Tyres on any trailer are easy to cheapen out on. This is not wise if you plan to spend a long time on the road, or towing particularly heavy loads.
Let’s get this clear. Tyres are literally the only physical connection your trailer, camper, caravan, whatever has to the road. All the grooves and channels in the treadface of those tyres are designed to direct water away from the tyre and allow the tread blocks (the actual blocks of rubber touching the road) to contact the road.
The better or worse the tyre’s groves and blocks are designed, in addition to how you load your trailer, will determine how those tyres handle behind you.
Air pressures in your caravan tyres are critical. Not just for wear and tear, but for fuel economy and grip.
Under-inflation means the tyre will sag, causing increased rolling resistance, which means burning more fuel to pull it along the road. It’ll dramatically accelerate the wear of the tyre’s outer shoulders as they spend longer touching the road during every rotation, which is a huge increase in friction, meaning greater heat stress in the tyre, making it more susceptible to punctures and cutting damage from sticks, rocks, cracks and potholes (like the ones you cannot avoid).
Under-inflation also means the likelihood of a blowout increases if you’re heavily loaded because the tyre sidewall flexes more than it should, which means the air inside the tyre is being compressed harder and therefore getting hotter than it would if more air was taking more of the load. When air gets hot, it expands. Tyre goes bang in aforementioned circumstances.
Over-inflation means you’ll prematurely wear out the centre of the tyre’s treadface where the majority of the water dispersion happens, meaning you’ll much sooner have a trailer that is likely to aquaplane in heavy rain where it might have just ploughed on had the tread been in better condition. It also means you’ll be butchering one narrow section of the tyre while the shoulders remain in good nick - but the tyre still needs replacing early owing to the tread depth being reached sooner than it would’ve been had the whole tyre face been doing all the work.
It’s important to inflate your caravan or camper tyres when they’re cold, because that’s when their pressure measurement will be most accurate.