BasilB wrote:

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"hayman reese engineers" they bleated.


cheers

-- Edited by BasilB on Sunday 11th of February 2024 05:33:29 PM

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 Another well thought-out, and highly intelligent contribution from one who seems to have overlooked the fact that this thread is titled "WDH" and Hayman Reece is a producer of probably the highest number of WDH made. Too complicated for you?

May be too complicated for you, but you are more than welcome to approach HR to point out to them the error of their ways.

Otherwise, you might like to simply look and learn? OR you could try to make an intelligent comment?

watsea wrote:

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Plain Truth wrote:

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 I would be very happy to discuss my calculations with someone from Hayman Reese.  But not worth my time unless they wanted to discuss, and I am not going to approach them. 

However many folk of the normal public would not understand the concepts and lead to dangerous loadings. 
Also I understand for policing TBW compliance, the TBW is taken as a measured weight.  It is pretty hard to measure TBW while the WDH is applied.  So for me, to make sure of compliance, I take a TBW as measured during an unhitched procedure, then making sure my towbar, hitch etc limits are all ok.

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 Watsea,

You are absolutely correct. Measured weight is the reality, finally some common sense.

Unhitch your van, measure the ball weight, compare with the relevant ratings to ensure you are compliant.

It's not rocket science.

Unless like some posters you are the privileged owner of an "assessing scales"

You are correct again Watsea, those nice officers are only interested in measured weights.

Brenda and Alan wrote:

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montie wrote:

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Brenda and Alan wrote:

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I'll say again that Haymen Reece is wrong in their claim. 

Alan

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 So the engineers who designed and manufactured the hitch are wrong!

The reality is it is useless information anyway and cant be measured.

Unfortunately, Alan, it is people like you who confuses the genuine buyer or prospective buyer who is looking for practical information before spending his hard earned on a caravan or motorhome. Forums such as this one are meant to be informative and helpful with genuine practical information, which is the reason I have contributed to this and other forums.

Surely there must be an engineering nerds forum out there where people like you can spruik your gobbledegook.

I suggest you take your argument up with Hayman Reece, I'm sure their engineers will have plenty of time to debate Newton's Law with you! 

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 Its at least 50 years since a WDH was invented probably in a backyard she, what makes you think an engineer was involved.

I would doubt that HR have an engineer on staff, they would most likely use a consulting engineer when required who would only do what he/she is paid to do.

Alan 

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 The Companys Quality Management System has been certified in 1994 to ISO 9001 and proceeded to become QS9000 accredited in 1999. Their testing facility has been certified as a NATA accredited laboratory to AS ISO/IEC 17025 (1995). The Companys Environmental Management System has been certified to ISO 14001 (2001).

again they bleated "hayman reese", but their fallacy was old and their logic poor.


cheers

Gundog wrote:

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Both Alan and Yobarr are wrong ! anybody including HR or whoever can make a statement that TBW never changes, but no one has ever supported that statement with evidence.

Whatever method you use asertain the TBW, the one thing that is neccessary is the van must be level, either using a spirit level or by measurement or both, alas some may just visually do it.

Another thing we can agree on that using a weighbridge it comes with a variation of +/- 20kg, there are different types available multi plate, large single plate and small single plate, all will give you a result which you can work with, you can even calculate an approximate TBW without unhitching.

Then theres the option of portable weighing companies, after witnessing one operator whilst in Brisbane late last year, yeah nah not for me, if you intend to use one of these operators check currency of the calibration certificate.

So in the real world of towing your caravan, is it a possibility that the road conditions can effect the actual TBW whilst driving, lets say driving up or down say Cunninghams Gap with an 8% grade, or driving along the Gore Hwy with its undulations have an effect.

The reality is TBW is an ever changing number what it was 6 weeks ago when you started trip may in fact changed, do you check your TBW every time you hook up bet not, because even your caravan weights change as you consume or replenish its contents.

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 All absolutely correct with the condition that to be compliant your measured ball weight of the unhitched van must not exceed the relevant ratings of tug, towbar or van.

Monty wrote

Now, on the subject of useless information can anyone explain why a van manufacturer weighs the dry empty ball weight and then stamps it on the compliance plate?

The only reason I can see is for someone to buy a van from a dealer and think they can legally tow it away based on that number.

montie wrote:

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 The Companys Quality Management System has been certified in 1994 to ISO 9001 and proceeded to become QS9000 accredited in 1999. Their testing facility has been certified as a NATA accredited laboratory to AS ISO/IEC 17025 (1995). The Companys Environmental Management System has been certified to ISO 14001 (2001).

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 And all this proves they have how many engineers on their payroll. Consider that most manufactures run a chassis design for about 10 years. When a towbar is designed for that chassis it is good for 10 years. How much work would there be for a full time engineer with new design each year. that is why I suggested they would use consulting engineers.

Alan

BarneyBDB wrote:

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Monty wrote

Now, on the subject of useless information can anyone explain why a van manufacturer weighs the dry empty ball weight and then stamps it on the compliance plate?

The only reason I can see is for someone to buy a van from a dealer and think they can legally tow it away based on that number.

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Precisely! As with all things concerning weights in the "under 4500kg GVM" category, it is nothing but deception, based around the common "smoke-and-mirrors" sales methods.  

Anybody who has any understanding of weights knows that listed towball weight means absolutely  NOTHING, Zip, zero, zilch, nil, nada, and is likely a number plucked out of thin air to make it appear that the van involved can be towed by your totally unsuitable car.

Just as some caravans are issued lower ATMs to make them attractive to owners of smaller cars who do not understand that it is perfectly legal, and usually safe, to tow a 3500kg ATM van behind a car with 3000kg ATM towing capacity. Cheers

P.S Was going to elaborate, but I'll see if any responses are received.

