Weighing the combined unit.

iana · Guru

Weighing the combined unit.

yobarr · Guru

iana wrote:
I have an opportunity to get our rig weighed (over a weigh bridge), so how should we do it. I want to weigh the ute and van empty, plus fuel, water and gas, the other half thinks we should weigh it with all the basic stuff in it. Not really interested in ball weight at the moment. We were above our combined mass limits, but since buying a house, our van is now empty.
What's the best.

Hi Ian.Not quite sure why you'd be "Not really interested in ball weight",as that is one of the most important figures,along with rear axle weight on the car.Anyway,if you go to the weighbridge,with the van in tow,weigh front axle of car,move forward and weigh whole car.Check you're not over your GVM rating.Subtract front axle weight from total weight to get rear axle weight. Check that against axle carrying capacity.Drive forward until both car and van are on bridge,and note the total weight.From total weight subtract weight of car,and you will have your GTM (Gross Trailed Mass,or weight on van wheels).If the weighbridge is too short for car and van together,after you've established the total weight of the car,simply drive the car off the weighbridge,but leave the van's wheels on bridge to get GTM.Add that to car's total weight to get your all-up weight,and compare that with your GCM rating. If you want to check total weight of van does not exceed tge ATM rating,just lower jockey wheel onto bridge with car not on bridge. You then can calculate towball weight,but not very accurately.That's another story though! Good luck! Cheers

P.S Some people don't care about towball weight

-- Edited by yobarr on Friday 21st of May 2021 02:21:34 PM

oldbloke · Guru

From another thread.

Van method.jpg

iana · Guru

Soooooo does that mean weighing the rig empty, or filled with basic gear, or loaded ready to go ?

yobarr · Guru

iana wrote:
Soooooo does that mean weighing the rig empty, or filled with basic gear, or loaded ready to go ?

Preferably loaded ready to go.Otherwise you're just guessing how any added load affects things like towball weight and rear axle load.Cheers

iana · Guru

Done. Bt50 Agg 3200kg, Weighed two occupants and full fuel otherwise empty 2520kg. Van Agg. 3260, Weighed empty 2.94.
CCM 6000kg as weighed 5460kg. Nothing loaded. No water or gas. Its all yours Yobar.

yobarr · Guru

iana wrote:
Done. Bt50 Agg 3200kg, Weighed two occupants and full fuel otherwise empty 2520kg. Van Agg. 3260, Weighed empty 2.94.
CCM 6000kg as weighed 5460kg. Nothing loaded. No water or gas. Its all yours Yobar.

Sorry Ian,but I do not understand your what you're asking? Unless you're loaded,ready to go,we're shooting in the dark,unfortunately. Are you saying that your van's ATM is 3260kg,and that it weighs 2940kg empty? If so,it has only 320kg carrying capacity,which is nowhere near enough. The BT50 has GVM of 3200kg,so I expect that that is what you're referring to when you write "Agg 3200kg",and the car weight appears about right at 2520kg with two occupants and full fuel tank.This leaves apparent carrying capacity of 680kg,but you'll never get there.The generally accepted 10% towball weight of 325kg puts around 470kg onto your car's rear axle,having taken around 150kg OFF the front axle. Adding the universally accepted "cure all" of a WDH increase your TBO (towball overhang,or distance from rear axle to hitch point),adding even more weight to your car's rear axle. To enable me to give you any useful advice,you need to first load your car and van,ready for travel,and visit the weigh bridge again.To avoid having to do lots of repeat weighing,you first need to ensure that your towball weight is right,at about 325kg. THEN 1)Drive the front axle of car onto bridge and record weight.2) Drive whole car onto bridge and record weight.3) Subtract front axle weight from total weight to get rear axle weight. This is critical on your car,because your rear axle capacity is only 1850kg. Next,drop van on bridge,supported by jockey wheel and wheels,and note weight,after driving car off bridge. Reconnect van and move forward until only van wheels are on bridge.Note that weight (GTM) and subtract it from total weight of van to get towball weight. Please note that while this is inaccurate,it is a lot better than the alternative,which I will not confuse anybody with! By totalling your front axle weight,your rear axle weight,and your GTM you will have your GCM,or all-up weight.Assuming your provided figures are what I think they are,with absolutely perfect loading of both your car and your van,the GCM of 6000kg MIGHT be attainable. If your van was loaded to 3260kg, and had 10% towball weight,you would have weight on van wheels of 2935kg.Careful loading of your car might enable you to reach weight on car wheels (GVM if you like) of 3065kg,thus getting to 6000kg.The weight on car wheels would then be around 5% greater than the weight on the van's wheels-certainly not ideal,but a darn sight better than many of the combinations around.HOWEVER,until you do your weights when fully loaded,ready to travel,we are simply shooting into the dark.REAR AXLE WEIGHT WILL BE YOUR STUMBLING BLOCK,as the BT50 cannot SAFELY tow more than around 3100kg ATM.Hope I haven't confused you too much,but again I will say that unless your weights are done with a ready-to-go car and van,there are simply too many variables.Hope this helps,but please feel free to ask questions. Cheers

