orid wrote:

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Yobarr will probably answer this .

What is the formulae to work out the approx weight transfered from the tow ball weight ,to the tow vehicles rear axle ,without a WDH?

I was surprised to see mine had increased by 360kg from a 240kg towball wieght.

Also front axle has reduced by 140 kg to 1100kg ,

Is there a minimum recommended front axle weight ,regards steering braking ?

Im tempted to place the spare wheel on roof as far forward as poss to balance things out, somewhat.

Regards Orid

-- Edited by orid on Wednesday 10th of February 2021 01:11:17 PM

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 Hi Peter...Pajero,wasn't it? Please confirm or correct,but that is a 50% increase in towball weight transferred to rear axle.Usually the only car that does that is an LC200,because of its ridiculously short 2850mm wheelbase,and big TBO,so something is not right here.I suspect that these weights may have been done on a weighbridge with 20kg increments,so really they mean little.You need to measure exactly your unhitched towball weight,using bathroom scales,and we then can do the calculations for you.When checking your towball weight, your drawbar must be at exactly the same height as it is when the van is attached to the car.If you need details of bathroom scales weighing method,just send me a PM.Cheers

OK...just saw "Pajero" in your avatar.Derrrr! 

orid wrote:

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Actually going by the weigh bridge figures ball weight was 220 kg.

I will put up full figures later.

I used a scale from the caravan shop , shoed 240kg I know they are not the greatest.

Regards Orid

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 Hi Peter...forget the towball weight scales.I have seen massive differences when using several fivevdifferent brands on my van,as a test.So far,I have given away 4 different types,while one takes up space in the back of my shed.Once I have correctly established my towball weight,with bathroom scales,I will see what my flash towball scales say.From then on,I will simply load to what the towball scales read at my correct towball weight... doesn't matter if they are actually 50kg out,as I already know what the real weight is! Cheers

orid wrote:

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what brand scales do you have Yobarr? mine dont go anywhere near 150kg never mind 240 kg ,or do you use some kind of leverage method ?

Regards Orid

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 Used correctly,a set of scales that goes to,say,120kg, will accurately measure a 360kg towball weight.Details and pictures tomorrow.Cheers

orid wrote:

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oky doky spent last couple hours , measuring tow ball weight, using Yobarrs method ,

This is it..                                         Yobarr accurate.                caravan scales                             weighbridge

van slightly high at tow ball                 195kg                                 210kg

van level                                           186kg                                   200kg

van slightly low at tow ball                  180kg                                  ---                                              220 kg ?? I usually tow at this slightly low.

Van fully loaded to the hilt .ready for big trip,
gonna have to increase the tow ball load some how..
Regards Orid

now to work out the rear axle thingy m e bob :) wink wink

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 Thanks for these figures Peter.They show how towball weight varies as you raise or lower the drawbar.Does your van have non-load sharing suspension? Easy to increase towball weight by loading a few boxes of beer forward of the rear axis. Water tanks also can be used to play with weights,provided they are plumbed separately,or can be selectively isolated.Well done on showing how inaccurate towball scales are,and that weighbridges are virtually useless for measuring ball weight.You will note the 40kg difference between the accurate measurement,and the weighbridge reading.Anyone who has any faith in towball scales is delusional,although they can be of use if you use them to record your previous accurately measured weight,and then always load to that figure.Cheers

orid wrote:

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I got that towball weight from weighbridge by weighing car only 2620 kg and taking that from car with van attached 2840kg = 220kg

Exact same load in car.

actual is 180 kg say give + 5% error for scales = 189 still over 10% .maybe I will work to this to get a little more accurate on the rest

What you think ?

Orid

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 Hi Peter...bit tired at moment,but was your car not a Pajero? If so,you cannot load your van to more than 2500kg ATM without having your maximum towball weight limited to 180kg.If you can confirm that your car is indeed a Pajero,and advise what your loaded van weighs,I will do some numbers for you tomorrow.Cheers

yobarr wrote:

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montie wrote:

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There are two ways to establish your actual ball download.

You calculate it at a weighbridge by weighing tug with van attached then unhook van and weigh tug only. The difference is your ball download as calculated using the scales.
Problem here can be the scales error margin however the same margin would apply to both weights. Obviously remove WDH for first weighing.

With a ball weight scales, van level, weigh at the coupling only. This is the most accurate method.

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 Montie,I have to disagree that ball weight scales are the most accurate method...from my experience,they're not even close. Because always I am suspicious of such "gadgets",at one stage I purchased several different brands of ball weight scales,and tested them,one after another,on my caravan. Same day,same site and always same drawbar height.The variance in indicated loadings was ridiculous,with HUGE differences.And not one set came within cooee of the accurate weights given using a couple of different sets of bathroom scales.With the exception of the most accurate set,ALL  my newly-purchased ball weight scales were given to people I don't like,along with a warning of how far "out" they were. Peter's figures above show similar results.In a dealership such as yours,they no doubt serve a useful purpose in assisting your customers,but,from my experiments,I would suggest that you don't ever believe them to be accurate.Weighbridges generally weigh in 20kg increments,so there can be 20-40kg error using the van on-van off method. Anything is better than nothing,I suppose. However,I most certainly concur that all weighing must be done at the coupling,and with the van level. Cheers

-- Edited by yobarr on Saturday 13th of February 2021 08:33:44 AM

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 Most dealers use a specific ball weight scales that is calibrated and audited by weights and measures annually.

