Author Topic: Question About GVM Weight - Are We Under Or Over?  (Read 11385 times)

0 Members and 1 Guest are viewing this topic.

Offline edz

  • Hard Top Camper User
  • ******
  • Posts: 6880
  • Thanked: 926 times
  • Gender: Male
  • " I dont like Sheeple "
« Last Edit: October 03, 2019, 11:14:06 PM by edz »
" IMPROVISE  ADAPT   OVERCOME   and  PERSEVERE  "

Offline #jonesy

  • Hard Floor Camper User
  • *****
  • Posts: 1326
  • Thanked: 163 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #26 on: October 04, 2019, 06:20:15 AM »
What the dealer said was wrong.
Yes you have towball weight, so GVM is decreased. Yes you still have to include that weight in the total weighed GVM.

Weighbridge accuracy is 20kg, because of the increments it can show, i.e 20, 40, 60 etc.
It can't show 50, 55, 56

Even if you ball weight is 180, and you reduce GVM by 210 instead of 300, you are still over.

To suggest it is 170/180 without weighing or seeing it is fraught with danger. The 200 as calculated by the weighbridge is the most accurate you have at the moment.
The best way would be to have a post the same height as the towball (when loaded) put that on the scale and lower the coupling on.

Also looking at you car specs for axle load, their total is only 65kg, (< 1 person) over GVM.  so you would have to get your load fairly well balanced.

As GBC said your rear axle weight, is what I'd be looking at if you to do anything. Put front axle on plate, trailer attached and subtract that from your GVM as weighed.


Towball scales aren't great. I've got one and can get reading between 90 and 190 kg for exactly the same setup, depending on how I use it.

I know you said you can't, but anything out of the car to the rear of the camper will help more than its weight.  10 kg out of car is -10 off GVM. Add it to the rear of the trailer, and it will also reduce ballweight, and GVM even further.

In reality you should be fine, I'd keep in mind rear axle Weight for next time.
2013 Aussie Jays - Crusher      2013 Toyota Hilux. 

Offline Redback

  • Hard Top Camper User
  • ******
  • Posts: 1931
  • Thanked: 26 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #27 on: October 04, 2019, 08:35:46 AM »
I agree with Jonesy, once you find out what your rear axle max weight  is, go from there, I wouldn't stress too much a few kilos over won't be a problem if you do get pulled over, which I doubt you will, as long as your setup looks nice and level it shouldn't be an issue.

Unlike some of these grey nomads that drive around with the arse of the car dragging on the ground >:D
Cheers Baz.

2011 Discovery 4 TDV6
1990 Perentie FFR  
Lightweight Camper.
1973 Kawasaki H2a 750 
1979 BMW R80/7
1983 BMW R100RT ex Police
2006 BMW R1200GS
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fool

Offline Fizzie

  • Hard Top Camper User
  • ******
  • Posts: 5067
  • Thanked: 753 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #28 on: October 04, 2019, 09:10:54 AM »
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

Thanks, Gronk - makes sense! :-[
Winner PotM comp Jan 2021!

Isuzu: 2017 MU-X LST
Coromal: 2023 Soul Seeker 18'
Sunnie:  2010 Sunliner Holiday

Offline Merts

  • Soft Floor Camper User
  • ****
  • Posts: 364
  • Thanked: 53 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #29 on: October 04, 2019, 01:40:53 PM »
Towball scales aren't great. I've got one and can get reading between 90 and 190 kg for exactly the same setup, depending on how I use it.

100kg variance? They are just a spring inside a couple of tubes and the spring will compress at a known rate for any given load. Unless the tubes are binding or something like that it's simply not possible for the readings to vary that much. I've used mine a few times and whilst I don't know exactly how accurate it is, it reads the same each time unless I alter the weight in the camper.
Towing a a National Campers 'Hermit 10' hybrid with an MQ Triton. Previously towed an Outback Campers 'Sturt' softfloor. (PM me if you want to buy the Sturt!)

