Many people take their caravan and trailer tyres for granted. We tend to assume that tyres need changing when the tread depth begins to threaten the annual MOT test. This works for our car tyres, but the caravan is a different matter.
A touring caravan spends far more of it's time standing still rather than actually touring and covers far fewer miles than our cars. This means that it'
s tyres rarely actually wear out
the tread, but this brings other factors into play. Unfortunately the materials they are made from have a limited life which often runs out before the tread wears away.This can lead to unexpected blow-outs causing damage to your van as well as
trauma to you and your passengers.
This photograph shows age-related cracking of a tyre wall. If yours look like this, it's time they were changed.
In order to give owners guidance as to the age of a tyre, for a number of years now they have carried a date code amongst the array of markings around the sidewall. This code also tells insurance company loss adjusters the exact age of the tyres should you end up blocking the motorway with a jack-knifed caravan.
To keep safe, here is a typical date code:
DOT EK 4D 2BY X 4208
The DOT means the tyre meets American Department of Transport requirements 
EK 4D 2BY
These are used to identify the manufacturer and which of their factories produced the tyre.
4208
The last four digits provide the date that the tyre was made. Until the year 2000 this was a group of three digits giving the month and year of manufacture. If yours have this three digit group, they are well past their usefull life! Since then the group has consisted of four digits, the first two telling the week number, the last two the year. The above example refers to week 42 in 2008. If your tyres are over 5 years old you should be thinking about changing them. If they are getting toward 10 years it's beyond the time you changed them.