Larger Trailer Weight Distribution Hitches - who uses 'em on their boat trailer - why

[ozscott]

Thanks Noel - it makes sense!

Cheers

[Noelm]

it is a simple concept, if you see a set, and sit and think about it, or ever need to fit some, you will see exactly how they work, and to a point they do work, but nothing is as good as a well designed and loaded trailer, be it boat or caravan or even a box trailer.

[Bros]

hey, I might add, I do not use nor have ever used a set of levelling bars, but I have connected up heaps of them for "pensioners" that are traveling and cannot do so themselves, after unhooking the van to use the car for a bit, and indeed as FNQ says, they were a very common thing in the years ago,

Don't ever air your feelings on any of the caravan forums as you will be quickly beaten into submission. As for common years ago they are extremely common now.
I use them on my van so I know the effect when you use and don't use them and I only have a ball weight of 130kg but there are many vans out there with ball weights >200 kg.

[dnej]

This is something I read
David


Have you ever loaded the back of your pickup or SUV with all your gear and then noticed that the rear end has hunkered down? Maybe you then tried to tow a trailer with your trail rig on it. The next thing you knew, the back end of your tow rig was almost dragging.


If you haven’t yet experienced this woe, you still might. And if you have, then you know the feeling of fear and dread that riding nose-high instills in a driver. The dread is there because as the back end of a truck is pushed down, and the front is forced up, things get hard to control.

Steering control is reduced and the braking ability is adversely affected. Further, you’ll find that the trailer is unstable. If you tow a lot, as we do, you know that sometimes you can move your trail rig around on the trailer to help to offset this problem. But only sometimes. Usually the trouble isn’t too much tongue weight, but rather too much trailer weight overall.


For things to work properly when towing a trailer, you should load your trailer so that the tongue weight is 10 to 15 percent of the total weight. This means that if your trailer and trail-rig combination weighs 8,000 pounds, for instance, you should have between 800 to 1,200 pounds of tongue weight.

Now with an average of 1,000 pounds pushing down on the very back of your truck, you’re sure to get some settling of the suspension. When you add the weight of gear to your rig too, well, you see the problem.

The solution is to stiffen the rear spring rate. Yet you don’t want this stiff suspension when you’re driving around town unloaded.


There are two ways to overcome the problem of a suspension that is occasionally too soft when you load your truck or SUV for the long haul. One is to install helper leafs that only come into play when the suspension is loaded. When you choose this solution, an extra spring and stop are added to the rear suspension and when the load compresses the stock springs far enough, you begin to use the helper leaves.

The trouble is, your truck was built to handle best when it sits level. By its very nature, this solution guarantees you’ll ride a little nose-high no matter what. A better option is an airbag load-leveler system.

Airbag systems can be mounted to almost any truck and have several advantages over other methods of load-leveling.

First of all, you’ll be riding on a cushion of air just like those city buses and large moving vans do. This means a smoother ride than any spring system can offer when loaded. In addition, you can usually fill the airbags enough to bring your truck back to a level pre-loaded height for the best handling.

Further, if you are forced to load the bed of your truck unevenly, you can level the load side-to-side if you need to (for this option you need to have a split-air system).


Airbag load-leveling systems are available in a wide range of configurations and from several sources. However, when you get down to the basics, you really have two types of airbags. There’s the in-coil bag, and the outside-the-coil bag. In-coil airbags are just what they sound like—pressure bags that go inside the coil springs of your rig’s rear suspension.

Of course, if you have leaf springs you can use the out-of-coil bags that mount with brackets either to the side of the frame or between the axle and the frame. Both serve the same function and you’ll be happy with whichever system your rig’s rear-suspension system requires. Installation is simple in most cases and usually can be done in less than a day.

As a plus, you’ll get an air compressor and a storage tank for your truck that can be used to fill tires when, for instance, you have to get on the highway after towing down a sand wash. If you want to, you can even install a compressor to match the one on your trail rig so you’ll have a spare in emergencies.

[ozscott]

I like the idea of the air bags (except that they reduce articulation by about an inch at least on compression even when fully aired down) but there are a number of articles about how that is not replacement for using load levelling.

