lance camper porpoising and tires cupping

IQ wrote:
thanks everyone for responding. i appreciate it. I especially appreciate those those that have shared what they have done and how it changed things. Mostly thanks to those that read my original post correctly and responded as I had requested. It sounds like nobody is suggesting the cabover struts, and I know it doesn't happens 100% of my trips or all the time so perhaps a different speed will be key. Thanks for the similar reports with the ford front suspension (leaf spring / twin i-beam). Has anyone had better/worse results while having a front hitch cargo carrier?

Tires cupping and truck bouncing are unrelated.
Cupping how? MT or AT? How often do you rotate, how bad of cupping after how many miles? The more aggressive the tire, the less you rotate and the more you drive on Mountian roads the more they will feather or cup.

Bouncing on I5 and not all the time? It's I5. Nothing wrong with your truck. I can get my new 1/2 ton or any other truck to start chattering or bouncing depending on how much I'm hauling or towing.
It's an old truck, how good is the front end? If the ball jts are wore out, that typically causes neg camber and wears the insides. Outside is from pos camber which is highly unlikely, excessive toe in on both tires which is unlikely, or normal wear on aggressive tires on a heavy vehicle, more so on curvy roads.