a block of concrete on the tow ball is no different than (from?) having a person sit on the back seat of the car. A trailer sits on the ground with part of its weight on the tow ball you can't apply a WDH to any towbar without a trailer of some sort and if you cant understand that i cant explain it thats why these devises are called weight distribution hitches
Sorry Gary, but your ignorance of the workings of a WDH is distressing. However, I know I'd be wasting my time even trying to explain. Cheers
boab said
12:59 PM Jul 25, 2022
no worries yobarr but can you explain to me how would you attach any wdh to a vehicle that does not have a caravan or trailer or at least a draw bar hooked onto the said tow ball i am not arguing that they work or not i dont care one way or the other but i look forward to your explanation of how you attach one that has nothing behind the tug
Gundog said
05:58 PM Jul 25, 2022
The way I understand is the contention is the validity of ball weight, the acceptance is ball weight can only be measured with the van not connected to the towing vehicle.
How do you accurately measure ball weight is it a simple as lowering the ball coupling on to a measuring device ? What is the true towball weight if the caravan coupling is level ? Then if the difference if the coupling 50mm lower and or 50mm higher.
Which has the lesser effect load sharing or non load sharing axle groups and how does that differ on single axle caravan.
Does the CofG change when the attitude of the caravan changes?
yobarr said
06:39 PM Jul 25, 2022
Gundog wrote:
The way I understand is the contention is the validity of ball weight, the acceptance is ball weight can only be measured with the van not connected to the towing vehicle.
How do you accurately measure ball weight is it a simple as lowering the ball coupling on to a measuring device ? What is the true towball weight if the caravan coupling is level ? Then if the difference if the coupling 50mm lower and or 50mm higher.
Which has the lesser effect load sharing or non load sharing axle groups and how does that differ on single axle caravan.
Does the CofG change when the attitude of the caravan changes?
The van would need to be disconnected in order for an accurate tow ball weight reading to be achieved. To achieve a "true" reading, the drawbar of the van should be at exactly the same height when the weight reading is taken as it is when the van is connected to the car, ready for travel. After trialling several different so-called "towball weight" devices I determined that they all are hopelessly inaccurate. Not only were there huge differences in the results shown when weighing the same van, none was within coo-ee of actual towball weight. Getting the "settled" drawbar to the correct level for a true reading to be taken was a mission in itself! Tricky. The absolute best thing that can be said about these devices is that they give a "very rough idea" of actual towball weight, and that's being nice! Although I am a little suspicious about the reasons for your other questions I will answer them in the right spirit! A height difference of 50mm in coupling height would cause such a small change in towball weight that it would be almost immeasurable on both suspension types although lowering the towball height on the non-weight sharing van's suspension would increase the weight on the van's lead axle. This is why vans with non-load sharing suspension should always be level, with slightly lower tyre pressure in the lead axle so that in sharp turns the van can "shuffle" that axle sideways, rather than using that axle as a pivot. Running the lead axle's tyres at slightly lower pressure also helps minimise the effects of yaw. Your second last question can be answered by saying that single axle vans, and van's with load sharing suspensions would achieve the same results. COG changes also would be neglible, and so small they'd be virtually immeasurable. Cheers
-- Edited by yobarr on Monday 25th of July 2022 06:45:01 PM
DMaxer said
07:19 PM Jul 25, 2022
Whilst I have no qualifications in mechanical engineering I have found this topic pretty interesting.
What really intrigues me though Yobarr is your total dismissal of anyones opinion that does not coincide with the view that you hold.
Now tell me, what are your qualifications to assert that your view is correct and those dissenting are wrong. Is it just that if you think it then it must be right or do you have some academic qualifications in this area that make your opinion beyond question.
yobarr said
08:22 PM Jul 25, 2022
DMaxer wrote:
Whilst I have no qualifications in mechanical engineering I have found this topic pretty interesting. What really intrigues me though Yobarr is your total dismissal of anyones opinion that does not coincide with the view that you hold. Now tell me, what are your qualifications to assert that your view is correct and those dissenting are wrong. Is it just that if you think it then it must be right or do you have some academic qualifications in this area that make your opinion beyond question.
Unlike the situation with most topics on the forum, with weights there is no room for opinion. Your weights are either right or they're wrong. Period. If you previously had been following the many threads on the topic you would likely have noted that I have provided many pages of indesputable information and helpful advice, along with referrals to facts supplied by people like Hayman Reese, and Collyn Rivers, who has over 60 years experience in weights and dynamics and has written many books on the subject. (RV Books) Because some of the advice I have offered is taken direct from the Hayman Reese website, I have previously suggested that those members who disagree with such advice should, instead of endlessly arguing with me, contact HR direct, and tell them that after 60 years designing and producing WDHs they still don't know what they're talking about. To date, none has done so. Strange? Many times I have posted that although I have years of experience with weights I have no formal qualifications, but none is needed. It all is just simple physics. You might like to consider that you don't need to be a meteorologist to know it's raining, surely? It's that simple. If you care to use the search feature you will be able to access many threads on the topic, but you could start with "The effects of using a WDH" , dated 6th May, 2020. (From memory). Coincidentally perhaps, the present thread was started by the same member who posted the rubbish contained in that 2020 thread. Cheers
-- Edited by yobarr on Monday 25th of July 2022 08:59:52 PM
Brenda and Alan said
08:57 PM Jul 25, 2022
Yobarr
Despite 5 pages of comments on this subject all you have added is others opinions.
You still have not supplied any evidence that my arithmetic that shows conclusively that a WDH reduces towball download is not correct.
Take some time to examine the figures and with your supposed knowledge of physics you might finally see the light.
To my knowledge one of your oft quoted sources is a journalist and not an engineer and Clarky has given you Haymen-reeces explanaination.
Alan
yobarr said
09:24 PM Jul 25, 2022
Deleted.
