GMC SIERRA 2020 Owner's Manual page 300

Measurement
(H2 H1)/2
H2 [(H2 H1)/2]
Towing with Model 2500/3500
Trucks
1. Position the truck so that the
trailer is ready to connect.
Keep the trailer detached.
2. Measure the height of the top
of the front wheel opening at
the fender to the ground (H1).
3. Attach the vehicle to the trailer.
Do not attach weight
distribution bars at this time.
4. Measure the height of the top
of the front wheel opening on
the fender to the ground (H2).
H1
H2
H2 H1
5. Install and adjust the tension in
the weight-distributing bars per
the manufacturers
recommendations so that the
height of the front fender is
approximately H2 [(H2 H1)/4]
(1/4 the difference between the
two measured ride heights,
below the secondary ride
height {H2}).
6. Visually inspect the trailer and
weight-distributing hitch to
ensure that the manufacturers
recommendations have
been met.
Driving and Operating
Height Example 1500 (mm)
1 000
1 050
50
25
1 025
299