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  • § 393.11
    Lamps and reflective devices.
  • § 393.17
    Lamps and reflectors—combinations in driveaway-towaway operation.
  • § 393.24
    Requirements for head lamps, auxiliary driving lamps and front fog lamps.
  • § 393.25
    Requirements for lamps other than head lamps.
  • § 393.28
    Wiring systems.
  • § 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.
  • § 393.48
    Brakes to be operative.
  • § 393.51
    Warning signals, air pressure and vacuum gauges.
  • § 393.52
    Brake performance.
  • § 393.60
    Glazing in specified openings.
  • § 393.61
    Truck and truck tractor window construction.
  • § 393.62
    Emergency exits for buses.
  • § 393.65
    All fuel systems.
  • § 393.67
    Liquid fuel tanks.
  • § 393.70
    Coupling devices and towing methods, except for driveaway-towaway operations.
  • § 393.71
    Coupling devices and towing methods, driveaway-towaway operations.
  • § 393.75
  • § 393.76
    Sleeper berths.
  • § 393.81
  • § 393.82
  • § 393.83
    Exhaust systems.
  • § 393.87
    Warning flags on projecting loads.
  • § 393.88
    Television receivers.
  • § 393.89
    Buses, driveshaft protection.
  • § 393.92
  • § 393.93
    Seats, seat belt assemblies, and seat belt assembly anchorages.
  • § 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?
  • § 393.106
    What are the general requirements for securing articles of cargo?
  • § 393.201

Part 393

Below is a the available guidance for the given section. To return to the list of parts, use the Parts link above. The menu to the left provides a full list of sections that have guidance. To view guidance for a different section, click on the menu item.

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View the regulations for Part 393

Guidance for § 393.75: Tires.

Question 1: If a Commercial Motor Vehicle (CMV) has a defective tire, may the driver remove the defective tire from the axle and drive with three tires on an axle instead of four?

Guidance: Yes, provided the weight on all of the remaining tires does not exceed the maximum allowed under §393.75(f).

Question 2: May a Commercial Motor Vehicle (CMV) be operated with tires that carry a greater weight than the weight marked on the side wall of the tires?

Guidance: Yes, but only if the Commercial Motor Vehicle (CMV) is being operated under the terms of a State-issued special permit, and at a reduced speed that is appropriate to compensate for tire loading in excess of the rated capacity.

Question 3: May a vehicle transport HM when equipped with retreaded tires?

Guidance: Yes. The only Commercial Motor Carrier (CMV) that may not utilize retreaded tires is a bus, and then only on its front wheels.

Question 4: May tires be filled with materials other than air (e.g., silicone, polyurethane)?

Guidance: §393.75 does not prohibit the use of tires filled with material other than air. However, §393.3 may prohibit the use of such tires under certain circumstances. Some substances used in place of air in tires may not maintain a constant physical state at different temperatures. While these substances are solid at lower temperatures, the increase in temperature from highway use may result in the substance changing from a solid to a liquid. The use of a substance which could undergo such a change in its physical characteristics is not safe, and is not in compliance with §393.3.

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