There are many fallacies surrounding caravan/trailer wheels and tyres, and even credible sources of advice, such as caravan manufacturers and tyre fitters seem to regularly make errors, or at least fail to give comprehensive guidance. This page attempts to address some of these issues, based on our long experience of dealing with such advice.
Whats the difference between car and caravan/trailer wheels and tyres?
Caravan and trailer wheels may look similar to car ones, but they are usually specially made for towing use. Principally, this means they are stronger than a car wheel of similar size, although it may also mean that some of the wheel dimensions are different On a single axle trailer, it is clear that each wheel has to support about half the weight of the trailer, which is often more than one quarter of the weight of a typical car.
The relative simplicity of both trailer and caravan suspension also means that while travelling along, it is possible for much more than half the weight of the trailer or caravan to be borne by the wheel(s) on one side from time to time. It is important, therefore, to consider carefully any change in wheel specification for your caravan or trailer. As a general rule, it is not a good idea to use car wheels on a caravan/trailer, unless you can establish (usually from the wheel manufacturer or supplier) that they are appropriate.
When should I replace my tyres?
It should go without saying that tyres which are damaged or worn to the legal minimum tread depth must be replaced immediately. However, tyres which are visually OK, and which have seen little or even no use are also recommended to be replaced when they reach a few years of age.
As a general rule (and following guidance issued by the tyre makers‟ trade body, the British Tyre Manufacturers‟ Association, it is advised that caravan or trailer tyres should ideally be replaced when 5 years old, and should never be used when more than 7 years old. This advice is provided by our own experience and research into caravan tyre failures, which confirms that the likelihood of a tyre problem increases after such age.
Our research further suggests that tyres which need a high inflation pressure (say 50psi or more) require greater care still. Such tyres should be closely examined for signs of deterioration from 3 years old, and it would be strongly advised not to use them beyond 5 years old. It is not the case that all tyres over these ages will rapidly fail. However, the statistical likelihood of a problem occurring increases noticeably with age. Given the disruption to your holiday that a tyre failure could cause (let alone the risk involved), it is strongly recommended that you follow this guidance.
Since tyres deteriorate with age even when not in use (unless kept under very strictly controlled conditions of temperature, humidity, light level etc), it is usually necessary to consider a tyre’s age from the date it was made, and not from when it was bought or fitted to the caravan.
Checking your Wheels and Tyres
Tyres are the only part of the trailer or caravan which are in contact with the road surface. Safety in acceleration, braking, steering and cornering all rely on the tyres’ relatively small contact area with the road surface. In addition, tyres also play a fundamental role in the suspension systems of both trailers and caravans.
With such an important role, it is essential that tyres are properly maintained and regular checks are carried out. With the correct care and attention your tyres will help to ensure you arrive safely at your destination safely, without disruption and with minimal cost.
What is "Load Rating"?
The load capacity of a tyre determines what weight each tyre is able to carry.
It is vital that you check with your vehicle handbook as to what capacity should be put on your car. In some cases your insurance can become void if you select the incorrect tyres.
The load rating is generally found after the diameter reading and before the speed rating on the sidewall marking:
The following table shows the weight that each index specification is able to carry: