All good advice. If your are going to keep the big one, think of the tie downs as part of a flexible (no pun intended) package. Wha.....?
Let's look at the internal physics here. A pick up truck bed will twist (rack) with the four bolts holding it to the frame of the truck. This only becomes a problem if you have a TC in the bed and go off-road, as most TC's are built to resist flexing. Early on in my ongoing TC education i tore one of those four 3/8's inch bolts right thru the bracket. Hm? too much stress here. What to do? I used a thick fender washer and re installed the bolt. It has been fine.
What i learned was to allow the bed to flex but loosen the rear tie downs to limp in order to allow the box to lift at the rear, one side or the other, as the rearmost part of the frame has the most rack. In my assessment of the relative weight of my TC (which has a very long front overhang) front vs. rear I found most of the weight is on the front two jacks with maybe 20% on the rear. No, I have not scientifically weighed these, but just note how much resistance is on each MANUAL jack as i try to lift. So I keep the front tie down snug (not tight) and loosen the rears mightily to allow for lift. Push come to shove, it's kind of a Zen thing. I have been on some pretty tortuous roads lately using this system and so far, so good. The TC is not pulling itself apart. What I'm trying to do is take tension out of the picture. So how do you keep the box in the bed if it's not snugly tied down?
A combination of hardware including:
1. Sturdy tie downs with easily adjustable tension. My Happie Crappie tie downs are good enough as the fronts have a stiff spring in the bezel, and the rears tie to the bumper which has some flex, enough to need no internal spring; or so the engineers at Lance believe. But that set up is for flat, paved roads with an occasional pull off in the gravel to by some apricots.
2. Centering brackets. They actually transfer the stress from the tie downs to the base shear wall of the TC. If using the brackets you can actually loosen the tie downs. I use the Lance brackets, but there are some great home-made ones by fellows on here that I would much rather have.
3. A thin, fluted rubber bed mat. This helps further keep the TC from sliding, rocking or swaying from side to side. If the TC is too close to the roof of the cab, then build up a framework underneath but don't just use a thicker mat as the sway will return.
4. On the inside rear of a p.u. there are footman's loops to tie down cargo. I'm going to start using these with 1K pound ratchet straps to keep the TC from wanting to slide out the back when going up a very steep hill. By doing this I may be able to loosen the side tie downs a bit looser too. My bro John now used much heavier ratchet straps to tie down his OUTFITTER! after he found his frame was being racked by too much tension on his factory tie downs and he has a '99 long bed Ford pickup that does a lot of flexing.
One of the successes of my set up is that i have a Dodge hydro formed short bed frame, a stiffy, which gets not a lot of rack front to back as it's so short. I also have an 8 foot, 6 inch floor on my TC which hangs over the rear about 20 inches. That's 20 inches that are not being racked by the frame twisting.
There really is NO way to make a pickup bed into a three-point bed, like so many of the high bucks euro campers use. Going to a flatbed with a three-point system is very do able and will mitigate the set up trying to pull itself apart as the platform remains flatform.
And, of course, take the jacks off when you get the camper loaded on the truck.
My last advice is to just get it on there with some secure tie downs and have a blast.
jefe
