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  • § 393.1
    Scope of the rules in this part.
  • § 393.3
    Additional equipment and accessories.
  • § 393.5
    Definitions.
  • § 393.7
    Matter incorporated by reference.
  • § 393.9
    Lamps operable, prohibition of obstructions of lamps and reflectors.
  • § 393.11
    Lamps and reflective devices.
  • § 393.13
    Retroreflective sheeting and reflex reflectors, requirements for semitrailers and trailers manufactured before December 1, 1993.
  • § 393.17
    Lamps and reflectors—combinations in driveaway-towaway operation.
  • § 393.19
    Hazard warning signals.
  • § 393.20
  • § 393.22
    Combination of lighting devices and reflectors.
  • § 393.23
    Power supply for lamps.
  • § 393.24
    Requirements for head lamps, auxiliary driving lamps and front fog lamps.
  • § 393.25
    Requirements for lamps other than head lamps.
  • § 393.26
    Requirements for reflectors.
  • § 393.27
  • § 393.28
    Wiring systems.
  • § 393.29
  • § 393.30
    Battery installation.
  • §§ 393.31-393.33
  • § 393.40
    Required brake systems.
  • § 393.41
    Parking brake system.
  • § 393.42
    Brakes required on all wheels.
  • § 393.43
    Breakaway and emergency braking.
  • § 393.44
    Front brake lines, protection.
  • § 393.45
    Brake tubing and hoses; hose assemblies and end fittings.
  • § 393.46
  • § 393.47
    Brake actuators, slack adjusters, linings/pads and drums/rotors.
  • § 393.48
    Brakes to be operative.
  • § 393.49
    Control valves for brakes.
  • § 393.50
    Reservoirs required.
  • § 393.51
    Warning signals, air pressure and vacuum gauges.
  • § 393.52
    Brake performance.
  • § 393.53
    Automatic brake adjusters and brake adjustment indicators.
  • § 393.55
    Antilock brake systems.
  • § 393.60
    Glazing in specified openings.
  • § 393.61
    Truck and truck tractor window construction.
  • § 393.62
    Emergency exits for buses.
  • § 393.63
  • § 393.65
    All fuel systems.
  • § 393.67
    Liquid fuel tanks.
  • § 393.68
    Compressed natural gas fuel containers.
  • § 393.69
    Liquefied petroleum gas systems.
  • § 393.70
    Coupling devices and towing methods, except for driveaway-towaway operations.
  • § 393.71
    Coupling devices and towing methods, driveaway-towaway operations.
  • § 393.75
    Tires.
  • § 393.76
    Sleeper berths.
  • § 393.77
    Heaters.
  • § 393.78
    Windshield wiping and washing systems.
  • § 393.79
    Windshield defrosting and defogging systems.
  • § 393.80
    Rear-vision mirrors.
  • § 393.81
    Horn.
  • § 393.82
    Speedometer.
  • § 393.83
    Exhaust systems.
  • § 393.84
    Floors.
  • § 393.85
  • § 393.86
    Rear impact guards and rear end protection.
  • § 393.87
    Warning flags on projecting loads.
  • § 393.88
    Television receivers.
  • § 393.89
    Buses, driveshaft protection.
  • § 393.90
    Buses, standee line or bar.
  • § 393.91
    Buses, aisle seats prohibited.
  • § 393.92
  • § 393.93
    Seats, seat belt assemblies, and seat belt assembly anchorages.
  • § 393.94
    Interior noise levels in power units.
  • § 393.95
    Emergency equipment on all power units.
  • § 393.100
    Which types of commercial motor vehicles are subject to the cargo securement standards of this subpart, and what general requirements apply?
  • § 393.102
    What are the minimum performance criteria for cargo securement devices and systems?
  • § 393.104
    What standards must cargo securement devices and systems meet in order to satisfy the requirements of this subpart?
  • § 393.106
    What are the general requirements for securing articles of cargo?
  • § 393.108
    How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?
  • § 393.110
    What else do I have to do to determine the minimum number of tiedowns?
  • § 393.112
    Must a tiedown be adjustable?
  • § 393.114
    What are the requirements for front end structures used as part of a cargo securement system?
  • § 393.116
    What are the rules for securing logs?
  • § 393.118
    What are the rules for securing dressed lumber or similar building products?
  • § 393.120
    What are the rules for securing metal coils?
  • § 393.122
    What are the rules for securing paper rolls?
  • § 393.124
    What are the rules for securing concrete pipe?
  • § 393.126
    What are the rules for securing intermodal containers?
  • § 393.128
    What are the rules for securing automobiles, light trucks and vans?
  • § 393.130
    What are the rules for securing heavy vehicles, equipment and machinery?
  • § 393.132
    What are the rules for securing flattened or crushed vehicles?
  • § 393.134
    What are the rules for securing roll-on/roll-off or hook lift containers?
  • § 393.136
    What are the rules for securing large boulders?
  • § 393.201
    Frames.
  • § 393.203
    Cab and body components.
  • § 393.205
    Wheels.
  • § 393.207
    Suspension systems.
  • § 393.209
    Steering wheel systems.

Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION

§ 393.75: Tires.

(a) No motor vehicle shall be operated on any tire that—

(1) Has body ply or belt material exposed through the tread or sidewall,

(2) Has any tread or sidewall separation,

(3) Is flat or has an audible leak, or

(4) Has a cut to the extent that the ply or belt material is exposed.

(b) Any tire on the front wheels of a bus, truck, or truck tractor shall have a tread groove pattern depth of at least 4/32of an inch when measured at any point on a major tread groove. The measurements shall not be made where tie bars, humps, or fillets are located.

(c) Except as provided in paragraph (b) of this section, tires shall have a tread groove pattern depth of at least 2/32of an inch when measured in a major tread groove. The measurement shall not be made where tie bars, humps or fillets are located.

(d) No bus shall be operated with regrooved, recapped or retreaded tires on the front wheels.

(e) A regrooved tire with a load-carrying capacity equal to or greater than 2,232 kg (4,920 pounds) shall not be used on the front wheels of any truck or truck tractor.

(f) Tire loading restrictions (except on manufactured homes). No motor vehicle (except manufactured homes, which are governed by paragraph (g) of this section) shall be operated with tires that carry a weight greater than that marked on the sidewall of the tire or, in the absence of such a marking, a weight greater than that specified for the tires in any of the publications of any of the organizations listed in Federal Motor Vehicle Safety Standard No. 119 (49 CFR 571.119, S5.1(b)) unless:

(1) The vehicle is being operated under the terms of a special permit issued by the State; and

(2) The vehicle is being operated at a reduced speed to compensate for the tire loading in excess of the manufacturer's rated capacity for the tire. In no case shall the speed exceed 80 km/hr (50 mph).

(g)(1) Tire loading restrictions for manufactured homes built before January 1, 2002. Manufactured homes that are labeled pursuant to 24 CFR 3282.362(c)(2)(i) before January 1, 2002, must not be transported on tires that are loaded more than 18 percent over the load rating marked on the sidewall of the tire or, in the absence of such a marking, more than 18 percent over the load rating specified in any of the publications of any of the organizations listed in FMVSS No. 119 (49 CFR 571.119, S5.1(b)). Manufactured homes labeled before January 1, 2002, transported on tires overloaded by 9 percent or more must not be operated at speeds exceeding 80 km/hr (50 mph).

(2) Tire loading restrictions for manufactured homes built on or after January 1, 2002. Manufactured homes that are labeled pursuant to 24 CFR 3282.362(c)(2)(i) on or after January 1, 2002, must not be transported on tires loaded beyond the load rating marked on the sidewall of the tire or, in the absence of such a marking, the load rating specified in any of the publications of any of the organizations listed in FMVSS No. 119 (49 CFR 571.119, S5.1(b)).

(h) Tire inflation pressure. (1) No motor vehicle shall be operated on a tire which has a cold inflation pressure less than that specified for the load being carried.

(2) If the inflation pressure of the tire has been increased by heat because of the recent operation of the vehicle, the cold inflation pressure shall be estimated by subtracting the inflation buildup factor shown in Table 1 from the measured inflation pressure.

Table 1—Inflation Pressure Measurement Correction for Heat
Average speed of vehicle
  • in the previous hour
  • Minimum inflation pressure buildup Tires with 1,814 kg (4,000 lbs.) maximum load rating or less Tires with over 1,814 kg (4,000 lbs.) load rating
    66-88.5 km/hr (41-55 mph) 34.5 kPa (5 psi) 103.4 kPa (15 psi).

    Citation: [34 FR 9344, June 13, 1969, as amended at 40 FR 44557, Sept. 29, 1975; 41 FR 36657, Aug. 31, 1976; 44 FR 25455, May 1, 1979; 44 FR 47938, Aug. 16, 1979; 53 FR 18057, May 19, 1988; 53 FR 49401, Dec. 7, 1988; 63 FR 8339, Feb. 18, 1998; 65 FR 70220, Nov. 21, 2000; 66 FR 67694, Dec. 31, 2001; 70 FR 48054, Aug. 15, 2005]

    Disclaimer:

    Although we make every effort to assure that the information we provide is complete and accurate, it is not intended to take the place of published agency regulations. Regulations issued by the U.S. Department of Transportation and its Operating Administrations are published in the Federal Register and compiled in the U.S. Code of Federal Regulations (CFR). Copies of appropriate volumes of the CFR in book format may be purchased from the Superintendent of Documents, U.S. Government Printing Office, or examined at many libraries.

    The CFR may also be viewed online at http://ECFR.gpoaccess.gov.


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