In fact a trailer generates a number of additional forces on the tow vehicle. Trailers require extra braking force and any type of steering input on the tow vehicle can cause a variety of reactions at the trailer. This makes a stable tow vehicle one of the most important factors in safe towing. It may seem that stiffening up the rear shock absorbers is all that is needed, but the front shocks actually have a larger effect on towing than the rear shocks.
Front shocks affect steering response, tracking, nose lift and adhesion.
So while good rear shock absorbers are important, well-designed front shocks are critical to good towing stability. Pickups with campers are well recognized as one of the least stable vehicles on the road. The high weight of the camper acts like an upside down pendulum so that any steering motion or side wind makes the vehicle rock and sway. One important method for reducing stability problems is to install well-designed shock absorbers. If the truck is showing much rear sag then stiffer springs are necessary.