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In the last two issues, we've explained how to
determine the weight-carrying limits of your tow
vehicle and your caravan as separate vehicles. In
this issue, we will look at what happens when you
combine the two and, trust me, this is where it
gets very interesting.
LOADED BALL
You will recall we discussed Gross Vehicle Mass
(GVM) and Gross Combined Mass (GCM) and
what they mean in real terms. These two
ratings now come into play and, as we will
see, depending on the type of tow vehicle you
have, one will end up being more important
than the other.
When you connect a trailer to a tow vehicle,
the towball mass of the trailer is transferred
to the tow vehicle in much the same way as
putting any weight into the vehicle itself.
This transfer of mass is the source of
much confusion among drivers trying
to assess if their rig is legal and safe.
The key to understanding this is to realise
that the towball mass doesn't magically
disappear from the trailer's weight. It is
still there; however, rather than resting
on the jockey wheel, it now rests on the
rear of the tow vehicle and it must be
factored into the weight calculations.
The best way to understand this is to
look at a few examples…
The Y62 Patrol is a solid tow
vehicle but the GVM is reduced
depending on towball mass.
gorv.com.au
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