weight distributing hitch

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Although the toungue weight is low on my 13' Scamp (short wheelbase) I notice some oscilation on certain Interstate Highways. Some say a weight distributing hitch will take care of that problem or is there a better /cheaper fix ?

Noel

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Many people prefer a ‘Sway-Bar’ if they don’t have too much tongue weight. Cost is much, much less and it is very effective for Sway (fish tailing).

I hope this helps.

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Before we head out to buy different hitches...

How is the trailer loaded??? Having too much weight in the back of the trailer can also cause this problem. I've seen others report having major sway problems - after sticking a bike rack onto the back of the trailer and loading it up. Is it possible that the trailer is loaded more heavily toward the rear, contributing to the problem?

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Thanks Michael for the comment. My problem is more of an up/down motion (hobby horse effect) and is probably some what inherent in the tow vehicle as much as the trailer (1998 Ford Ranger XLT 4dr) Truck suspension is fairly stiff and it's wheelbase doesn't help matters either. :reyes

Noel

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Good point Mike.:chin

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Orginally posted by Noel M. Lutsey

Thanks Michael for the comment. My problem is more of an up/down motion (hobby horse effect) and is probably some what inherent in the tow vehicle as much as the trailer (1998 Ford Ranger XLT 4dr) Truck suspension is fairly stiff and it's wheelbase doesn't help matters either. :reyes

Noel

Another thing you might check. Have a wheel alignment check of your trailer. sometimes one side gets slightly bent. How are the tires wearing? Just a wild thought.

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Excellent ideas and woth double checking. Toungue weight is around 150-175lbs with battery and propane and no extras on the bed or in the storage cabinets and only the factory spare on the rear.
The tires are new (2,000 miles) and show no unusual wear at this point. Handling seems to be OK no dragging or pullinf to one side and when following the rig down the road appears to track just fine.

Noel

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Hi ----Maybe the problem is suspension in tow vehical causing the up and down motion.You should look to see your rating on the vehical suspension. If it is not quite up to par look at getting air mounted shocks which you can adjust yourself. Just a thought.
Another thing I do is to make sure my trailer is level when hooked with tow vehical. Some trailers i have seen look like there ready to take of for the moon when hooked up.:r

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This is not just true with fiberglass rv's ... but on some set-ups, with certain tow-vehicles attached to certain trailers on certain highways hit the highway expansion joints just right to cause trailer bounce.

It's something to do with the combination and permutation of the tow vehicle wheel base, length of the hitch, spacing of the highway expansion joints, etc.

Sometimes the bounce or rythmic motion can be cured by attaching a "hitch extender" (available at on line , or your Local Bubba's RV which adds up to 18 inches to the length of your ball mount ... giving more distance between your tow vehicle and trailer.

http://www.crbrophy.com/hitchacc.html

Please note: Using a hitch extender reduces the effective "carry" weight of your hitch. I wouldn't use one with a heavy trailer ... but with a 13 inch Scamp ... shouldn't be a problem.

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:wave Good point Charles.

I had a 3/4 ton Ford Supercab Long bed that I could not go 55 mph without getting what you are talking about. The harmonic bounce from the road seams, wheel base length, and the F-250’s stiff suspension drove me crazy.
:o

My F-150, I had just before the F-250, with a short wheel base rode like a dream.

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Thanks Mike, Michael, Chester and Charles. Some of this I knew already and of course some of this is new to me :reye2 all of it bears reviewing (like checking the alignment and re-weighing the toungue). Now if some one can come up with a formula for calculating vehicle wheel base vis-a-vis trailer wheelbase....... if nothing else the longer extension would help the turning radius.

Interesting.

Noel

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These conversations are so interesting, but I wish I really understood.
1. this bouncing can be caused by the seams in the road. and the vehicle hitting two different seams at the same time or slightly off?
2. lenthening tongue can repair, but what if diffferent roads have just enough difference that the next raod doesn't like the last roads fix, so you would get it again?
3. this rocking motion? couldn't this be mainly from a light tongue? Mine did a yanking motion and weighting the tongue of the trailer solved it. the only yanking then was if the ridge in the road was huge, like when getting on a bridge. or are you even talking about this, and I'm in a totaly different realm?