iana · Guru

Copied pasted and spread out to read.
Thanks Yobar.

iana · Guru

I think we can just scrape in weight wise, may have to go to a lithium house battery, ball weight is a concern, very light at the moment. I think by moving the vans spare wheel from the rear to the front I will get about 6%. Looking at putting the utes spare wheel behind the cabin of our extra cab, as well as any other heavy items. I have wired the ute so that all the added electrics run off an AGM auxillary battery, while I have been told this is a good way to do it, any faults don't effect the vehicle computer, that battery may have to go as well. This I hope will bring the rear axle loading within spec.
Not living in the van we can avoid taking all the stuff we had.

yobarr · Guru

iana wrote:
I think we can just scrape in weight wise, may have to go to a lithium house battery, ball weight is a concern, very light at the moment. I think by moving the vans spare wheel from the rear to the front I will get about 6%. Looking at putting the utes spare wheel behind the cabin of our extra cab, as well as any other heavy items. I have wired the ute so that all the added electrics run off an AGM auxillary battery, while I have been told this is a good way to do it, any faults don't effect the vehicle computer, that battery may have to go as well. This I hope will bring the rear axle loading within spec.
Not living in the van we can avoid taking all the stuff we had.

Hi Ian. Great to see that you're making progress,but getting your ball weight up to at least 300kg is critical if you intend loading your van to its ATM. Because your van presently weighs 2940kg,you have only 320kg to play with,which is not much,and would require exact loading to reach correct ball weight! There are many ways to increase ball weight,such as putting gear into the front boot,under the bed (assuming front bed) and playing around with the water tanks,but 6% is ridiculously,and dangerously, low. However,it would be stupidity in the extreme to have a van with GTM of over 3000kg,with only 200kg towball weight,behind a car that weighs a lot less than 3000kg. Remember,a 300kg towball weights puts about 430kg onto your car's rear axle,so you need to have that axle under about 1420kg without the van connected.You're making good progress,so keep up the good work! However,you must get towball weight up,and make your car as heavy possible,within GVM and rear axle capacity limitations. Cheers

-- Edited by yobarr on Thursday 22nd of July 2021 06:38:52 PM

iana · Guru

Thanks yobar, there's a bit of weight reduction to be carried out, lithium battery etc. Moving the spare wheel from under the back to the front will be no easy task, will have to explore the wheel winch that the Ranger/BT50 use and fit that to the A frame.
The problem I have is that in order to have recliner chairs, Jayco have moved everything to the back, so the front area of the van is empty. I don't like considering water as a ballast, as it is a consumable, so only concentrating on fixed weights.

yobarr · Guru

iana wrote:
Thanks yobar, there's a bit of weight reduction to be carried out, lithium battery etc. Moving the spare wheel from under the back to the front will be no easy task, will have to explore the wheel winch that the Ranger/BT50 use and fit that to the A frame.
The problem I have is that in order to have recliner chairs, Jayco have moved everything to the back, so the front area of the van is empty. I don't like considering water as a ballast, as it is a consumable, so only concentrating on fixed weights.

Interesting,Ian.You might like to ask Mr Jayco to explain to you how to get your towball weight up to 300kg+. See photo below.This caravan's fate was sealed by low ball weight, with the ensuing accident killing 3 family members.No matter what you do,if you propose to tow 3260kg with a BT50 (or similar) you must have towball weight over 300kg,if safety is of any concern.At 3260kg ATM,you already are severely pushing the boundaries for a BT50 towing a PIG trailer,so you must get your car as heavy as possible,within its GVM and rear axle capacity limitations.Cheers

P.S Poor coverage in the bush here in FNQ,so I'll have to post photo later.Sorry.

