Thread: Have I got my weight sums right?

Just took the D4 over the weighbridge again, this time to measure weight over the rear wheels only. Came in at 1,660kg, so with gross vehicle weight currently at 3,040kg including me and the bride and full fuel, fridge, rear drawer and some odds and sods, I'm assuming that means there's 1,380kg over the front wheels (1450kg max allowable)

In any case, gives me some comfort, knowing max allowed rear axle weight of 1,885kg gives me about 225kg wriggle room at the back end. If I can get the camper trailer nose weight down to 150kg or thereabouts, happy days.

Originally Posted by GregMilner

Just took the D4 over the weighbridge again, this time to measure weight over the rear wheels only. Came in at 1,660kg, so with gross vehicle weight currently at 3,040kg including me and the bride and full fuel, fridge, rear drawer and some odds and sods, I'm assuming that means there's 1,380kg over the front wheels (1450kg max allowable)

In any case, gives me some comfort, knowing max allowed rear axle weight of 1,885kg gives me about 225kg wriggle room at the back end. If I can get the camper trailer nose weight down to 150kg or thereabouts, happy days.

Hi Greg thanks for sharing the thread with me... your spreadsheet is brilliant.... I constructed a similar one to calculate the TBM on my caravan, but nothing as fancy....

I completely disagree with Ron by the way... I can see how one can misinterpret the wording in the owners manual as it is very poorly written.... my interpretation is that if your Payload has taken you to GVM and you have a van attached, Land Rover are saying that the vans TBM portion of the payload must not exceed 150kgs.... GVM is GVM, it is not GVM plus 150... if it was Land Rover would increase it to 3,390. When one attaches a van the full TBM is spread over the axles just as your spreadsheet shows and the GVM is eaten into by the same amount....

I have updated your spreadsheet for my use to include the sliding scale GVM for the TBMs over 150kgs.... I remain convinced this is correct, but as stated in my post I would love to be proven wrong...

Thanks again and good luck getting your TBM to 150...

Cheers

David

Sorry, my post should have said that any tow ball weight over 150kg should be deducted from the payload, not the GVM. Agreed, GVM is GVM and won't change.

Ron

Originally Posted by IndusD4

Sorry, my post should have said that any tow ball weight over 150kg should be deducted from the payload, not the GVM. Agreed, GVM is GVM and won't change.

Ron

Sorry Ron, I am still not certain we are in agreement.

If your vehicle is at GVW sitting on a weighbridge, then you are at its legal maximum weight and you can legally not add any further payload to it. If you chose to attach a trailer in this situation, your total weight will increase by the TBM of the trailer and you will exceed the GVW by the TBM. Its all very simple and obviously there is no magical reduction in the TBM by 150kgs. I think that very poorly worded sentence in the owners handbook has muddied the waters..

Cheers

David

I think the question needs to be asked of an engineer at LRA for a definitive answer: "If the car sits on the weighbridge at GVM of 3240kg, can I then hitch up a trailer with a tow ball mass of 150kg and still be legal?"

It's a yes or no answer.

On another matter, as I said in the original post, we're about to head off on a long mostly highway trip to the Kimberley and back. I run Maxxis Bravo 980 light truck tyres on these trips, given that we're going to be loaded up pretty heavily, am I right in thinking that we'll need about 45psi in the tyres (cold) to handle the weight? (That's on the blacktop obviously, down to maybe 28psi on the Gibb.)

H

Originally Posted by GregMilner

I think the question needs to be asked of an engineer at LRA for a definitive answer: "If the car sits on the weighbridge at GVM of 3240kg, can I then hitch up a trailer with a tow ball mass of 150kg and still be legal?"

It's a yes or no answer.

On another matter, as I said in the original post, we're about to head off on a long mostly highway trip to the Kimberley and back. I run Maxxis Bravo 980 light truck tyres on these trips, given that we're going to be loaded up pretty heavily, am I right in thinking that we'll need about 45psi in the tyres (cold) to handle the weight? (That's on the blacktop obviously, down to maybe 28psi on the Gibb.)

hi Greg

those pressures sound about what I’d use. On the car I’d go 40psi front, 45ish psi on the rears and see how they go using the 6psi rule because they are LT tyres. Maybe 28psi front and 30psi rear. Similar principle on the van. I tow an AOR Odyssey (max 1800kg) and I run 35psi on bitumen and 25psi on gravel. NEVER had an issue...

Cheers
David

Originally Posted by GregMilner

I think the question needs to be asked of an engineer at LRA for a definitive answer: "If the car sits on the weighbridge at GVM of 3240kg, can I then hitch up a trailer with a tow ball mass of 150kg and still be legal?"

It's a yes or no answer.

Yes.


Assuming a 10% ball weight, if you have a trailer that weights 1,500kg and the car 3,240kg. I hook the trailer to the car. You'll need to explain to me why the car is now suddenly 150kg heavier as I don't see why it made the car heavier.

Axle weight on the rear axle of the car would have increased but not the 3,240kg GVM. The trailer didn't lose 150kg of weight either, it still weighs 1,500kg but has less of that 1,500kg weight pushing down on its axle.

If you got stopped by Plod and they wanted to see if you were overweight they would have to check the trailer weight on its own, the car weight on its own and then work out the combined weight to see if you weren't exceeding any of these 3. They can't leave the trailer attached to the car to check the car's weight.


Ron

If the 150kg towball weight is included in the GVW, as it is for my Defender, then you are sweet, I believe.