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When we had a boler 13 in the 80s, ours would bounce so badly that the cushions ended up all over the camper. Occasionally cabinet doors would pop open and dump everything. When you pulled in, you had some major straightening up to do.

So, how common is this? Is this characteristic of the 13' units? Let's here from some of you 13 and 16 owners -- do things stay put in your unit while towing, or do you suffer from the "popcorn effect"?

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We tow our 16ft Scamp with an 83 Chev Blazer (full size) powered by a turbo charged 6.2 liter diesel through 3.73 to 1 gears. The hitch is a fully equalizing unit that we also use to tow our 26ft Avion. With the bars set to minimally equalize, the amount of bounce I get on the concrete pavement is less than with the Blazer alone. We have never had a problem with stuff bouncing out of cupboards, etc. unless we happened to go over a railroad intersection fast, or got into some real bad road.

In my previous business I towed a tandem axle utility box trailer extensively. When I changed from a non-equalized to an equalized hitch I couldn't believe how less tired I was at the end of the day. I would expect that even with the Scamp, if I were to tow it unequalized I would do it only once.

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I just read this thread and saw the comment about hitch extension. Be careful, as adding distance between the hitch ball and the truck's rear axle gives the trailer *more* leverage and more effect (both bounce and sway) on the truck.

OTOH, *shortening* the hitch bar will reduce the effects. Last summer, I pulled the pin on my hitch bar, pushed it into the receiver as far as it would go and drilled a new set of holes -- made quite a bit of difference even tho I only shortened it by a few inches. Recently, I modified my receiver to move it further forward and up a few inches each on my truck; the effect was even better but not as noticiable as the first shortening.

Another way to attack the effect of balance on the truck would be to *lengthen* the tongue of the trailer by attaching a longer arm with coupler underneath the original one. I have seen a 13 Scamp with a tongue long enuf to have a bike rack between trailer and truck and have plenty of turn room; the owner constucted a "T" and welded it to the A-frame underneath.

BTW, lengthening the tongue will have the effect of lightening the tongue weight as the torque lever between trailer axle and coupler will be longer. Anyone contemplating carrying more load on the tongue (genset, extra propane, bikes, etc) could benefit from this.

Pete and Rats, with better ground clearance under the truck

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A WDH may help some but you are going to get some oscillation bounce on some roads. I have a WDH (not my first) and some roads (I-10 in Louisiana) still give me the bounce. I have tried several adjustments with no difference. But it is better than without a WDH. It will also stop any hitch rattle or jerking. I don't need one for my rig but I like the ride better.

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To all who uses a wdh.
Why did you install a wdh?
For noseweight compensation and/or for stabilising the TT?
Or .... ?

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When you hook a trailer to a vehicle the hitch is a hinge. A WDH helps stiffens the hinge in the vertical plain and can transfer some of the hitch weight to the vehicles front wheels and trailers wheels. Because it puts tension on the hitch receiver it stops any rattle or jerking in that area. Also as in this discussion it helps the bounce that you can get on certain roads by stiffening this hinge to help prevent oscillation. The vehicle and trailer tends to bounce on a single plain rather than two different ones.

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ka-dunk, ka-dunk, ka-dunk.

Not only the expansion joints but some concrete 'slumps' (if that is the right word) when curing. So its got a crown from one expansion joint to another. Noticable in a car, really noticable towing a trailer. Then if the speed/wheelbase is just right you get the 'harmonic bounce' mentioned. This harmonic bounce is sort of the same thing that happens when you'd push a heavy ball on a pendulum, it swings a little, when it comes back, push a little more and so on til that sucker is really swingin back and forth.

Back in 99 I remember a stretch of I-10 west of NuAulins when I thought the front axle of the motorhome was gonna come up thru floorboard.