Chassis Vehicle Towing Mass Guide - 2014 Updated

Jun 12, 2011
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Brisbane
#21
Yeah, from a salesman's point of view you'd think the risk of being sued would have removed all doubt about what is and isn't legal. All fun and games I guess!
 

Mat

New Member
Aug 13, 2014
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Ayr Qld
#22
I've looked at 6 or 8 different sites and I still can't find an unambiguous answer to my latest question: For the "legal towing mass" of the tug, are we concerned with the ATM or the GTM of the trailer? e.g. with a 2500kg rated towbar, can I tow a van with a GTM of 2500kg and ATM of <2750kg? This is what a van salesman seemed to be telling us recently, and when you consider that the towball weight gets included in the tug's GVM, it does only seem fair that you don't count the same weight twice by adding it to the total of the "towing mass."

I'd always assumed it was the ATM you went by, and the Towing Guide (p.2) says ATM, but it then mentions "including the towball mass/download rating". (Sorry, it won't let me cut and paste from the document).
I have been wondering the same thing.
I asked my local Jayco dealer this question and this was his reply
"The GTM is the weight that you need to look at with towing , the GTM is calculated by subtracting the Ball weight from the ATM
So as long your tow vehicles towing capacity is above GTM you are meeting all legal requirements ."
I am sure he would have been asked this question 1000 times so I am assuming he knows what he is talking about.
 

Gadgets 21.63.1

aka - adam 18.57.9
Jun 29, 2013
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mornington peninsula victoria
www.bifolds.co
#23
atm is the total weight of the van including ball weight as we all know, however this is the weight that your tug can tow. so if your atm is 2750 and gvm is 2500 and your tug can only tow 2500 with a ball weight of 250kg, then you cannot tow the van. the ball weight is not a weight that is added to your max towing limit. if you can tow 2500kg, then that is the total weight including ball weight you can attached to your tug. if you have a pajero, then 2500kg with 250kg ball weight means still only 2500 total on the tug, they are also rated at 3000, however only with a 100kg ball weight at this load, but this 3000kg is still the max you can put on the ball in total, it just means that the down force ball weight cannot exceed 100kg at this weight.
 

twscoot

Well-Known Member
Jun 9, 2013
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Brisbane
#24
I agree with Gagets (except the ball weight for a Pajero towing 3000kg drops to 180kg not 100kg).

ATM is the figure to look at.

When I was looking for a replacement van I found many salesmen (not with the Jayco dealer I have bought my three vans from I might add) have no idea and will unfortunately say anything to get a sale.

Usually this surrounds the poor soul who has a car (like I did when I owned the Pajero) which is close to the towing capacity of a van they are interested in but in fact not close enough making it illegal.
 
Likes: skippy
Jun 26, 2014
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#26
The reason the salesman says GTM is because if by chance your rig gets stopped at a weigh station they weigh the van on the car. They are concerned about the GVM... Gross vehicle mass. If your rig and car exceed this they then weigh the van separately but still attached to the car which gives the vans Gtm. Insurance uses the ATM. It is the insurance we need to be concerned about. Hope this helps.
 

fishinglizard

Active Member
Nov 4, 2012
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West of Sydney East of Lithgow
#27
The reason the salesman says GTM is because if by chance your rig gets stopped at a weigh station they weigh the van on the car. They are concerned about the GVM... Gross vehicle mass. If your rig and car exceed this they then weigh the van separately but still attached to the car which gives the vans Gtm. Insurance uses the ATM. It is the insurance we need to be concerned about. Hope this helps.
yup its clear as mud

The other thing I don't understand and a bit off topic, my friend has a van, not jayco, the company obviously has the chasis built off site and they put the van on top. Now his chassis has a compliance plate state max load on chassis is 2750kg. So the company that make the van put his plate on the van stating max load 2450kg, so if its built on a frame designed for 2750 then wheres his other 300 kg gone? and how did they work that one out? the way I see it an empty chassis with wheels and electric brakes is just a big trailer put what you want on it up to 2750? It does my head in.
 
Jun 26, 2014
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#28
All the van companies are the same... I actually asked my jayco dealer if I could make my ATM up to the axel loading if I wanted to and he said I could. Like you, I can't understand why they don't just do it in the first place.
 
Likes: Bmhdg76

Bluey

Well-Known Member
Mar 31, 2014
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victoria
#29
Dont know if this thread is the right place for this but jayco are now putting on there plates a max ball weight of N/A
Not Applicable its now up to us and how we load our vans to keep them under we can no longer say but my plate says X amount this would be on new vans....... i think so many of there vans are over what they state they have given up ...... next there atm will be you weight it cause we are probably wroung
 

Dobbie

Well-Known Member
Jun 18, 2014
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#30
All I can say about this is.......we're currently sourcing a new van and salesmen look at us askance when we ask specific questions such as
  • What is the likely GVM?
  • What is the likely tare?
  • What is the likely tow ball weight?
  • How will these be affected by any inclusions we're looking at
  • What is the axle rating?

