I have a slightly smug smile, because at last other caravanners are actually realising the realities of how inadequate available nose weight gauges are. Quite simply to accurately measure the nose weight the height of the trailers hitch must be at the same height from the ground as when it is hitched to the tow vehicle. Measure it at any other height and you are not recording the true nose weight.
The reasons for this requirement stems from the fact that every trailer must produce a nose weight which is created by the effective position of the trailers center of gravity just forward of the main axle. The COG in a caravan is always located above chassis, so if the nose height changes (i.e. tilting the caravan) the horizontal for and aft position of the COG relative to the axle which affects the nose weight. This is relatively easy to understand for a single axle caravan , but it is far more complex with twin axles where there is an interaction between the suspension of the two axles which can change the nose weight by a substantial amount in only a few millemeters of hitch height adjustment.
Now it is a legitimate question about how accurate do you need to be? It is unclear how precise the authorities are when they look at nose weight, but the regulations are clear that the prescribed nose weight capacity of a tow bar is a limit and it is an offence to exceed it. So despite any margin of error a gauge has, it must always ensure you remain below the tow bar limit.
So it is important to be able to set the measurement height.
It is well within the capabilities of manufactures to make a weight measuring device with a consistent weight measuring accuracy of +/-1% or 2Kg in 100Kg. I would suggest that is a reasonable degree of accuracy for this type of measurement.
Some commercial nose weight gauges have substantially under read a trailers actual nose weight, One must also assume that some gauges must over read, but whether its the same margin of error or not, regardless its scandalous that manufactures are allowed to sell gauges with such little accuracy yet are sold to help users stay legal.
There is an alternative commercial type of nose weight gauge that sits on top of the cars tow hitch. Even these alter the height of the hitch when measuring, and consequently they do not measure the exact nose weight. However one manufacturer claims they have compensated for this height and the corrected result is displayed.
Now this claim is tenuous, because the factors that determine the rate of change of nose weight with change in hitch height are not same for every caravan. So again a manufacture is making an generalised assumption. To be fair the difference may be relatively small between caravans, but never the less it is still a compromise.
The same manufacture recognises the problem because they tell users of the device not to use it on TA caravans. They have another model to cope with the dynamics of TA's
The point is that using a pair of bathroom scales and a well designed support reasonably accurate nose weight measurements can be made without spending a fortune on a special product with just one use.
The reasons for this requirement stems from the fact that every trailer must produce a nose weight which is created by the effective position of the trailers center of gravity just forward of the main axle. The COG in a caravan is always located above chassis, so if the nose height changes (i.e. tilting the caravan) the horizontal for and aft position of the COG relative to the axle which affects the nose weight. This is relatively easy to understand for a single axle caravan , but it is far more complex with twin axles where there is an interaction between the suspension of the two axles which can change the nose weight by a substantial amount in only a few millemeters of hitch height adjustment.
Now it is a legitimate question about how accurate do you need to be? It is unclear how precise the authorities are when they look at nose weight, but the regulations are clear that the prescribed nose weight capacity of a tow bar is a limit and it is an offence to exceed it. So despite any margin of error a gauge has, it must always ensure you remain below the tow bar limit.
So it is important to be able to set the measurement height.
It is well within the capabilities of manufactures to make a weight measuring device with a consistent weight measuring accuracy of +/-1% or 2Kg in 100Kg. I would suggest that is a reasonable degree of accuracy for this type of measurement.
Some commercial nose weight gauges have substantially under read a trailers actual nose weight, One must also assume that some gauges must over read, but whether its the same margin of error or not, regardless its scandalous that manufactures are allowed to sell gauges with such little accuracy yet are sold to help users stay legal.
There is an alternative commercial type of nose weight gauge that sits on top of the cars tow hitch. Even these alter the height of the hitch when measuring, and consequently they do not measure the exact nose weight. However one manufacturer claims they have compensated for this height and the corrected result is displayed.
Now this claim is tenuous, because the factors that determine the rate of change of nose weight with change in hitch height are not same for every caravan. So again a manufacture is making an generalised assumption. To be fair the difference may be relatively small between caravans, but never the less it is still a compromise.
The same manufacture recognises the problem because they tell users of the device not to use it on TA caravans. They have another model to cope with the dynamics of TA's
The point is that using a pair of bathroom scales and a well designed support reasonably accurate nose weight measurements can be made without spending a fortune on a special product with just one use.
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