Cheers

[charleville]

I had a couple of Holden Statesmen motor cars a few years ago and a awesome feature about them was the self-leveling trick.

I would load my boat onto the towbar with the motor switched off and of course, it would all sink down a bit. However, when I turned on the ignition, up would come the back and the car was level again. Awesome!

I never bothered to find out how they did that but I guess that it was a pneumatic system. Gee, it was good.

I went from the long wheel base Statesmen back to standard length cars because a longer wheel base towing car is just a bit inconvenient to back my boat into my side yard where I have to back around a tightish corner flanked by gate posts. But I sure miss that self-leveling feature.


.

[ozscott]

The following is one of the articles that says that stiffer springs etc in the back of the tow vehicle do not load shift and thus do not do the job of the weight dist' bars...http://www.lets-getaway.com/hitches-...stribution.htm

"

‘Weight Distributing Hitch’ (springs and levers that transfer part of the imposed mass back onto the front wheels of the towing vehicle and, to a lesser extent, the caravan).
There are various terminologies used for stabiliser bars such as weight distribution hitches, anti-sway bars and load equalisers.
When a caravan is placed on the ball of the tow hitch it places a lot of weight on the rear of the tow vehicle and changes the axis whereby there is less weight on the front of the tow vehicle raising the front wheels. This makes steering and braking less effective. Loss of traction can also be an issue especially for front wheel drive vehicles.
By using better heavy duty springs or incorporating air bags to raise the rear of the tow vehicle will have no effect on the weight distribution. Some sway control devices do not necessarily act to assist with weight distribution.
Fitting a weight distribution device of the correct type and size will mean that the tow vehicle becomes level. For example, weight distribution hitches are available in various load capacity eg: 550 lbs (250 kg), 750 lbs (340 kg) and 1000 lbs (450 kg) capacity ball load weights. Always buy the product that has the manufacturer’s plate stating the maximum towing load and ensure this is adequate for your purposes. "





Cheers

[ozscott]

...and here is an even better article from Caravan and Motorhome Mag - Australia:www.candm.com.au/tips_pulling.php



