Tow Ball Weights

Pradokakadudavid · Senior Member

Tow Ball Weights

yobarr · Guru

Pradokakadudavid wrote:
This question is for Yobarr as you have assisted me with weights etc before but all feel free to dive in.
Please all be patient and gentle with me in answering this question as I have already been abused and belittled on the Y62 Patrol Modified Action Site for exploring a simple question.
Ok I have had my caravan and Y62 Patrol for three years.
Weighs are:
Y62 Patrol - GVM 3500.
Max TBW 350 (I never get near this).
GCM - 7000
Caravan GVM - 3500.
I have been discussing caravan and 4 wheel drive weights for several years and although I have used weigh bridges to weigh my 4x4 and my own scales to weigh the caravan, I am finally going to bite the bullet and get the whole rig professionally weighed.
And yeah I know I should have done this three years ago but I have always been reasonably confident (or naive) that my weights are ok.
The only reason I am panicking is that I am finally venturing up to the north of WA and need to fill my water tanks which I don't usually need to do for caravan parks.
The question is about tow ball weight and I am seeking a simple answer that I can understand (as simple as me!!!!)
My fully loaded caravan is 3200kgs without being attached to the 4x4 (no water).
This means the TBW when caravan is attached to 4x4 is approximately 300kg ( I have weighed this with my own TBW scales). Note the caravan has been manufactured to lessen TBW.
My understanding (or lack of) from what people have suggested (during their abusive belittling) is that you only count TBW once and usually this is added to the GVM of the tow vehicle.
My stupid question is: If I count the 300kg TBW in the 4x4 GVM, does this 300kg then come off the GVM of the caravan? This is what some people have suggested but I can't seem to get my stupid head around it.
What I want to know is what does the caravan weigh when attached to my 4 x 4.
As Pauline Hansen says, "Please explain".
As my Patrol is bordering on maximum GVM once caravan with water is attached, I have decided to add a minor GVM upgrade to the Patrol to give me an extra 200kg GVM (and yes although stupid, not stupid enough to realise that this does not increase my GCM which remains at 7000kg).
Please explain (with acknowledgement to Pauline Hansen!)

Hi David. The weight of your fully loaded van is 3200kg, and this does NOT change when you hook it up to your car.
When the van is in your garage, or whatever, the 3200Kg is supported by the jockey wheel and the van axle group.

When you connect the van to the car the jockey wheel weight then becomes your towball weight, (300kg) and becomes part of the car GVM.

However, the weight on your vans axle group (GTM) remains constant at 2900Kg. (3200Kg total weight minus 300Kg towball weight). IF you were to then add 300 ltres of water to your van you still would be legal and safe PROVIDED that your van has an AGR (Axle group rating) of 3200Kg or more.
This figure can ve found on your can compliance plate, usually in front boot.

BEWARE:- GVM upgrades as they are next to useless on tow vehicles. Your car already has a great rear axle carrying capacity of 2030Kg with 1650Kg on front.
Without having the exact figures at hand, all I can say is that unless the GVM upgrade substantially increases rear axle capacity it is a waste of money.

It seems that you already are in WA, as am I. If so, where abouts are you at the moment?
This can get very complicated thing to deal with, and you will get all sorts of "help" from people with a vested interest, but if you wish to make a list of questions and PM me a contact number I can call you to help, as I have with several members who had already been given well-intentioned but incorrect advice. Cheers

P.S Unfortunately your wife is incorrect about Voila. see below! Cheers

-- Edited by yobarr on Sunday 16th of July 2023 06:28:39 PM

Are We Lost · Guru

I agree pretty much with what Yobarr said, with a couple of small tweaks.

You said the van GVM is 3500kg. I assume you mean ATM ... Aggregate Trailer Mass. This is the maximum the van may weigh when disconnected from the tow vehicle and resting on the jockey wheel.

Then there is GTM ... Gross Towing Mass. This is the maximum weight of the van wheels on the ground when connected to the tow vehicle.

GVM... Gross Vehicle Mass. This is the maximum weight of the tow vehicle wheels on the ground. This rating is not relevant for vans. However, in NSW and maybe other states, there is no provision for recording ATM or GTM for vans. So the GTM is recorded in the GVM field and the ATM not recorded at all. Due to ambiguity in the wording of legislation and other documents, many vans have their ATM recorded in that field instead of GTM. The compliance plate should show both these ratings.

Now with those definitions out of the way, let's have a look at your situation.

You say the van when loaded would be about 3200kg total weight. So, assuming the ATM is 3500kg it is 300kg under the limit.

