GMC 1996 Sierra Owner's Manual page 208

A B
If you're using a weight-carryipg hitch, the trailer
tongue (A) should weigh 10 percent of the total loaded
trailer weight (B). If you're using a weight-distributing
hitch, the trailer tongue (A) should weigh 12 percent of
the total loaded trailer weight
(B).
After you've loaded your trailer, weigh the trailer and
then the tongue, separately, to see if the weights are
proper. If they aren't, you may be able to get them right
simply by moving some items around in the trailer.
Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the limit for
cold tires. You'll find these numbers
on
the Certification
label at the rear edge of the driver's door or see "Tire
Loading" in the Index. Then be sure you don't go over
the GVW limit for your vehicle, including the weight of
the trailer tongue.
Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are a
few reasons why you'll need the right hitch. Here are
some rules to follow:
If you use a step-bumper hitch, your bumper could
be damaged in sharp turns. Make sure you have
ample room when turning to avoid contact between
the trailer and the bumper.
0
If you'll be pulling a trailer that, when loaded, will
weigh more than 4,000 Ibs. (1 800 kg), be sure
to
use
a properly mounted, weight-distributing hitch and
sway control of the proper size. This equipment is
very important for proper vehicle loading and good
handling when you're driving.