Last year brought the Pro series tow ball weight scales, haven't used them yet, but I noticed that my max tow bar ball weight is 350kg, the max weight marked on the scales is 350kg.
But has anyone questioned the accuracy of these, and how would one go about testing it to see how accurate it is.
Its basicly just a tube and spring, the markings could be meaningless.
Possum3 said
02:50 PM Feb 4, 2018
Ian you could check accuracy by placing hitch on a board (in centre), put the towball scale on one end and support other end of board with pavers or similar - if the hitch is placed in exact middle between supported end and towball scale the weight displayed should be half of the displayed weight measured at ball - if weight displayed is either more or less by a Kg. - the scale is incorrect. Otherwise you could weigh something with a known mass.
iana said
06:02 PM Feb 4, 2018
Just did a rough check using a bridge across two bathroom scales, with the tow ball scales sitting on top, under the chassis of the ute, using a trolley jack. Found the tow ball scales to be reading about 15kg more than the bathroom scales.
-- Edited by iana on Sunday 4th of February 2018 06:03:05 PM
aussie_paul said
06:14 PM Feb 4, 2018
iana wrote:
Just did a rough check using a bridge across two bathroom scales, with the tow ball scales sitting on top, under the chassis of the ute, using a trolley jack. Found the tow ball scales to be reading about 15kg more than the bathroom scales.
-- Edited by iana on Sunday 4th of February 2018 06:03:05 PM
Now, that is annoying...
Aussie Paul.
iana said
06:25 PM Feb 4, 2018
What is annoying is not knowing if its the bathroom scales or the tow bar scales which are out, however I won't dwell on it as the tow ball weight I have, 15kg will make little difference. Soon it will be another trip to the weigh bridge.
Stephcott said
08:48 PM Feb 4, 2018
Only accurate way to check the scales against a weighbridge. My scales are about 10kg out.
villatranquilla said
08:58 PM Feb 4, 2018
when I was booking our van in for a service I noticed they had towball scales rated to 400kg for sale for $50 - so I bought some. First time I used them the ball weight showed 340kg - then did it again 10 mins later and they read 400 - mmm. So asked the service centre to do the ball weight when it went in for the service - came back as 320kg so took the scales back and they were happy to give a refund when I explained.
Will take it over the weighbridge before the next trip.
-- Edited by villatranquilla on Sunday 4th of February 2018 08:59:30 PM
Brenda and Alan said
08:50 AM Feb 5, 2018
Weighbridges are not accurate to the degree that you think. They are affected by all sorts of environmental conditions such as wind speed and direction,temperature, wet ,dry or actually raining as well as other factors. As an example the National Heavy Vehicle Regulator allows for an error or +/- 250 Kgs on a single weighing of gross mass of a heavy vehicle before a penalty is applied. Google "Heavy Vehicle Regulator weight adjustment"
Alan
-- Edited by Brenda and Alan on Monday 5th of February 2018 08:55:46 AM
PeterD said
08:20 AM Feb 7, 2018
Stephcott wrote:
Only accurate way to check the scales against a weighbridge. My scales are about 10kg out.
Are you sure they are 10 kg out? Most weighbridges are only calibrated to the nearest 20 kg. If your test bridge was one of those then your scales could have been more accurate than the bridge.
PeterD said
08:24 AM Feb 7, 2018
One thing to watch is that the van coupling is at the same height as it would be when coupled to the van. This is particularly important with dual axle vans that do not have load sharing suspension.
rockylizard said
08:27 AM Feb 7, 2018
Gday...
It is very interesting reading through this thread.
From the answers provided it seems that -
a dedicated ball weight scale is rarely accurate - with considerable variance;
bathroom scales set-up is only a 'best guess';
and weighbridges are variously calibrated in increments that make it very hard to get an accurate figure.
If my interpretation of the advice provided is correct, so just how does one get an ACCURATE TBM?
Cheers - John
iana said
10:57 AM Feb 7, 2018
Now that, John is the main question. And if and only if one was to be weighed by the authorities, what is their allowable tolerance to allow for this.
So long as I can be within the allowable and have about 6-10% ball weight, I'll be happy.
PeterD said
11:13 AM Feb 7, 2018
I would not get too hung up on weights. If your tow bar has a say 250 kg maximum load then aim for a ball weight unless you are going to weigh the van every time you hitch up. You never know how the navigator is going to rearrange the van and through all your weights out. If the authorities start checking us then the time you get weighed is bound to be the time the navigator upsets things. I'm not worried much about a 10% variance in the ball weight if I keep it down to allow for such things. At the last weighing our total weight was 50 kg below the ATM, I suppose I should get it checked next trip to see what loading she has sneaked into the van.
Craig1 said
08:42 PM Jan 5, 2019
Auto barn have Hayman Reese tow ball scales at the moment $49.99. No affiliation , just had pleasant service
fwdoz said
08:52 PM Jan 5, 2019
I have the Hayman Reese ones. Accurate to within 5kgs compared to my weighbridge readings.
Last year brought the Pro series tow ball weight scales, haven't used them yet, but I noticed that my max tow bar ball weight is 350kg, the max weight marked on the scales is 350kg.
But has anyone questioned the accuracy of these, and how would one go about testing it to see how accurate it is.
Its basicly just a tube and spring, the markings could be meaningless.
Just did a rough check using a bridge across two bathroom scales, with the tow ball scales sitting on top, under the chassis of the ute, using a trolley jack. Found the tow ball scales to be reading about 15kg more than the bathroom scales.
-- Edited by iana on Sunday 4th of February 2018 06:03:05 PM
Now, that is annoying...
Aussie Paul.
when I was booking our van in for a service I noticed they had towball scales rated to 400kg for sale for $50 - so I bought some. First time I used them the ball weight showed 340kg - then did it again 10 mins later and they read 400 - mmm.
So asked the service centre to do the ball weight when it went in for the service - came back as 320kg so took the scales back and they were happy to give a refund when I explained.
Will take it over the weighbridge before the next trip.
-- Edited by villatranquilla on Sunday 4th of February 2018 08:59:30 PM
Weighbridges are not accurate to the degree that you think. They are affected by all sorts of environmental conditions such as wind speed and direction,temperature, wet ,dry or actually raining as well as other factors. As an example the National Heavy Vehicle Regulator allows for an error or +/- 250 Kgs on a single weighing of gross mass of a heavy vehicle before a penalty is applied. Google "Heavy Vehicle Regulator weight adjustment"
Alan
-- Edited by Brenda and Alan on Monday 5th of February 2018 08:55:46 AM
Are you sure they are 10 kg out? Most weighbridges are only calibrated to the nearest 20 kg. If your test bridge was one of those then your scales could have been more accurate than the bridge.
Gday...
It is very interesting reading through this thread.
From the answers provided it seems that -
If my interpretation of the advice provided is correct, so just how does one get an ACCURATE TBM?
Cheers - John
So long as I can be within the allowable and have about 6-10% ball weight, I'll be happy.
I have the Hayman Reese ones. Accurate to within 5kgs compared to my weighbridge readings.