"
Roothy learns the importance of installing a weight distribution hitch.
Words and photography by John Rooth
So where do you deal with the weight distribution hitch? Does it come under our caravan or our tow vehicle project columns? I guess it really should sit in between but because that’s not possible, we’ll call it part of the tow vehicle series instead.
Why? Because a good weight distribution hitch – and Haymen Reese’s are the best in the world – not only makes all the difference to a tow vehicle’s driving manners, it saves a lot of unnecessary wear on tyres and suspension too.
Big claims, but until you’ve experienced the difference between a well set up WD hitch and a naked A-frame it can be hard to appreciate just how radically the tension on a couple of springs can affect the entire rig.
So what sort of caravans and tow vehicles should be using a weight distribution hitch? Not so long ago they were almost the exclusive preserve of the so called heavyweight brigade – the vans that weighed a couple of tonnes or more with too much of that sitting on the ball. Without WD hitches these things were un-towable but the fact is that virtually any trailer over the un-braked limit (750kg) will benefit from a weight distributing hitch.
But I hadn’t planned on investing in one for our project tow vehicle just yet because being a heavy four wheel drive fitted with ARB’s 50mm suspension rated to towing specs it shouldn’t – according to conventional wisdom – really require one. After all, Vicki’s only a 16 footer and at around 1.3 tonnes not much heavier than a camper trailer.
Yep, well ‘conventional wisdom’ was about as wrong as it can be. It all happened when I towed the old girl out to Caboolture Caravan Repairs for her final gas fitting and certification. Adrian took one look at the rig sitting on the road and said “where’s yer Haymen Reese?”
I asked him why he thought it was necessary. After all, it’s not as if the front wheels were pawing the ground or anything. The rig sat almost dead level. I say ‘almost’ because until Adrian broke out the tape measure I couldn’t see any appreciable ‘tail drop’ at all.
But it was there alright, and measurable.
“Johno,” said one of Australia’s most experienced caravan engineers, “just about every rig on the road could benefit from a weight distribution hitch. Many people never realise that and frankly, they don’t know what they’re missing. And then we see heaps of them that have been installed incorrectly and aren’t pulling their weight.”
Actually, Adrian didn’t say ‘incorrectly’ but ‘arse about face’ doesn’t sound near as technical. I knew what he meant though so I pushed the point and got his team to install one so we could see how it should be done. It was a Haymen Reese of course, the top blokes in the industry won’t recommend anything else.
Essentially a weight distributing hitch works by distributing the ball weight evenly to the front and rear axles of the tow vehicle. Without one, all the ball weight sits directly on the rear axle, pushing it down while at the same time reducing the weight on the front axle. This causes an imbalance in weight distribution on the tow vehicle which naturally affects stability and traction.
Yep, which is why good old ‘conventional wisdom’ said that, “whenever the tow vehicle’s front wheels are clawing the air, you need some weight distribution hitches”. Without them you won’t have steering or brakes – a couple of primary functions in the towing equation if ever there were some! But where conventional wisdom gets it wrong is that almost any weight on the ball directly affects the tow vehicle’s balance which in turn affects steering and traction. Transfer that weight and you restore the tow vehicle’s manners completely making towing as easy – and as safe - as driving solo.
But a weight distribution hitch has to be installed properly and that means taking into account the vehicle’s static (unloaded) heights back and front as well as the caravan’s. The ideal is to have both units stay at those solo levels once hitched up, which is the why Haymen Reese developed their unique adjustable ball mount. This unit allows the ball mount plate itself to be raised or lowered to suit any height differences between car and van and it can be tipped back or forwards too. This latter ability is crucial to getting the right load on the springs.
Fortunately Haymen Reese supply extensive fitting instructions as well as plenty of practical back up through their web pages. Plenty of things have to be taken into account like the positioning of the snap up brackets on the A-frame (allowing the chain to fall as vertically as possible) right down to the minimum number of links required for smooth operation – at least four, any less will pull too hard on the brackets under hard cornering.
It should be noted that while a weight distributing hitch can restore level to a towing rig, if you’re carrying a big and constant load in the rear of the tow vehicle you should still consider heavier rated springs or even air bags. The point is that if you start with the vehicle sagging at the rear you’re behind the stability eight ball no matter what.
But our 80’s already got good suspension rated slightly stiffer than standard at the rear to compensate for the fridge and all the paraphernalia a family of five requires. It handles very well, steers impeccably and is quite comfortable too. What the Haymen Reese unit did was maintain all those attributes with the van hitched up.
On the drive home the difference was immediately apparent because the Toyota handled exactly the same way it does solo. That made the entire rig feel more controllable – and it’s an excellently balanced chassis thanks to Adrian’s engineering – and took all the effort out of towing the caravan.
Almost all, it’s still necessary to remember that we’re twice as long as normal and a lot higher too. And we’ve got to stop for fuel more often and remember to put the step up and close the hatches. But what we don’t have to worry about is stability, whether it’s steering or under brakes. Thanks to a well fitted Haymen Reese weight distribution hitch, this rig tows as if all it’s doing is filling the mirror!"


Cheers

[FNQCairns]

FNQ - I would have thought the exact same thing as you (and I must admit I am struggling with the engineering and physics principles of load level bars) but many of the sites and explanations about load bars say that stiffer springs in the rear of the tow vehicle do not throw load forward onto the front axle of the tow vehicle even if they keep the load 'level' - ie even if the stiff springs keep the car level...I would have thought the opposite but I need an engineer to explain it to me!

Cheers

Yeah i know what you mean, i think the way they work is to create a spring effectively trying to make the hitch junction and thus the entire car and trailer do this ^ at all times so it must have the effect of transferring weight to the front springs (and to the trailer springs) compared to just heavier springs fitted to the vehicle alone.

Reading about the air bags i used to have a mazda 626 RWD with pump up shockies and used to tow too heavy with it up the highway fairly often. If i pumped the shocks right up the ride stayed controllably solid even in the front end (it still went up and down) but if I didn't pump them up the front used to move up and down all over the place even over the lightest irregularities . This car would have made a good test case for levellers with flat shockies, i bet it would have been better but not by very much, simply it would have settled a bit faster.

