Author Topic: Question About GVM Weight - Are We Under Or Over?  (Read 1056 times)

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Offline baz1

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Question About GVM Weight - Are We Under Or Over?
« on: October 02, 2019, 06:10:53 PM »
We went to a weighbridge in Caboolture with our Opus Camper to get everything weighed, to check we are compliant, the guy there was really helpful. He explained that the weighbridge is accurate to plus / minus 20kg, and we identified the following weights :

1. Laden weight Opus camper = 1820kg
2. Laden weight Nissan with luggage and occupants, but without camper attached = 2380kg.
3. Laden weight Nissan with luggage and occupants, with camper attached = 2580kg
4. Ball weight on Nissan = 200kg
5. Combined weight of Nissan and camper = 4200kg

So my question is this :

The GVM of the Nissan is 2715kg.

In relation to the max weight we can place on the towball of the Nissan, the Nissan instructions state when the towball weight is 200kg, the GVM should be reduced by 300kg. So this gives us two possible scenarios:

1. With the GVM of 2715kg being reduced by 300kg, our new GVM is 2415kg. Given the Laden weight Nissan with luggage and occupants, and the camper attached, and therefore also the weight of the ball, is 2580kg, this means we are 165kg over our GVM.

2. Given the Laden weight Nissan with luggage and occupants, and the camper attached and therefore also the weight of the ball, is 2580kg, we do not need to reduce the GVM by 300kg, as we know what the total weight of the Nissan, including the weight of the ball of the camper, is 2580kg. Given the ‘un de-rated’ GVM of the Nissan is 2715kg, this means we are 135kg under our GVM.

I’d appreciate anyone’s advice, as to which scenario is correct, are we 165kg over our GVM, or 135kg under?

Also, if our ball weight came in at 200kg, our car can take 200kg, do you really think it will make any (adverse) difference if we add another 9kg gas bottle?

Cheers!

Offline weeds

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #1 on: October 02, 2019, 07:20:33 PM »
At a guess they are ensuring rear axle weight stays within limits.

Did you happen to get front and rear axle weights??

Either way your miles ahead of the majority.....as the majority dont even consider going over s bridge.


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Offline baz1

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #2 on: October 02, 2019, 07:26:11 PM »
I did ask the bloke about doing axle weights, but he said he didn’t usually do those. I imagine it might be difficult to identify the axle weight as it would be affected by exactly how far the axle is from the edge of the bridge, so not an exact science. From the trip to the weighbridge, assuming someone is able to awnser the question I posed and we are under the GVM, I think we are compliant, but only just, with not much room to move.

Offline weeds

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #3 on: October 02, 2019, 07:30:31 PM »
Axle position on the bridge doesn’t matter......

If you stand on the very edge of the bridge than in the middle you should have the same weight.


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Offline HKB Electronics

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #4 on: October 02, 2019, 08:21:17 PM »
towball weight is 200kg, the GVM should be reduced by 300kg, rather strange, I would suggest you redistribute the weight in the camper to make the
towball weight 199kg, problem solved.
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Offline batto

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #5 on: October 02, 2019, 08:57:27 PM »
Position on bridge doesnt matter as weight is weight, there are multiple load cells en each bridge plate for that reason. Option 2 is correct you are under GVM. GVM is inclusive of all weight imposed on vehicle including ball weight. So as long as axle weights are good and i would assume they are you are good to go legally. Regarding the extra 9kg bottle, adverse difference cant really say though all weight limits are conservative from manufacturers, the legal standing is cant ne done. This being that it exceeds manufacturers ratings, insurance may not payout in an event either. If a random check was done correctly you may end up with a fine over it even though all other weights are good. Cheers Batto.

Offline #jonesy

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #6 on: October 02, 2019, 09:58:14 PM »
Option 1 you are over.
With your ball weight GVM is less 300.

The weighbridge could do axle Weight as the approach and departure area should be on the same level.

The other question is do you know the rated  GCM? Which you weighed at 4200
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Offline baz1

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #7 on: October 02, 2019, 10:06:38 PM »
Option 1 you are over.
With your ball weight GVM is less 300.

