checks are vital
Caravan Council of Australia discusses
the nuts and bolts of keeping safe
Have your say
CARAVANNERS have been urged to keep a
closer eye on their RV's wheel nuts.
The Caravan Council of Australia's general manager, Colin Young, said the
CCA continually received reports of broken or
loose wheel studs.
"Sometimes the nuts unwind completely off the studs," he said.
"It must be stressed that if a stud breaks, it is certainly no proof that
the stud itself was faulty. There are a number of reasons for the
Mr Young advised caravanners to precisely follow all supplied instructions
regarding wheels and wheel nuts.
"It is vital to ensure that if owners or dealers fit aftermarket wheels
and nuts, they thoroughly check to ensure the replacement wheels and nuts
are completely suitable for the vehicle and axles."
Possible reasons for problems include:
* The pitch circle of the studs in the (imperial) hub not exactly the same
as that of the holes in some (metric) wheels, such that all studs bend
when the nuts are tightened
* The angle of the taper on the nuts not the same as the angle of taper in
* Low-grade steel studs being used
* The hole in the wheel centre not compatible with the spigot diameter of
* The serrated studs not 'fully driven home' when pressed into the hubs,
so they gradually 'give a little' and cause the nuts to become loose
* Rattle-guns used to tighten rather than to undo wheel nuts set at
unknown high-torque levels, causing the studs to stretch and become
* Nuts being tightened in a circular pattern in one action, rather than in
a criss-cross pattern, using two or three (increasing) torques
* Wheel centres being highly dished, thus acting as a large spring-washer
that gradually looses its tension and causes the nuts to loosen
"Clearly, all nuts must be tightened to the correct torque, and in the
correct pattern, in strict accordance with the instructions provided by
the wheel or chassis manufacturer," Mr Young said.
"It is strongly recommended that pencil lines are made on one face of each
nut ‒ with a mating line on the wheel
‒ so that a quick visual inspection can detect
any loosening of a nut."
Clip-on plastic 'indicators' ‒ fitted to each
nut with their adjacent 'arrow-heads' aligned ‒
provided an even-quicker warning of any nut loosening.
Mr Young said that continual vibrations and occasional heavy impacts from
road surfaces inevitably had an adverse effect
on the wheel assemblies.
This was severely aggravated if the tyre pressures and spring rating
were too high for the actual wheel-loading.
"Stresses on the wheel assemblies are further increased if shock
absorbers (dampers) are not fitted.
"Leaf springs do provide some damping of
vibrations, but unfortunately it is mainly on the 'bump' (upwards)
movement of the wheel rather than on the 'rebound' (downwards) movement of
the wheel … where it would be far more beneficial."
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