Ford 2013 Explorer Owner's Manual page 285

Hitches
Do not use hitches that clamp onto the vehicle bumper. Use a
load-carrying hitch.
You must distribute the load in your trailer so that 10–15% of the total
weight of the trailer is on the tongue. Do not to exceed the maximum
tongue load of 500 pounds (227 kilograms) on a Class III receiver.
Weight-Distributing Hitch
WARNING: Do not adjust a weight-distributing hitch to any
position where the rear bumper of the vehicle is higher than it
was before attaching the trailer. Doing so will defeat the function of the
weight-distributing hitch, which may cause unpredictable handling, and
could result in serious personal injury.
When hooking-up a trailer using a weight-distributing hitch, always use
the following procedure:
1. Park the vehicle (without the trailer) on a level surface.
2. Measure the height of the top of the front wheel opening on the
fender, this is H1.
3. Attach the trailer to the vehicle without the weight distributing bars
connected.
4. Measure the height of the top of the front wheel opening on the
fender a second time, this is H2.
5. Install and adjust the tension in the weight distributing bars so that
the height of the front fender is approximately halfway between H1
and H2.
6. Check that the trailer is level. If not level, adjust the ball height
accordingly and repeat Steps 3–6.
Safety Chains
Note: Never attach safety chains to the bumper.
Always connect the safety chains to the hook retainers of the vehicle
hitch.
To connect the safety chains, cross them under the trailer tongue and
allow enough slack for turning tight corners. Do not allow the chains to
drag on the ground.
2013 Explorer (exp)
Owners Guide gf, 2nd Printing
USA (fus)
Towing 285