held constant throughout the test shall be provided. Accelerations shall be measured
on a running-gear member, usually on axle or spindle, that has a motion identical to
that of the wheel center. The magnitude of the accelerations shall be not more than
6 g nor less than 3 g, where 9 represents the weight imposed.
Tow the trailer chassis through mud at least 6 inches deep for not less than 100 feet.
Any prime mover may be used for this phase.
Tow the trailer chassis over highway v-ditches (standard FHWA Bureau of Public
Roads type) at least 36 inches wide and 18 inches deep. Negotiate the ditches both
perpendicularly and at an angle of 45 degrees to the direction of travel for no fewer
than 10 times. Inspect the underside for damage.
Measure and record the DOT FMCSR deviation or off-tracking of trailer chassis with
respect to the prime mover when the trailer chassis is towed straight ahead on a paved
Jackknife the trailer chassis at angles up to 60 degrees for all CCE sizes and
40 degress for size 9 MD trailer chassis from straight ahead both to the left and to the
Turn the prime mover, towing the trailer chassis, in a rolling sharpest-turning circle
for two complete turns and repeat in the opposite direction.
When uncoupled from the truck, raise the front of the trailer chassis not less than
4 inches from a concrete surface and rapidly allow the trailer chassis to fall on the
support leg or landing jack. Visually inspect and compare before and after
measurements for evidence of permanent deformation.
For size 9 ND trailer chassis only, maneuver the uncoupled trailer chassis on a paved
surface for not less than 50 feet in distance and complete not less than one full
360-degree rolling turn.
184.108.40.206 Brakes. Test the trailer chassis for conformance to the DOT Motor Carrier Safety
Regulations and Federal Motor Vehicle Safety Standards, the California Vehicle Code, and to
the requirements specified herein. Runs shall be conducted with rated payload unless different
loading is specified. In addition to the DOT and California legal tests, perform the following:
a. With the trailer chassis stopped on a paved surface, uncouple the truck brake lines
from the trailer chassis and bleed down all trailer chassis air reservoirs. Determine by
the drawbar pull method or on actual grades the maximum holding ability of the
trailer chassis emergency parking brakes. Release the emergency parking brakes.
Release the emergency parking brakes using only tools supplied with each trailer
chassis or with an external resupply of compressed air; simulate earthmover
equipment towing without air supply.
b. Test the trailer chassis airbrake system as specified in TTMA RP No. 12 and
RP No. 44.
c. Remove the chock blocks and place them, first to prevent the trailer chassis from
rolling forward, and then repeat to prevent the trailer chassis from rolling rearward.
Do not unsnap the captive chain from the cradle loop.