3.8.2 Spare wheel or rim. When specified (see 6.2), a spare wheel or rim shall be furnished.
3.8.3 Spare tire assembly. When specified (see 6.2), an inflated spare tire mounted on the
spare wheel or rim shall be furnished. The spare tire shall be of the same size, tread design and
ply rating as the tires furnished on the trailer.
* 3.8.4 Carrier for spare tire assembly. When specified (see 6.2), a carrier for a spare wheel or
rim and tire assembly shall be installed in a readily accessible location on the vehicle. Threaded
fasteners, when used to secure the spare tire in the carrier, shall be constructed of or plated with
corrosion-resistant material. Carrier design shall enable safe removal or mounting of a spare
wheel assembly using only the tools specified in 3.8.5. The carrier shall enable the safe removal
and installation of the spare tire assembly from and to the vehicle and carrier without personnel
positioning themselves or any part of their body under the spare tire assembly.
3.8.5 Tools. When specified (see 6.2), the vehicle shall be furnished with tools required for
exchanging mounted tire assembly with the spare assembly, and shall include at least a jack, jack
handle and wheelnut wrench. The jack shall be of such closed height as to permit its location
under axle, or other satisfactory lift point, at any wheel with the tire flat. The jack, without
blocking, shall be capable of raising any wheel of the loaded vehicle to a height adequate to permit
removal and replacement of the wheel and tire assembly.
3.9 Service brakes. Unless inertia brakes are specified (see 3.9.1), the trailer shall be
equipped with a 12-volt electric brake system. Brake linings shall be of nonasbestos material.
The system shall include a manual controller kit for mounting on the dash of the towing vehicle, a
controller kit for synchronizing the trailer electric brakes with the brakes of the towing vehicle,
and an emergency breakaway kit. Kits shall be complete with all necessary parts (except storage
battery for breakaway kit) and installation instructions. Unless otherwise specified, the
synchronizing controlled shall be for use with hydraulic brake equipped towing vehicles. When
specified (see 6.2), the synchronizing controller shall be for use with air brake equipped towing
vehicles. The kits shall be boxed, marked as to contents and securely attached to the trailer for
3.9.1 Inertia brakes. When specified (see 6.2), the trailer shall be furnished with an inertia
(surge) applied hydraulic brake system in lieu of electric brakes. The inertia brake actuator,
mounted on the tow bar, shall include a master cylinder, an accumulator chamber and a hold-off
spring to prevent brake applications due to road shook or trailer pitching. The system shall
provide for modulated brake applications, shall be protected against the entrance of foreign
matter, shall include breakaway features conforming to Federal Motor Carrier Safety Regulation
393.43(d), and shall enable the trailer to be backed up without continued application of the trailer