"off-roading" - frame twisting in a C
What is the maximum diagonal height difference that the suspension will accommodate without twisting the frame? Found a great boon-docking site, but the "jeep trail" road was off-camber and rose ab...
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Washboard driving is of course merely up-and-down vertical pounding of the RV - which can be made just about completely harmless by driving slow enough on any given washboard surface. However, even expedition vehicle interior contents can get beat up from too-fast driving on washboard if everything inside isn't really lashed down. For instance, all eating plates and drinking glasses are carried inside cabinets with custom cutouts for each plate and glass.
It's the end-to-end length-wise torsional twisting of the frame - if the frame isn't strong enough versus the weight it's carrying to remain in a plane - that does the real damage to the coach if three-point or other ultra-isolation techniques aren't used between the coach box and the frame.
You might wonder how all of today's frameless unity-body passenger vehicles (sedans and SUVs) can go "offroad" without being ruined structure-wise. Well ... they in fact are designed to remain completely rigid at any road surface canting angle with full passenger loading - no twisting of the structure occurs. i.e. A couple of years ago a small passenger sedan right in front of us went off a road out in the desert such that one of it's rear corners was up in the air while the other three points (tires) remained on the irregular/rutted ground. (This air-borne configuration probably would have been very bad, permanently, for a 14000 lb. Class C motorhome on even an E450 frame.) Myself and one of the passengers literally rocked and pushed the vehicle at the air-borne corner as the driver gently steered and applied power just enough so that the remaining rear drive wheel pulled the vehicle ahead onto level ground - while we were pushing. The sedan continued on with no damage other than to the ego of the driver.
The best chance you have of making it offroad in a typical mass produced Class C is to get the lightest weight one you can but sill on the E450 chassis, slow down, and hope that the frame will remain in a plane at all times for the coach to sit on. "Remain in a plane" does not mean the frame has to be level - the frame can be tipped width-wise or length-wise on bad roads - it means that all four frame corners must remain flat relative to each other so no coach box bending will result. I call this having a Class C RV that is built on an "over-kill" chassis .... maybe hard riding but very rigid, overall, for better long term performance and reliability on irregular road surfaces.
It's the end-to-end length-wise torsional twisting of the frame - if the frame isn't strong enough versus the weight it's carrying to remain in a plane - that does the real damage to the coach if three-point or other ultra-isolation techniques aren't used between the coach box and the frame.
You might wonder how all of today's frameless unity-body passenger vehicles (sedans and SUVs) can go "offroad" without being ruined structure-wise. Well ... they in fact are designed to remain completely rigid at any road surface canting angle with full passenger loading - no twisting of the structure occurs. i.e. A couple of years ago a small passenger sedan right in front of us went off a road out in the desert such that one of it's rear corners was up in the air while the other three points (tires) remained on the irregular/rutted ground. (This air-borne configuration probably would have been very bad, permanently, for a 14000 lb. Class C motorhome on even an E450 frame.) Myself and one of the passengers literally rocked and pushed the vehicle at the air-borne corner as the driver gently steered and applied power just enough so that the remaining rear drive wheel pulled the vehicle ahead onto level ground - while we were pushing. The sedan continued on with no damage other than to the ego of the driver.
The best chance you have of making it offroad in a typical mass produced Class C is to get the lightest weight one you can but sill on the E450 chassis, slow down, and hope that the frame will remain in a plane at all times for the coach to sit on. "Remain in a plane" does not mean the frame has to be level - the frame can be tipped width-wise or length-wise on bad roads - it means that all four frame corners must remain flat relative to each other so no coach box bending will result. I call this having a Class C RV that is built on an "over-kill" chassis .... maybe hard riding but very rigid, overall, for better long term performance and reliability on irregular road surfaces.
