GMC 1993 Safari Owner's Manual page 201

Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important weight to measure because it
affects the total or gross weight of your vehicle. The gross vehicle weight (GVW)
includes the curb weight of the vehicle, any cargo you may carry in it, and the
people who will be riding in the vehicle. And if you will tow a trailer, you must
add the tongue load to the GVW because your vehicle will be carrying that
weight too. See "Loading Your Vehicle in the Index for more information about
your vehicle's maximum load capacity.
A
B
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AN490002
If you're using a "dead-weight" hitch, the trailer tongue (A) should weigh 10% of
the total loaded trailer weight (B). If you have a "weight-distributing" hitch, the
trailer tongue (A) should weigh 12% 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 the "Tire Loading" in the Index.) Then be sure you don't go over the GVW
limit for your vehicle.
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