Answers: we'll have to get back to you as we aren't sure

And then: when can we expect delivery?

Again....its dependent on the factory.

At least, with jayco the answers were within reaching distance. But not so with many others.

Not one salesman has asked us yet which vehicle will be towing the hypothetical van....and they can't tell as we turn up in a much smaller vehicle.

I rest my case!

But I am seriously concerned by the lack of duty of care!

Don't even mention the phone calls not returned.

My tent is starting to look very attractive.

8-)
 

Bluey

Well-Known Member
Mar 31, 2014
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#31
A camper trailor is much lighter and cheaper but more hassel sell my van bank the cash 10 grand on camper trailor mmmmmmmmmmm not ............. well not now anyway but never say never
 
Likes: dagree

millers

Active Member
Mar 25, 2011
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Adelaide
#32
To my mind n/a on the trailer / van for max ball weight is the correct way to go. A trailer / van design should allow for a significant margin in the A frame to have no practical limit on the tow ball weight that the A frame can transfer to the tow vehicle. The car (tow bar) manufacture should be the one that is limiting the tow bar weight or modifying the amount you can tow.
Another way of putting it is a van / trailer manufacturer placing a max ball weight on the van is essentially saying that if you go over that max (plus safety margin) you will break the van (the chassis to A frame connection and the A frame can not handle a ball weight over that value).
Now I know you can find lots of pictures where A frames have been bent or broken, but I would suggest that the van / trailer has been un-realistically overloaded or modified.
Also consider that the ATM / GTM etc of the trailer van should be set at their design limits (plus safety margins) and that it is the person towing that is responsible for making sure that when hooked up the weights are within limits of both the tow vehicle and the van.
For example if I am towing an empty van with a tare of 2900 and an ATM / GTM greater than 3200, than as long as I check that it is less than 3000, I can tow it with a vehicle that has a tow limit of 3000 (plus working out the ball weight limitations etc). By the way if I was to do this I would also have the van weighed and carry the details.
Limits need to apply to the product that they are associated with. When combining two items then you need to meet the limits of both with the actual values not the max limits.

My thoughts
 

Dobbie

Well-Known Member
Jun 18, 2014
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#33
And many of the upper limits of the van weights are actually determined by the axels, wheels etc and very difficult to establish before you order / buy the van.

I totally agree that limits need to be applied....but few seem to know them, let alone follow them.

Eg....one van we've been considering has a tare of 1780 and an ATM of 2050 which gives a payload of 270. When considering add ons that we want..probably around the 50kg mark, then full gas and full water tanks (total 200) that leaves us with 20kg for everything else.

Not enough.....so we contacted the builder to ask for payload increase but, eventually, the answer came back that it wasn't possible as axles are rated to 2000. ATM listed is 2050.

This is an off road model, designed and set up for free camping but not suited to that.

Their answer/ solution is to empty at least one of the water tanks!

Or tow with an overloaded setup.

I looked at an oztent setup this morning ....shame I can't convince myself that it's an option as we gave that up years ago.

And I've just been listening to the grumbles about census privacy issues from a generation who live on Facebook, Instagram etc etc where everything is out there!

(I've got the grumbles today....more so than usual)

:biggrin-26:
 
Likes: Bluey
Jun 3, 2015
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Leeming / Perth
#34
And many of the upper limits of the van weights are actually determined by the axels, wheels etc and very difficult to establish before you order / buy the van.

I totally agree that limits need to be applied....but few seem to know them, let alone follow them.

Eg....one van we've been considering has a tare of 1780 and an ATM of 2050 which gives a payload of 270. When considering add ons that we want..probably around the 50kg mark, then full gas and full water tanks (total 200) that leaves us with 20kg for everything else.

Not enough.....so we contacted the builder to ask for payload increase but, eventually, the answer came back that it wasn't possible as axles are rated to 2000. ATM listed is 2050.

This is an off road model, designed and set up for free camping but not suited to that.

Their answer/ solution is to empty at least one of the water tanks!

Or tow with an overloaded setup.

I looked at an oztent setup this morning ....shame I can't convince myself that it's an option as we gave that up years ago.

And I've just been listening to the grumbles about census privacy issues from a generation who live on Facebook, Instagram etc etc where everything is out there!

(I've got the grumbles today....more so than usual)

:biggrin-26:
Correct me if I am wrong but doesn't the ATM of the caravan include ball weight and Tare is just the weight of the caravan empty. So a tare of 1780 and an ATM of 2050 which must include the towball weight? This is assuming the ball weight is approximately 10% of the ATM so would mean there would be no room for extras at all. Maybe I'm confused.
 
