Tow Vehicle and Caravan Weight

rockylizard · Guru

Tow Vehicle and Caravan Weight

kesa32 · Senior Member

Hi John , this was exactly my thinking too, thats why we went for our Bailey van with an 1800kg ( upgraded ) atm , to tow behind our diesel Territory ....not perfect weight wise but we did'nt want a larger 4wd for general day to day stuff either.........once we retire we might revisit tugs etc , though for now the combination works great :)

dirvine · Senior Member

Must be a misprint on Dicso 4. 2570 on 1 to 1? Also I have trouble with all these weight things. But i thought a LC and a Disco can tow 3500 providing weight in car is not over.

-- Edited by dirvine on Saturday 20th of May 2017 12:28:47 PM

Mike Harding · Guru

Here's an interesting document:

https://www.sa.gov.au/__data/assets/pdf_file/0003/6375/MR25-Light-vehicle-towing-trailer-regulations-GVM-4.5-tonnes-or-less-8.14.pdf

If there is no manufacturer's spec. on towing weight AND the trailer has electric brakes operated in sympathy with the tow vehicle brakes they recommend 1.5 times the unloaded tow vehicle weight.

I wonder how the physics of this concern apply to semi-trailers?

Edit:
Another interesting read:
http://www.outbacktravelaustralia.com.au/driving-towing-towing/towball-weight-and-trailer-stability

-- Edited by Mike Harding on Saturday 20th of May 2017 01:13:02 PM

Bryan · Guru

I still don't fully understand these various figures. I've always relied on the manufacturers figures but its a moot point as my little Goldstream Explorer ST has an ATM of 2000kgs.

macka17 · Guru

Hey.
The 1 2 1. and 1.5 of unladen tug. are paper figures.
As are the stated figures given by MOST MFG's.

When\as you load rear of tug. and apply drawbar weight to those figures.
The ALLOWABLE towed weights figures all drop.

Quite substantially in some cases.

The only figures anybody should take notice of.
Apart from the fact of keeping both Vehicles UNDER MAX Gross weight.
and Max Combined. For safety and legality.(IE put off road till lightening.)

Is to make sure that,, when loaded and balanced to tow.
The tug. is PREFERABLY around 400kg's MINIMUM. heavier than what it is towing.
I try for 700 to a ton. on larger rigs.
The more the merrier.
IE SAFER your rig is. In unforseen circumstances.

Disco's (unfortunately) have always been dangerously over rated,
on paper.

I had a 3 ltr Patrol.
3.2t max, with tinnie on roof.
THEN bought the Van, and had interior weights to suit the variation of.
NOT the other way around.

DO NOT buy a large van first. Unless you have experience on figures.
You could just be stuck with something you need a US Ute, or a truck to legally tow.
With the Highways starting to get serious.

Basically. Patrol. Landcruiser. 3 ton.
Pretty much ALL the others, a mix of between 2 and 2.5 ton.
Utes the same.
No matter what the paper figures say.
The Highways will sort them out shortly.
Don't be one of them

Smaller rigs.
Just weigh yours, Loaded over weighbridge. Keep under legal limits.
and tow something lighter than yourself. Up to paper figures in Handbook.??
The lighterer the betterer.

Have fun with it.

I've pretty much finished nowadays. Just a coupla fishing dams basically.
So we're sweet.

Baz421 · Guru

Mike Harding wrote:
Here's an interesting document:
https://www.sa.gov.au/__data/assets/pdf_file/0003/6375/MR25-Light-vehicle-towing-trailer-regulations-GVM-4.5-tonnes-or-less-8.14.pdf
If there is no manufacturer's spec. on towing weight AND the trailer has electric brakes operated in sympathy with the tow vehicle brakes they recommend 1.5 times the unloaded tow vehicle weight.
I wonder how the physics of this concern apply to semi-trailers?
Edit:
Another interesting read:
http://www.outbacktravelaustralia.com.au/driving-towing-towing/towball-weight-and-trailer-stability

-- Edited by Mike Harding on Saturday 20th of May 2017 01:13:02 PM

Mike I highlighted the red edit above. I used to work for engineers who calculated this stuff in the early 90's and to me this look the most credible I've seen so far.

John's example unfortunately has kerb weight and ATM in direct comparison, which in real life would never happen (no pax or fuel or laod of any kind and assumes max loaded ATM etc etc) so to me is not very creditable or good reading for novices.

Thanks for link.

Baz

Mike Harding · Guru

Hi Baz

It is an interesting article indeed.

I haven't done much towing (yet) in Oz but when I lived in the UK I towed a large caravan all over Europe including the Alps and the high towball weights here were a considerable surprise to me. In Europe I used an old pair of bathroom scales and a piece of 2"x1" to directly weigh the ball weight so it must have been below 100kg (I cannot recall what it was).

Oz/USA weighs of 200kg+ must give the vehicle rear suspension one hell of a hard time.

Baz421 · Guru

Mike Harding wrote:
Hi Baz
It is an interesting article indeed.
I haven't done much towing (yet) in Oz but when I lived in the UK I towed a large caravan all over Europe including the Alps and the high towball weights here were a considerable surprise to me. In Europe I used an old pair of bathroom scales and a piece of 2"x1" to directly weigh the ball weight so it must have been below 100kg (I cannot recall what it was).
Oz/USA weighs of 200kg+ must give the vehicle rear suspension one hell of a hard time.

Yes I weighed mine too 260kg once and 290kg for ATM of 3000kg and it's fully loaded.

USA suspensions I would hazard a guess and say:

longer spring travel combined with differential rate
longer wheel bases so you don't "feel" the stiffer suspension.

One of the engineers I worked for referred to the stability issue ie the article says positive stability is diminishing oscillations and negative is increasing oscillations as dynamic stability.

Just different terms I assume.

One thing about European vans I (as a casual observer only) have observed is that the vans are lighter, the axle group is more toward the rear and the therefore the rear overhang is less. To my mind all these factors equal better stability.