weight distributing hitch

[classic4x4s]

I have a 2006 F 350 diesel dually long bed crew cab to tow a 28' International. The tv has a 15000# tow rating for conventional trailers. The gvwr for the trailer is 7300# with a 880# hitch weight. Will i need to install a weight distributing hitch and or anti sway devices. I want to be safe and am willing to do whatever is necessary. Thanks Stu

[nickcrowhurst]

Stu, a good first step is to read carefully the owner's manual for the tow vehicle. My Dodge manual stipulates load distribution hitch and sway control for any tongue weight over 350 pounds, IIRC.
As you've invested over $50k in a trailer, I would say that a few hundred dollars is money well spent on a system that can only improve safety and handling.
If you really want to try to understand the physics involved, try reading
http://www.airforums.com/forum...sis-19236.html?
That thread will calculate how much tension you need from the bars to restore the front axle to its original height before the trailer was attached.
There has been much discussion over the need for somewhat lighter (lower-rated) bars when using a tow vehicle with stiff rear suspension, such as your dually, in order to avoid damage to the trailer. If you try out the search facility at the top of the screen you will find much to read and learn. Try "load distribution", or "sway control" for a start, and you will get more information than you need.
Alternatively, wait for one of the forum members with a similar outfit to come up with a recommendation for the rating of the bars for your rig.
Nick.

[overlander63]

To answer your questions, yes, and yes.
While a duallie is not the ideal tow vehicle, they can be tamed to tow your coach. If you are buying new stuff, a Reese dual-cam sway control and weight distribution bars would be the best equipment for the money. You will need very low eight bars for your truck. Try to find 500 pound bars if you can, although they haven't been available for a while through the manufacturer.
Try reducing the tire pressure in the rear tires to the minimum for your truck, maybe 55 psi or so, and you will also find the truck will handle the trailer better if you put about 500 pounds of "stuff" in the bed. Airstreams seem to behave better with a more softly sprung vehicle.

[classic67]

Stu,

It seems what Nick and Terry said is the suggestion others are making as well. My dealer installed the Reese dual cam & weight distribution bars. After reading what others have said about using a 500lb bars, I checked what mine are and they are the 1000lb bars. Since this is the set-up my A/S dealer recommended and sold to me, I went with it figuring they know best. I will discuss with the Service department the suggestion and comments Andy and others have made in an effort to make sure my set-up will not lead to A-Frame fatigue failure.

I'll post a follow-up on how this turns out.

[bhayden]

Yeh, I don't think you'll find anybody here that disagrees that a WD hitch is (more than) worth the money. Lots of opinions on what's the best hitch and there are a lot of choices that offer value, easy of hook-up, ground clearance ( probably not your problem ), etc. I can't think of any brand that wouldn't work for your situation. With your weight I think what you're after is a Class IV hitch. Make sure that what you buy will allow for proper hitch height adjustment. There are different shanks that allow you to raise/lower the hitch and they can be spendy to replace if the one that it comes with isn't right. Getting the trailer level is as important as distributing the tongue weight; maybe more so with your rig.

It seems like the bar rating should be more a matter of tongue weight than tow vehicle rating but granted you may not need (or want to) move a lot of weight from the back to the front. One advantage of lighter bars is an adjustment of one link on the chain will be more subtle than with heavier bars. Changing the number of links in the chain that are in tension is a lot easier than adjusting the hitch angle.

Originally Posted by overlander63

Try reducing the tire pressure in the rear tires to the minimum for your truck, maybe 55 psi or so, and you will also find the truck will handle the trailer better if you put about 500 pounds of "stuff" in the bed. Airstreams seem to behave better with a more softly sprung vehicle.

Mmm, I'm not sure about this. Tire pressure that is; adding weight to the bed is a time honnored way to tame a stiff truck suspension. I've tried to find out if having heavier rated trailer tires which could be run at slightly lower pressure would provide an added safety margin and the issue is a bit murky. Load ratings are decreased by hot temperatures, speed (which causes heat) and wear and tear on the tires (caused by heat). Therefore it seems moving up one load range would be a good idea. However, lower pressure increases heat buildup in the tire and I've also seen evidence that it decreases stopping distance and otherwise adversely affects handling. If your gas mileage decreases with lower tire pressure then it's a good bet the tires are doing a lot more work than they would otherwise. That extra work will undoubtedly translate into heat in the tires.

There is a device that some folks on the forum report great results with and that's an "air ride" hitch attachment. I'm not familiar with how these work but from the description it may be just the ticket for your heavy duty truck.

-Bernie

[dwightdi]

I have a Chevy dually long box with the crew cab. I trailer a 63 26 foot Overlander that is pretty light without sway or w/d bars. It works for me. I do reduce the tire pressure on the dually because I am not carrying anywhere near the rated load. I do not detect any abnormal temperature gain in the tires. When I tow my 31 foot 77 (which is considerably heavier), I use a Reese dual cam setup with 750 pound bars. It works well and you never even notice the trucks passing you. It is straight as an arrow. I do increase the rear tire pressure a bit when I pull the 77 but still not up to the maximum rated for the truck if it were carrying a full load in the bed.

[davidz71]

Originally Posted by bhayden

...I've tried to find out if having heavier rated trailer tires which could be run at slightly lower pressure would provide an added safety margin and the issue is a bit murky. Load ratings are decreased by hot temperatures, speed (which causes heat) and wear and tear on the tires (caused by heat). Therefore it seems moving up one load range would be a good idea. However, lower pressure increases heat buildup in the tire...
-Bernie

Bernie,
I found out several months ago that my trailer has 3 Goodyear Marathon ST225-75-15 C rated tires and one D rated tire. What I have found with all tires aired up to 50 psi cold, once I have been on the road for 30 minutes or so, the D rated tire was 2 psi cooler than the C rated tire. I checked about an hour later and the same difference was noted with the digital tire pressure gauge. I wonder if I swapped this rear curbside with the one on the axle in front of it, if the same 2 psi would show up.

[bhayden]

Craig,
That's interesting data. It would be interesting to confirm that the hot/running pressure of the D load range tire is consistant irregardless of what position it's in. I might have guessed the D load range tire would be carrying more load and therefore run hotter. The D tire must be more stable and therefore running cooler. I guess it would be pretty hard to determine load for one tire as opposed to the load for the axle. I assume all three C tires are showing the same increase in pressure?

How much pressure increase are you seeing? I haven't had my trailer on the road enough to get a good feel for it but on the few times I've checked I haven't seen any increase in pressure and the tires (bias ply Monach (private brand mfg by Goodyear) are barely warm to the touch. Then again we don't get the scorching temperatures here in the Pacific NW that most of the rest of the country sees and I try to avoid the heat of the day because of our tow rig.