A WDH (in effect) is a springy semi-flexible beam between the caravan and its tow vehicle. It levers back up the tow vehicles rear tyres and its front wheels back down.

 

Do not attempt to level the rig

To adjust a WDH, adjust the lowered jockey wheel until the caravan is level. Now measure (and note) the front of the caravan chassiss height from the ground. Then, with the tow vehicle laden and the equivalent weight of driver and passengers on board, lower the caravan onto the tow ball. Again measure the caravans front chassis height from the ground. Adjust WDH bar spring tension so as to correct no more than 50% of that height difference.

Another way of adjusting is to measure the height of the tow vehicles front mudguard. When adjusted correctly, it increases that height by about 50 mm. This is likely to cause the front of the caravan to be about 50 mm lower than when level.

The SAE standard, Performance Requirements for Determining Tow-Vehicle Gross Combination Weight Rating and Trailer Weight Rating, (J2807) quantifies this. The standard used only 50% correction in its main WDH stability testing.

At one time, Hayman Reese in Australia recommended 100% correction. Chief Engineer (Rick McCoy) of its US parent (Cequent), however, has long recommended only 50% correction be used.

The Australian company does not appear to use percentage terms, but its current recommendations seem now to accord with its parent company.
Correcting tow ball mass by 50%  typically results in the caravans nose being lower by about 50 mm.

 

The above is a copy from a Collyn books.

I had a discussion with him on another forum and a couple others a few years ago about using J2807 as a  justification for 50% FALR, pointing out that, SAE in their J2807 testing report had nothing to do with WDHs except that one style of weight distribution hitch without sway control was used as a segement test for calculation of the GCWR and TWR for Vehicles in the USA.

I also concur that Cequent (USA HR) did in fact recommend a 50% maximum FALR on only one model of their weight distribution hitches, none of remainder of their hitches they sold made no reference to the 50% FALR.

In the fairness of comparision I sourced a from a number of WDH manufacturers their installation and setup of their hitches. I found that not one of those companies recommending a 50% FALR, in fact they all suggested 100% restoration.

At the time of that discussion, prior to my research I was open to the suggestion that the reduction maybe a serious consideration, but rather than go to a 50%, I reset my hitch to approximatly 75% which was ½ a link in the chain, on the road test I found the steering lighter and the caravan had greater sway caused by overtaking trucks, at the first opportunity, I stopped and returned the hitch settings to 100% FALR.

 

Radar wrote:

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Hi, 

What is FALR?

 

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 Front Axle Load Return

Radar wrote:

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Hi, 

What is FALR?

 

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 Front Axle Load Return

Brenda and Alan wrote:

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yobarr wrote:

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 Without inferring that it is beyond  your range of abilities, coukd I suggest that you might like to do your own research instead of demanding that I help you?

Simply ask Mr Google "Collyn Rivers" and much i formation is available.

But please don't come back bleating that you can't find what you want, or that you do find what you don't want. 

And at the risk of confusing you, could I point out to you that it was not I who steered this "off topic"?

P.S Have you managed to contact HR to inform them of their misunderstandings regarding the effects of a WDH on towball weight, or are you more intent on continuing to throw  Red Herrings into the discussion, further confusing those who simply are trying to understand their weights?

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 What I am interested in is not more red herrings ,but for you to give us your definitive proof that a car becomes lighter as you claim. Instead you try to steer off track to avoid any justification.

If you can't do this vjust admit it.

Alan

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 Alan, when most people discuss the weight of a vehicle they are referring to the weight applied by its wheels to the ground.

Most people understand that when a WDH is tensioned, weight is removed from the car's rear axle and distributed to both the car's front axle, and the caravan's axle group.

The car's wheels now are applying less weight to the ground than they were before the WDH was tensioned, while the van's wheels are applying more weight than previously. Car is lighter. Van is heavier.

We don't need such a simple issue confused by mention of mass, weight on moon, moments, or any other gobbledy gook you habitually throw into the discussion in an effort to appear knowledgeable.

All you're doing is confusing those who simply are trying to learn about weights. 

 

yobarr wrote:

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The car's wheels now are applying less weight to the ground than they were before the WDH was tensioned, while the van's wheels are applying more weight than previously. Car is lighter. Van is heavier.

