance BASIC with 15 weighted points. Points accumulate across all inspections in the 24-month rolling window, so a pattern of 393.75(c) citations compounds quickly and can push a carrier toward an FMCSA intervention threshold.

Get the tires measured and replaced or retreaded before your next dispatch. Here's the immediate checklist:

1. Document the current tread depth on every non-steer tire before anything is touched — photos with a tread depth gauge dated and timestamped.
2. Pull the truck from service if any tire is at or below 2/32 inch on the non-steer axles; don't wait for the next PM cycle.
3. Get a repair receipt that specifies the axle position and new tread depth — you'll need this for a DataQs challenge if the measurement was disputed.
4. Notify your safety department the same day so the citation gets logged and the CSA severity weight of 5 is factored into your BASIC score tracking.
5. Check peer violations — our records show 393.75(c) frequently appears alongside other vehicle maintenance write-ups, so do a full walk-around before returning to service.

It's mid-range in OOS risk but high in citation frequency. The national average OOS rate across all FMCSR codes in our database is 31.4%. At 8.8%, 393.75(c) sits well below that average, meaning inspectors cite it often but don't park trucks at the same rate as heavier mechanical violations. However, consider the volume: with 86,013 all-time citations, it ranks #22 out of 3,036 FMCSR codes nationwide — that's a top-1% enforcement target. For context, a peer code like 396.3(a)(1) carries a 45.3% OOS rate, and even 393.9(a) for inoperable lamps sits at 15.4%. Frequency alone means inspectors know exactly what to look for, so don't assume a low OOS rate means low risk of being cited.

Yes, equipment-based findings like this are contestable through the FMCSA DataQs system. Because 393.75(c) is a physical measurement violation — not a missing document — a successful challenge typically requires proof that the tread depth was actually at or above 2/32 inch at the time of inspection. That means submitting dated tread-depth gauge photos, a repair shop inspection report from close in time to the roadside stop, or a second independent measurement. DataQs challenges go to the issuing state agency as a Request for Data Review (RDR). If the state agrees the measurement was inaccurate or the violation was incorrectly recorded, the citation is removed from your CSA profile. Keep in mind the 60-day window from the inspection date — challenges filed late are harder to process.

Our inspection records show FRHT-make vehicles alone account for 9,648 citations, pointing to where heavy commercial traffic concentrates enforcement. On the carrier side, the top-cited carriers in our database are CNC LOGISTICS S DE RL DE CV (383 citations), HLH LOGISTICS INC (360 citations), and RS TRANSFER SA DE CV (333 citations) — all cross-border or regionally concentrated operations. The data does not break down citations to specific U.S. states in the statistics available, so we can't name the top three states by count for this code without risking an inaccurate claim. What is clear is that border-corridor and high-mileage freight lanes dominate the citation pattern based on which carriers appear at the top of the list.

Don't wait for your next scheduled PM. While the last 12 months and last 90 days show 0 new citations in our current dataset snapshot, the all-time record of 86,013 citations and an 8.8% OOS rate make clear that inspectors actively enforce this standard. Any non-steer tire measuring below 2/32 inch tread depth is an immediate violation the next time your truck goes through a weigh station or roadside inspection. Operating with a known defect also exposes the carrier to increased liability in the event of a tire-related incident. Repair it before the next trip, document it, and update your maintenance records.

It follows both, but in different ways. In the FMCSA CSA system, vehicle maintenance violations like 393.75(c) are attributed to the carrier's Vehicle Maintenance BASIC — that's where the severity weight of 5 shows up and where intervention thresholds are calculated for the motor carrier. The driver's PSP (Pre-Employment Screening Program) record also logs the violation, and prospective employers can see it during hiring checks. So a single citation creates a mark on the carrier's safety score and a record on the driver's individual history. Drivers who accumulate equipment violations across multiple carriers will carry that PSP history with them, making it relevant well beyond the current job.