You say you run close to Y62 GVM when the van is connected. So let's assume the Y62 weighs 3100kg when fully loaded but not connected. You are 400kg under the GVM. Now, when the 300kg coupling of the van is dropped onto the towbar you have ....

Total weight of Y62 on wheels now = 3400kg (3100kg + 300kg). You are 100kg within GVM of the Y62.
Total weight of Van on wheels now = 2900Kg (3200kg - 300kg). You have not stated what the GTM is to confirm that this weight is within that rating.
Total combined weight = 3100 + 3200 = 6300kg. Well within the GCM of 7000kg.

If you add water (say 200kg), most of that would be added to the weight on the van wheels, and a small amount to the towball weight (important: that assumes the tanks have been positioned fairly centrally). So the Y62 should still be within GVM. It depends what your van GTM is. I believe this is the critical rating to confirm. Apologies if the 3500kg you quoted is actually the GTM, in which case you would be well within.

Note that ATM, GTM, GVM and GCM are all ratings. They don't change with loading. It is better to NOT refer to actual weights using these terms. Often you will see it written that way but that does not make it correct. Also, don't confuse Axle Group Rating (AGR) with the van GTM. They are often the same, but not always. GTM is what you need to measure against.

Are We Lost · Guru

Just a followup to the above post, Yobarr mentioned the excellent 2030kg rear axle limit on the Y62. Yes it is, but the weights you are talking about here may well be pushing pretty close to that limit.

My Ford Ranger has 1850kg rear axle limit, and when fully laden for travel I can't take the extra fuel and water that I would like, because it would go over that limit. Yet your Patrol will have a lot more weight than mine. Weight on the towball, adds close to 150% of that weight to the rear axle. So that 300kg probably becomes 420-440kg additonal load on the rear axle.

If you measure the towball to rear axle distance it is a simple ratio with the wheelbase to calculate that load.

Possum3 · Guru

G'day David,
I drive a very similar rig to you (Y62, series 5 Patrol, towing Evernew E 900, ATM 3500).

Let's get down to basics without using the confusing terminology. As explained above by Chris, you are within your maximum allowable legal limits - on supplied weights you can be confident if/when you get pulled over by Mermaids (those with scales).

Being "Legal" doesn't seem to be your main worry, I suspect that you have a little uncertainty about the "Feel" of your rig. This is natural and common with the Y62 as it's raw power is unsettling particularly with a six and a half meter long "dual axled brick" hanging off the end.
Your rig won't handle like an XK120, which is a good thing, in that it is a constant reminder of the fact that your 7 tonne juggernaut needs to be driven in a safe manner.

Attached link to Caravan Council technical information and checklists may help you with your deliberations. www.caravancouncil.com.au/technical-articles

yobarr · Guru

Possum3 wrote:
G'day David,
I drive a very similar rig to you (Y62, series 5 Patrol, towing Evernew E 900, ATM 3500).

Let's get down to basics without using the confusing terminology . As explained above by Chris, you are within your maximum allowable legal limits - on supplied weights you can be confident if/when you get pulled over by Mermaids (those with scales).

Being "Legal" doesn't seem to be your main worry, I suspect that you have a little uncertainty about the "Feel" of your rig. This is natural and common with the Y62 as it's raw power is unsettling particularly with a six and a half meter long "dual axled brick" hanging off the end.
Your rig won't handle like an XK120, which is a good thing, in that it is a constant reminder of the fact that your 7 tonne juggernaut needs to be driven in a safe manner.

Attached link to Caravan Council technical information and checklists may help you with your deliberations. www.caravancouncil.com.au/technical-articles

Thanks Possum, for your support. When answering questions I try to keep things as simple as possible without omitting important details. David initially referred to his 3500kg all-up weight as GVM, so I continued with that. Always there will be someone who argues trifles, confusing others, which is why I do most of my work via PM, as I previously have done with many, and now with David.

Interesting theory you have about the Y62 handling! Davids caravan actually gets lower towball weight with full water tanks, but we are going to work through that after his official weighing exercise on Friday. Take care. Cheers.

Pradokakadudavid · Senior Member

Thanks everyone for your responses.

I think I feel better now and the confusion is easing (I think).

Yep no doubt the Y62 is a beast of a tow vehicle and it tows in a very stable manner with no wobble etc etc.

Although it would easily break the speed limit by a long shot, I try to travel at 90-95ks per hour as this give me the best fuel economy.

