Whenarewethere wrote:

---

A good portion of the problem these days is next to no people can do even the simplest of mathematics, 2+2 = she'll be right "mate" (fidus achates).

 

Only the other day I bought 2 spring rolls & the shop assistant, who was studying at university for a BA, grabbed the phone to add up $1.50 + $1.50. I had the correct "shrapnel" on the counter well before they could find their phone.

 

At least they had the foresight to invest in phone which had a Doctorate, two MAs & triple Emeritus Professorship. I suppose I should be grateful... at least the internet worked in that area!

---

Of course, you're right Jonathan. The inability of some people to do simple maths, think logically, or understand simple physics is regularly a source of frustration to me, but I battle on. Many are the stories that I could relate, including the young lass who grabbed her calculator to find the total cost of 10 items at $2 each. Spare me, and this lot will breed, probably unintentionally. Cheers

Craig1 wrote:

---

                                                       On  mighty LC200, Yobarr your 275mm is only 250mm. And that is to rear of chassis, not the little chassis extension.

---

 It matters not what that distance is, Craig. The point I'm making is that, all things being equal, the seemingly misunderstood McHitch will increase your car's TBO by 125mm, thus mutiplying weight transfer to the car's rear axle and increasing yaw. The universal cure-all WDH further increases the problem. Simple stuff really. All well and good for lazy people with small vans, but with many  cars running at or over their rear axle capacity, the McHitch simply increases your problems. The LC200 is a prime example, with less rear axle weight tolerances than the popular twin-cabs, but the Ram 1500 is even worse, having such a low rear axle capacity that is a joke,IMHO. "Eats utes for breakfast". Yeah, right. Cheers

 

 

-- Edited by yobarr on Sunday 16th of October 2022 02:14:48 PM

-- Edited by yobarr on Sunday 16th of October 2022 02:24:48 PM

Greg 1 wrote:

---

Oh dear old mate. You just can't put it down.
Like a dog on a bone.

If you are happy with the hitch you have good for you but quit rubbishing something that you obviously have done little or no testing of.

After 80,000 kms of towing with a McHitch Autoloader over all types of roads, I think I have some runs on the board to comment, and have to say it is the best damned hitch I have ever used bar none.
Absolutely no additional instability in the rig whatsoever. Period.

Please have a chew on a fresh bone now. This and WDH's have been done to death.

---

 Hi Greg. Could I respectfully suggest that for a man of your undoubted knowledge of weights and dynamics your indefensible stance on this issue is confusing? Surely you are not trying to convince me, and the more gullible amongst us, that adding 125mm to a car's TBO has no effect on weight transfer to the rear axle, and has no effect on yaw? The fact that you have towed 80,000km while using a McHitch means nothing more than that you've towed 80,000km while using a McHitch, but your stance is similar to that of others who waffle-on about travelling a million kilometres towing 3500kg vans with the popular twin-cabs. "Just gotta drive to the conditions mate". Such a "feat" is more a result of good luck than it is of "driving to the conditions mate". Again, I will say I respect your undoubted knowledge and experience in this area, but your indefensible stance on this issue is confusing. Cheers 

P.S Contrary to your assertion, I do indeed have experience with a McHitch, having been given a brand new example by a friend. However, I quickly established its deficiencies when used on anything but a lightweight van, and "donated  it back" to the friend who had supplied it. There is little doubt that it is a good bit of gear, but its inadequacies need to be pointed out to those who have little understanding of simple physics, and weights.

 

-- Edited by yobarr on Monday 17th of October 2022 09:28:02 PM

The photo of the RAM with broken back is pure sensationalism. Have a closer look at the box trailer. The sides are maybe 1 metre high, and appear to be wider than the RAM. Then, the pile of soil in it is about shoulder height, so it could easily be a few tonnes. Then we don't know if it was gently filled or dropped with some huge thump.

As for the Mchitch overhang ....

I agree that the greater the overhang, the more it adds to rear axle weight and decreased stability. But it is certainly not the major impact that Yobarr makes out.

Yobarr, have you actually calculated what difference that overhang makes to rear axle load? It's a very elementary calculation. I'm sure you will have no problem providing an actual example.

Great posts from you once again Greg.

With respect, yobarrs persistent bleating on tow ball overhang on the 200 series and some other vehicles always fails to include the variables in tow ball overhang on the now infamous but still just a tow vehicle, the 79 series.

