Thread: Have I got my weight sums right?

D4 manual says something similar, effectively you reduce the payload by the excess over 150kg.

Ron

Originally Posted by IndusD4

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

Im afraid the answer is No Ron... see response from Land Rover that follows:

Dear Mr Tapper,

Thank you for your patience whilst we investigate into your query.

To confirm, our Product team have liaised with our UK Office for assistance with your weight and towing query.

They have advised based on your VIN details provided and Australian Design Rules:

Curb Weight = 2568 kg (that includes 90% fuel but not a Driver)

GVW (Gross Vehicle Weight) = 3240 kg

GVW (Gross Vehicle Weight) – 350 kg nose load = 2890 kg

2890 – 2568 kg = 322 kg available payload for passengers and cargo providing stipulations below are met.

- Make sure to never exceed the Gross Vehicle Weight (GVW), the Gross Train Weight (GTW), or the front and rear axle weights.
- Include the trailer's nose weight when calculating the GVW and the rear axle weight.
- When calculating the vehicle's rear axle weight, the vehicle's payload weights must also be considered. Include the combined weights of all the rear passengers, the loadspace, roof rail, accessory equipment, and the trailer nose weight. The combined weights must never exceed the GVW or the maximum weights for the front and rear axles.
- Make sure that the GVW, the GTW, and the maximum rear axle weight limits are not exceeded when applying the trailer nose weight. If required, reduce the weight of the vehicle's payload.

For your records, it is best recommended to print a copy and leave one in your vehicle's glovebox for future reference.

Assuring you of our best intentions at all times.

Kind regards,


Daniel
Customer Relationship Centre Administrator
Jaguar Land Rover Australia



Cheers

David

Seems this doesn’t match what the D4 manual says. Anyway, you now know you need a D5.

Ron

Greg,

I am currently in Victoria after leaving home in late February, now towing the Kimberley Karavan with the much lighter Range Rover Vogue. No more weight issues since there is no bull bar, rear bar or long range tank. The 2013 TDV6 RRV also has the highest payload of all RRV's, due to its lighter weight.

I seem to remember that you and I both had the same issue when we went on the GRR together a couple of years ago. That is why I removed the third row seat, two of the second row seats and the second spare wheel arm of my Kaymar bar. That put me pretty close to legal at that time.

Originally Posted by IndusD4

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

Not quite sorry, Ron. If the trailer weighs 1500kg and if that is its ATM, and if it has 10% of the weight on the ball, then 150kg is transferred to the tow vehicle, and 1350kg is occurs via the wheels. The 150kg from the trailer goes to the vehicle via the tow ball.

That 150kg transferred via the tow ball adds to the weight of the vehicle in the Gross Train Weight calculation, as the trailer adds only 1350kg to that figure. You are definitely right that the trailer didn't suddenly lose weight, but part of its weight is transferred to the vehicle rather than going through the wheels.

If the vehicle starts at 3240kg before you attached the trailer in this scenario, and if 3240kg is the allowable GVM for the vehicle, then you are overloading the vehicle (by the aforementioned 150kg transferred from the trailer to the vehicle) when you attach the trailer. You are OK provided you don't attach the trailer.

So in the Gross Train Mass calculation in the above case, you have the vehicle being 3240 + 150 = 3390kg (overloaded) plus the trailer component of the weight being 1350kg = total GTM of 4740kg.

So the only issue in all of this is the tow vehicle weight, if it started at 3240kg before the trailer was hitched up, as it becomes illegal once (and only once) you hitch the trailer because the vehicle is already at the allowable GVM limit before the trailer is added.

That's what all the hullabaloo is about in the Caradvice articles looking at the GVM of the tow vehicle and then looking at what happens to available payload when you bung a trailer on the back.

Hope that helps.

That's not what the manual for my Defender says. It says 150kg TBW is included in the Gross Vehicle Weight. Only any amount above 150kg TBW has to be reduced from the vehicle weight. See below:

Originally Posted by Bewtiched

Not quite sorry, Ron. If the trailer weighs 1500kg and if that is its ATM, and if it has 10% of the weight on the ball, then 150kg is transferred to the tow vehicle, and 1350kg is occurs via the wheels. The 150kg from the trailer goes to the vehicle via the tow ball.

That 150kg transferred via the tow ball adds to the weight of the vehicle in the Gross Train Weight calculation, as the trailer adds only 1350kg to that figure. You are definitely right that the trailer didn't suddenly lose weight, but part of its weight is transferred to the vehicle rather than going through the wheels.

If the vehicle starts at 3240kg before you attached the trailer in this scenario, and if 3240kg is the allowable GVM for the vehicle, then you are overloading the vehicle (by the aforementioned 150kg transferred from the trailer to the vehicle) when you attach the trailer. You are OK provided you don't attach the trailer.

So in the Gross Train Mass calculation in the above case, you have the vehicle being 3240 + 150 = 3390kg (overloaded) plus the trailer component of the weight being 1350kg = total GTM of 4740kg.

So the only issue in all of this is the tow vehicle weight, if it started at 3240kg before the trailer was hitched up, as it becomes illegal once (and only once) you hitch the trailer because the vehicle is already at the allowable GVM limit before the trailer is added.

That's what all the hullabaloo is about in the Caradvice articles looking at the GVM of the tow vehicle and then looking at what happens to available payload when you bung a trailer on the back.

Hope that helps.

Nothing to be sorry about, happy to be proven wrong. From what you're saying you'd never be able to tow 3,500kg if (going by a 10% tow ball weight) you need to transfer 350kg of weight to the car.

Ron

I'll concede defeat on this

But would still like to know how you'd ever get to a GCW of 6740kg (assuming GVM of 3240kg) if you need to take your tow ball weight from the trailer and have this to be included in the GVM. As I see it, it would never be possible.

Ron