-- Edited by yobarr on Monday 25th of July 2022 09:26:10 PM
Gundog said
10:39 PM Jul 25, 2022
Yobarr,
I see you have not responded to my 1033 post today 25/07 challenging your and the person whom you are quoting i regards to J2807
From Motortrend
In response to the confusion that resulted when buyers wanted to compare maximum tow ratings, the Society of Automotive Engineers (SAE) has developed the J2807 set of recommended practices. The tow test procedures designed by the big brains at the SAE consist of a series of rigorous real-world challenges to determine the Gross Combined Weight Rating (GCWR) of a vehicle and trailer combination.
Are We Lost said
12:44 AM Jul 26, 2022
Yobarr, the chorus is building for you to show that you really do know how a WDH works. Is it 7 or 8 members now with differing questions that you seem unable to answer and justify your position? It seems that all you can do is relate what others have said on what it does. But when it comes down to something that requires understanding of how, you just repeat the same.
In my case (talking about increased towball load), you told me you explained it (you didn't), then said it was tension, then said you purposely did not explain it because I was setting you up. But this extract from your post 5:39pm on 22 July clearly shows you have no concept of how it works.
"Maximum download weight allowed on a DO35, and other hitches, is 350kg but this fella is trying to tell us that his magical WDH has applied 510kg to that hitch, and all is good. Yeah,right. Most larger cars have a towbar download limit of 350kg while many cars have limits a lot less than that. How would any of these cars handle 510kg towbar weight? They couldn't, and any resultant breakages would likely not be covered by insurance"
Yobarr, if you would like to rethink that and let us know what you should have said, then maybe you will retain a little bit of credibility. We all make mistakes from time to time and then realise in hindsight that it was wrong. If you don't understand it, that's fine. But don't pretend that you do.
-- Edited by Are We Lost on Tuesday 26th of July 2022 12:54:27 AM
Gundog said
08:13 AM Jul 26, 2022
Weights Let's go back to the HR diagram, the weights and measurements are contradictory. Red flags #1 For a caravan with an ATM of 1450kg isn't a 220kg ball weight excessive, at 10% 145kg, at 15% is about the 220kg mark. #2 when the caravan attaches to the tow vehicle the front of the caravan drop 80mm and the back rises 50mm a combined variation of 130mm. #3 The bull in the china shop 50% FALR, is not evident in this diagram so the per dates the assumptions of J2807. From all this diagram presents to me it a caravan that is not laden as if it was going to be used, no publication of the caravans ratings, nor GVM, GCM of the tow vehicle. Therefore if this is being presented in a demonstration at a caravan show etc is a very poor sales gimmick.
Brenda and Alan said
08:54 AM Jul 26, 2022
Gundog I think you has missed the whole point of my claim. The weights on the diagram are what they are. Whether or not you don't you like them is irrelevant.
My claim is that a WDH reduces towball download when tensioned. Look at the chart,do the arithmetic and see if you agree that this is so.
If we go down Yobarrs course that towball download doesn't change, then the weight recorded by the scales would not reduce. But hang on it does. So as a consequence the only inference that makes any sense is that the mass of the car has magically been reduced by 60 Kg Wt. This of course is total nonsense, but is the only outcome of following Yobarrs assertion. The mass equivalent to that of a paper clip was destroyed in the Hiroshima bomb.
Alan
montie said
09:37 AM Jul 26, 2022
I lost intererest in thread 2 days ago and haven't really been following but a WDH distributes weight from the tug's rear axle to the front axle and a percentage to the van wheels.
I would suggest the 60kg referred to would be the proportion distributed to the van axles.
KJB said
09:56 AM Jul 26, 2022
montie wrote:
I lost intererest in thread 2 days ago and haven't really been following but a WDH distributes weight from the tug's rear axle to the front axle and a percentage to the van wheels. I would suggest the 60kg referred to would be the proportion distributed to the van axles.
The last half of your first sentence says it all ....it is as simple as that. (and so easy to follow and understand....) KB
Brenda and Alan said
09:57 AM Jul 26, 2022
Montie I have no problem with this statement, The problem the arises that if the 60 Kg Wt is on the wheels of the van and we know the mass of the van has not changed in any way then the towball down load must have reduced by 60 Kg Wt. If not then the van has miraculously increased by 60 Kg in mass by the simple imput of the energy required to tension the WDH. Ridiculous. See reference to Hiroshima bomb.
As a caravan dealer I would have thought it in your interest to get the facts correct.
Alan
-- Edited by Brenda and Alan on Tuesday 26th of July 2022 09:59:47 AM
Gundog said
10:06 AM Jul 26, 2022
Alan I agree with your statement where does the 60kg come from.
My last post about the HR diagram was that it contained misleading data.
montie said
10:11 AM Jul 26, 2022
Brenda and Alan wrote:
Montie I have no problem with this statement, The problem the arises that if the 60 Kg Wt is on the wheels of the van and we know the mass of the van has not changed in any way then the towball down load must have reduced by 60 Kg Wt. If not then the van has miraculously increased by 60 Kg in mass by the simple imput of the energy required to tension the WDH. Ridiculous. See reference to Hiroshima bomb.
As a caravan dealer I would have thought it in your interest to get the facts correct.
Alan
-- Edited by Brenda and Alan on Tuesday 26th of July 2022 09:59:47 AM
As I said I lost interest in this thread some time ago because like many other threads on this forum it has been hijacked by a group of posters who believe their opinions are the only ones that matter to the exclusion of some who actually know what they are talking about.
I have explained very simply how a WDH works and I can't find any connection to the Enola Gay.
I really don't think there is anything further I can add to this topic so I'll leave it to you guys to spruik on about how you can make weight disappear.
