Air Bag Suspension Versus Weight Distribution for 2004 Jeep Grand Cherokee Towing 400 lb TW Camper

Expert Reply:

An air suspension system like the Air Lift Helper Springs you referenced is primarily designed to suspend the weight of anything carried on the vehicle, and although they would indeed eliminate the sag you are experiencing, the tongue weight of the trailer applied to the rear axle of your Grand Cherokee would lower the amount of the vehicle weight applied to the front axle. This is potentially dangerous because shifting too much weight away from the front axle of the vehicle can cause diminished steering and front braking response, since the front brakes provide the majority of the stopping power.

A weight distribution system that is properly matched to the fully loaded and ready to tow tongue weight of the trailer is your best bet. Rather than providing a fulcrum at the rear axle that can dangerously lighten the front end of the tow vehicle, weight distribution uses leverage provided by spring bars to transfer a portion of the trailer tongue weight from the rear axle to the front axle of the tow vehicle. This provides a level ride height for the trailer and the tow vehicle. I will link you to our Weight Distribution FAQ Article that will explain how weight distribution works in more detail.

To choose the correct system for you, determine the fully loaded tongue weight of the trailer. The weight of anything stored behind the rear axle of the tow vehicle also needs to be considered as tongue weight. If the tongue weight is under 600 lbs, the Reese Trunnion Bar System, part # RP66540 would be ideal for your needs. This system is designed for trailer tongue weights ranging from 200-600 lbs, and should be perfect for your needs. If the tongue weight is over 600 lbs, going with the # RP66541 would be your best bet.

Both systems include a shank, but the appropriately sized trailer ball would be needed. For a 2 inch ball, use part # A-90, or # 19286 for a 2-5/16 inch ball.

expert reply by: Mike L