Is the reduction of 300 not excluded, because we know the weight of the Nissan, its contents, and this weight also includes the weight of the camper on the ball, therefore we do not have to made an additional deduction to compensate for the ball weight (as its already been done)

The weighbridge could do axle Weight as the approach and departure area should be on the same level.

The other question is do you know the rated  GCM? Which you weighed at 4200

I'm afraid I have no idea what the rated GCM is.

Offline GBC

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #8 on: October 03, 2019, 06:55:07 AM »
Rear axle weight isn’t ball weight, it is ball weight plus lever weight from the towball to the centre of the rear axle. Your actual ball weight will be somewhat less than 200 kg (170/180 at a guess). You should be able to use a slightly easier gvm reduction figure.
When you get pulled over and weighed they will be checking your rear axle weight which you don’t know, and don’t know if you are in tolerance. This is important.
Were you full of fuel when weighed? Y62 patrols look to be tare weighted with no fuel. What model Nissan have you got?

Offline baz1

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #9 on: October 03, 2019, 07:09:05 AM »
Hi mate, we have a 2015 Nissan Pathfinder ST, it was full of fuel, and fully loaded.

Why do you think the ball weight would be less than 200kg as measured? I was told the tolerance on the weighbridge is plus / minus 20kg.

Offline Aaron Schubert

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #10 on: October 03, 2019, 07:49:45 AM »
I'd suggest you contact Nissan and ask for clarification. I would be surprised if they wanted to reduce the GVM by 300 and then take the tow ball weight off.

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Offline baz1

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #11 on: October 03, 2019, 08:01:56 AM »
This is the sticker on our Pathfinder, but I agree with you, I can’t see how we would be expected to take the total loaded weight of the Nissan, including the weight of the camper which is attached to the trailer, so this weight is taken into account, and then do a ‘double whammy’ and reduce the GVM by another 300kg, to take into account the weight of the camper, which we have already taken into account?


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Offline Fizzie

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #12 on: October 03, 2019, 08:24:23 AM »
Interesting bit I see on that label - "For Trailer Towing Only" ???

What, you aren't allowed to tow a caravan ???

What else would / could you tow if it's not a trailer ???
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Offline GBC

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #13 on: October 03, 2019, 08:57:03 AM »
Hi mate, we have a 2015 Nissan Pathfinder ST, it was full of fuel, and fully loaded.

Why do you think the ball weight would be less than 200kg as measured? I was told the tolerance on the weighbridge is plus / minus 20kg.

Because you measured axles, not ball weight.

You'll note that on your GVM reduction chart that for each 50KG of ball weight, they require you to reduce GVM by 90 KG.

That is because the 2nd class lever (long wheelbarrow handles theory) from the towball on the car to where the mass hits the ground (rear wheels), actually increases the ball weight of the trailer.
It also works in reverse, so it would pay you to get a mobile van weigher to come to your house and measure your actual ball weight because a bloke by the name of Archimedes guarantees it is going to be less the 200 k.g. and you need every break you can get.
Using that GVM reduction chart you can plot a line on an X/Y axis, and when you get your actual ball weight, you can look at exactly what your GVM reduction is going to be.
A mobile guy will also be able to check your rear axle weight because it looks like you only have 1415 kg to play with depending on the model you have and that is a more relevant figure if you wish to make it in and out of a transport department check unscathed.

Offline Bird

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #14 on: October 03, 2019, 09:04:43 AM »
Glad you asked? ROTFLMAO!!!!!!!!!!!!!!!!
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Offline DrewXT

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #15 on: October 03, 2019, 11:16:10 AM »
GCM for the Pathfinder is 5880kg so you're technically under GCM, but you need to factor in ball weight and axle loading.  I can't recall what the axles are rated at, but I'd suspect that's why you have to change vehicle weight as ball weight goes up.

A good engineer like the guys at Enklemans should be able to give you some advice over the phone, as they deal with these queries every day.

Bear in mind also that manufacturer axle ratings are usually very conservative, and that you can get you GVM upgraded, but no longer your GCM

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Offline Redback

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #16 on: October 03, 2019, 03:16:10 PM »
I know it's not your vehicle specs but they should be readily available from the net, here are our vehicle specs.