-- Edited by montie on Tuesday 26th of July 2022 10:18:10 AM
Brenda and Alan said
01:21 PM Jul 26, 2022
Gundog wrote:
Alan I agree with your statement where does the 60kg come from. My last post about the HR diagram was that it contained misleading data.
I don't think the data is misleading as this diagram was prepared quite some time ago when caravans were much lighter than todays. Still this concern doesn't change the way the figures play out in the arithmetic. The 60Kg Wt is the amount that the towbar download is reduced when the WDH is tensioned Note that is not 60 Kg (mass) but60 Kg Wt (force).
Alan
Are We Lost said
01:24 PM Jul 26, 2022
In my post a few back I said "We all make mistakes from time to time and then realise in hindsight that it was wrong." It was a lead in for Yobarr, but also because I would like to address a couple of things I have said.
The first is in use of terminology. Back on 18th July I pre-empted this when I warned .
"Also I have not tried to use the correct physics terminology ... weight, mass, torque, force, load. My high school physics is now forgotten."
It was (Brenda and) Alan who raised the issue that weight was the wrong term to use, and perhaps even measuring in Kg was incorrect. So after a little Youtube refresher I see he was correct. Weight is Mass x Gravity (acceleration). Weight does not exist in space, and the rig would weigh less if parked on the moon. However, tensioning the bars to the same extent would apply the same load wherever it was. I will leave it to others to explain better than I can. But I will use the term load instead. Hopefully this is OK. Still sticking with Kg however.
For the second point, on 22 July following the Cruisemaster video, KJB compared the 510kg reading on the scale to the forces from a G clamp (increase of 325kg). I agree that it is a reasonable comparison, however there are some difference. A G clamp would not redistribute weight, because that requires the use of levers. The car and van are two separate entities joined at a pivot point, and the levers act differently on each .... which is why a WDH works. However, in addition to the terminology issue, his comment did lead me to realise where the wording I used was not entirely correct.
In that video, the additional 325kg reading is the cumulative effect of download force from the WDH at the coupling and uplift force from the bars attachment at the hitch. While this is what I have been saying all along, my wording suggests it is just the download.
But the important part is that (for example) if the download was 130kg and the uplift was 195kg, this would show as that 325kg difference on the scales, but the rear end of the vehicle would rise. This goes to explain Alans repeated questions to Yobarr to explain how the car can be 60kg lighter in the HR chart.
I think part of the confusion with this whole issue is that some consider the load on the towball as being the same as the load on the towbar (or rear end of the car). I dont and in my explanations have treated them separately. The bars lift the back of the car via the hitch assembly, while those same bars apply a download via the drawbar and then coupling to the towball. The net effect of those forces to the hitch assembly is what gets applied to the towbar, which causes the rear of the car to rise.
I have come close to eplaining where Yobarr got it wrong with his howler that a I referenced in my post late last night. I see he has been online so has probably seen it, but will give him a little more time to clarify and show that he does understand.
-- Edited by Are We Lost on Tuesday 26th of July 2022 01:32:34 PM
Brenda and Alan said
01:29 PM Jul 26, 2022
Montie it is not I that is spruiking that mass disappears, that is the only way to explain what would need to happen if both yours and Yobars ideas that towball download does not change. Neither you nor Yobarr understand the physics involved nor that mass and weight are not the same thing.
Alan
snap1946 said
07:18 PM Jul 26, 2022
instead of all this BS why doesn't some one go to the transport dep or the scalies who do checks and hand out the fines and ask them .
for they are the ones that will give reports to our insurance companies on our weights simple
cheers snap
Are We Lost said
10:41 PM Jul 26, 2022
yobarr wrote:
As stated in an earlier post this video is a nonsense and seems to be no more than an advertising tool aimed at gullible people. However, it is pleasing to note, from the so-far muted response, that it may have been exposed for what it really is, and our less-gullible members have seen right through it? Many caravanners attest that a WDH reduces towball weight, which is patently untrue. BUT, people who have this belief might like to explain how, in this video, there is an apparent increase of 325kg in towball weight? The totalweight on the wheels of the car and van does not change , so where did this magical 325kg added weight come from? It didn't come from anywhere, as it is simply an increase in the clamping pressure between the towball and the hood, as Kerry has quite rightly pointed out. Maximum download weight allowed on a DO35, and other hitches, is 350kg but this fella is trying to tell us that his magical WDH has applied 510kg to that hitch, and all is good. Yeah,right. Most larger cars have a towbar download limit of 350kg while many cars have limits a lot less than that. How would any of these cars handle 510kg towbar weight? They couldn't, and any resultant breakages would likely not be covered by insurance, being 50%(+/-) overloaded. No WDH changes towball weight. No WDH changes total weight on wheels. All a WDH does is distribute weight differently , taking weight off the car's rear axle and putting some of that weight back on to the front axle of car, and some on to van's axles. Again I will say, a WDH does not change towball weight. Never has. Never will. If anyone else is interested in attempting to change the indisputable laws of physics perhaps they could initiate an interesting debate by stating that the earth is flat? Makes about as much sense as insisting that a WDH changes towball weight. Cheers
Late last night I posted about the above comment made by Yobarr that shows he has totally misunderstood how a WDH works. His comment relates to a marketing video made by Cruisemaster that I posted a day earlier.
I suggested maybe he made a mistake, and he would like to rethink and revise it. So I gave him a day to do so. But no such response has been made.
In the video (at 1:55) the first obvious thing is that as the bar is being tensioned, the rear end of the tow vehicle rises. No problem with that and most on here agree that is the way it works. That indicates that the load on the towbar has decreased. Not increased as Yobarr's words suggest.
Then, "most larger cars have towbar limit of 350kg ...... How would they handle 510kg?" They don't. Before the bars are tensioned, the towbar load was 185kg. Then when tensioned, the towbar load is actually less, not more. This is because the bars act as levers operating in different ways. The lift from the bars on the car is greater than the download on the van. The net effect causes the rear end to rise. So to suggest that this video is showing that the car has to support 510kg on the towbar just highlights a misunderstanding of how WDHs work.
