The wheels and tyres of your caravan are the most important as far as road safety goes. After all, they provide the only contact your trailer has with the road.
Reflecting the importance in road safety terms, there also legal obligations relating to the condition of the wheels and tyres. The motoring organisation, the AA, spells it out and warns that you are legally required to ensure that the tyres not only on the car towing your caravan, but the caravan itself, must be “fit for purpose” and free of any defect that may cause a road safety problem.
This means that in addition to the tyres being inflated to the correct pressure, they must also be:
- of the same specification as other tyres on the trailer;
- the tyres on your caravan – just as your car – need a minimum tread depth of 1.6 mm running continuously throughout the centre three-quarters of the tread and around its whole circumference;
- tyres must be free of tears, bulges, lumps or any other indication of potential failure;
- they must be free of tears or cuts extending for more than 25 cm or across more than 10% of the tyre’s width; and
- no part of the tyre’s cord or ply must be exposed.
You may be prosecuted for using the caravan with such a defective tyre or in an otherwise unroadworthy condition.
The wheels on your caravan are specifically designed for the job they do. They are different from the wheels you normally find on cars, the Caravan Club explains in a guidance note.
They are different largely because of their need to withstand greater pressures than car wheels. They are therefore generally stronger to support the weight of the caravan – usually on just two wheels – and because of the caravan’s lack of the sophisticated suspension system you might find on a car.
As a matter of routine maintenance, the wheels need to be checked to ensure that the rims are not rusted, scuffed or cracked. The stud bolts also need to be in sound condition and fit snuggly into the stud holes – which should not be elongated or damaged.
Your caravan’s only contact with the road along which it is being towed are a few square inches of tyre. It is critical, therefore, that they are correctly inflated and remain in good condition.
The tyres on your car, of course, need their tread for traction from the engine and to grip the road as the vehicle is being steered. Neither is so important for your caravan’s tyres and, as a result, there is typically much less wear through normal use.
Mileage and ageing
Your caravan is also likely to cover a much smaller annual mileage than your car.
Although it is important to check the tread (for signs that the tyre has been improperly inflated) and for tears and bulges, wear and tread depth is probably less noticeable than on your car tyres.
Rather than mileage, the tyres on your caravan are much more likely to be vulnerable to the simple process of ageing. These tyres are vulnerable because:
- they tend to take more of the shocks and bumps from the road than those on your car – since the caravan’s suspension is less sophisticated and has less dampening effect than your car’s;
- the rubber from which the tyres are made suffer the effects of degradation simply through the effects of sunlight and the atmosphere – even when they are not being used, therefore, their condition is still deteriorating; and
- wear is especially pronounced when the tyre is under pressure from the weight of the caravan itself – when the trailer is left for long periods of time resting on the same few square inches of tyre rubber, therefore, wear is most pronounced.
Care needs to be taken about this last vulnerability in particular. When the caravan is being stored for any length of time, the wheels need to be rotated from time to time to even out the load on particular patches of the tyre. An even better precaution is to remove the wheels entirely and take the weight of the caravan on axle stands.
The removed wheels may then be stored horizontally and out of direct sunlight.
When the new season begins and it is time to refit the wheels, that is a good time to give the tyres an especially close inspection. Remove small stones or other objects embedded in the tread and use detergent to remove paint, oil or fuel from the tyre’s surface.
Tyres need to have just the same minimum tread as your car – 1.6mm – but remember that they are likely to need replacing long before the tread is worn down to anything like this low point.
Finally, even if your tyres look in great condition, if they are more than 5 – 7 years old, it may be time to replace them.