Caravan Tyres
Most caravan owners know that it is critically
important to have safe and legal tyres. Yet each year
many serious accidents occur and numbers of caravans are
destroyed because this most obvious fact is overlooked.
The reason why caravan tyres are frequently overlooked
is that they are often half hidden under the caravan.
Few people pay much attention to their tyres anyway.
Also it is not easy to interpret the sidewall markings
to ascertain the date of manufacture to see if the tyres
are too old. Additionally it is not easy to maneuver a
caravan in and out of a tyre depot. etyres mobile
service answers all these difficulties because we come
to you. We are fully conversant with all aspects of
supplying and fitting caravan tyres. And we do this with
our mobile tyre fitting vans at your selected location.
Most caravans are fitted with 13 inch tyres but 14 inch
tyres are now being widely used on new models. The
reason for this is twofold. Firstly the larger sizes of
caravan tyres provide additional stability and secondly,
as most tyre retailers do not carry large stocks of
caravan tyres they, perfectly correctly, satisfy orders
by using regular commercial tyres which do not
frequently occur in 13 inch. The same applies on the
Continent where specialists who sell caravan tyres are
few and far between. Common sizes of caravan tyres are
175/80/13c (8 ply), 165/80/13c (8 ply), 155/80/13c
(8ply) and 185/65/14c (8ply).
Unless a lot of touring miles are covered it is unlikely
that you will wear out your caravan tyres. Like any
other tyres caravan tyres deteriorate with age.
Organisations such as the Tyre Industry Council and the
British Rubber Manufacturers’ Association advise a
caravan tyre life limit of between seven and ten years.
However after as little as five years caravan tyres can
become distorted if they are left unused in the same
position. Also surface cracking of the sidewalls can
occur if the tyres are allowed to become under-inflated
and remain for a long period of time in that condition.
Caravan tyres, like all car or light commercial tyres
must have a minimum tread depth of 1.6mm in order to be
legal and roadworthy. However, due to the infrequent use
and low mileage of many caravan tyres it is good
practice to consider replacing them after five years,
regardless of the amount of remaining tread. At the end
of this section we include a paragraph entitled
“Manufacturing dates of caravan tyres”. This is designed
to assist you in reading the sidewall marking of your
caravan tyres. This shows how to establish the date of
manufacture.
In some European countries the minimum tread depth for
all car, light commercial and caravan tyres is 2mm. So
it is possible to drive legally as far as the boarder of
a neighbouring country only to become immediately
illegal as soon as you drive on foreign roads. Prior
checking of your caravan tyres is therefore vital.
Sidewall impact damage of caravan tyres is quite common
because of the relative ease with which kerbs can be
clipped while towing. The high stress loading when a
sidewall impact occurs causes the plys of the tyre
sidewall to delaminate. This is sometimes, but not
always, visible if air escapes and forms a bubble
between the plys. The invisible damage is obviously of
greater potential danger. During cornering the load on
caravan tyres can be up to 1? tonnes. For motor caravans
the load factor can even be as high as 3 tonnes. So it
is not surprising that sidewall impacts can easily cause
irreparable damage. A bulge in the sidewall of any tyre
cannot be repaired and calls for immediate replacement.
All caravan tyres are designed to carry a specific load
or weight, an overloaded tyre will quickly overheat.
This greatly increases the risk of the tyre blowing out.
For single axle caravans this is particularly dangerous.
The Load Index is shown on the sidewall of all caravan
tyres immediately behind the size coding and in front of
the speed letter code. A typical example will be:-
175/80/R/13 97T.
175 is the tyre width in millimeters, 80 is the
sidewall height, expressed as a percentage of the
width.R indicates a radial type construction.13 is the
wheel diameter in inches.97 is the Load Index. T is the
speed rating. The load rating is a very important factor
with all caravan tyres. It is not sensible to compromise
by fitting a regular car tyre instead of a properly load
rated caravan tyre.
In fact in most cases this is actually false economy
because there is little or no difference in price. The
compromise often occurs because the correct tyre is not
available. Ordering from etyres overcomes this problem.
To be legal, and safe, a single axle caravan must have
tyres designated as suitable to carry at least half of
the maximum allowable weight or Technically Permissible
Laden Mass (MTPLM). The Load Index number represents the
tyre maximum weight limit in kilograms. A pair of car
tyres index coded 79 may not used on a caravan having a
MTPLM in excess of 874 kg.
Over the last few years there have been a number of
reports of caravan tyres disintegrating in service. This
has been more common on heavy caravans and often when
the caravans had been used in southern Europe during the
summer. This suggests the tyres may have been running
very hot at some time in their life. The inference being
that if you are covering long distances in high
temperatures it is a good precaution to stop for rest
periods to allow your caravan tyres to cool.
Before every trip
- Check the manufacturing dates of your caravan
tyres. If they are over five years old consider
replacing them.
- Inspect your caravan tyres for cuts, sidewall
cracking or imbedded objects. This includes the
inner sidewalls.
- Check the pressures of all your caravan tyres,
including the spare.
- Check the pressure of the tyres of the towing
vehicle. Some vehicle manufacturers specify slightly
high rear tyre pressures when towing.
- Check the tread depths. If this is less than 3mm
consider replacing, particularly if you are planning
a long trip.
- Check caravan wheel bolt tightness with a torque
wrench.
- Check jack operation. Most jacks benefit from a
drop of oil on the screw mechanism. As caravans are
frequently parked off road, have a suitable piece of
board available to prevent the jack from sinking
into soft ground.
Manufacturing dates of caravan tyres
Date of Manufacture is shown on the sidewall of all
caravan tyres as part of the DOT (U.S. Department of
Transport) code found close to the wheel rim.
Example of a code is DOT A87C DEF 699, the final set
of three, or four, numbers being the date code.
Tyres made between 1990 an 1999 use a three digit
code followed by a triangle and indicate the month
and year in which the tyre was made (699 being June
1999). From 2000 onward a four digit code is used to
show the week and year (0102 being the first week of
2002). A small number of tyres may not have the DOT
code but in these cases the date of manufacture may
still shown elsewhere on the tyre, for instance if
you see as a separate group of letters 4202 that is
definitely 42nd week of 2002. |
