In regard to safety, tyres play a more important part on a car and caravan than any other single component. A vehicle can only accelerate, brake or steer if the correct contact exists between the tyre and the road.
If the tyres are not inflated correctly, or are the wrong type, the stability and ride of the car and caravan combination can be severely effected. Considering that at 80 km/h the average tyre rotates 40,000 times per hour it can be appreciated that proper tyre care is very important to ensure a safe and trouble free journey. Tyres can deteriorate just as much when a vehicle stands for long periods than when it is being used. When a caravan is not being used it is a good idea to take the load off the tyres and cover them to prevent deterioration by the sun. What is usually not realised is that a tyre has to be inflated to its maximum pressure before the load rating stated on the tyre can be achieved, The maximum pressure for normal passenger car tyres are 250 kPa (36 PSI) and 280 kPa (40 PSI) for a 6 ply rating. Should the inflation pressure of the tyre be less than that stated above, the load carrying capacity will also be reduced. For light truck tyres the pressures and load carrying capacities are correspondingly higher.
As a rule always inflate caravan tyres to the maximum permissible pressure unless they are 8ply light truck tyres. The rear tyres on the towing vehicles, because they are subjected to much greater loads when towing, should also be inflated to near their maximum. Front tyres will need an extra 25 kPa (4 PSI) above normal. Always be careful to check tyre pressures when the tyres are cold. Early in the morning is best. During a trip heat build up will increase pressures, giving an incorrect reading. Never let air out of a tyre when it has been on the move or standing in the sun.