I was compiling a series of pictures to illustrate the true overhang probabilities of the so called perfect tow vehicle but my current health condition is preventing me from completing this project.
Rather than argue for the other vehicles dimensions my purpose was to point out to the forum that as with the McHitch figure above his quoting of the 79 series TB overhang is grossly misquoted so as to support his agenda.

The variables of TB Overhang is very limited on a 200 series due to a fixed tow bar assembly included in the vehicle manufacture from the factory.

The variables of the TB Overhang on the 79 series is dependant on many different circumstances
.
We have the length of tray or body fitted.
The design of the tow bar which bolts onto to chassis and is manufactured aftermarket.
The length and design of the tongue or hitch which again is hugely variable.
Owner / Operators choice also is a big factor as to the need for actually climbing in and under the body to attend to coupling and uncoupling of the hitch.

Prior to my illness I was actually asking owners of 79 series of their choice of tow bars, tongues, and various hitches and was writing measured figures down but unfortunately I have misplaced my note book during the current upheaval in our van and having to relocate to a more permanent home.

The measurement figures from the centre of the rear wheel to the tow ball varied from vehicle to vehicle on the 79 and for the most part the figures I found on a cross cut sample exceeded the fairly standard dimension of the 200 series.
From what I found Yobarr could be correct with his understated overhang dimension but this short figure can only be achieved by shortening the body and avoiding the common types of tow bar to have something specifically manufactured to suit.
Of course the alternative is to climb under the body to connect and to disconnect the hitch from might be the standard set up.

The excessive overhang on a 79 series can be seen on a regular basis if anyone wishes to actually have a look at any 79 series towing a trailer..
Yobarr may have built his vehicle to obtain a short overhang but we all can rest assured that this figure will not be the normal.

When I find the pics I had obtained from the internet I will post them here but unfortunately I am not physically able to do this at the moment.
So far the info that I found was easily available to anyone that was interested.

Thats a very neat drawing Yobar. To make Yobar feel better and perhaps be able to sleep at night, he is correct, an increase of distance from the centre line of the rear wheels to the trailer hitch point will increase the load on the rear axle, however as in a post I made some time ago on this subject showing the calculations, the increase is insignificant.
Yaw right about yaw, (joke) but again it will vary from insignificant to significant, and could only be measured by dynamic testing, now who's going to do that.
In regard to a short drawbar verses an extended drawbar, its really about the distance from the trailer's wheels to its hitch point, not the length of the draw bar, and I would say the longer the better.
Please Guys go back to sleep.

Gundog wrote:

---

yobarr your problem is you cannot establish 125 or 90mm of additional overhang with acertain type of hitch until you know all the variables.

You assume far to much in almost every post when it comes to Twin Cabs and 3500kg Caravans, likewise 10% towball weight and the tow vehicle must out weigh the towed load.

IYHO what is the difference in stability of 2 identical caravans, say Jayco Stirling 25' except one has a short A frame.

---

 Firstly, anybody who reckons a McHitch increases TBO by only 90mm is living in LaLa land, as the measurement needs to be from the hole in the towbar to the centre of the universal yoke of the McHiitch. As far as me regularly using 3500kg as a standard weight, it would be unrealistic to expect me to do the calculations for every possible weight, so I simply use claimed  tow capacity as the base. Towball weight of 10% is the generally accepted figure if safety is of any concern, but this can vary if the van is a shorter or lighter model, or the tow vehicle is substantially heavier than the van it is towing. Again, it is unrealistic to expect me to cover every scenario on an open forum, although I am willing to help anybody who asks. People seek my advice via PM because they understand that I know what I'm talking about. It is all very well to bleat and moan about my figures, but these are the generally accepted base figures, designed to help people who are willing to learn. There is no one correct response to your last question as there are many variables.

Ian's post acknowledges that increased TBO multiplies weight applied to the car's rear axle, but his suggestion that this increase is "insignificant" is wrong. As an example, putting a 350kg ball weight onto a car with wheelbase of 3180mm and TBO of 1250mm results in 487kg being added to the rear axle of the car. If the TBO of the car is increased by the 125mm McHitch, the weight applied to the car's rear axle increases to over 500kg, hardly "insignificant". Ian also has acknowledged that there is an increase in yaw. All pretty basic stuff really.

