Are individually weighed, loaded, axles (on a semi-trailer and tractor unit) a reliable guide to the gross train weight of the vehicle?
In other words — whilst scales that measure the weight on a single axle at a time can determine “axle weights”, will all six axle weights, when added together, then give the accurate Gross Train Weight? I suspect that it might not, and that the GTW can only be determined on a full-size weighbridge — can anyone confirm either way (and if not, is the gross weight likely to be higher or lower than the total of all the axle readings)?
Axle weights will usually add up to more than the plated gross weight to allow for various positioning of the load
GVW must not be exceeded
Individual Axle weights must not be exceeded
The GTW must not be exceeded
If all those are ticked as ok then fine
What cannot be done is for the axle weights to be loaded to their max on the towing vehicle and the trailer to be under weight so that it just complies with the GTW and the MAM of the trailer because that would leave the GVW of the towing vehicle over the permitted max
I’m going to hazard a guess here with a bit of logic, or not…
the total weight of the vehicle and load will be transferred through the axles so should get you the same weight.
Haystack:
Are individually weighed, loaded, axles (on a semi-trailer and tractor unit) a reliable guide to the gross train weight of the vehicle?
In other words — whilst scales that measure the weight on a single axle at a time can determine “axle weights”, will all six axle weights, when added together, then give the accurate Gross Train Weight? I suspect that it might not, and that the GTW can only be determined on a full-size weighbridge — can anyone confirm either way (and if not, is the gross weight likely to be higher or lower than the total of all the axle readings)?
so, if the total of the 6 axles does not equal the GTW on an axle weigher, can you please explain how it can equal the GTW on a full size weighbridge?
after all, you are putting the same 6 axles over the weighbridge as you would over an individual axle weigher
personally, the axle weigher is a better method, this way it shows if you are overweight on an axle, as you can be overweight on one axle, but under the MGW of 44 tonne
shuttlespanker:
so, if the total of the 6 axles does not equal the GTW on an axle weigher, can you please explain how it can equal the GTW on a full size weighbridge?
after all, you are putting the same 6 axles over the weighbridge as you would over an individual axle weigher
personally, the axle weigher is a better method, this way it shows if you are overweight on an axle, as you can be overweight on one axle, but under the MGW of 44 tonne
That wasn’t what he said. It DOES equal the gross train weight it would when you add them all up the same as it would on a fullsize weighbridge. However as you pointed out you can be over on an axle and still under the GVW.
And the combined PLATED weight of all the axles actually exceeds the total GVW. For example, take a 6x2 with a tri-axle trailer. Each of the trailer axles will be rated at 8 tonne each, 24 tonnes in total. The front steering axle of the unit will be 6.5t, the mid axle 5.5t and the drive axle 10.5 tonnes totalling 22.5 tonnes. Add the trailer plated axle weights and you’ve got 46.5 tonnes, 2.5 tonnes more than the max GVW.
shuttlespanker:
so, if the total of the 6 axles does not equal the GTW on an axle weigher, can you please explain how it can equal the GTW on a full size weighbridge?
after all, you are putting the same 6 axles over the weighbridge as you would over an individual axle weigher
personally, the axle weigher is a better method, this way it shows if you are overweight on an axle, as you can be overweight on one axle, but under the MGW of 44 tonne
That wasn’t what he said. It DOES equal the gross train weight it would when you add them all up the same as it would on a fullsize weighbridge. However as you pointed out you can be over on an axle and still under the GVW.
And the combined PLATED weight of all the axles actually exceeds the total GVW. For example, take a 6x2 with a tri-axle trailer. Each of the trailer axles will be rated at 8 tonne each, 24 tonnes in total. The front steering axle of the unit will be 6.5t, the mid axle 5.5t and the drive axle 10.5 tonnes totalling 22.5 tonnes. Add the trailer plated axle weights and you’ve got 46.5 tonnes, 2.5 tonnes more than the max GVW.
yes it is what he said
you have been very selective on your quoting again Conor
Haystack:
will all six axle weights, when added together, then give the accurate Gross Train Weight? I suspect that it might not
Haystack:
Are individually weighed, loaded, axles (on a semi-trailer and tractor unit) a reliable guide to the gross train weight of the vehicle?
Yes.
Correctly used, an axle weighbridge will produce the same gross weight as a static weighbridge.
It will not, if the vehicle is driven over it too fast or too slow, or, in the case of a liquid load,
enough time has not been allowed for the surge to settle.
Haystack:
Are individually weighed, loaded, axles (on a semi-trailer and tractor unit) a reliable guide to the gross train weight of the vehicle?
Yes.
Correctly used, an axle weighbridge will produce the same gross weight as a static weighbridge.
It will not, if the vehicle is driven over it too fast or too slow, or, in the case of a liquid load,
enough time has not been allowed for the surge to settle.
Regards,
Nick.
Generally a liquid tanker with a slack load will be given the benefit of the doubt, but as most tanker loads are weighed at the loading point, it is less of a problem than someone collecting 26 pallets that are allegedly one tonne each.
Even if there isn’t a weigh bridge available the driver can be very accurate using a calibrated dipstick or ullage chart.
The other thing is that you cannot adjust the load in a single compartment tanker
Hiya… your better going onto a axel weighbridge then a weigh plate if your unsure…a pal of mine who did
spuds from farms a few years back new he had a percentage on each axel… so at 38 tons on 6 axels plus
his percentage could get away with nealy 41 tons…but on a weigh plate it was 38 tons dead…
dodgy mate…but a good one
John
