Caravan weights

Submitted: Friday, Feb 06, 2015 at 20:36
ThreadID: 111022 Views:2342 Replies:5 FollowUps:14
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I'm a bit confused. I have bought a new Coromal, tare is 2043 kgs, ATM is 2665 kgs GTM is 2538. Ball Weight 220kgs. With the van fully loaded (water/gas) etc. the weight is 2540kgs which is ok with GTM but is 95kgs over ATM because ATM is Tare+payload+ball weight. Which weight do i work from on a legal/insurance point?
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Reply By: Shaker - Friday, Feb 06, 2015 at 21:16

Friday, Feb 06, 2015 at 21:16
ATM is Tare plus Payload only!

AnswerID: 545513

Follow Up By: Member - BRAD n JENNY - Friday, Feb 06, 2015 at 21:20

Friday, Feb 06, 2015 at 21:20
That's what I thought also Shaker but according to the AL-KO website it adds ball weight as well.
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Follow Up By: Member - Bigred13 - Friday, Feb 06, 2015 at 21:30

Friday, Feb 06, 2015 at 21:30
ATM is the total weight of the van including tow ball weight
GTM is the loaded weight inc tare ,but not towball weight
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Follow Up By: phil300 - Friday, Feb 06, 2015 at 22:14

Friday, Feb 06, 2015 at 22:14
So ATM is when the van is un-hooked,
and GTM when hooked to the tug,is this correct.

cheers Phil.
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Follow Up By: Member - Rodney J2 - Saturday, Feb 07, 2015 at 11:39

Saturday, Feb 07, 2015 at 11:39
Correct Phil
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Reply By: Member - Rodney J2 - Friday, Feb 06, 2015 at 22:41

Friday, Feb 06, 2015 at 22:41
Hi,
ATM: ATM refers to the weight of a Caravan with its full load when not connected to a tow vehicle = Aggregate Total Mass.
GTM: GTM is also the total weight of the Caravan with its full load, but this measurement refers to the weight of the Caravan when it is attached to the tow vehicle, and will be lower because the tow vehicle absorbs some of the weight (ie the ball load) = Gross total Mass
Ball Load: This is the weight that the Caravan places on the vehicles tow ball.
Now that you have all the weights right for the van are you still within your Tow Vehicle specifications? Your GTM of the Tow Vehicle reduces as you transfer weight from Van onto tow ball, so if your ball weight is 220kg that has to be deducted from the ATM of the tow vehicle.
To get the ATM of van it needs to be disconnected from tow vehicle at the weighbridge.
To get the GTM leave van attached to tow vehicle at the weighbridge, but tow vehicle must be off the weighbridge and van on the weighbridge.
Hope this helps.
AnswerID: 545519

Follow Up By: Member - BRAD n JENNY - Saturday, Feb 07, 2015 at 09:30

Saturday, Feb 07, 2015 at 09:30
Thanks for the help Rodney, when i took these weights the weight bridge was busy and i was unable to detach the van. The van and ute (BT 50 with 3 tonne towbar) together were 4.86T and ute 2.32T, i took one from the other and got the loaded weight of the van at 2.54T would this be close enough for ATM as manufacturers ATM is 2.668T? Alternatively I pick a quieter time at the bridge and do it properly.
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Follow Up By: Member - Rodney J2 - Saturday, Feb 07, 2015 at 10:09

Saturday, Feb 07, 2015 at 10:09
Hi Brad,
For peace of mind I would weigh the van separately to get the actual ATM which should equal or be under the Manufacturers listed ATM on the vans ID Plate. When doing a GTM ie weighing the BT 50 as well you would have to allow for any extra weight that has been added to the BT 50 over and above the Manufacturers rated Tare weight, passengers, luggage, modifications, fuel, water, tools, generators, batteries frigs etc and check that it is still within its ATM. Then combine the weight of BT 50 and Van and that should be equal or less than the GCM (Gross Combination Mass) allowable for the BT 50
Clear as mud?
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Follow Up By: Nomadic Navara - Saturday, Feb 07, 2015 at 10:31

Saturday, Feb 07, 2015 at 10:31
Quote "For peace of mind I would weigh the van separately to get the actual ATM"

Rodney the actual ATM is the figure is the figure on the compliance plate, nothing more or nothing less. The ATM is a limit and not a weight you can measure.