And "this fella is trying to tell us that his magical WDH has applied 510kg to that hitch". Yes, he is, (actually to the towball where it is being measured). The uplift and download from the bars add together in this case ...... 185kg plus the two opposing forces created by tensioning the bars. So it reads 510kg. That is what it was designed to do. The hitch assembly sees the net load and transfers this net load to the car via the towbar.
Note that I have been careful to distinguish between towball and towbar. They each carry vastly different loads. Also, the few kilograms of weight from equipment has been ignored. There would also be a rotational torque at the hitch.
Before closing I would like to mention that through all these pages the focus has been on static loads. The beauty of the WDH is the way it works in a dynamic situation .... while you are on the road. At this time the effect is stronger the more it is needed. By that I mean that when the van nose puts more weight on the towball, perhaps from a road undulation, the WDH tension becomes greater. That transfers more weight from the back wheels to the front when it is most needed. When the van nose bounces back up, the WDH tension is reduced, adjusting the weight distribution from where it is least wanted to where it is most needed. A subject for another time.
-- Edited by Are We Lost on Tuesday 26th of July 2022 10:48:54 PM
Are We Lost said
10:43 PM Jul 26, 2022
snap1946 wrote:
instead of all this BS why doesn't some one go to the transport dep or the scalies who do checks and hand out the fines and ask them .
for they are the ones that will give reports to our insurance companies on our weights simple
cheers snap
And ask what? There is not much disagreement here on what a WDH actually achieves. It's more about the way it does so and claims of other things that have not been supported.
DMaxer said
08:56 AM Jul 27, 2022
I have been fascinated with the knowledge of posters on various subjects, especially this one. I have a couple of questions that I hope don't sound too stupid and I am not looking at starting WW3 but here goes.
1. If I have a single axle van and I hook it up to my tug and then notice there is a drop of say 2" in the rear. If I put scales under the van's single wheels and another set of scales under the front wheels of the tug and then placed a jack under the tow ball and hitch and proceeded to lift the tow ball and hitch until I raised it 2". would the scales under the van's wheels and the car's front wheels show an increase? If I also had scales under the jack, when I lifted the tow ball and hitch the 2" would the reading be different than before I commenced lifting.
2. I understand the lever principles of the WDH but does the WDH lift the tow ball and hitch that then results in the weight being distributed or does the lever action of distributing weight cause the tow ball and hitch to lift.
Unfortunately, my physics classes at high school were spent by me either drawing sailing boats or looking out the window at the girls doing PE on the basket ball court. Not too much, if any, was retained of physics.
Ivan 01 said
11:43 AM Jul 27, 2022
Unfortunately due to other topics being locked or removed we have lost good links on how the WDH works on a weigh bridge.
Clarky has said it all,
the use of a WDH is not illegal and is beneficial in many instances.
Codagans credentials list him as an engineer.
That is fine. I would be surprised if he had ever used that credential apart from to boost his car sales business.
It appears to me that he will recommend anything if he is paid or there is money in it for him.
HR would not pay for distorted reviews.
HR would get enough distorted reviews from caravan sales people who are anti the WDH
Rivers is a journalist with experience in testing cars for manufacturers in the mid part of last century and has reportedly done some motor homing and caravanning. In other words he was a paid driver with a flair for writing.
His paid testing jobs have never reported caravans or WDH hitches to my knowledge.
His views are only his opinion and are worth no more than anyone elses.
This pic which came from another deleted or locked post says it all.
It shows a demonstration of a front wheel drive car connected to a caravan with a WDH attached and having the rear wheels removed and the operator is driving the combination around on the streets.
This action proves that the weight IS removed from the tow ball and is transfered to the front wheels of the car and probably the rear wheels of the van.
If it didnt do this the tow ball and drawbar would be dragging on the road and the exercise would not work.
Argue on, call it weight or force or whatever.
Claim that a WDH is dangerous or listen to vehicle manufacturers and thousands of users who explain the benefits.
A WDH IS NOT ILLEGAL and if some dont want to use one then fine but dont offer dangerous advice to any newbies on here
DMaxer All scales in your example would show an increase in weight, the one under the tow bar the most.
A WDH is not the same as a ground mounted jack. The spring steel bars are mounted onto the receiver/hitch and tensioned upwards and fixed to the draw bar under tension. It is this lifting force that is responsible for lowering of the original towball weight and puts that weight reduction onto the caravans wheels because the bars are pushing down on the drawbar. The change in weights on the front and rear wheels are due solely to the reduction in tow bar weight.
Alan
DMaxer said
04:57 PM Jul 27, 2022
Thanks for your reply Alan. Initially I used a WDH on my tug and van but then decided to have an extra leaf fitted to the rear suspension.
Although there is no sag I still use the WDH but not cranked on as hard as before as I find the van and tug travel so much better with one and seems to fix the issue of porpoising on sealed roads that seem to have dips in the carriageway.
yobarr said
05:15 PM Jul 27, 2022
Ivan 01 wrote:
Unfortunately due to other topics being locked or removed we have lost good links on how the WDH works on a weigh bridge.
Clarky has said it all,
the use of a WDH is not illegal and is beneficial in many instances.
Codagans credentials list him as an engineer.
That is fine. I would be surprised if he had ever used that credential apart from to boost his car sales business.
It appears to me that he will recommend anything if he is paid or there is money in it for him.
HR would not pay for distorted reviews.
HR would get enough distorted reviews from caravan sales people who are anti the WDH
Rivers is a journalist with experience in testing cars for manufacturers in the mid part of last century and has reportedly done some motor homing and caravanning. In other words he was a paid driver with a flair for writing.
