Its not so much a matter of "age" or mileage but.. exposure to the weather..
or UV

Getting "weather checking" on the sidewalls.. can you look between the tread
and see "White cord".. replace..

Most tires even on auto's don't last much beyond 4 yrs for the weather or UV
effects.. although they may have plenty of miles left in them.

If the tires are removed and stored inside, or shielded from the effects of
the sun.. you may get an extra season out of them.

BT

"Greg Arnold" wrote in message
news:xGTpd.175805$hj.6434@fed1read07...
How old can trailer tires get before they should be replaced?