The issue with tyres are 1. the lack of mileage leads people into a sense of false security and as the requirement for regular inspection (MOT) is not applicable to caravans, degradation to the tyres may go unnoticed until they fail catastrophically . 2. if they do fail , you may not be aware of it as soon as you would if a car tyre blew and the rim will most certainly be damaged by running on our our lovely roads. 3 the damage a failed tyre carcass causes to the caravan is far larger than on a car due the materials used in construction ( wheel spats disintegrate, wheel box shattered and caravan frame, wall and lower trim piece all damaged )and repairs ain't cheap.Compare this with the cost of two new tyres every five/seven years to me its a no brainer, which reminds me, I need to take off my wheels and get the tyres replaced.