I bought a `77 3/4-ton 4x4 Suburban this Fall and have been slowly fixing it up. I've discovered that a large number of the things wrong with it were caused by the rough ride (door hinge area on front doors cracking, multiple electrical issues, fuel tank sender issues, window tracks falling apart, etc.). I've owned many 4x4s and this one is the worst riding one I've ever owned. My driveway is 1.5 miles of gravel, broken asphalt, and dirt. I use the Suburban to get to my construction sites, which are also on wash-boarded roads. The ride is so stiff that I have to literally drive 5 mph or I get beat so bad my back hurts . It has been lifted 4", with new springs up front and blocks in the back. Shocks are Rancho RS5000. I think the major culprit is the tires. They are 265/75/16s with 10-ply ratings and load range "E". They look small on my Suburban and are usually aired to 70 psi. To test my theory that the tires are simply too hard, I aired them down to 20 psi. The Suburban rode much, much better. How about the shocks? Do Rancho RS5000s provide a stiffer ride? I just ordered new tires and hope that will ease my pain. I stepped up to 315/75/16s in an 8-ply tire in load range "D"(Maxxis Bighorns). I'm hoping the bigger sidewall and lower load rating will help. If not, My next step will be to replace the shocks. If that doesn't work, then I'll go with new springs. Any other suggestions?? How much do the body mounts affect ride? Mine are rotted out and look pretty bad.