• The frame, chassis, bolts, or brackets securing the cab or body to the vehicle, must not be cracked, loose, sagging, missing or broken.
• No cab compartment door may be wired shut or otherwise secured in the closed position, unless the CMV is loaded with pipe or bar stock that blocks the door and the cab has a roof exit.
• Wheels and rims must not be cracked or broken, stud or bolt holes on the wheels must not be out of round, and nuts or bolts must not be missing or loose.

Vehicle frames, cabs and body components, and wheels are some of the parts and accessories necessary to the safe operation of a commercial motor vehicle (CMV). The specifications for these parts are described below.

Frames

The rules relating to CMV frames provide that:

• The frame or chassis must not be cracked, loose, sagging or broken.
• Bolts or brackets securing the cab or the body of the vehicle to the frame must not be loose, broken, or missing.
• The frame rail flanges between the axles must not be bent, cut, or notched, except as specified by the manufacturer.
• Parts and accessories must not be welded to the frame or chassis except in accordance with the vehicle manufacturer’s recommendations.
• Any welded repair of the frame must also be in accordance with the vehicle manufacturer’s recommendations.
• No holes may be drilled in the top or bottom rail flanges, except as specified by the manufacturer. (393.201)

Cab and body components

The cab compartment doors or door parts must not be missing or broken, the doors must not sag so that they cannot be properly opened or closed, and no door may be wired shut or otherwise secured in the closed position. An exception to the blocked door rule exists when a CMV is loaded with pipe or bar stock that blocks the door and the cab has a roof exit.

Other rules pertaining to the cab and body components provide that:

• Bolts or brackets securing the cab or the body of the vehicle to the frame must not be loose, broken, or missing.
• The hood must be securely fastened.
• All seats must be securely mounted.
• The front bumper must not be missing, loosely attached, or protruding. (393.203)

Wheels

Wheels and rims must not be cracked or broken, stud or bolt holes on the wheels must not be out of round, and nuts or bolts must not be missing or loose. (393.205)