Likes: Bluey

Dobbie

Well-Known Member
Jun 18, 2014
3,061
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#35
My understanding...can always be wrong....is that ATM is the measured weight of the van (no gas or water) as it leaves the factory.

Different ATMs depending on options etc.

Towball weight is measured separately and influenced by how things in the van are distributed and balanced but the 10 pc is a rough guide only. A range is given on the compliance plate...eg empty 173, max 208 in our case.

Then the tare is the ATM less the allowable payload and influenced by axle weights allowed.

In the case of our jayco:

Tare was 1817
ATM was 2172

And so max payload was the 375 common to the outbacks.

Ball weight affects the allowable payload on the towing vehicle ...deducted from the total, along with vehicle extras such as bull bars, tow bars, etc and passengers and is taken from the vehicle manufacturers, as listed in that published table earlier in the thread.

It's an absolute minefield!

As said, I could be wrong and can stand corrected but that's my understanding of it.

(I did do a spreadsheet to help make sense of it on an earlier thread)
 

Base23

Well-Known Member
Jan 17, 2016
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Adelaide
#36
I think this explains it well.

GLOSSARY OF TERMS

ATM (Aggregate Trailer Mass): The mass of the laden caravan when carrying the maximum load recommended by the manufacturer ā€“ including water, luggage, the lot. This includes both the mass resting on the wheels of the van, and the mass resting on the towbar of the tow vehicle. This figure must not exceed the rated towing capacity of the tow vehicle.

GTM (Gross Trailer Mass): Almost the same as the ATM, but always a lower figure. This is what rests on the rig's tyres, but does not include what rests on the towbar when coupled to a tow vehicle. Like the ATM, it includes the maximum carrying load recommended by the manufacturer. This figure must not exceed the rating for the axle group (wheels, tyres, suspension and axle) specified by the chassis manufacturer.

Tare: Effectively the "empty" weight, this is the mass of the van with all OEM equipment fitted, but with no luggage or personal effects on board, and with empty water tanks. This is what a van weighs when it leaves the production line. Like the ATM, but unlike the GTM, it combines the mass that rests on the tyres and the mass that rests on the towball.

Ball weight: The ball weight (or ball load) is the load (or force) exerted on the towbar of the tow vehicle. The ball load should always be eight to 15 per cent of the ATM. Vehicle specifications include a ball load figure, although it is not generally as easy to find as the rated towing capacity. A van should always be loaded with any heavy items near the axle, and not at the extreme ends where they will alter the ball load.

Load-carrying capacity: The total permitted load that may be legally carried in the van ā€“ your water, luggage, food and the like. Subtract the Tare from the ATM and you have the load-carrying capacity. Any options or accessories not included in the Tare will obviously reduce the load-carrying capacity available for luggage and personal effects.
 

Dobbie

Well-Known Member
Jun 18, 2014
3,061
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#37
Yes, it explains the terminology in respect to van weights but not the relationship between these and the rated capacity of the tow vehicle.

That's what the detailed list concentrated on...so, IMHO, the two should be combined to make complete sense of the effect of the van weight, the towball weight and the specs of the tow vehicle.

So GCM is a critical figure, as is the payload impact of both van and vehicle.

Don't want to open another can of worms but it's the combination that must be considered and that's the point of the list as published at the beginning of this thread.

I'm never happy when I see a smallish vehicle towing a behemoth with all the bells and whistles.....not that anyone here would do so, but thousands do.

:faint:
 
Likes: Drover

Drover

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Nov 7, 2013
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Cooloola Coast, QLD
www.expandasdownunder.com
#38
I love these conversatations where everyone gets tangled up, imagine what it's like for a truckie ?????? What @Base23 pointed out in his glossary of terms helps things out quite well I think, basically look at what the GTM is, thats the weight of your van that the Scaly is interested in, now delete the ball weight (actual not dream time plate stamp) from the tug carrying capacity, that will show you how much you have left to put into the tug, don't forget to add fuel to the equation, now the delete the tugs loaded weight from it's GCM, whats left tells you the weight of the van you can carry............................3.5t tow cap usually means 2.8t tow cap in reality............

Now if you want to get really techo find out what the axle weight is for your tug....
 
Likes: dagree
Feb 29, 2016
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#39
For example if I am towing an empty van with a tare of 2900 and an ATM / GTM greater than 3200, than as long as I check that it is less than 3000, I can tow it with a vehicle that has a tow limit of 3000 (plus working out the ball weight limitations etc). By the way if I was to do this I would also have the van weighed and carry the details.
Iā€™m doing the same. My ATM is 3199 but I can only tow legally 3000. My weighbridge ticket comes in at 2900.

But I can tell you there is so much misinformation around on this topic.