SkiMore wrote:
Is the "house" portion of a regular class C strong enough for the rigors of off road driving?
It partially depends upon what is included in "the house portion".
Twisting of the house structure due to the vehicle's frame it's mounted on twisting and torquing the coach floor is never good for the house's walls and roof structure. That's why true offroad expedition type RV's have their entire house/coach portions mounted as disconnected as possible from any non-planar twisting and/or bending of the underlying vehicle's frame lengthwise or laterally. One way to do this is to mount the house structure onto the frame at only three places so that, through geometry, the frame can "do as it pleases" while still keeping the floor of the house in a non-twisted or bent plain so it's box shape is not under any stress that might act to deform the walls.
How do you do kindof attain this in a Class C motorhome that is affordable to us mortals?
We did it as best we could this way:
1) We bought a somewhat small Class C, weight-wise and length-wise.
2) It's internal wall and roof structure uses aluminum framing (instead of wood) with an interlocking joint between the walls all along the rolled over sides of the single-piece fiberglass roof. All house steel or hardwood structures are attached to the joints instead of directly to any thin wall materials. All door/drawer hardware is steel and screwed into solid hardwood. All drawers are gravity-locked.
3) We bought it on an optional truck chassis that is rated for considerably more weight than the coach required. This adds over-kill ruggedness in several areas.
4) This means that the truck chassis actually has a stiffer (thicker) frame than the next lower rated chassis that usually comes under our size Class C. What this provides is more frame strength against tendencies to twist as the front and rear suspensions articulate. This in turn means less twisting gets transferred into the floor of the house, thus keeping the floor in a plane so as to not deform the walls or roof.
5) All of the heavy house items are hung from the steel house floor underneath or hung from the truck frame underneath so their weight does not pull on the walls on laterally tipped roads or roads with steep grades. This also serves to keep the actual center of gravity very low even though the roof height may appear "high".
6) Our Class C has NO SLIDES. Slides compromise the shear strength of any wall they're in ... plus overall structure strength to some degree ... especially so when traveling on non-flat road surfaces.
In addition to all of the above, we do not take our Class C on serious offroads. When we do take it on mild offroads, we slow way down in order to very carefully pick a track that will minimize frame twisting from the front and rear suspensions articulating at the same time with opposing tilt angles.
This is about the worse offroads we travel on with our 24 foot 11,800 lb. Ford E450 Class C:
Even though constraining our Class C offroad RV'ing to roads approximately no worse than those in the photo above, at lot of great boondock camping and exploring is still opened up to us. It's a great feeling being out in the middle of nowhere in the comfort of a fully self-contained non-cramped Class C.