His paid testing jobs have never reported caravans or WDH hitches to my knowledge.
His views are only his opinion and are worth no more than anyone elses.
This pic which came from another deleted or locked post says it all.
It shows a demonstration of a front wheel drive car connected to a caravan with a WDH attached and having the rear wheels removed and the operator is driving the combination around on the streets.
This action proves that the weight IS removed from the tow ball and is transfered to the front wheels of the car and probably the rear wheels of the van.
If it didnt do this the tow ball and drawbar would be dragging on the road and the exercise would not work.
Argue on, call it weight or force or whatever.
Claim that a WDH is dangerous or listen to vehicle manufacturers and thousands of users who explain the benefits.
A WDH IS NOT ILLEGAL and if some dont want to use one then fine but dont offer dangerous advice to any newbies on here because you have your vehicle set up without one.
It is your choice not to use one, nothing else.
Ivan, you are so lost in the WDH wilderness that you should ALMOST be able to sight Alan. For a couple of days I decided to just sat back, taking the view that, like Montie, I'd done as much as I could to help, and let those who know little continue their waffle about WDHs, but your post contains so many untruths that I had to reply. Let's first consider JOHN CADOGAN whose credentials you seem to doubt, which you're entitled to do, no matter how wrong you are. The man is either an Engineer or he is not. However, it must be noted that he is not recommending a WDH, but simply explaining how it works. He shows that a WDH transfers weight FROM the car's REAR AXLE to the car's FRONT AXLE, and to the VAN'S AXLE GROUP. Simple stuff. You then proceed to tell anyone silly enough to believe you that Collyn Rivers is no more than a journalist with experience in testing cars for some manufacturers. This is either a blatant lie or you are totally ignorant of the man's achievements which include designing suspensions etc for car manufacturers, vast travel in Africa, Libya and Australia, and being the author of many books (RV books) on topics such as Caravanning, Solar and Electronics. This all is documented in the list of his credentials posted by Plain Truth ( To call him 'Alan' might cause him to be confused with another member who, despite pages and pages of facts and reference to appropriate sites, STILL doesn't understand that a WDH DOES NOT change towball weight) Thanks Plain Truth for posting this as I have it somewhere but couldn't find it in my records. We now will visit the supplied picture of the car and van. (Oldsmobile?) If you had ANY understanding of a WDH you would know that all it does is create what is essentially a "stiff arm" from the car's front axle, through the hitch point, to the van's axle group. Many times I have pointed out that because of the weight being removed from the car's REAR AXLE there is increased risk of OVERSTEER, which CAN be dangerous. Can you begin to imagine the enormous stresses on the chassis of both the car and the van, as well as on the towbar unit? How you can determine that this means that weight is removed from the towball is beyond any comprehension, and defies both logic and simple physics. Where did all the REAR AXLE WEIGHT go? Spare me! The physics is so simple, but it is concerning that so many don't appear to understand. Seems we have a case of "There is none so blind as he who WILL NOT see". Cheers
yobarr said
06:12 PM Jul 27, 2022
Brenda and Alan wrote:
DMaxer All scales in your example would show an increase in weight, the one under the tow bar the most.
A WDH is not the same as a ground mounted jack. The spring steel bars are mounted onto the receiver/hitch and tensioned upwards and fixed to the draw bar under tension. It is this lifting force that is responsible for lowering of the original towball weight and puts that weight reduction onto the caravans wheels because the bars are pushing down on the drawbar. The change in weights on the front and rear wheels are due solely to the reduction in tow bar weight.
Alan
This is absolute rubbish, Alan, and I am amazed that you STILL don't understand that a
WDH DOES NOT CHANGE TOWBALL WEIGHT.NEVER HAS. NEVER WILL.
Your total confusion does not bother me but I do despair that your hare-brained 'theories' and constant spruiking of incorrect data is beginning to influence some of our members who have little understanding of weights but who are seeking some sort of reassurance that all is well with their cars. Several of us who DO understand weights etc have devoted much time to helping newbies and existing members with their weights. Your input causes nothing but confusion for these members. Several times we have suggested that you contactHR DIRECT and explain to them that, for 60 years their engineers have had NO IDEA what they're talking about. You no doubt would then post a copy of their acknowledgement of the error of their ways, along with their suitable apology? Cheers
Sorry Gary, but your ignorance of the workings of a WDH is distressing. However, I know I'd be wasting my time even trying to explain. Cheers
The way I understand is the contention is the validity of ball weight, the acceptance is ball weight can only be measured with the van not connected to the towing vehicle.
How do you accurately measure ball weight is it a simple as lowering the ball coupling on to a measuring device ? What is the true towball weight if the caravan coupling is level ? Then if the difference if the coupling 50mm lower and or 50mm higher.
Which has the lesser effect load sharing or non load sharing axle groups and how does that differ on single axle caravan.
Does the CofG change when the attitude of the caravan changes?