WEIGHTS(kg)

Kerb Weight 2,540kg(includes 75kg driver and fuel (80lts)

Gross Vehicle Weight (GVW) 3,240kg

Maximum mass on each axle (front) 1,450kg

Maximum mass on each axle (rear) 1,855kg

TOWING (kg)

Unbraked trailer 750kg

Maximum towing (Braked trailer) 3,500kg

Maximum coupling point/nose weight 350kg

Maximum vehicle and trailer combination/Gross Train Weight 6,740(GCM)
« Last Edit: October 03, 2019, 03:17:57 PM by Redback »
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Offline Merts

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #17 on: October 03, 2019, 04:11:37 PM »
Just an FYI for you and others. You can buy a ball weight scale from places like Autobarn or Supercheap which will give much more accurate figures than a weighbridge which has +/-20kg accuracy. They can be bought for around the $80 mark and are pretty useful for checking what effect shifting the load around in your van or camper has on the ball weight.
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Offline baz1

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #18 on: October 03, 2019, 04:29:40 PM »
If our towball was identified at 200kg, and GBC says its more likely 170-180kg, for reasons which i do not understand, but is consistent with what the guy at the weigh bridge was saying, it sounds like we are ok on that front.

I rang our local dealer where our vehicle is serviced, and trying to get a strait response was pretty difficult, but he seems to be of the view that if the total weight of the vehicle plus the weight on the ball of the vehicle is identified, which it was, then there is no need to reduce the GVM of the vehicle by the 300kg, as we have already taken into account the weight on the vehicles lowball, therefore there is no need to de-rate. That being said, i wasn't inspired with confidence by what the bloke said. So hopefully we are under the GVM.

That just leaves the axle weight, and who knows, as we never for it measured. Maybe that's one for next time we go to the weigh bridge. The rear axle weight limit of the Nissan is 1454kg, i can only hope that if we are under our GVM, we should be under the axle weight limit. To be honest, there isn't a huge amount we can do anyway, as we can't move any weight around, to put weight behind the axle of the camper trailer to reduce the weight on the rear of the Nissan, and its not like we can buy a new car.

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #19 on: October 03, 2019, 04:33:38 PM »
Just an FYI for you and others. You can buy a ball weight scale from places like Autobarn or Supercheap which will give much more accurate figures than a weighbridge which has +/-20kg accuracy. They can be bought for around the $80 mark and are pretty useful for checking what effect shifting the load around in your van or camper has on the ball weight.
yea theres another thread by this dude on that and how inaccurate they were :(
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Offline gronk

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #20 on: October 03, 2019, 06:48:55 PM »
Interesting bit I see on that label - "For Trailer Towing Only" ???

What, you aren't allowed to tow a caravan ???

What else would / could you tow if it's not a trailer ???

Not meant for any other purpose.....like snatching, pulling over trees, hanging the 4wd upside down from a cliff or any other stupid idea that a human could think up !!   ;D ;D
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Offline Merts

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #21 on: October 03, 2019, 08:43:57 PM »
yea theres another thread by this dude on that and how inaccurate they were :(

If you buy one that's certified to the relevant AS you will get a weight to the nearest 10kg.
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Offline gronk

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #22 on: October 03, 2019, 09:50:05 PM »
If you buy one that's certified to the relevant AS you will get a weight to the nearest 10kg.

Or you can use the bathroom scales...if done properly, accurate to the kilo.
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Offline IanS

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #23 on: October 03, 2019, 10:29:55 PM »
The easy way to get your rear axle weight is drive onto the bridge and weigh the front axle, drive forward and weigh both front and rear of tow vehicle (with trailer attached of course), subtract the front axle weight from the total and you have your rear axle weight. As you have already identified on a bridge with +/- 20kg accuracy your 200kg ball weight could be anywhere between 180kg and 220kg.

Offline Merts

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Re: Question About GVM Weight - Are We Under Or Over?
« Reply #24 on: October 03, 2019, 10:46:44 PM »
Or you can use the bathroom scales...if done properly, accurate to the kilo.
Yep. IF done properly....
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