As said by Yobarr, once I get a more accurate picture of weights once professionally weighed I will have a clearer picture of what is going on.

I will let you on know what the outcome is.

As already said, it is only when I put 220kls of water in the tanks that I get anywhere near max caravan weight hence the weighing exercise for my trip up north.

Have a great week everyone.

Cheers.

David

PS: Possum - I can recommend (from personal experience) you fit a heavy duty transmission cooler and scan gauge to your Y62 to decrease transmission temps and monitor transmission temps (assuming you have not already done this).

Several Y62 owners (including me) have had significant transmission slipping issues, probably caused by excessive heat build up in the transmission.

A heavy duty trans cooler is an inexpensive insurance policy to prevent this from happening.

Possum3 · Guru

Thanks David; I had heard of overheating transmissions, Nissan in Rockhampton said not in my model, although I monitor this pretty closely.

Pradokakadudavid · Senior Member

Possum let me assure you that Nissan deny all responsibility for their "f---- " transmissions.

I can't believe Nissan told you that this gearbox problem was with previous Y62 models as the S4 and S5 are identical apart from some minor headlight and trim changes.

There is sooooooooooo much evidence of these transmissions failing on Y62 sites (that Nissan still deny even though I have cut and pasted them owner responses).

Your engine and transmission in your S5 is identical to mine.

S5 owners have also had these trans failing issues.

It was only after 6 months of evidence, advice from CCC, consumer affairs and videos of the breakdown in action, that Nissan finally agreed to replace the transmission under warranty.

And then the "new" transmission" failed in exactly the same manner.

I had many conversations with Y62 owners (S4 and S5) on Y62 websites about these failures.

Whilst it was clear that not every transmission will fail, the insurance of this extra transmission cooler cannot be over exaggerated.

It was only after some serious software upgrades and the heavy duty trans cooler (from Wholessale Automatics) that the problem seems to have fixed itself.

Wholesale Automatics claim the thermostats in the standard Y62 trans stick hence preventing fluid from being cooled and I have heard this from many sources.

Do not believe anything a car salesman tells you about their transmissions as they have obviously been instructed from above the refute claims of the weakness of this transmission.

If I end up buying a new S5 (or wait for the Y63!!!!!) the first mod I will make will be a new heavy duty trans cooler and valve body.

Considerable research from auto trans mobs have shown these parts on the Y62 trans fail.

Good luck and thanks for the advice.

Cheers David.

Gundog · Guru

The question is why is the transmission overheating, is it because you are towing in the wrong gear, it should not be in Drive.

The other factor to big a transmission cooler, might not allow the trans fluid to reach the correct operating temp, therefore that could cause some damage.

One could say poor driving decision that cause the oil temp too high and then fitting an oil cooler maybe a band aid.

yobarr · Guru

Gundog wrote:
The question is why is the transmission overheating, is it because you are towing in the wrong gear, it should not be in Drive.
The other factor to big a transmission cooler, might not allow the trans fluid to reach the correct operating temp, therefore that could cause some damage.
One could say poor driving decision that cause the oil temp too high and then fitting an oil cooler maybe a band aid.

Unfortunately Graham, I think that youre flogging a dead horse because what you say is not what people want to hear.
You are, of course, absolutely correct with your assertion, but there is none so blind as he who will not see.

Using a lower gear often is better for the transmission, and also results in better fuel consumption figures because the engine is running a lot more efficiently.
The Roadtrain that I currently drive has a 650hp engine, and weighs well over 120 ton.
When loaded, rarely do I use top gear because to do so means that the engine often is labouring, with an associated increase in fuel consumption, whereas if I drop down one gear the engine runs more freely and uses less fuel. Cheers

Lower revs does NOT mean less fuel usage. Cheers

Pradokakadudavid · Senior Member

I always tow in manual mode to keep the revs above 2000rpm otherwise the vehicle labours.

HandyWalter · Senior Member

What all the discussion here highlights is that the car is not fit for purpose. If it cannot tow 3.5T without issues or modifications, then it should be sold with printed specifications of what it can tow straight off the showroom floor under all condition, not just the "ideal". I wonder how well JEEP will now go given they have reduced their towing capacity with the new models. FWIW, my car does not overheat towing and I never select anything but D when towing. The electronic smarts of the vehicle soon work out what gear is needed.

yobarr · Guru

HandyWalter wrote:
What all the discussion here highlights is that the car is not fit for purpose. If it cannot tow 3.5T without issues or modifications, then it should be sold with printed specifications of what it can tow straight off the showroom floor under all condition, not just the "ideal". I wonder how well JEEP will now go given they have reduced their towing capacity with the new models. FWIW, my car does not overheat towing and I never select anything but D when towing. The electronic smarts of the vehicle soon work out what gear is needed.