The van would need to be disconnected in order for an accurate tow ball weight reading to be achieved. To achieve a "true" reading, the drawbar of the van should be at exactly the same height when the weight reading is taken as it is when the van is connected to the car, ready for travel. After trialling several different so-called "towball weight" devices I determined that they all are hopelessly inaccurate. Not only were there huge differences in the results shown when weighing the same van, none was within coo-ee of actual towball weight. Getting the "settled" drawbar to the correct level for a true reading to be taken was a mission in itself! Tricky. The absolute best thing that can be said about these devices is that they give a "very rough idea" of actual towball weight, and that's being nice! Although I am a little suspicious about the reasons for your other questions I will answer them in the right spirit! A height difference of 50mm in coupling height would cause such a small change in towball weight that it would be almost immeasurable on both suspension types although lowering the towball height on the non-weight sharing van's suspension would increase the weight on the van's lead axle. This is why vans with non-load sharing suspension should always be level, with slightly lower tyre pressure in the lead axle so that in sharp turns the van can "shuffle" that axle sideways, rather than using that axle as a pivot. Running the lead axle's tyres at slightly lower pressure also helps minimise the effects of yaw. Your second last question can be answered by saying that single axle vans, and van's with load sharing suspensions would achieve the same results. COG changes also would be neglible, and so small they'd be virtually immeasurable. Cheers
-- Edited by yobarr on Monday 25th of July 2022 06:45:01 PM
Unlike the situation with most topics on the forum, with weights there is no room for opinion. Your weights are either right or they're wrong. Period. If you previously had been following the many threads on the topic you would likely have noted that I have provided many pages of indesputable information and helpful advice, along with referrals to facts supplied by people like Hayman Reese, and Collyn Rivers, who has over 60 years experience in weights and dynamics and has written many books on the subject. (RV Books) Because some of the advice I have offered is taken direct from the Hayman Reese website, I have previously suggested that those members who disagree with such advice should, instead of endlessly arguing with me, contact HR direct, and tell them that after 60 years designing and producing WDHs they still don't know what they're talking about. To date, none has done so. Strange? Many times I have posted that although I have years of experience with weights I have no formal qualifications, but none is needed. It all is just simple physics. You might like to consider that you don't need to be a meteorologist to know it's raining, surely? It's that simple. If you care to use the search feature you will be able to access many threads on the topic, but you could start with "The effects of using a WDH" , dated 6th May, 2020. (From memory). Coincidentally perhaps, the present thread was started by the same member who posted the rubbish contained in that 2020 thread. Cheers
-- Edited by yobarr on Monday 25th of July 2022 08:59:52 PM
Yobarr
Despite 5 pages of comments on this subject all you have added is others opinions.
You still have not supplied any evidence that my arithmetic that shows conclusively that a WDH reduces towball download is not correct.
Take some time to examine the figures and with your supposed knowledge of physics you might finally see the light.
To my knowledge one of your oft quoted sources is a journalist and not an engineer and Clarky has given you Haymen-reeces explanaination.
Alan
-- Edited by yobarr on Monday 25th of July 2022 09:26:10 PM
Yobarr,
I see you have not responded to my 1033 post today 25/07 challenging your and the person whom you are quoting i regards to J2807
From Motortrend
In response to the confusion that resulted when buyers wanted to compare maximum tow ratings, the Society of Automotive Engineers (SAE) has developed the J2807 set of recommended practices. The tow test procedures designed by the big brains at the SAE consist of a series of rigorous real-world challenges to determine the Gross Combined Weight Rating (GCWR) of a vehicle and trailer combination.
Yobarr, the chorus is building for you to show that you really do know how a WDH works. Is it 7 or 8 members now with differing questions that you seem unable to answer and justify your position? It seems that all you can do is relate what others have said on what it does. But when it comes down to something that requires understanding of how, you just repeat the same.
In my case (talking about increased towball load), you told me you explained it (you didn't), then said it was tension, then said you purposely did not explain it because I was setting you up. But this extract from your post 5:39pm on 22 July clearly shows you have no concept of how it works.
"Maximum download weight allowed on a DO35, and other hitches, is 350kg but this fella is trying to tell us that his magical WDH has applied 510kg to that hitch, and all is good. Yeah,right. Most larger cars have a towbar download limit of 350kg while many cars have limits a lot less than that. How would any of these cars handle 510kg towbar weight? They couldn't, and any resultant breakages would likely not be covered by insurance"
Yobarr, if you would like to rethink that and let us know what you should have said, then maybe you will retain a little bit of credibility. We all make mistakes from time to time and then realise in hindsight that it was wrong. If you don't understand it, that's fine. But don't pretend that you do.
-- Edited by Are We Lost on Tuesday 26th of July 2022 12:54:27 AM
Weights
Let's go back to the HR diagram, the weights and measurements are contradictory.
Red flags
#1 For a caravan with an ATM of 1450kg isn't a 220kg ball weight excessive, at 10% 145kg, at 15% is about the 220kg mark.
#2 when the caravan attaches to the tow vehicle the front of the caravan drop 80mm and the back rises 50mm a combined variation of 130mm.
#3 The bull in the china shop 50% FALR, is not evident in this diagram so the per dates the assumptions of J2807.
From all this diagram presents to me it a caravan that is not laden as if it was going to be used, no publication of the caravans ratings, nor GVM, GCM of the tow vehicle. Therefore if this is being presented in a demonstration at a caravan show etc is a very poor sales gimmick.
Gundog I think you has missed the whole point of my claim. The weights on the diagram are what they are. Whether or not you don't you like them is irrelevant.
My claim is that a WDH reduces towball download when tensioned. Look at the chart,do the arithmetic and see if you agree that this is so.
If we go down Yobarrs course that towball download doesn't change, then the weight recorded by the scales would not reduce. But hang on it does. So as a consequence the only inference that makes any sense is that the mass of the car has magically been reduced by 60 Kg Wt. This of course is total nonsense, but is the only outcome of following Yobarrs assertion. The mass equivalent to that of a paper clip was destroyed in the Hiroshima bomb.
Alan
I would suggest the 60kg referred to would be the proportion distributed to the van axles.
The last half of your first sentence says it all ....it is as simple as that. (and so easy to follow and understand....) KB
Montie I have no problem with this statement, The problem the arises that if the 60 Kg Wt is on the wheels of the van and we know the mass of the van has not changed in any way then the towball down load must have reduced by 60 Kg Wt. If not then the van has miraculously increased by 60 Kg in mass by the simple imput of the energy required to tension the WDH. Ridiculous. See reference to Hiroshima bomb.
As a caravan dealer I would have thought it in your interest to get the facts correct.
