GMC SIERRA 2020 Owner's Manual page 301

300 Driving and Operating
Measurement
(H2 H1)/4
H2 [(H2 H1)/4]
Tires
Do not tow a trailer while using a
compact spare tire on the
vehicle.
Tires must be properly inflated to
support loads while towing a
trailer. See Tires 0 379 for
instructions on proper tire
inflation.
Fifth-Wheel and Gooseneck
Trailering
Fifth-wheel and gooseneck trailers
can be used with many pickup
models. These trailers place a
larger percentage of the weight
(kingpin weight) on the tow vehicle
than conventional trailers. Make
H1
H2
H2 H1
sure this weight does not cause the
vehicle to exceed GAWR or GVWR.
Fifth-wheel or gooseneck kingpin
weight should be 15 25% of the
trailer weight up to the maximum
amount specified in the trailering
chart for the vehicle. See Trailer
Weight" under Trailer Towing 0 292.
The hitch should be in the pickup
bed so that its centerline is over or
slightly in front of the rear axle. Take
care that it is not so far forward that
it will contact the back of the cab in
sharp turns. This is especially
important for short box pickups.
Trailer pin box extensions and
sliding fifth-wheel hitch assemblies
may be used. There should be at
least 15 cm (6 in) of clearance
Height Example 2500/3500 (mm)
1 040
1 080
40
10
1 070
between the top of the pickup box
and the bottom of the trailer shelf
that extends over the box.
Make sure the hitch is attached to
the tow vehicle frame rails. Do not
use the pickup box for support.
Safety Chains
Always attach safety chains
between the vehicle and the trailer.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer.
If the trailer being towed weighs up
to 2 271 kg (5,000 lb) with a
factory-installed step bumper, safety
chains may be attached to the