Hi Walter. Until there are changes to the way tow ratings are issued there will continue to be thousands of people conned into believing that their twin-cab buzz box, among other vehicles, can safely tow a 3500kg ATM van. They cannot do that when towing a PIG trailer. Simple.
When challenged, the manufacturers "out" always is that their product can indeed tow a trailer with the claimed ATM, but the trailer/van MUST be a DOG trailer.
The vast majority of caravanners would not have the slightest clue what the difference is, which is why we see so many setups such as this. "All legal mate".Yeah, right. You gotta be joking!

The other picture shows the ONLY way these little buzz-boxes can safely tow 3500Kg. Cheers

Gundog · Guru

HandyWalter wrote:
What all the discussion here highlights is that the car is not fit for purpose. If it cannot tow 3.5T without issues or modifications, then it should be sold with printed specifications of what it can tow straight off the showroom floor under all condition, not just the "ideal". I wonder how well JEEP will now go given they have reduced their towing capacity with the new models. FWIW, my car does not overheat towing and I never select anything but D when towing. The electronic smarts of the vehicle soon work out what gear is needed.

Hi Walter, most 3.5t caravans are not fit for purpose because fillings water tanks becomes prooblematic and that's the start, just like 3.5 tonne rated tow vehicles, yes they can tow the weight legally, but they start to run into problems once you load both ute and caravan.

Evidence is shown that marketing and engineering are not on the same page, example the advertising blurb for the launch of RAM 1500 in Australia, said it can tow 4.5 tonne, yeah right that was proven wrong by a number of factors. Other vehicles brands run into the similar issues. Then look at the popular twin cabs if the human element, could understand that every piece feel good equipment, like side steps, canopies, drawers etcetera all add non essential weight, hence the need to get a SSM to proform a GVM/GCM upgrade.

Your choice of tug and caravan, fit within the spec's hence no problems, but choosing to just put it in D when towing and let the computer work it out, you say your disco does not overheat when towing, do you have a temp gauge for the transmission? With your combination you may get away choosing to tow in D and never have an issue, but then one day it might just bite you on the arse and cook you tranny half way up a big hill. All that being said you maybe right, but what does your owners manual advise when towing?

So the answer for most punters who have seen elevated trans temps the solution is to fit oil coolers, lock up kits etc, rather than learn to drive because they are basically lazy, I have a manual yes I could put it in top gear use the cruise control, make a gear change when necessary, but that would cause evaluated fuel consumption, and possible damage top gear, however using the 1:1 gear without cruise control gives me advantages greater fuel economy and better control of the combination.

-- Edited by Gundog on Wednesday 26th of July 2023 03:52:09 AM

HandyWalter · Senior Member

Yes Gundog, I have a GAP ID Tool and it can (and I do use it) Auto Temp, EGT temp etc.
Only advice straight from owners manual is

"The diesel engine management system incorporates sensors to determine optimum performance. It is also designed to protect the engine when arduous conditions are encountered during towing. When ambient temperature exceeds 40°C (104°F) the engine coolant temperature may increase above normal operating level. If this occurs, the management system will initiate a series of actions to restore normal operating conditions.

The actions may include:

A message centre message.

Engine performance reduction.

Air conditioning system cycling. The system temperature output will fluctuate between hot and cold in order to dissipate engine heat.

"To avoid overheating the gearbox, it is not advisable to tow heavy trailer loads at speeds of less than 32 km/h (21 mph) in High range. Select Low range instead."

A few years ago we went from Melbourne to Port Augusta when the temp was 45C. Climbing the hills I was a bit concerned. But as soon as the temps rose the car automatically changed to lower gear, (in fact it felt like it was in limp mode), Fan went to max boost and suddenly the temps started reducing. Once they dropped the car started to change gears up and speed accordingly. When I got car serviced next (respected Indy) he said the car has electronic smarts to a) know you are towing, b) selects the correct transmission mapping, and c) instigates measures to protect the running gear. I have never heard anyone with a D3 or D4 having to have tranny coolers or bigger radiators. As I said a car fit for purpose, towing 2.6T van well within specs, and no mods needed. People need to do homework before buying tug and van but many just read the specs and think "she'll be apples". eg Ram towing 4.5T

-- Edited by HandyWalter on Wednesday 26th of July 2023 12:02:31 PM