Alan
-- Edited by Brenda and Alan on Tuesday 26th of July 2022 09:59:47 AM
As I said I lost interest in this thread some time ago because like many other threads on this forum it has been hijacked by a group of posters who believe their opinions are the only ones that matter to the exclusion of some who actually know what they are talking about.
I have explained very simply how a WDH works and I can't find any connection to the Enola Gay.
I really don't think there is anything further I can add to this topic so I'll leave it to you guys to spruik on about how you can make weight disappear.
-- Edited by montie on Tuesday 26th of July 2022 10:18:10 AM
I don't think the data is misleading as this diagram was prepared quite some time ago when caravans were much lighter than todays. Still this concern doesn't change the way the figures play out in the arithmetic. The 60Kg Wt is the amount that the towbar download is reduced when the WDH is tensioned Note that is not 60 Kg (mass) but60 Kg Wt (force).
Alan
In my post a few back I said "We all make mistakes from time to time and then realise in hindsight that it was wrong." It was a lead in for Yobarr, but also because I would like to address a couple of things I have said.
The first is in use of terminology. Back on 18th July I pre-empted this when I warned .
"Also I have not tried to use the correct physics terminology ... weight, mass, torque, force, load. My high school physics is now forgotten."
It was (Brenda and) Alan who raised the issue that weight was the wrong term to use, and perhaps even measuring in Kg was incorrect. So after a little Youtube refresher I see he was correct. Weight is Mass x Gravity (acceleration). Weight does not exist in space, and the rig would weigh less if parked on the moon. However, tensioning the bars to the same extent would apply the same load wherever it was. I will leave it to others to explain better than I can. But I will use the term load instead. Hopefully this is OK. Still sticking with Kg however.
For the second point, on 22 July following the Cruisemaster video, KJB compared the 510kg reading on the scale to the forces from a G clamp (increase of 325kg). I agree that it is a reasonable comparison, however there are some difference. A G clamp would not redistribute weight, because that requires the use of levers. The car and van are two separate entities joined at a pivot point, and the levers act differently on each .... which is why a WDH works. However, in addition to the terminology issue, his comment did lead me to realise where the wording I used was not entirely correct.
In that video, the additional 325kg reading is the cumulative effect of download force from the WDH at the coupling and uplift force from the bars attachment at the hitch. While this is what I have been saying all along, my wording suggests it is just the download.
But the important part is that (for example) if the download was 130kg and the uplift was 195kg, this would show as that 325kg difference on the scales, but the rear end of the vehicle would rise. This goes to explain Alans repeated questions to Yobarr to explain how the car can be 60kg lighter in the HR chart.
I think part of the confusion with this whole issue is that some consider the load on the towball as being the same as the load on the towbar (or rear end of the car). I dont and in my explanations have treated them separately. The bars lift the back of the car via the hitch assembly, while those same bars apply a download via the drawbar and then coupling to the towball. The net effect of those forces to the hitch assembly is what gets applied to the towbar, which causes the rear of the car to rise.
I have come close to eplaining where Yobarr got it wrong with his howler that a I referenced in my post late last night. I see he has been online so has probably seen it, but will give him a little more time to clarify and show that he does understand.
-- Edited by Are We Lost on Tuesday 26th of July 2022 01:32:34 PM
Montie it is not I that is spruiking that mass disappears, that is the only way to explain what would need to happen if both yours and Yobars ideas that towball download does not change. Neither you nor Yobarr understand the physics involved nor that mass and weight are not the same thing.
Alan
instead of all this BS why doesn't some one go to the transport dep or the scalies who do checks and hand out the fines and ask them .
for they are the ones that will give reports to our insurance companies on our weights simple
cheers snap
Late last night I posted about the above comment made by Yobarr that shows he has totally misunderstood how a WDH works. His comment relates to a marketing video made by Cruisemaster that I posted a day earlier.
I suggested maybe he made a mistake, and he would like to rethink and revise it. So I gave him a day to do so. But no such response has been made.
In the video (at 1:55) the first obvious thing is that as the bar is being tensioned, the rear end of the tow vehicle rises. No problem with that and most on here agree that is the way it works. That indicates that the load on the towbar has decreased. Not increased as Yobarr's words suggest.
Then, "most larger cars have towbar limit of 350kg ...... How would they handle 510kg?" They don't. Before the bars are tensioned, the towbar load was 185kg. Then when tensioned, the towbar load is actually less, not more. This is because the bars act as levers operating in different ways. The lift from the bars on the car is greater than the download on the van. The net effect causes the rear end to rise. So to suggest that this video is showing that the car has to support 510kg on the towbar just highlights a misunderstanding of how WDHs work.
And "this fella is trying to tell us that his magical WDH has applied 510kg to that hitch". Yes, he is, (actually to the towball where it is being measured). The uplift and download from the bars add together in this case ...... 185kg plus the two opposing forces created by tensioning the bars. So it reads 510kg. That is what it was designed to do. The hitch assembly sees the net load and transfers this net load to the car via the towbar.
Note that I have been careful to distinguish between towball and towbar. They each carry vastly different loads. Also, the few kilograms of weight from equipment has been ignored. There would also be a rotational torque at the hitch.
Before closing I would like to mention that through all these pages the focus has been on static loads. The beauty of the WDH is the way it works in a dynamic situation .... while you are on the road. At this time the effect is stronger the more it is needed. By that I mean that when the van nose puts more weight on the towball, perhaps from a road undulation, the WDH tension becomes greater. That transfers more weight from the back wheels to the front when it is most needed. When the van nose bounces back up, the WDH tension is reduced, adjusting the weight distribution from where it is least wanted to where it is most needed. A subject for another time.
-- Edited by Are We Lost on Tuesday 26th of July 2022 10:48:54 PM
And ask what? There is not much disagreement here on what a WDH actually achieves. It's more about the way it does so and claims of other things that have not been supported.
