RV FEATURE
Police can and do conduct roadside
checks to ensure Gross Combined
Mass is not exceeded.
GCM rating displayed on their compliance
plate – surprising, given how important it is.
Fortunately most will have this specification
listed in the user manual or on the
manufacturer's website. the engine, transmission or even wheels and
tyres. The Land Rover Discovery 5 TD4 has a
GCM of 6090kg. The SD4 variant has a GCM
of 6630kg. The top spec TD6 has a GCM of
6670kg.
Be careful, as some manufacturers don't call
it GCM. Land Rover, for example, calls it Gross
Train Weight or GTM. Other manufacturers
may refer to Gross Combined Weight Rating
or GCWR. Another term used is Maximum
Authorised Mass or MAM. How GCM is calculated is also something of
a mystery. Logic would say that it should be
equal to the tow vehicle's Gross Vehicle Mass
(GVM) plus its maximum towing capacity, and
for many manufacturers that's exactly how it
is calculated.
To make matters more confusing, some
manufacturers have a different GCM rating
for the same model of vehicle, depending on For others, there doesn't seem to be any logic
behind how the figure is calculated. See the
table on page 16.
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