Likewise, when you are travelling at 65 km/h on a road with an 80 km/h limit is the actual speed limit 65 km/h or 80?
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Follow Up By: Member - Rodney J2 - Saturday, Feb 07, 2015 at 11:05

Saturday, Feb 07, 2015 at 11:05
Weighbridges are used to measure weight, if Brad doesn't put his vehicles over the weighbridge how is he tell if he is approaching or exceeding the ATM? To answer your question if the speed limit is 80km/h the speed limit is 80km/h, you can drive at a lesser speed if you like but if you exceed the limit you run the risk of being fined. I check the Speedo in my car to see if I am approaching or exceeding the speed limit
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Follow Up By: Nomadic Navara - Saturday, Feb 07, 2015 at 12:09

Saturday, Feb 07, 2015 at 12:09
Well Rodney, that went right over your head, didn't it. I'm still puzzled as to how you think you can measure a limit whether it be a weight limit or a speed limit.
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Follow Up By: Member - BRAD n JENNY - Saturday, Feb 07, 2015 at 12:49

Saturday, Feb 07, 2015 at 12:49
Well Nomadic Navara you've just shown everyone following this post just what an arrogant pompous ass you are by implying Rodney is of a lower intellect and you of a higher intellect, please do everyone a favour and don't post anymore.
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Reply By: Nomadic Navara - Saturday, Feb 07, 2015 at 10:23

Saturday, Feb 07, 2015 at 10:23
When referring to vehicle weights we have to be mindful of actual weights and weight limits. ATM and GTM are limits, you can't actually measure them just as you can't go out and measure a speed limit. They are declared weights limits that the vehicle manufacturer declares and records on the compliance plate. The following are copy and pasted from "Vehicle Standard (Australian Design Rule – Definitions and Vehicle Categories) 2005."

"AGGREGATE TRAILER MASS (ATM) - the total mass of the laden trailer when
carrying the maximum load recommended by the ‘Manufacturer’. This will
include any mass imposed onto the drawing vehicle when the ‘Combination
Vehicle’ is resting on a horizontal supporting plane."

Or simply the ATM is the maximum weight your can be when travelling.

"GROSS TRAILER MASS (GTM) - the mass transmitted to the ground by the 'Axle‘ or
'Axles‘ of the trailer when coupled to a drawing vehicle and carrying its maximum
load approximately uniformly distributed over the load bearing area, and at which
compliance with the appropriate Australian Design Rules has been or can be
established."

Or simply the maximum weight your wheels can impose on the road when the van is coupled.

The tare weight is something that is weighed, hopefully as the trailer is delivered from the factory. (often only the first one of a particular model is weighed and assumed to be the tare for future models even though extras are added to the van.)

"TARE MASS - mass of a vehicle other than a L-group vehicle ready for service,
unoccupied and unladen, with all fluid reservoirs filled to nominal capacity except
for fuel, which shall be 10 litres only, and with all standard equipment and any
options fitted."

Note, if you order accessories and the agent fits them then they are probably not included in the tare weight.

What generally happens is that the manufacturer weighs the van, both total weight and the weight on the axles. He then declares the ATM to be the total (tare) weight plus 400 kg (or 300 for single axles.) He also declares the GTM to be the weight on the wheels plus 400 (or 300.)

At that time the ball weight will be ATM - GTM. This is the only time that that relationship will be true. Any loading you put on or in the van will effect the ball weight, the effect will depend on where you place the load.

Switched on manufacturers will allow you ask for heavier loadings at the time of ordering and declare ATM and GTM figures to allow you to carry more than what some claim to be the standard load allowance for caravans. Also I stated above the unladen weight of your model of van will have grown since the first one is weighed. If the manufacturer has applied the original tare weight for the model to your unit then the load allowance will be less than you reckon on.

Quote " With the van fully loaded (water/gas) etc. the weight is 2540kgs which is ok with GTM but is 95kgs over ATM because ATM is Tare+payload+ball weight."

