Caravan tyre ageing
Regardless of use or mileage, all tyres have a lifespan. Even a caravan tyre never driven on will deteriorate over time. Natural ageing of the composite materials that form tyres occur from day one and it is widely recommended that caravan tyres should be replaced at 5 years old. To help you, new tyres have a date mark stamped on them to show the week and month of manufacture.
It is not always possible to determine how long the tyre has physically been fitted to the wheel on the caravan. As a general rule of thumb if you are in any doubt as to the age or condition of the tyre, don’t take the risk.
Checking your Caravan tyres
You can check how old your caravan tyre or tyres are yourself. The information you need is found on the sidewall, and denoted by four numbers printed in a window. For example: 
In this example, the manufacture date code is 1413 – where 14 denotes the week of manufacture and 13 represents the year, meaning this tyre was made in the 14th week of 2013.
If your tyres are printed with only a 3-digit number, it means your tyres were manufactured before 2000 and should be replaced asap. If your tyres are older than 5 years old, you should consider replacing them.
This information is provided by KwikFit