The purpose of the struts is not to carry weight. With the load concentrated toward the front of the bed, bumps tend to flex the truck frame in the middle. Any steel structure is a spring, and the frame can take this flexing. The issue is that it is a pretty good spring, and returns most of the energy it stores. There is virtually no damping. Over some roads, usually concrete with expansion joints, the bouncing can build up to very high levels. The struts soak up some energy with each bounce and keep the amplitude from building up.

Most of the flex is in the middle of the frame, the bed moves in relation to the cab. This creates a lot of motion between the cabover and the cab, making this the ideal place to put the damping. There is virtually no motion between the rear of the camper and the rear bumper/trailer hitch.

The struts do not restrain the cab from moving on the isolators. They do pass a small amount of frame/bed/camper vibration to the cab in theory. In practice I don't notice any difference in ride quality/noise, but I do note a marked reduction in the cab-over motion on rough roads.

To achieve this with a cushion between the cab and the camper, it should be some sort of energy adsorbent material...memory foam like they use on mattresses or something like silly putty. In grit ridden New Mexico this would result in paint damage in short order I would think.

When it is off the truck, lift one rear jack and put a scale under it. Then lower that foot until the other rear foot is off the ground with the camper level. Read the scale. (W1) If the scale tops out before that other foot lifts, then you need to use a lever to multiply the range. Put one end of the lever on the scale, the other end on a fulcrum on the ground, and the foot in the middle for 2:1, 1/3 from the fulcrum for 3:1 etc. Or you can use two or more (use boards to spread the load) scales and add up the readings. You can put scales under both rear feet, as long as the whole rear weight is supported by scales.

Now measure from the front jacks to the rear (L1) and from the front jacks to the middle of the overhead.(L2) Use inches, cm, or furlongs...doesn't matter as long as you use the same units for both.

Now you can calculate the weight (W2) in the overhead that will lift the rear feet:

W2=W1*L1/L2


This assumes the weight will be centered in the middle of the overhead.

Put it on the roof. Tie it down when you put it up there so you don't forget when you break camp. Garbage is light, and it is about the only thing I have found works well to carry on the roof.