Chassis Have i got this setup right? WDH

[DiDExceed]

Hi all been doing a few mods to the can over the weekend and have just finished putting on the wdh.
When i picked the van up it was too low for the lowest holes in the shank so used my standard tounge to get it home, ive given the van a lift for a number of reasons and i know atm my hitch height isnt legal ill get to that later, we are going away after xmas and wont have time to sort the hitch height b4 then.
So with the current height ive flipped the shank (instructions said can be used either way, and currently have it in the bottom holes as it looked like doing it this way would give the best result. The van is nose up about 40mm with 6 working links, 55 or smm with 5 and a whopping 70 odd mm with the minimum 4 working links, the bum of the pajero is still down a bit, should i flip the hitch back the other way and set it up lower and the bars should bring it all up? Not much effort is required to snap up the chains either so i dunno how effective it is in its current setup, any pointers would be much appreciated

 

[17triton]

Have you got some pics of it to show the whole setup?

 

[DiDExceed]

I do but ios wont let me upload them, ill jump on the pc

 

[dagree]

Hi @DiDExceed Have a look through the attached PDF link..... Might be an answer or suggestion to your question in there!

http://www.southcoasttrailers.com.au/picts/WDH_Installation_Instructions.pdf

 

[DiDExceed]

Reading through that i think i might need the ball height lower, but i think its going to end up too tow, i dunno ill have to have a play

 

[Bushman]

You say the van is nose up, it should sit as level as possible, looking at that I would suggest turning it over and going to a lower hole on the shank, I originally used a Eza-Lift WDH on mine, ended up swapping to a genuine Hayman Reece because the adjustments are much finer, mine being an back with the coupling on the bottom of the A-frame also added a hitch raiser.

 

[twscoot]

Here's a photo of my old 16.49-2 (outback) being towed by my Pajero and before that a Territory.
The trick to getting the end of the bars high enough is to angle the ball slightly forward. As Bushman says, the HR WDH has fine adjustments. I still us exactly the same angle with my Jeep but a shorter shank.
This setup photographed here never scrapped the ground once after 5 years of use.

 

[DiDExceed]

I had a fiddle tonight snd have got it to a point the van is nose up 10mm and the paj bum down 10mm with 4 working links, took it for a drive and must say im pleasantly suprised with the way the combo drives, much less pitching and the steering is definatly heavier so in the end a good investment

 

[dagree]

Good to hear @DiDExceed ...
If all else fails do what I do as a last resort.... Read the instructions

 

[DiDExceed]

The hr instrctions are a bit better re setup to the camec ones, thanks everyone for the help

 

[twscoot]

The 16.49-2 always travelled slightly nose up. Good to hear it's working for you.

 

[Smergen]

@DiDExceed do you have factory springs in it? Also, what's the expected ball weight of the van?

I only ask as I have an NM and tow a 17.56.2 with it without a WDH. I've got some upgraded springs and shocks in the rear, along with airbags and it sits nice and level. I've been contemplating a WDH as well, but if the purpose of it is to level the tug out, then I'm not sure what more it would bring... Thoughts?

Before

After


Mind you... not exactly conclusive photos here but the were the best I could drum up.

 

[DiDExceed]

I have 2" medium linear rear lovells and firestone bags, did have h/d kings but were too stiff for me unladen, being single axle i think theres a bit more weight than a tandem, and the axle is a fair way back, we orinally wanted a 17.55-5sh but budget didnt allow it so this was the best we found for what we had our last two outback expandas never used a wdh with, but a liitle one is on board now so safety i guess is looked at more closely

 

[Smergen]

Thanks for the feedback mate. It's a pretty stiff ride in the Paj in it's current set up, but it just ferries me to the train stations most mornings and the family stays in the Conformodore. It's an interim set of wheels for now, but I'm pretty impressed with it. Agricultural, but effective.

 

[twscoot]

Hi Smergen. The WDH does more than just level things out. It actually puts a bit more weight onto the front steering wheels so has been great in the three vehicles I have used it in terms of control and overall stability.
The physics is most easily explained by saying it spreads the load across all three axles and in the process also levels things up (in a single axle caravan). - 100's of pages of arguments about all this on other sites where people get cranky and self righteous... Don't want to go there!
Stiffer springs/airbags level things up but simply can't add weight to the front wheels.

Here's the best explanation I have been able to (previously) write up if you are interested in the physics!

Weight Distribution Hitch - Explained

Explaining how a weight distribution hitch works is complicated and does require some understanding of physics ? but here goes....

Think about a typical 4 wheel car with a towbar sticking out the back.

Think about the fact that your tow bar, sits behind the rear axle.

Hook up the caravan and apply (say) 200kg tow ball caravan weight to the towbar.

The back wheels now have (approximately) 200kg more weight.

But, the now 6 wheel car/caravan combination, can easily flex in the middle ? this is key to understanding how adding a WDH will make a difference.

The tow bar without a WDH is just a hinge that can move up and down and sideways.

The front wheels of the car, because of the effect of leveraging the weight behind the rear axle, now have less weight.

This is simply because the weight from the caravan is levering up the front wheels using the back axle as a pivot point. (The towbar is just a hinge at this point remember).

Stiffening up the rear suspension (that's in effect what the Self Levelling Suspension/air bags/stiffer springs do while levelling the rear of car) makes no difference. It simply means the car won't sag as much ? the rear axle is still a pivot point and the tow bar a hinge.

Put your WDH on.

You will notice when you do, the rear of car the rises a little. What's happening?

The WDH is stiffening up the 6 wheel car/caravan combination. It is trying to stop the downward hinge effect of the tow bar and lift it up.

The effect of this is to transfer some of the weight to the front wheels and raise the rear of the car. It actually reverses some of the levering effect described above.

To go one step further this 6 wheel car/caravan combination now shares the weight more evently across all 6 wheels - including the van wheels. Like a 6 leg dining room table would. (Bigger stronger table legs don't actually make a difference - just as stronger springs/air bags don't).

There is a whole raft of physics to go with this but I hope this helps.

 

[Smergen]

I appreciate the time @twscoot that you've taken to put that together. It's more food for thought for me, a little late at night at the moment, but will re-read it tomorrow and see how I go.

 

[DiDExceed]

I definatly noticed the difference in steering feel, so it must work, i was very skeptical at first but must say im converted

 

[homerJ]

WDH are amazing things. I once had to tow my ASV RC30 Skid steer with my poor Hilux 2wd table top ute. It was sitting on the bump stops without the WDH but once it was hooked up the whole thing levelled out.

Poor little beasty. But the tipper was in the shop.