The Landing Gear
Every towable RV ( travel trailers and camping trailers included ) has the concept that the wheels form the two rear corners of the “houses” foundation and that there is a front “support” that forms the front foundation. In a travel trailer, this is usually called the “jack” and on fifth wheels it is called the landing gear.
The landing gear are an integral part of the leveling process.
First you level side to side. This is done by raising the low side by having the low side's wheels on top of something like a board or something you can drive the wheels onto that will also support the weight of the fifth wheel.
Then you level front to back. This is done by adjusting the landing gear to a height that levels the unit front to back. We check level in about 3-4 places – none of them necessarily agree perfectly with each other but we try to get as close as we can.
Most modern fifth wheels ( manufactured later than 2009 or so ) seem to have some form of powered front landing gear and many ( our Open Range 399BHS included ) have the landing gear working together with the rear landing gear ( usually a stabilizer only, but in our Open Range can be used to level the unit too ) to actually be used to level the RV.
I've also noticed that the fifth wheels have a left and right landing gear. I think this is for a number of reasons. First the design of the fifth wheel doesn't lend itself to a single jack as well as a travel trailer. Next, the fifth wheel puts a little more weight on the tow vehicle ( desired ) since it can place a little weight on all four corners of the tow vehicle. Since there is more weight, having the weight split across two “jacks” makes the job a little bit easier.
When you see many fifth wheels in parks, you'll notice a tripod that attaches to the fifth wheel hitch. This really isn't to support the weight of the fifth wheel, but its purpose is to tighten itself up to the hitch and make it so that the fifth wheel doesn't bounce as much.
When you understand that the RV is on wheels and that the wheels MUST be allowed to absorb shocks from the road and not transfer those shocks to the RV's structure in full strength – then you're realize that the RV itself will not be ROCK solid when you are inside it and it is parked. So many RV's have different techniques to “STABILIZE” the RV. So whenever you see the the word stabilize in the RV industry, that is usually applied to the idea of making the RV not bounce, rock, vibrate, or shake when people are walking or moving inside the RV. Feeling other people move in the RV is very annoying to the other people.
In the Open Range stabilization scheme they have adjustable bars that you can tighten which transfer some of the pressure from the landing gear up along the frame to try try stiffen the frame. Open Range installs these from a 3rd party manufacturer – so that means you can install these yourself if you don't already have them. The brand is called JT Strong Arm. Can RV52 recommend them yet? I don't know. I do think if I get the weight transferred to the JT Strong Arms correctly it does stabilize the unit, but I can't say I've done it correctly. I guess I still feel our RV bounce a bit – so I guess I'm not perfectly sure. You can see the JT Strong Arms in the picture below.
Finally, when the RV is getting ready to move the landing gear should retract all the way into the RV so that it does not touch the road or create any safety hazard. When the landing gear is retracted completely, I still have to manually pull a pin and then push the landing gear up all the way to the shortest pin hole. In the opposite operation you pull then pin and the landing gear extension falls to the ground and then you insert the pin. This way the electric jack system does not have to extend and retract so far.
Here is the picture of a fifth wheel RV's landing gear – along with the stabilizer rod :