-- Edited by yobarr on Friday 23rd of July 2021 10:07:18 AM

iana · Guru

I guess you can now understand why I got the van weighed empty. Am aiming for 50-50 weight distribution on the 6000kg GCM, at the same time keeping weight in the ute as far forward as possible. Incidentally the compliance plate reads ball weight empty 153, tare 2785, giving the van about 5.5% ball weight. The salesman recommended putting the spare under the van at the back, this would not have helped matters. But even so with a lightish ball weight we have traveled about 35,000km with no issues and the van towing very well, its only now that we have stopped being on the road full time that gives me the opportunity to address the weight and balance issues, mainly to be legal.
Incidentally I did bring the compliance issues up with Mr Jayco after purchase, mainly the max ball weight, at that time there was a second water tank mounted up forward, filling both tanks without any thing stowed inside the van put the ball weight over the stated limit. Mr Jayco fixed the problem by issuing another compliance plate with the max ball weight left blank.

yobarr · Guru

iana wrote:
I guess you can now understand why I got the van weighed empty. Am aiming for 50-50 weight distribution on the 6000kg GCM, at the same time keeping weight in the ute as far forward as possible. Incidentally the compliance plate reads ball weight empty 153, tare 2785, giving the van about 5.5% ball weight. The salesman recommended putting the spare under the van at the back, this would not have helped matters. But even so with a lightish ball weight we have traveled about 35,000km with no issues and the van towing very well, its only now that we have stopped being on the road full time that gives me the opportunity to address the weight and balance issues, mainly to be legal.
Incidentally I did bring the compliance issues up with Mr Jayco after purchase, mainly the max ball weight, at that time there was a second water tank mounted up forward, filling both tanks without any thing stowed inside the van put the ball weight over the stated limit. Mr Jayco fixed the problem by issuing another compliance plate with the max ball weight left blank.

Hi Ian.Ball weight at tare means absolutely nothing,and Mr Jayco should be aware of that.We are getting a bit complicated here,as there is no way that you can ever safely have your car and van 50-50. Can you please check your compliance plate and supply the axle group load capacity,as well as your GTM? Removing the front water tank because it "put the ball weight over the stated limit" was a bad move,as there seems never to have been a towball limit to exceed,only what towball weight was at tare? Seems you have been dealing with people who know nothing about weights and physics,as with the front water tank in place,at least you could get towball weight up nearer to where it should be.Granted,towball weight will vary as the tanks are emptied,but at least you can manage that weight by using them alternately until both are empty.At the moment,your maximum ball weight is when your rear water tank is empty,so you're no worse off,and potentially better overall.Anyway,if you can supply tge requested figures,I'll try to sort it for you.Cheers

Bill B · Guru

yobarr wrote:

"put the ball weight over the stated limit" was a bad move,as there seems never to have been a towball limit to exceed,only what towball weight was at tare?

Yobarr, your are wrong as Jayco at one stage did stipulate a maximum ball weight on the complianc plate.

yobarr · Guru

Bill B wrote:
yobarr wrote:

"put the ball weight over the stated limit" was a bad move,as there seems never to have been a towball limit to exceed,only what towball weight was at tare?
Yobarr, your are wrong as Jayco at one stage did stipulate a maximum ball weight on the complianc plate.

Sorry Bill,but I did not say that Jayco didn't stipulate a maximum ball weight.READ CAREFULLY. Ian said that AT TARE,his van's ball weight was 153kg. He went on to say that,when he queried this figure,Jayco supplied a new compliance plate with "max ball weight left blank".Please note that "Put the ball weight over the stated limit" was a quote from Ian's post,and I simply pointed out that there never was a maximum ball weight to exceed.Only ball weight at tare,which neither Ian nor Jayco seemed to understand is NOT related to maximum ball weight.With respect Bill,it seems that whenever you respond to one of my posts,it is to tell me that I'm wrong,but,once again,you're the one who is wrong.However,don't give up.One day you may catch me out? But I doubt it.Have a great day.Cheers

KevinJ · Senior Member

Hi Ian, if you look at my previous post at https://thegreynomads.activeboard.com/t67501652/weights-and-measures-by-a-layman/ there is a spreadsheet included which may help with your calculations.

yobarr · Guru

KevinJ wrote:
Hi Ian, if you look at my previous post at https://thegreynomads.activeboard.com/t67501652/weights-and-measures-by-a-layman/ there is a spreadsheet included which may help with your calculations.