-- Edited by yobarr on Tuesday 13th of February 2024 08:47:06 PM

Placing a load cell under the towball in a hitched condition will prove nothing as you will also be getting a read on part car weight. TBW does not change because like the loaded weight of the van, is measured with the van off the car. That load or force that the van is exerting on the towball doesn't change with the fitting of a WDH. All the WDH does is change how the whole car and van weight is supported by shifting some of that weight from one axle to the others. It is a fairly simple concept and I cannot understand why this is constantly rehashed and why it fills up 7 pages of mostly BS. We have those that dislike WDH's, and don't have to use them, and those like myself who like them and wouldn't leave home without one, so how about we finish this pointless discussion right here because it is getting very silly.

Gundog wrote:

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montie wrote:

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Gundog wrote:

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Both Alan and Yobarr are wrong ! anybody including HR or whoever can make a statement that TBW never changes, but no one has ever supported that statement with evidence.

 

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 Gundog, I responded to your post earlier but in hindsight that statement deserves an additional response.

A WDH distributes weight as explained by HR on their website. The system has been tried and proven over many years.

Why, as a dealer, would I need evidence to support HR's statement to prove a piece of useless information....does the ball weight change?

You know what Gundog, I'll take their word for it....am I going to look for evidence? No! I'm busy trying to pay my overheads.

Now, on the subject of useless information can anyone explain why a van manufacturer weighs the dry empty ball weight and then stamps it on the compliance plate?

   

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 Montie,  the operation of a WDH is as you said it distributes weight across the axle groups, but the one thing that I have never found is a a picture or video of a load cell attached under the ball.

 https://m.youtube.com/watch?v=aOKg3IIg7wY&embeds_referring_euri=https%3A%2F%2Fwww.autonovus.com.au%2F&source_ve_path=OTY3MTQ&feature=emb_imp_woyt

 There are a number of YouTube videos on the weigh safe suite of products at some stage I might make time to view them to see if they provide the answer

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 Again Gundog, why would I bother? It's useless information.

montie wrote:

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Greg 1 wrote:

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Placing a load cell under the towball in a hitched condition will prove nothing as you will also be getting a read on part car weight. TBW does not change because like the loaded weight of the van, is measured with the van off the car. That load or force that the van is exerting on the towball doesn't change with the fitting of a WDH. All the WDH does is change how the whole car and van weight is supported by shifting some of that weight from one axle to the others. It is a fairly simple concept and I cannot understand why this is constantly rehashed and why it fills up 7 pages of mostly BS. We have those that dislike WDH's, and don't have to use them, and those like myself who like them and wouldn't leave home without one, so how about we finish this pointless discussion right here because it is getting very silly.

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 What a great idea!

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 ...... someone might want to see "scientific proof" that the finishing of this "pointless discussion", which is most likely agreed to by the majority of readers, is a "great idea".......!!   

And so the endless pedantic stirring  goes on ......

I cant remember if the joke about Murray Walker, the iconic Formula 1 commentator was about racing or the weight and hitch discussions on this forum.

He is jokingly said to have commented one day, when fed up with it all,

Theyre going round and round and round and round again. Is that a change? No theyre just going around some more, and round again and again!

Brenda and Alan wrote:

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I am still waiting for Yobarr and Montie to prove Newton is wrong. I think it will be a long wait considering all space travel is predicated on Newton being correct.

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 We are not saying Newton is wrong, what I would say is that your extremely simplistic interpretation of his laws is wrong.

My engineering background includes many years of measuring and calculating the weight and balance of aircraft, the forces and principles are the same.

-- Edited by BarneyBDB on Tuesday 13th of February 2024 06:46:02 PM

Are We Lost wrote:

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montie wrote:

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Contrary to the belief of some GTM is nothing more than a calculation (ATM minus measured ball weight). No other science or engineering is involved and again contrary to common belief is not IMO an engineered rating. 

Plated ball weight means nothing.......what matters is the measured ball weight of the loaded van.

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 In my case the GTM is the maximum the axle group and chassis, etc will support. This was defined by the suspension manufacturer as the starting point and the van manufacturer's engineer could not allocate a higher rating for the GTM. The ATM was calculated based on that.

When determining ATM, the GTM is the limiting factor driven primarily by the axle group rating. The chassis, coupling, chains, tyres (maybe more) then determine if the GTM needs to be lower than the axle group rating.

Once GTM is defined, the ATM is often a simple "add x kg". Again the engineer making the assessment would need to be satisfied that the rest of the structure supports that ATM.

It would be illogical to calculate an ATM first without knowing what the GTM is. For example, take a hypothetical single axle van plated for 215/65R15 tyres .... typically load rating of 96. What is the maximum ATM? You can't say, but you do know the tyres' maximum load rating is 710kg each, so the maximum GTM would be 1420kg regardless of the axle group rating or chassis strength. Maybe a small chassis section would reduce it further but it could not be increased. Only once you know the GTM can you specify the ATM.

Apart from that I agree that towball weight on the plate is useless, and probably misleads numerous buyers and owners, except for the occasional one that lists maximum towball weight.

-- Edited by Are We Lost on Tuesday 13th of February 2024 05:39:52 PM

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 You are confusing Axle Group Rating with GTM.

Axle Group Rating is an engineered rating set by the chassis/suspension manufacturer and one important rating when setting van's ATM.

GTM is a calculation done by the van manufacturer as explained earlier, probably when he's having a beer after work.

VSB defines GTM as the weight transmitted to the ground via the axle group when the van is level excluding any towball weight.

It is a matter of contention whether GTM is a rating....IMO it is not, others may disagree.