Offline Bird

  • Once Was Lost, now am found
  • Hard Top Camper User
  • ******
  • Posts: I am a geek!!
  • Thanked: 1874 times
  • Gender: Male
  • Life is far too long....
    • My Place.
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #30 on: October 04, 2019, 01:53:21 PM »
Quote from: Merts
100kg variance? They are just a spring inside a couple of tubes and the spring will compress at a known rate for any given load. Unless the tubes are binding or something like that it's simply not possible for the readings to vary that much. I've used mine a few times and whilst I don't know exactly how accurate it is, it reads the same each time unless I alter the weight in the camper.

it should be simple...
but its not unusual which is what I was saying earlier.. 50kg diff in weighbridge and towball scales.. 2 people in my club with towball scales.. both give massive reading differences.

'He then went home, and used a tow ball weigh scale from somewhere like BCF, no change to the load, it comes in at 110kg. How would you account for a 50kg difference, and which one would you trust?'

http://www.myswag.org/index.php?topic=56655.0
-
Click to enlarge

Gone to a new home

Offline #jonesy

  • Hard Floor Camper User
  • *****
  • Posts: 1326
  • Thanked: 163 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #31 on: October 04, 2019, 02:04:47 PM »
100kg variance? They are just a spring inside a couple of tubes and the spring will compress at a known rate for any given load. Unless the tubes are binding or something like that it's simply not possible for the readings to vary that much. I've used mine a few times and whilst I don't know exactly how accurate it is, it reads the same each time unless I alter the weight in the camper.


http://www.myswag.org/index.php?topic=56655.msg996294#msg996294

Has how I managed to achieve wildly different readings.  I couldn't and get it to bounce up and down like a normal spring type bathroom scale.
2013 Aussie Jays - Crusher      2013 Toyota Hilux. 

Offline Merts

  • Soft Floor Camper User
  • ****
  • Posts: 364
  • Thanked: 53 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #32 on: October 04, 2019, 02:17:53 PM »
http://www.myswag.org/index.php?topic=56655.msg996294#msg996294

Has how I managed to achieve wildly different readings.  I couldn't and get it to bounce up and down like a normal spring type bathroom scale.


That is pretty bad. It seems like it's binding between the two sections that are supposed to move smoothly. I'd take it back for a refund.
Towing a a National Campers 'Hermit 10' hybrid with an MQ Triton. Previously towed an Outback Campers 'Sturt' softfloor. (PM me if you want to buy the Sturt!)

Offline weeds

  • Hard Top Camper User
  • ******
  • Posts: 2149
  • Thanked: 164 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #33 on: June 17, 2020, 08:57:26 AM »
Off for a weigh in today...after new fitout


Sent from my iPhone using Tapatalk Pro

Offline NZMarkb

  • Hard Floor Camper User
  • *****
  • Posts: 1202
  • Thanked: 163 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #34 on: June 17, 2020, 09:07:23 AM »
This is well worth watching
Very good explanations

https://www.youtube.com/watch?v=Gv394M0ZMqo

If your not prepaired to stand behind our troops
Then feel free to stand in front of them
The following users thanked this post: Fizzie

Offline Wazza999

  • Soft Floor Camper User
  • ****
  • Posts: 307
  • Thanked: 31 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #35 on: June 17, 2020, 09:46:37 AM »
Something to keep in mind is that all errors are additive. This means that a weighbridge with an accuracy of +/-20 kg is effectively useless to calculate a ball weight. If each measurement is +/-20 kg, the calculated ball weight will be +/-40 kg. A result of 200 +/-40 kg is not really a useful figure. Even if measured directly on the weighbridge you get 200 +/-20 kg, again not terribly useful if 200 kg is an important value.

2011 NT Pajero; 2007 Goldstream Crown 4B

NT Pajero/2007 Goldstream Crown

Offline Fizzie

  • Hard Top Camper User
  • ******
  • Posts: 5067
  • Thanked: 753 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #36 on: June 17, 2020, 10:24:25 AM »
This is well worth watching
Very good explanations

https://www.youtube.com/watch?v=Gv394M0ZMqo

Thanks for that Mark!