Hi Kevin.Great to see your calculator up and running,but Ian's SOLE problem is not enough towball weight to tow SAFELY.With 5.5% or 6%,and the caravan heavier than the car,he is playing with fire,no matter how lucky he has been so far.With luck,Ian will supply the van's maximum axle capacity and its GTM so we can do some calculations for him.Putting it bluntly,you can't safely tow 3260kg ATM behind a car with 6000kg GCM unless you have AT LEAST 300kg towball weight. Assuming the van weighs 3260kg,the MOST the car can weigh is 2740kgwon't work. At least if Ian can get his towball weight to 300kg,he would have 2960kg GTM behind a car with total weight (GVM if you like) of POSSIBLY 3040kg,although that too is impossible. Unless he can get the towball weight up,he is piddling into the wind.Happy to help,but we need the figures I've asked for.Cheers

Craig1 · Guru

" Moving the spare wheel from under the back to the front will be no easy task, will have to explore the wheel winch that the Ranger/BT50 use and fit that to the A frame "

This could well create clearance issues if mounted under your drawbar.

iana · Guru

Axle group capacity 3333 Kg. GTM 3107 ATM 3260 Empty ball mass 153kg Tare 2785, figures off replaced compliance plate.
Re spare wheel, I have asked on a Jayco Silverline face book page for photos of the cradle that front mounted spare use. I did enquire many moons ago about buying the original parts, but they were hellishingly expensive. And yes I agree re ground clearance, but being an outback model, there is a fair bit of clearance.
Yes Jayco were putting max ball weight on the compliance plate, it was after my issue (and no doubt others) that Jayco left that square blank. I do know that the maximum ball weight that I have is the rated figure on the tow bar, and I am well within limits smile .

Regardless of the smiley, I am not seeing this as a joke.

KevinJ · Senior Member

No argument there as so far the software has confirmed everything you have said on all your various posts. The difference is that the software calculates all values accurate to a kg whenever any one of the parameters change. At a broad brush level, all your advice has been sound. It proves experience is always as important as science. The Wright brothers did not have a computer.

yobarr · Guru

iana wrote:
Axle group capacity 3333 Kg. GTM 3107 ATM 3260 Empty ball mass 153kg Tare 2785, figures off replaced compliance plate.
Re spare wheel, I have asked on a Jayco Silverline face book page for photos of the cradle that front mounted spare use. I did enquire many moons ago about buying the original parts, but they were hellishingly expensive. And yes I agree re ground clearance, but being an outback model, there is a fair bit of clearance.
Yes Jayco were putting max ball weight on the compliance plate, it was after my issue (and no doubt others) that Jayco left that square blank. I do know that the maximum ball weight that I have is the rated figure on the tow bar, and I am well within limits .
Regardless of the smiley, I am not seeing this as a joke.

Thanks Ian,for those figures,as that tidies up a few loose ends.To avoid any confusion,I will not elaborate on where I was going,but,put simply,there is no way known that you'll get anywhere near 50/50,or 6000kg GCM,unless you increase the towball weight to around 300kg.Already I have suggested a couple of ways to achieve this,but unless you try to do this,quite frankly,we're pushing spit uphill.There is NO WAY KNOWN that you can safely tow a 3260kg van,with 6% towball weight,behind a car that weighs only 2740kg.Some VERY heavy tow vehicles MAY get away with 6% ball weight when towing much lighter caravans,but in your case you have every chance of the tail wagging the dog. This may well not be what you want to hear,but always I say what I mean,and mean what I say.GET YOUR TOWBALL WEIGHT UP TO AROUND 300kg. I can see no other solution.Cheers

iana · Guru

Thanks for that spread sheet KevinJ, however I have made up a simple sheet to give me the data I want on this task. At the moment I am looking at weight removal ideas i.e. removing solar panel from the rear of the van, and replacing the two front with 300w, this will bring the weight forward, and give about 13 kg extra load capacity.
Replacing the two 120 Ah AGM batteries with one lithium this will free up another 25kg or so, but no ball weight change
I could wire the breakaway unit to the house battery, no change in ball weight, but frees up another i.5 kg guess.
Spare wheel to the front which moves about 30 kg forward.

