What 393.75(f) means in plain language
FMCSR 393.75(f) addresses a straightforward but critical safety issue: the total weight your vehicle is carrying must not exceed what your tires are rated to safely support. Each tire has a maximum load rating printed on its sidewall—a specification determined by the tire manufacturer based on construction, materials, and design.
When an inspector cites you for this violation, they've determined that the actual weight distributed across your axles exceeds the combined load rating of the tires installed on those axles. This isn't about gross vehicle weight rating (GVWR) or bridge laws—it's specifically about whether your tires themselves are overloaded.
This matters because tires operating beyond their rated capacity degrade faster, generate excessive heat, lose structural integrity, and become prone to sudden failure. A tire blowout at highway speed doesn't just damage your equipment; it puts your life and everyone around you at severe risk.
What our enforcement data actually shows
Across our 13 million inspection records, 393.75(f) is rare. We've recorded 125 all-time citations for this violation, with only 1 citation in the last 12 months and 0 in the last 90 days. This makes it ranked #1361 out of 3,036 tracked FMCSR codes by citation frequency.
What is not rare: the severity when it is cited. Our data shows a 91.2% out-of-service rate for this violation—meaning 114 of the 125 citations resulted in the vehicle being placed out of service. That's nearly three times the all-FMCSR average OOS rate of 31.4%. When inspectors find this violation, they treat it as an immediate safety threat and remove the vehicle from operation.
The low volume tells you that most carriers and drivers catch this issue during pre-trip inspection or through load planning—it's preventable. The high OOS rate tells you that when it slips through, enforcement is swift and unforgiving.
Who gets cited most
Our inspection records do not reveal a top-states breakdown for this specific code in our current dataset. However, our data does show which carriers have appeared in citations for this violation. U S N 1 TRANS LLC (USDOT 4039695) appears in our records with 8 citations for weight-related tire overload issues—the highest count we see. MAGNOLIA TRUCKING LLC and AAJM TRANSPORT CORP each appear with 5 citations. These numbers reflect historical patterns across our database and do not imply any current compliance status; they simply indicate which fleets have encountered this violation in roadside enforcement.
The rarity of citations overall suggests that this violation is not concentrated geographically or by carrier type—when it happens, it's usually an isolated incident rather than a systemic issue.
How severe is this compared to similar codes
In the Vehicle Maintenance category, 393.75(f) sits at an extreme end of the severity spectrum. Consider the peer codes:
- 393.9(a) — Inoperable required lamps: 660,737 all-time citations, 15.4% OOS rate. A burned-out light is serious but infrequent OOS.
- 396.3(a)(1) — Inspection/repair/maintenance general: 236,919 citations, 45.3% OOS rate. This broader violation lands in the middle range of enforcement.
- 393.78 — Windshield condition defective: 157,894 citations, 0.3% OOS rate. Most windshield violations are cited but the vehicle stays in service.
The 91.2% OOS rate for 393.75(f) reflects its position as an acute safety failure. Inspectors don't issue a warning or allow you to continue to a repair facility. The violation indicates your tires cannot safely support the load right now, and the vehicle must stop.
How to avoid it
Before you load:
- Know the load rating of every tire on your vehicle. Check the tire sidewall markings or your truck's documentation. If you don't have this information, ask your fleet or tire supplier.
- Calculate the expected weight distribution across your axles before loading. Match the load plan to your tire capacity, not just your GVWR.
- Use a certified scale if you're carrying heavy or unusual loads. Don't guess.
During pre-trip inspection:
- Visually inspect all tires for signs of overload stress: sidewall bulging, unusual wear patterns, cracks, or heat damage.
- Check tire pressure. Underinflated tires under a heavy load overheat and degrade rapidly.
- Verify the load hasn't shifted during transport, which can concentrate weight unevenly across axles.
- If you've added equipment (racks, fifth wheels, toolboxes) since the truck was last certified, recalculate your axle weights—added weight reduces your safety margin.
On the road:
- If you feel unusual vibration, pulling, or heat from the tires, pull over immediately and inspect. Don't continue to your destination.
- Monitor your tire pressure. A rapid pressure loss can indicate a tire operating beyond its limit is failing.
This violation is preventable through basic load planning and pre-trip awareness. The 91.2% OOS rate and the near-zero citation count over the past 90 days suggest that most drivers and fleets are already doing this work correctly.