It is accurate.

Scales depending on their purposes will have different standards.

One would need to look at ISO (International Organization for Standardisation) for weighing standards.

Let's say for argument's sake on a weigh bridge:

+/- 0.1% but they will add X amount to the figure, then that will be in 20kg increments up to 10,000kg. Up to 50,000kg it could be +/- 0.08%.... in 40kg increments.

Your cheap towbar scales may be +/- 3%. It is less accurate but it is weighing up to 500kg. So at 250kg it will be +/- 7.5kg, but the reading will be to 250kg with a tolerance of +0kg / -15kg.

You need a tolerance for environmental factors like temperature variations let alone the tolerances of the various components of the scales.

orid wrote:

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Thanks Yobarr , rear axle weight on car with van attached is 1566kg well under max .

Room for a few more cartons .

Pity I dont drink , ex alcoholic ,on the wagon almost 15 yrs , Still crave for a beer daily ,TORTURE

I;m Very happy with the outcome . And thanks for all your help ,really appreciated .

Regards Orid

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Hi Orid

If you are stil craving for beer after all of those years try Heineken zero at calton zero tastes like beer but no alcohol looks like beer and no head aches and can still drive after a six pack

Cheers to that 

This is the calculation to find out the effect on your Rear axle loading by the Tow Ball download.

yobarr wrote:

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Plain Truth wrote:

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This is the calculation to find out the effect on your Rear axle loading by the Tow Ball download.

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 Hi Alan....Thankyou for these 'figures'......whilst your calculations are on the money,there is no way known that an LC200 has TBO of only 1350mm, and when people add the universally accepted cure-all of a WDH,that TBO increases. These highly overrated,IMO,cars have a ridiculously low rear axle capacity of only 1950kg.Let's get back to REAL figures.....these cars TARE at over 2740kg,so when you add 350kg towball weight,there is well over 500kg....actually around 520kg......applied to the car's rear axle.And your weight on wheels is now already up to around 3100kg.....no passengers, no tools,no luggage,and no accounting for the weight of the actual towbar structure. Although the car's weight on wheels (GVM if you like) has increased by only 350kg,the rear axle quickly becomes overloaded. "Ah ha" you may say "We'll whack-on a WDH...that'll sort it". Wrong. When the universally accepted "cure all" WDH is tensioned,and takes weight off the car's rear axle (NOT the towball),some of that weight is transferred to the car's front axle,with the rest going onto the van's axle group. Thus,GTM increases,towball weight stays the same,and the van exceeds its ATM..... overloaded,unsafe and uninsured.Whilst your calculations are good,it needs to be noted that an LC200 cannot safely tow more than 3000kg ATM.Hope this helps? Cheers

-- Edited by yobarr on Tuesday 16th of February 2021 08:15:03 PM

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 Yobarr,

I'm a tad intrigued as to how you establish your ATM/GTM theory....The van needs to be unhooked to establish if the measured weight exceeds the ATM.

Surely it's an assumption that if GTM is exceeded so is ATM given imo GTM is not a rating.

yobarr wrote:

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Hi Montie...if a 3500kg ATM van is hooked up to a car,assuming the generally accepted 10% towball weight,there will be 350kg on the towball and 3150kg on the van's axle group.(GTM). When the universally accepted cure-all WDH is fitted,and tensioned, weight is removed  from the car's rear axle. Some of that weight....around 70-75%.....is returned to the car's front axle,from where it came,while the balance is transferred to the van's axle group. Thus GTM has increased,as has ATM,because towball weight does not change when a WDH is tensioned..We now have 350kg towball weight plus the 3150kg that already was on the van's axle group PLUS 25-30% of the weight that was removed from the rear axle of the car. Therefore GTM has increased,but towball weight always remains the same,so consequently the total weight of the van (ATM if you like) also has increased.Because the total weight now exceeds its legal 3500kg ATM rating,the van is overweight,unsafe and uninsured.Cheers

 

-- Edited by yobarr on Tuesday 16th of February 2021 09:00:48 PM

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 So how does an Insurance Company prove the van's measured weight exceeds the ATM without unhooking and weighing the van?

I think we are probably working on the assumption here that the majority of rigs are operating on the border of maximum limits which is probably not the case.

We all know the purpose of a WDH which theoretically transfers weight but at the end of the day it's the actual measured weight that matters. The percentages of weight that is distributed by a WDH can be calculated but not measured. Ball weight of a hooked van cannot be measured.