I have been fascinated with the knowledge of posters on various subjects, especially this one. I have a couple of questions that I hope don't sound too stupid and I am not looking at starting WW3 but here goes.
1. If I have a single axle van and I hook it up to my tug and then notice there is a drop of say 2" in the rear. If I put scales under the van's single wheels and another set of scales under the front wheels of the tug and then placed a jack under the tow ball and hitch and proceeded to lift the tow ball and hitch until I raised it 2". would the scales under the van's wheels and the car's front wheels show an increase? If I also had scales under the jack, when I lifted the tow ball and hitch the 2" would the reading be different than before I commenced lifting.
2. I understand the lever principles of the WDH but does the WDH lift the tow ball and hitch that then results in the weight being distributed or does the lever action of distributing weight cause the tow ball and hitch to lift.
Unfortunately, my physics classes at high school were spent by me either drawing sailing boats or looking out the window at the girls doing PE on the basket ball court. Not too much, if any, was retained of physics.
Unfortunately due to other topics being locked or removed we have lost good links on how the WDH works on a weigh bridge.
Clarky has said it all,
the use of a WDH is not illegal and is beneficial in many instances.
Codagans credentials list him as an engineer.
That is fine. I would be surprised if he had ever used that credential apart from to boost his car sales business.
It appears to me that he will recommend anything if he is paid or there is money in it for him.
HR would not pay for distorted reviews.
HR would get enough distorted reviews from caravan sales people who are anti the WDH
Rivers is a journalist with experience in testing cars for manufacturers in the mid part of last century and has reportedly done some motor homing and caravanning. In other words he was a paid driver with a flair for writing.
His paid testing jobs have never reported caravans or WDH hitches to my knowledge.
His views are only his opinion and are worth no more than anyone elses.
This pic which came from another deleted or locked post says it all.
It shows a demonstration of a front wheel drive car connected to a caravan with a WDH attached and having the rear wheels removed and the operator is driving the combination around on the streets.
This action proves that the weight IS removed from the tow ball and is transfered to the front wheels of the car and probably the rear wheels of the van.
If it didnt do this the tow ball and drawbar would be dragging on the road and the exercise would not work.
Argue on, call it weight or force or whatever.
Claim that a WDH is dangerous or listen to vehicle manufacturers and thousands of users who explain the benefits.
A WDH IS NOT ILLEGAL and if some dont want to use one then fine but dont offer dangerous advice to any newbies on here
because you have your vehicle set up without one.
It is your choice not to use one, nothing else.
Collyn Rivers credentials
DMaxer All scales in your example would show an increase in weight, the one under the tow bar the most.
A WDH is not the same as a ground mounted jack. The spring steel bars are mounted onto the receiver/hitch and tensioned upwards and fixed to the draw bar under tension. It is this lifting force that is responsible for lowering of the original towball weight and puts that weight reduction onto the caravans wheels because the bars are pushing down on the drawbar. The change in weights on the front and rear wheels are due solely to the reduction in tow bar weight.
Alan
Ivan, you are so lost in the WDH wilderness that you should ALMOST be able to sight Alan. For a couple of days I decided to just sat back, taking the view that, like Montie, I'd done as much as I could to help, and let those who know little continue their waffle about WDHs, but your post contains so many untruths that I had to reply. Let's first consider JOHN CADOGAN whose credentials you seem to doubt, which you're entitled to do, no matter how wrong you are. The man is either an Engineer or he is not. However, it must be noted that he is not recommending a WDH, but simply explaining how it works. He shows that a WDH transfers weight FROM the car's REAR AXLE to the car's FRONT AXLE, and to the VAN'S AXLE GROUP. Simple stuff. You then proceed to tell anyone silly enough to believe you that Collyn Rivers is no more than a journalist with experience in testing cars for some manufacturers. This is either a blatant lie or you are totally ignorant of the man's achievements which include designing suspensions etc for car manufacturers, vast travel in Africa, Libya and Australia, and being the author of many books (RV books) on topics such as Caravanning, Solar and Electronics. This all is documented in the list of his credentials posted by Plain Truth ( To call him 'Alan' might cause him to be confused with another member who, despite pages and pages of facts and reference to appropriate sites, STILL doesn't understand that a WDH DOES NOT change towball weight) Thanks Plain Truth for posting this as I have it somewhere but couldn't find it in my records. We now will visit the supplied picture of the car and van. (Oldsmobile?) If you had ANY understanding of a WDH you would know that all it does is create what is essentially a "stiff arm" from the car's front axle, through the hitch point, to the van's axle group. Many times I have pointed out that because of the weight being removed from the car's REAR AXLE there is increased risk of OVERSTEER, which CAN be dangerous. Can you begin to imagine the enormous stresses on the chassis of both the car and the van, as well as on the towbar unit? How you can determine that this means that weight is removed from the towball is beyond any comprehension, and defies both logic and simple physics. Where did all the REAR AXLE WEIGHT go? Spare me! The physics is so simple, but it is concerning that so many don't appear to understand. Seems we have a case of "There is none so blind as he who WILL NOT see". Cheers
This is absolute rubbish, Alan, and I am amazed that you STILL don't understand that a
WDH DOES NOT CHANGE TOWBALL WEIGHT.NEVER HAS. NEVER WILL.
Your total confusion does not bother me but I do despair that your hare-brained 'theories' and constant spruiking of incorrect data is beginning to influence some of our members who have little understanding of weights but who are seeking some sort of reassurance that all is well with their cars. Several of us who DO understand weights etc have devoted much time to helping newbies and existing members with their weights. Your input causes nothing but confusion for these members. Several times we have suggested that you contact HR DIRECT and explain to them that, for 60 years their engineers have had NO IDEA what they're talking about. You no doubt would then post a copy of their acknowledgement of the error of their ways, along with their suitable apology? Cheers