Thread: Can a Disco 4 tow a van with 350kg ball weight... I think not fit for purpose..

Originally Posted by tapda01

Hi, I am a little frantic and would appreciate some validation of my calculations please.... I purchased a single axle off road van with ATM of 2,700 kgs and a ball weight of 270kgs. I calculate when sensibly loaded with full water tanks that the ball weight will increase to about 320 kgs. I also purchased a 2013 SDV6 Disco 4 to tow the van with, assuming (wrongly I now believe) that it had ample power and as it was rated as 3,500kgs max tow weight and 350 kgs max ball weight it would handle the van with ease. If only I had done the calculations fully beforehand....

The Disco 4 has a Tare stated in the handbook of 2,546kgs.
The tank takes 82 litres of diesel. 10 litres I understand are included in Tare so the remaining 72 add 60kgs giving kerb weight of 2,606
The manual states the CGM of 3,240 is only valid with a ball weight of 150kgs or less. For every kilogram of ball weight over the 150, the CGM decreases by 1 kg. This means that the CGM if towing a 3,500kg van with a ball weight of 350KG will reduce to 3,040kgs.
This gives us a legal payload of 3,040 minus the kerb weight of 2,606 minus the ball weight of 350 equalling 84kgs!!!! Â… the wife and kids will need to stay at home and I will need to go on a diet to legally drive the rig... So, are my calculations incorrect, have I misunderstood the manual or did Land Rover have brain fade? Â…. you can tow a big van Mr customer,but you have to do so by yourself ....not fit for purpose I suggest....

I think my calcs are correct, but I would love them to be wrong...



With the van I purchased, I can just about squeeze in my wife and an esky... it has to be empty.. all recovery gear moved into the van.... Do I replace the car or the van?

Thanks

David

You are maybe reading the section in the Owners manual which applies to English vehicles. There is an Australian Supplement advising 350kg is max towball weight. Be sure not to get your GCM mixed up in your calcs as it has nothing to do with towball weight. I am towing a 2.9T van with 310 kg towball weight and definitely legal and tows beautifully. In many cases, adding X kilos of water doesn't necessarily mean it all goes onto the towball. In my case it does not. F
illing my front 90 litre tank (90 kg) does not add 90 kg to my towball weight.

If the tank were behind the axle filling it could reduce the towball weight.

Also, a full tank of fuel and 75kg for the driver are already included, others have stated.

Originally Posted by DiscoMick

Also, a full tank of fuel and 75kg for the driver are already included, others have stated.

In reality, how many drivers are 75kg ???

Originally Posted by pop058

In reality, how many drivers are 75kg ???

The mythical international human. Same formula airlines and ships use for passenger weight.

Originally Posted by Discodicky

You are maybe reading the section in the Owners manual which applies to English vehicles. There is an Australian Supplement advising 350kg is max towball weight. Be sure not to get your GCM mixed up in your calcs as it has nothing to do with towball weight. I am towing a 2.9T van with 310 kg towball weight and definitely legal and tows beautifully. In many cases, adding X kilos of water doesn't necessarily mean it all goes onto the towball. In my case it does not. F
illing my front 90 litre tank (90 kg) does not add 90 kg to my towball weight.

Hi Fossiker, I am quoting the Australian specs and they clearly say that if your towball weight is greater than 150kgs then the GVM reduces by 1kg for every 1 kg of towball weight over 150kgs. I have no doubt your van tows beautifully, but if you are in a D4 then your payload will be GCM (3,240 - 160 = 3,080) minus Kerb weight (Tare 2,546 + Fuel 60 = 2,606) minus TBM (310) giving 164kgs.... this assumes you have added no extras like bull bars, roof rack, aux batteries etc etc.... enough for 2 people and an esky....

My van is single axle off road and both water tanks are in front of axle. I have calculated the moment of all extras in the van (weight x distance from axle) to establish the new ball weight...

I have reviewed most of the replies hoping for a different outcome, but no one has come up with any positive evidence yet. I am quoting page 71 in D4 owners manual where it specifies the towing weights. The general description could be clearer, but to quote it :

FITTING THE DETACHABLE DRAWBAR RECEIVER (Australia only), the nose weight can be increased to 350kg (772 lb) if the GVW is reduced by 200 kg (441 lb).

GVW is the Gross Vehicle Weight, which we refer to as GVM here..

Some people are suggesting that the Tare weight includes driver and 90% full tank. I would love this to be true, but I can find no evidence that UK define it this way. As a rule, the tare includes 10l of fuel to get to weighbridge. The kerbside weight is Tare plus full tank of fuel... I can find no documentation including driver... how could one... I weigh 88kgs and you may weigh 108kg.... meaningless..

Hence my comment about fit for purpose.... there is a lot of press about this at the moment, and I, like I suspect many land rover owners, thought that our vehicles were not effected by the over stating of weights.... sadly we are in no better a position than the average double cab ute.... actually, some are in a better position because their Tare is generally lower....

Appreciate your help and happy to be corrected on any point...

Cheers

david

Originally Posted by DiscoMick

Why do you calculate when the water tanks are loaded the ball weight will increase to 320kg? Does the caravan manufacturer say that?
Our camper trailer is different to your van of course, but filling our tank reduces, not increases, the ball weight. I have seen other caravans the same.
Might be worth checking.

Thanks Mick... I wish I was in the same position... both my tanks and most of the storage is forward of the axle. I have calculated the moment of all extras in the van (weight x distance from axle) to establish the new ball weight... I am going to have to move a tank behind the axle to bring the ball weight back to something reasonable...

Cheers

David

Originally Posted by Graeme

You subtracted the full 350kg ball weight instead of the excess over 150kg, being 200kg, so have another 200kg to play with.

I can' t be sure but thought that LR allowed for the driver and a full tank of fuel in the tare, unlike other manufacturers.

Hi Graeme, I wish I could accept what you say, but you are assuming, like many in my research, that 150kg of ball weight is already included in the GVM. This is just not the case. GVM is GVM. Page 71 of D4 manual is clear:

FITTING THE DETACHABLE DRAWBAR RECEIVER(Australia only), the nose weight can be increased to 350kg (772 lb) if the GVWis reduced by 200 kg (441 lb).

When I place a 350kg ball on the D4, the GVM is reduced by 350kg...

Some people aresuggesting that the Tare weight includes driver and 90% full tank. I would lovethis to be true, but I can find no evidence that UK define it this way. As a rule, the tare includes 10l of fuel to get to weighbridge. The kerbsideweight is Tare plus full tank of fuel... I can find no documentation includingdriver... how could one... I weigh 88kgs and you may weigh 108kg....

Thanks for your input... I am getting many opinions from forum members but I am looking for hard evidence that my calculations are incorrect... when flagged down by men in blue and weighed, I want to know I am legal...

Cheers

David