Now let's look at Rob's assertions. For the sake of this exercise, we'll assume that the  LC200 has only 1250mm TBO (which it doesn't) but the ridiculously short 2850kg wheelbase means that a 350kg towball weight puts around 504kg onto its lightweight rear axle and is likely to cause that axle to be overloaded if you've got full fuel tanks and a box of beer in the cargo area. "Ah ha, we'll just get a WDH" is the cry, but as well as increasing weight that immediately increases TBO and again multiplies weight applied to the rear axle. A McHitch further increases that weight by 10% or better. In response to Rob's assertion that it is difficult to climb under the tray of a 79 to connect and disconnect the hitch I would like to advise that my car's tray is the standard 2400mm long and has 880mm clearance under it. How much clearance does one man need? It also is well and good to claim that the "variables of TBO is very limited on LC200 series", which may be true if only a lightweight van  is being towed, but once you get to 350kg towball weight a WDH, with its associated increase in TBO, is almost obligatory. And that's before you further increase the TBO with a McHitch. 

Forum members might like to wonder why the manufacturers of at least two very popular brands of caravan no longer supply McHitch as standard. ex-factory but have now switched to DO35, I believe. There is no doubt that a McHitch is a nice bit of gear, used successfully by a very small minority of caravanners, but it has limitations which apparently are misunderstood or ignored by some.

The picture that I initially posted was not drawn by me, but was found on the internet during one of my regular fact-finding missions, as I like to always post only facts. With physics there is no room for opinion. Increased TBO=increased weight on rear axle and increased yaw. Cheers.

P.S Tomorrow I start driving the triple RoadTrain again, working 14 hour days, so probably I will not post for a while although I will have a quick look at the forum now and then. Cheers

P.P.S Stephen, thanks for your comments.

P.S Murray, if you look under the trailer there appears to be only one wheel visible on the far side, and the length of the sideboards would suggest single axle, I'd say. Cheers

 

-- Edited by yobarr on Tuesday 18th of October 2022 11:25:10 PM

iana wrote:

---

Thats a very neat drawing Yobar. To make Yobar feel better and perhaps be able to sleep at night, he is correct, an increase of distance from the centre line of the rear wheels to the trailer hitch point will increase the load on the rear axle, however as in a post I made some time ago on this subject showing the calculations, the increase is insignificant.
Yaw right about yaw, (joke) but again it will vary from insignificant to significant, and could only be measured by dynamic testing, now who's going to do that.
In regard to a short drawbar verses an extended drawbar, its really about the distance from the trailer's wheels to its hitch point, not the length of the draw bar, and I would say the longer the better.
Please Guys go back to sleep.

---

 Well a while ago I posted research by a mob in England and it was dismissed by the usual crowd claiming that it was only valid for English and European caravans where lighter cars and vans dominate, convienently overlooking that cars, aeroplanes, rockets and trucks which use scale models in wind tunnels during their design. 

shakey55 wrote:

---

Taken from another forum

Everyone should take not of this!!!!!

To get an answer and satisfy my curious nature as to the effects of the Weight Distribution Hitch (WDH) on the overhang of the Dmax, I contacted an RMS approved Automotive Engineer and asked him this question.

The manual for my 2017 Dmax dual cab LS-U states that the standard overhang is not to exceed 1377mm. That is measured from the centre of the axle to the centre of the tow ball. At this length, the Dmax is capable of towing 3500kg with a ball weight of 350kg.

My Hayman Reese WDH extends the overhang distance to 1577mm, therefore reducing the allowable ball weight.

Equation: Standard Overhang Distance divided by the Actual Overhang Distance (with the WDH attached) multiplied by the standard ball weight of 350kg.

With the WDH attached, my new ball weight is - 1377/1577 x 350 = 305.6kg

I would advise the owners of any/all vehicles to use this calculation.

Link to that forum discussion

www.newd-max.net/viewtopic.php

---

 Complicated detail for simple calculation. Anybody who thinks that an unmodified DMax can safely tow 3500kg is living in LaLa land, as it has only a 6000kg GCM. However, DMax is a great car that can safely tow up to about a 3200kg van. Cheers

-- Edited by yobarr on Wednesday 30th of November 2022 09:54:17 AM

Land Rover has solved the problem, just play the video in reverse!