the trouble with most tow vehicles is that they are designed to provide a somewhat smooth non harsh ride when empty. so the designe of the springs allow for the first couple inches to be rather soft to do this. now when Joe camper hooks up his RV and jacks the W/D bars up so everything is setting level like its suppose to. he is now setting on that soft part of the suspension spring. this allows easy up and down movement to get started. when I installed air bags on the rear it greatly reduced this problem and when not towing I let the air out for my smooth ride.
Jay D.