I don't get your figuring. The ATM is the figure you see on your compliance plate which you said is ATM is 2665 kgs. The 2540 figure, is that the total loaded weight or the group axle weight (weight on the main wheels?) If it is the total weight then you are 125 kg under the limit.
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Follow Up By: Nomadic Navara - Saturday, Feb 07, 2015 at 10:50

Saturday, Feb 07, 2015 at 10:50
On a second reading through the thread I saw you said "when i took these weights the weight bridge was busy and i was unable to detach the van." You therefore have not supplied enough info for a definitive answer. All you have is the group axle weight of the van. This is less than the GTM so you are OK there. Unless you have loaded most of the weight into the front of the van you will possibly be OK there as well. Vans do tend to load with an increase of weight on the ball but I doubt that you would have increased the ball weight enough to have exceeded the ATM.

You need to do the exercise again to get a definitive answer.

When going to a weighbridge to have the van weighed I always remove the WDH, the safety chains and the trailer plug just before the bridge. I also slacken the coupling and put the jockey wheel on, this way I can lift the coupling clear of the ball and get the total weight easily. You can manoeuvre the van around the bridge at the speeds you travel there without loosing the van (there should be enough weight on the coupling to keep it in place.)
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Reply By: TomH - Saturday, Feb 07, 2015 at 11:31

Saturday, Feb 07, 2015 at 11:31
The figures you get on a weighbridge are "Actual loaded weights" and should not exceed The ATM and GTM that is on the compliance plate.

Ball weight is governed by the tug manufacturer or the limits of the towbar.
Whichever is the lesser.

EG Old ser 80 Cruisers had a 3500/350kg vehicle limit but before 1995 approx only had 2500kg towbars.

That then was all they could tow, so check your towbar stats as well.

Your figures in the OP dont add up and the actual ball weight may well be far different from what you have posted. It will also be an empty weight probably.

Normally it is ATM minus GTM gives you supposed ball weight which in your case should be 127kg.

My Coromal loaded was 2865 with a 300kg actual measured ball weight.

Load rig up as if you are going away Everything in it, food, clothes,tools genny, everything No good having half a load.
Take it to a scale Pull it on with tug off Get figures Gross weight Unhook with jockey wheel on scale get figures Actual loaded weight. Back it up so only jockey wheel on scale get figure. Ballweight

All done unless you also want combined weight then put whole rig on scale with you mum kids everything in both vehicles, full fuel tanks the whole nine yards.

Only way to know true weights. Then go home and chuck out what you dont need to get down to legal weights. Dont laugh we had to LOL
AnswerID: 545535

Follow Up By: Member - BRAD n JENNY - Saturday, Feb 07, 2015 at 11:37

Saturday, Feb 07, 2015 at 11:37
Tom the weights I quoted for the van are loaded ready to travel weights. The ball weight was measured with a ball weight scale
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Follow Up By: Nomadic Navara - Saturday, Feb 07, 2015 at 12:04

Saturday, Feb 07, 2015 at 12:04
"The ball weight was measured with a ball weight scale" Yes Brad, that's the best way to get the ball weight. The modern weighbridges are often only calibrated in 20 kg steps so if you take the up to +/- 20 kg accuracy twice (with two weight measurements) your ball weight will be more accurate measuring it your way if you have a ball weight scale handy.
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Follow Up By: TomH - Saturday, Feb 07, 2015 at 15:43

Saturday, Feb 07, 2015 at 15:43
In answer to your first reply here you are overweight by 2 kg on the GTM and would be over on the ATM as those figures only give you 190kg for ball weight which on a Coromal would be too light.

See my reply with my weights..

Redo it the way suggested to be accurate. Also when weighing the tug you need to have you and the family in it and fuel tanks full as well.
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Reply By: Slow one - Saturday, Feb 07, 2015 at 14:58

Saturday, Feb 07, 2015 at 14:58
Bard & Jen,

I agree the quickest way is to just drive over the bridge so your vehicle is just off it and your van is on it. Just jack off the ball with the jockey wheel and when you get off the bridge yourself ask the operator for a weight, then just drop the van back on the ball.

Give the bridge operators a ring and ask if they have a quiet time to give yourself a little leeway.

I am a touch over my ATM so I had the ATM lifted by a licensed certifier. I just gave him the chassis max weight, axle group max weight and tyre max weights. He came to our house, checked the max weights, took a few photos for the audit inspectors and engraved a mod plate. Total cost $200 and from the time I first phoned it was 2 hours to all finished.

I only wanted 50kg extra but he said lets take it up to the chassis max weight which was up another 150kg.
AnswerID: 545549

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