On the ute I can remove the tray, and mount the canopy direct to the chassis rails. this can free up about 80kg, reducing rear axle loading.
I have just been to an auto electrician, and talked about my wiring and the way I have the aux battery, he agreed that the system I have is good, but he wanted to change that to lithium as well, no thanks that's expensive.

I can carry water in the ute up forward behind the cab, and so can leave the rear water tank on the van empty.
Mounting the spare wheel up forward will reduce rear axle weight as well.

Now that I have thought about that I will have a rest.

yobarr · Guru

KevinJ wrote:
No argument there as so far the software has confirmed everything you have said on all your various posts. The difference is that the software calculates all values accurate to a kg whenever any one of the parameters change. At a broad brush level, all your advice has been sound. It proves experience is always as important as science. The Wright brothers did not have a computer.

Thank you Kevin,for your kind words. It is great to see that at least your computer agrees with me,as there is one member here who seems to know little,posts rarely,but invariably disagrees with me! All I can do is battle on. C'est la vie.Thanks again. Cheers

-- Edited by yobarr on Saturday 24th of July 2021 07:04:43 PM

yobarr · Guru

iana wrote:
Thanks for that spread sheet KevinJ, however I have made up a simple sheet to give me the data I want on this task. At the moment I am looking at weight removal ideas i.e. removing solar panel from the rear of the van, and replacing the two front with 300w, this will bring the weight forward, and give about 13 kg extra load capacity.
Replacing the two 120 Ah AGM batteries with one lithium this will free up another 25kg or so, but no ball weight change
I could wire the breakaway unit to the house battery, no change in ball weight, but frees up another i.5 kg guess.
Spare wheel to the front which moves about 30 kg forward.

On the ute I can remove the tray, and mount the canopy direct to the chassis rails. this can free up about 80kg, reducing rear axle loading.
I have just been to an auto electrician, and talked about my wiring and the way I have the aux battery, he agreed that the system I have is good, but he wanted to change that to lithium as well, no thanks that's expensive.

I can carry water in the ute up forward behind the cab, and so can leave the rear water tank on the van empty.
Mounting the spare wheel up forward will reduce rear axle weight as well.

Now that I have thought about that I will have a rest.

Some great ideas there Ian.Is there any way that you can carry your AGM batteries at the front of the van,perhaps on the drawbar? Anyway,enjoy your rest as it's been a hard day! Cheers

iana · Guru

Enquired about that, seems that some Silverlines have the batteries under the club lounge at the front, since we do not have any storage in that area, they would have to go in the boot. Trouble is the gas bottles are in there, as is the diesel for the heater. I understand there should be 1200mm between ignition points and fuel, could be wrong, have been known to be. But also worried about voltage drop as the Setec unit is mounted mid way under the bed.

yobarr · Guru

iana wrote:
Enquired about that, seems that some Silverlines have the batteries under the club lounge at the front, since we do not have any storage in that area, they would have to go in the boot. Trouble is the gas bottles are in there, as is the diesel for the heater. I understand there should be 1200mm between ignition points and fuel, could be wrong, have been known to be. But also worried about voltage drop as the Setec unit is mounted mid way under the bed.

Not being any sort of an Electrician,I cannot advise on voltage drop and the like,but perhaps bigger cables would help? The cables in my van are bigger than 25mm diameter,and cost me a motza. Regarding stuff in the front boot,before I did my big upgrade there were gas bottles and batteries in there,separated by a simple wall,and I had all relevant safety certificates.The diesel heater tank also is in there.As stated,I am not at all conversant with the rules,but my post may be of some benefit? Could you put the gas bottles onto the drawbar,which seems to be a popular place to carry them? Cheers

iana · Guru

Maybe someone on here can shed light on the regs concerning the placement of batteries. Gas bottles stay as they are, design feature. Pic of the spare on the A frame under the plastic cover.