Might have to give them a call ???

Another link to when the two of them had their own weight checked

https://youtu.be/T_DNf0v1zMQ?t=867
Winner PotM comp Jan 2021!

Isuzu: 2017 MU-X LST
Coromal: 2023 Soul Seeker 18'
Sunnie:  2010 Sunliner Holiday

Offline weeds

  • Hard Top Camper User
  • ******
  • Posts: 2149
  • Thanked: 164 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #37 on: June 17, 2020, 01:26:25 PM »
Something to keep in mind is that all errors are additive. This means that a weighbridge with an accuracy of +/-20 kg is effectively useless to calculate a ball weight. If each measurement is +/-20 kg, the calculated ball weight will be +/-40 kg. A result of 200 +/-40 kg is not really a useful figure. Even if measured directly on the weighbridge you get 200 +/-20 kg, again not terribly useful if 200 kg is an important value.

2011 NT Pajero; 2007 Goldstream Crown 4B

In my experience, most public weigh bridges go up and down in 20kg increments...therefore the weight displayed can only be +/- 10kg....I’m not sure how your getting 40kg as a total error.

I’d say that’s pretty good for doing axle weights, tare, GVM and GCVM.

For towball weights on a weigh bridge which I ’ve done this many time, again not 100% accurate as your not measuring from the tow ball, it’s either at the jockey wheel or rear axle.

Either way, if your within +/- 10kg off your max. weights on a weigh bridge than it’s time to maybe monitoring things.


Sent from my iPhone using Tapatalk Pro

Offline weeds

  • Hard Top Camper User
  • ******
  • Posts: 2149
  • Thanked: 164 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #38 on: June 17, 2020, 01:33:42 PM »
Just rolled over a weight bridge...free as I didn’t want a docket although it helps when we use recycle steel with them.

Just picked the car up with new fitout, empty apart from driver at 100kg and full tank of fuel

1200 front axle
1440 rear axle
2640 tare

3050 GVM

410kg pay load available......hmm, be interesting to see Touring weight.



Sent from my iPhone using Tapatalk Pro

Offline Fizzie

  • Hard Top Camper User
  • ******
  • Posts: 5067
  • Thanked: 753 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #39 on: June 17, 2020, 02:17:48 PM »
Either way, if your within +/- 10kg off your max. weights on a weigh bridge than it’s time to maybe monitoring things.

I agree, but I noticed that the people in those videos ^^, mentioned an "80kg tolerance" ???

Anybody heard of that before ???
Winner PotM comp Jan 2021!

Isuzu: 2017 MU-X LST
Coromal: 2023 Soul Seeker 18'
Sunnie:  2010 Sunliner Holiday

Offline Wazza999

  • Soft Floor Camper User
  • ****
  • Posts: 307
  • Thanked: 31 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #40 on: June 17, 2020, 02:46:54 PM »
G'day weeds, The original poster quoted the weighbridge operator saying +/-20 kg. I agree it's most likely +/-10 kg. The point though is the additive nature of the errors, so for a 200 kg difference you would get +/-20 kg or 10%. Then if 200 kg triggers  a step change in capacity it is still problematic.

2011 NT Pajero; 2007 Goldstream Crown 4B

NT Pajero/2007 Goldstream Crown

Offline weeds

  • Hard Top Camper User
  • ******
  • Posts: 2149
  • Thanked: 164 times
  • Gender: Male
Re: Question About GVM Weight - Are We Under Or Over?
« Reply #41 on: June 28, 2020, 12:46:37 PM »
An option on the north side of Brisbane.....at least they advertise a price.

http://www.aussieescapecaravans.com.au/page/weigh-to-go/

Think they have a special @ $100 at the moment


Sent from my iPhone using Tapatalk Pro