Cadillac 2011 DTS Owner's Manual page 307

Using a weight-carrying hitch, the trailer tongue (A)
should weigh 10 to 15 percent of the total loaded trailer
weight (B).
After loading the trailer, weigh the trailer and then the
tongue, separately, to see if the weights are proper.
If they are not, adjustments might be made by moving
some items around in the trailer.
Be sure the vehicle's tires are inflated to the upper limit
for cold tires. These numbers can be found on the
Certification/Tire label. See Loading the Vehicle on
page 5 18. Make sure not to go over the GVW limit for
the vehicle, including the weight of the trailer tongue.
It is important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why the right hitch is needed. Here are
some rules to follow:
The rear bumper on the vehicle is not intended
for hitches. Do not attach rental hitches or
other bumper-type hitches to it. Use only a
frame-mounted hitch that does not attach to the
bumper.
Will any holes be made in the body of the vehicle
when the trailer hitch is installed? If there are, then
be sure to seal the holes later when the hitch is
removed. If the holes are not sealed, dirt, water,
and deadly carbon monoxide (CO) from the
exhaust can get into the vehicle. See Engine
Exhaust on page 3 33 for more information.
Always attach chains between the vehicle and the
trailer. Cross the safety chains under the tongue of
the trailer to help prevent the tongue from contacting
the road if it becomes separated from the hitch.
Instructions about safety chains may be provided by
the hitch manufacturer or by the trailer manufacturer.
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