Hi fugawi,
Welcome to the world of towing a camper and figuring out all the variables.
You have a "lot" of really good data to start with. Now figuring out what it means. I had some time this morning so I'll type and try to explain as you work to sort this out in your head. Good for you doing this. The rewards of better towing will come from it.
Yes, you need and want a WD hitch. Ideally you get one with integrated anti sway control. Your loaded tongue weight is over the rating of the receiver. The fine print in Fords owner manual tells you need one. In their eyes, it is a "must". This is really not a good place to be, over their rating. If there is ever an accident even if you did not cause it, someone drilling into the details can find you at fault of being negligent as you are the driver. While this is not gospel, you really do not want to be in this situation.
http://www.dangeroustrailers.org/Towing_The_LIne.html 3. What determines the 600 LB tongue weight in the manual? Is this the strength of the metal that comprises the hitch? Is it to help to not exceed the 4,300 LB Rear GAWR?
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In this case Ford did not tell us or you what the weak link is. Many times the ratings on SUV's are driven by what the rear axle can handle and stay inside it's rating on an "empty" truck. Why put a receiver with more ability then the truck can handle? When you are not using a WD hitch, the rear axle is bearing the raw tongue weight plus the leverage factor of the rear overhang increasing the load on the rear axle. (tow ball to rear axle distance). This can send the rear axle over it's limits. There is also the flexing of the receiver which is much higher in weight carrying mode then in WD mode leading to a fatigue failure of the reciever. And then there is a stability issue as no WD removes weight off the front axle making it not as stable under high winds, or slippery conditison to name a few.
You mentioned adding
fugawi wrote:
Is it possible to reduce the tongue weight by loading the back of the trailer with more weight? I am planning to put on a trailer receiver that may carry 300-400 LB of cargo.
I express extreme caution doing this. This one has many factors agasint you. The trailer rear axle can get overloaded by that much weight hanging very far off the back of the camper and yes, it will unload the tongue weight which may make the trailer unstable. And then is the camper frame strong enough to take that heavy rear over hang?
Yes you have a heavy TW for that small of a camper. 780/4260X100= 18.3%. Your fresh water tank if it is forward of the axles can/will be good part of that higher % pending how close to the front of the trailer it is. For the trailer, this is not a real bad thing, in your case for the truck it may be. By towing with no water this may drop you down % range, however you said only 50# less. This means the tank must be fairly close to the front TT axle. While moving some gear out of the front of the camper to more towards the middle or some towards the back can help butodds may be your floor plan really does not allow a lot of options on where to put stuff. I had the same issue on both of my campers. Thus the WD hitch can help deal with what you cannot move in gear as the TW is over 600#.
However, I myself would not try and shift gear a bunch to get out of using a WD hitch. Yes you can lower it but the WD hitch corrects many other towing issues like some of the stability issues you where talking about.
1. Would any part of my setup contribute to the bow wave push?
2. Would weight distribution reduce it?
To these questions, yes a WD hitch will help create stability in the rig. You did not list the truck front axle weight when "not" hitched to the camper so we cannot tell what weight was removed. Odds are very high that front end weight went way down. The WD hitch will put some of that weight back and make the truck more stable. It will also unload some of the rear axle and the rear suspension.
Tire pressures on the truck are part of this equation too. The SUV's ride like a cream puff and by design. However that nice ride can work against towing stability. After getting the WD hitch and setting it up right, you more than likely will find you need to up the tire pressure close to max side wall cold pressure when towing to get a more stable rig.
My suggestion, get a 800# rated WD hitch with built in anti sway controls, set up the hitch correctly with the truck and level out the camper with the shank adjustment afterwords. Then work on the tire pressures. The trailer tire pressures needs to be at max side wall cold pressure regardless.
I want to commend you on this effort. You are doing a great job, drilling into the details and trying to make your rig the best it can be. Good for you. Many do not take this extra effort. Keep it up, you are off to a good start.
Hope this helps
John