[wrxhoon]

The following is one of the articles that says that stiffer springs etc in the back of the tow vehicle do not load shift and thus do not do the job of the weight dist' bars...http://www.lets-getaway.com/hitches-...stribution.htm

"

‘Weight &nbspistributing Hitch’ (springs and levers that transfer part of the imposed mass back onto the front wheels of the towing vehicle and, to a lesser extent, the caravan).
There are various terminologies used for stabiliser bars such as weight distribution hitches, anti-sway bars and load equalisers.
When a caravan is placed on the ball of the tow hitch it places a lot of weight on the rear of the tow vehicle and changes the axis whereby there is less weight on the front of the tow vehicle raising the front wheels. This makes steering and braking less effective. Loss of traction can also be an issue especially for front wheel drive vehicles.
By using better heavy duty springs or incorporating air bags to raise the rear of the tow vehicle will have no effect on the weight distribution. Some sway control devices do not necessarily act to assist with weight distribution.
Fitting a weight distribution device of the correct type and size will mean that the tow vehicle becomes level. For example, weight distribution hitches are available in various load capacity eg: 550 lbs (250 kg), 750 lbs (340 kg) and 1000 lbs (450 kg) capacity ball load weights. Always buy the product that has the manufacturer’s plate stating the maximum towing load and ensure this is adequate for your purposes. "





Cheers

You answered your own question , the above is very true .

As to why caravaners use them and boaters don't , a few reasons why .
First most heavy boats have long draw bars ( that is the legth of the trailer from the group of axles to the coupling ) , much longer than caravans . This (long draw bar) has some positive effect on trailer stability .
Second , most caravaners cover huge distances at highway speeds , most boats only travel a few ks to the boat ramp at much slower speed. High speed has a negarive effect on stabillity.
I use to tow a 3.2 t boat doing several trips a year from Sydney to Bermagui ( 400 km trip) , I used a WDH , I still have the WDH but I dont use it on my current boat weighing 2.5 t because the LC200 sits level with a towball eight of about 170 kg .

[myusernam]

i didn't read all of the above posts but I have a commodore and a fairly large boat. My old man gave me his old leveller bars when he upgraded. I love them and use hem whenever I go out of town. They stop the boat swaying at high speeds and makes the whole think feel much more solid and safer. Don't know anything about physics but works great for me.

[gofishin]

There is no way that increased spring rates (stiffer springs) will distribute any load to the front wheels – it just aint physics, pure and simple. Yes, they will compress less and keep the tow vehicle more level, but they don’t effect the amount of force (or weight) exerted by the front/rear tyres on the road when a heavy tow ball down weight is exerted.

A WDH transfers most of the tow ball down load to the front wheels, and some to the trailer wheels (because the tension springs/chains are connected between the ball hitch and the trailer axles – lever principle). It does this by exerting a force and a twisting motion (Moment) to the vehicle tow hitch (and in doing so actually increases the downward force acting on the tow ball). If memory serves me correctly, the correct ‘physics’ term for this is called a ‘Couple’, but it has been a long time since I studied Statics/Mechanics .

I tow a 2.7 – 3t rig with a Navara D40. When I tow long distances I am normally loaded up pretty heavily, both car and boat. My rig tows very well, but even with shorter trips with nice smooth roads/motorways like BNE-GC it is much more pleasant when I use the HR WDH. BNE-1770 (rough, skinny, bumpy road at times) the WDH is a must. You can feel the truck is much more stable on the road, and brakes, turns and reacts very predictably and safely. It reduces sway, but more importantly significantly reduces pitching – which you get a lot of on bumpy country roads.

I previously had a 6m tinny (~1.8t), and would sometimes tow with a Falcon (HD towpack). Without the (same) WDH it was bloody awful in fact dangerous, but with it was a dream. I wouldn’t say my current rig is dangerous without the WDH, it is just so much better with it it’s not funny.

