So you’re about to head off on a Big Lap.
Better pack lots of spare parts for the tow
vehicle, and what’s the harm in fitting a second
spare wheel to the caravan’s rear bumper?
Another spare tyre is bound to be useful.
Actually, adding that weight to the rear of the
van could be a lot more harmful than you
might think.
First, ask yourself: does your caravan really
need two spare wheels? Your tow vehicle,
after all, is supplied with only one, and it’s a
fair bet that it spends much more time on the
road than your van ever will.
There are plenty of caravans, however, that
are supplied with two spare wheels mounted
to the rear bumper as standard. But there’s a
crucial difference between this scenario and a
hypothetical scenario in which a second spare
is added as an aftermarket item.
When supplying two spare wheels, the
manufacturer should have accounted for the
weight of these items in the overall design of
the caravan. Importantly, this includes the
position of the van’s axle(s), and calculating
the correct amount of rear overhang the van
should have relative to that extra weight.
Better to load that heavy equipment
towards the front of the van.
Furthermore, bunging on an extra spare wheel
will inevitable increase the stress on the
chassis. Welds and other joins that were not
designed to cope with that additional stress
are bound to be the first point of failure.
And then there’s the ‘bounce factor’. As it is
towed, every caravan will ‘bounce’ a little at
the back. Have you ever entered your van
after towing and found your toothbrush or
the shower rose on the floor? That’s probably
due to this rear bounce, which in a properly
setup van, with load properly distributed,
should be minimal.
Think of your caravan as a
barbell loaded with weights,
with the centre of the bar being
the pivot point (the axle/s). The
greater the weight either end,
the greater the chance of sway
and the harder it is to stop it
once it starts. This is especially
true with too much weight at
the rear, where there isn't a tow
vehicle to counteract the forces
that induce sway.