 

 

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 The car is not and cannot be lighter. what is lighter is the load on the towball from the van. When are you going to understand this fact.

Alan

yobarr wrote

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La La Land stuff from you again, Alan. Instead of continuing to confuse people who simply are keen to learn perhaps you should visit Hayman Reese and advise them that, for 50 years, they've been mistaken and have been giving false information to caravanners and others?

Na, TOO hard for you I'd say. Back to school, Alan. Cheers

P.S You should know that a WDH can lift a car's rear wheels right off the ground so ALL weight is on front axle and van"s axle.

Now try and tell me that the car still applies the same overall weight to the ground. NOT A CHANCE.

-- Edited by yobarr on Thursday 22nd of February 2024 03:24:52 PM

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cheers

Brenda and Alan wrote:

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yobarr wrote:

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La La Land stuff from you again, Alan. Instead of continuing to confuse people who simply are keen to learn perhaps you should visit Hayman Reese and advise them that, for 50 years, they've been mistaken and have been giving false information to caravanners and others?

Na, TOO hard for you I'd say. Back to school, Alan. Cheers

P.S You should know that a WDH can lift a car's rear wheels right off the ground so ALL weight is on front axle and van"s axle.

Now try and tell me that the car still applies the same overall weight to the ground. NOT A CHANCE.

-----------------------------------------------------------------------------------------------------------------------------------------------------
La La land is where you reside. I have been saying all along that HR is wrong.

As to going back to school, that's where you should be to learn some of that simple physics you like to talk about.

At the point of the rear wheels of the car losing contact with the ground ALL the weight of the car would be on the front wheels.

Now instead of your constant side tracking give us evidence in the form of calculations or physics to try to prove your point. To date you have been unable to do either.

PUT UP OR SHUT UP

Alan

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Alan, previously I bought and tested a WDH, and I have posted ALL my axle weights before and after it was tensioned. 

Don't have figures on me, but around 70% of the weight that was removed from the rear axle was distributed to tge front axle, with the remaining 30% being distributed to the van's axle group.

Simple stuff. Car got LIGHTER and van got HEAVIER. Do you understand? 

Nah, doubt it, but I can only try. Main reason is to prevent others from being negatively influenced by your ramblings.

yobarr wrote:

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Simple stuff. Car got LIGHTER and van got HEAVIER. Do you understand?

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 Yobarr, are you trolling? I am sure you did not mean what you just wrote. That is exactly what Alan has been saying you apparently believe.

Of course the car does not get lighter, or the van heavier. The weight on the wheels changes.

This stupid endless argument is so pointless. Alan provides reasoning, but you can't. If you did then there could be something worth discussing. Neither will ever agree, so why not drop it.

yobarr wrote:

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Sometimes you make mistakes that I politely correct for you. No big deal. It's great that you are learning, and I'm happy for you to have your say but could I suggest that you double check your contributions, and that you don't continually and incorrectly challenge my assertions?

You now seem to take great delight in disputing most of what I post, simply to appear to be authoritative.

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 your bleating doesn't change anything.





cheers

10 pages long, some people can still not/won't be convince

Thought I would check this topic out again, which started on the 27th May. I think if you are travelling around OZ, and tangled in this topic you must be bored, time to head home. It appears to me a lot of people are travelling because that is the done thing to do (woke thing to do) and are living a poor life. I feal for you. Get out and do a bit, dust the tennis racquet, push bike or fishing rod, enjoy your travels.

Still no data Yobarr, just same old same old.

Speaking of meetings have you had a meeting with a high school physics teacher who could set you straight on what mass is ,what weight is and what the relationship is between mass and weight on earths surface.

Alan

yobarr wrote:

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No magic formulae. No waffle about mass. No discussion of that vehicle's weight if it were on the moon. No confusing garbage.

No gobbledy gook. No disappearing towball weight. Simple facts.

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 too lazy to do your homework?
still feel the need to stay relevant?
then maybe bleating "hayman reese' is for you.





cheers

Brenda and Alan wrote:

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Still no data Yobarr, just same old same old.

Speaking of meetings have you had a meeting with a high school physics teacher who could set you straight on what mass is ,what weight is and what the relationship is between mass and weight on earths surface.

Alan

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still waiting to hear what your qualification are.