At 3200mm the D40 has a very long wheelbase (but soft springs), and still pitches a lot. As the tow vehicle’s wheelbase shortens, and the towed load increases, a WDH becomes more worthwhile. I think once you have used them you will always use them. I strongly recommend them.
cheers
Brendon

[White Pointer]

G'day,

The biggest problem we face towing is that trailer and caravan manufacturers don't follow the same rule as car makers. A factory towing hitch has the towball at the same height as the centre line of the axle of the towing vehicle. The Land Rover Disco S2 towing hitch is like this. I know - I have one.

Trailer manufacturers build straight rail chassis - therefore the axle line is way below the chassis centre and then they put the trailer hitch coupling on top of the rail. To get things back into plumb they need to make an "L" or "S" bend on the rail just before the trailer hitch coupling to get the coupling back to the right height.

The difference between the wheel and tyre diameter of the towing vehicle and the (usually) smaller W&T of the trailer doesn't compensate, but it helps.

Another problem with caravans has already been described - positioning axles for static balance - not for downforce.

The cheapest solution is to replace the towbar insert on the Land Rover with one that lifts 3" higher and by loading the forward part of the caravan to maintain static downforce on the towball of about 200Kg - but please read your owners manual for absolute limits. The lift you get on the tow coupling will foul the back door of the Land Rover - so be careful.

This and the back door fouling the winch post was such a pain that I bought a Rodeo as a boat tractor and retired the Land Rover to domestic duties. I fitted the Rodeo with a Nissan Patrol towing insert to get as much lift as I could but still allowing the tailgate to open and not foul the trailer coupling. Even with this I struggle to get the last 80 lt of fuel into the boats 250 lt tank because of the way the boat leans bow down on the trailer.

We are having fun managing our leasure!

Regards,

White Pointer

[finga]

In my opinion the weight distribution systems are used to mask an underlying problem.

We had a horse float years ago that you could not do more then 80km/hr with.
It was a factory built one and upon investigation the drawbar was out of line to the centreline of the float by 70oddmm at the tow hitch..and it had a drawbar that was only about 750mm out the front of the float.
2 weeks later after the front was stripped and a new, longer drawbar put on it towed like a dream.
Swaying is usually unheard of in a well balanced trailer (whatever the style) that is well built. A poorly loaded trailer or van is usually the problem of swaying.
The little cottage we have hear is next to a caravan park.
It amases me the percentage of vans that go in and out with the bum of the car on the ground and the @rse of the van shooting towards the heavens. No wonder they're exhausted after 2 hours of travel. They must be a handful to try to control at any speed.
I always wonder how many other factory built trailers, vans etc are not straight and true. Especially boat trailers that are dipped in really hot zinc.
I still reckon that towing a trailer should be an addition to a normal license.
A lot of people cannot back their trailer (go to any tip or boat ramp or caravan park on a week-end)
A lot of people do not have proper mirrors on their 2.495m wide caravans or boats or box trailers to see what's happening behind them (a lot of people cannot use the mirrors on their cars even)
A lot of people do not know how to use or set up their trailer brakes correctly (really handy to pull a sway out are those electric brakes).
Some people are just a danger to others when they're on the road with any trailer.
You need an additional license to tow a trailer behind a truck so why not a car?
You need to learn how to load a truck/trailer to gain a license so why not a car?
You need to balance the load on a truck otherwise you can, and will be, fined. ie weight over steer axle/axles and load over rear axle/axles etc. so why not a car and trailer??
You need a log book to operate a truck so why not a trailer (or car for that matter because fatigue affects everyone not just Blue in the roadtrain.)??

Just my opinion.

PS: I would love to weigh some of the vans getting about.

[ozscott]

White Pointer - are you saying that you want the trailer to sit up a bit at the front? I prefer level, but it may just be your standard vehicle height (if you have that) and trailer set up that needs a 3 inch increase (or maybe the LR tow point). I know the LR tow point receiver sits lower than the after market Hayman Reese one...I have the HR on my 02 Disco and it sits up (and gives better departure angle) and I actually use a 3 inch drop tongue to get it level (that and 31 inch tyres compared to the stock 29.5 seems to keep it all nice).

Keen to hear what you reckon.

Cheers