I had the same problem with my 2001 R50. In my opinion the rear springs are weak, period. Having my 6'2" son in the back seat was enough for the truck to bottom out on the freeway in any humps. I put in Airlift air springs about 5 years ago and they made a huge difference. I had the local mechanic down the street do the install but really it does not look difficult to put in. good luck
I have been looking at the different builds from the members of this group and am tempted to upgrade the rear springs and shocks, maybe even a lift. I need to self educate about the options availiable but it does sound like the guys who have upgraded the rear suspension dont have this problem.
