What 393.65(c) means in plain language
FMCSR 393.65(c) prohibits you from operating a commercial motor vehicle with a tire that is flat or has an audible air leak. This is straightforward: if a tire on your truck has lost pressure to the point where it's visibly flat or you can hear air escaping, you cannot legally drive that vehicle until the tire is repaired or replaced.
The violation doesn't require the tire to be completely deflated. "Audibly leaking" means an inspector—or you, during a pre-trip inspection—can actually hear the hiss of air escaping. This is a condition that can develop gradually as a tire ages, picks up a puncture, or develops a sidewall crack. The regulation exists because a compromised tire can fail suddenly at highway speed, causing loss of control, jackknife, or rollover.
You cannot defer this repair. Unlike some maintenance issues that might be fixed at the next available service center, a flat or leaking tire must be addressed before the vehicle moves.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.65(c) has generated 799 all-time citations, ranking it #778 out of 3,036 FMCSR codes by citation volume. In the last 12 months, there have been 0 citations recorded in our database, and in the last 90 days, 0 citations as well—suggesting this violation is either rare or highly underreported in recent months.
When 393.65(c) is cited, the enforcement consequence is severe. Our data shows 567 out-of-service placements against 232 non-OOS citations, yielding a 71.0% out-of-service rate. This is more than double the all-FMCSR average OOS rate of 31.4%, meaning an inspector who finds a flat or audibly leaking tire is far more likely to place your vehicle out of service than they would for a typical maintenance violation. The logic is clear: tire failure is a direct safety hazard that cannot be ignored.
Who gets cited most
Our inspection records do not include detailed state-level breakdowns in the data we have for this code. However, our top carriers by citation count include JOSE ALFREDO DELGADO HERNANDEZ (USDOT 1398440) with 6 citations, SWIFT TRANSPORTATION CO OF ARIZONA LLC (USDOT 54283) with 4 citations, and OLD DOMINION FREIGHT LINE INC (USDOT 90849) with 4 citations. We emphasize that high citation counts do not indicate systematic negligence—these carriers operate thousands of vehicle-weeks annually, and flat or leaking tires can occur despite strong maintenance programs due to road debris, age of equipment, or manufacturing defects.
Among vehicle makes, FRHT (Freightliner) leads with 96 citations, followed by UTIL (Utility trailers) at 39 citations, and FORD at 35 citations. INTL (International), FREIGHTLIN, and KW (Kenworth) also appear frequently in our records. The high count for Freightliner and utility trailers likely reflects their prevalence in the fleet population rather than inherent design flaws.
How severe is this compared to similar codes
To understand where 393.65(c) sits in the enforcement landscape, we compare it to peer codes in the Vehicle Maintenance category.
393.9(a) — Inoperable required lamps shows 660,737 citations with a 15.4% OOS rate. Lamp failures are far more common but rarely result in immediate out-of-service action.
396.3(a)(1) — Inspection/repair/maintenance - general has 236,919 citations and a 45.3% OOS rate, placing it between lamp violations and tire violations in severity.
393.78 — Windshield condition defective has 157,894 citations but only a 0.3% OOS rate, indicating inspectors treat visibility defects as much less critical than tire integrity.
The 71.0% OOS rate for 393.65(c) is among the highest in the vehicle maintenance category, reflecting the acute safety risk posed by a tire that cannot hold pressure. Inspectors do not issue warnings or allow you to limp to the nearest repair shop—they remove your vehicle from service immediately.
How to avoid it
Tire integrity must be part of your pre-trip inspection routine, and it must happen every single day before you move.
Walk around your rig and visually inspect every tire. Look for bulges, cuts, exposed cords, and uneven wear. Spend a few extra seconds on the drive tires and steer axle tires, which carry the most load and wear fastest. Do not trust tread depth alone—a tire can look adequate but have a sidewall crack or slow leak that becomes critical under load.
Listen and feel for air leaks. On a quiet morning, walk your truck and listen for hissing near the wheel wells. Press firmly around each tire sidewall and listen again. If you hear air escaping, mark that tire and do not operate the vehicle.
Check tire pressure if your fleet uses tire monitoring systems. If your vehicle has built-in TPMS or your fleet provides a pressure gauge, use it. Tire pressure should match the placard on the driver's door jamb. A tire losing pressure steadily is a harbinger of the kind of leak that triggers this code.
Know the condition of your tires' age. Tires older than six years are prone to cracking and slow leaks, even if they have tread remaining. If your fleet includes older trailers or you've been assigned a vehicle with original-equipment tires, be especially vigilant.
Report worn or suspect tires immediately. Do not hope a slightly soft tire will firm up overnight. Report it to your dispatcher or maintenance team so the tire can be pulled and inspected. A flat or leaking tire that you knowingly operated with is not only a violation—it's a safety incident waiting to happen.
Maintain consistent vehicle pre-trips. Use a written or digital checklist. The discipline of documenting your inspection creates a record that protects you and forces you to be systematic. You are less likely to miss a leaking tire if you have already caught three other minor issues on the same vehicle.