Air Bags

transamz9 wrote:
If your SUV has leaf springs in the rear (don't know much about the Ex's) the front half of the leaf spring is attached to the frame with a solid mount. When you add the weight of the trailer on the SUV the truck squats down. The laws of physics states that when you have a reaction there is going to be an opposite reaction. The natural arch in the leaf spring is flattened out when the load is applied so the front of the leaf spring is naturally going to lift the front of the SUV. Now when you add air to the bags, the weight on the truck is not changing but you are relieving pressure from the leaf spring allowwing the spring to relax also allowing the weight the spring was taking off of the front axle to return to the front axle. Make sense?

Yes, perfect sense. Thank you for your explanation. I was thinking that it is vehicle dynamics (suspension). I started thinking about trucks that can handle 1200 lb tongue weight without weight distribution. The fronts of those trucks don't rise much. Your explanation clears that up. The Ex has leaf springs and solid rear axle, same as an F250 or 350 of that vintage. The Ex has "SUV" springs to give it a better ride, not that they are bad for towing - just a little squishy. The air bags stiffened them up.

Long and short of it is that most front end rise due to hitch weight is related to the suspension, not the loss of weight from front axle due to the load behind the rear axle.

Makes me think that as far as a weight distribution hitch goes, it's really the act of raising the back of the truck that makes the difference in ride stability rather than the transfer of weight to the front.

Adding the airbags did not make or break my setup but I did notice that there is a lot less bounce in the back when I hit those type roads that have those wavy surfaces. More than likely, my WDH is doing less work now too.