This is perhaps the most popular subject or subject of concern on the forums.
The tire companies seem to like the idea of ambiguity in tire life expectancy.
Michelin says it won't resell tires over five years old yet there are Michelin and Goodyear tire recaps, over ten years on semi trailers. Perhaps the reason for so many gators on the road.
The Goodyear G670s were engineered for long life on a Mh and ten years was the figure they tossed out then went silent on.
Michelin says five years with the new "environmentally friendly" orange oil in the Mh tires.
However the Michelin 670s we pulled off 13 years after production, looked and felt as new inside and out. Michelin said they would destroy them. I bet they are on a semi trailer somewhere.
A lot of timess, in places like Indiana and farm country everywhere take offs from Mhs provide 50.00 tires for a lot of farm equipment that uses our type of ties. like trailers.
Our unit is stored indoors since 09. It has set, in the sun, of the Southwest for perhaps a total of a year in 11 years and about 10,000 miles in that heat.
So the answer is I don't know but I won't be changing tires at 5 years unless I detect something wrong.
I check the tires with a laser type heat gun when we stop.
The tires are inflated according to weight where we store it.
Only thing I need to do additionally is tire covers for when sitting at RV Parks regardless of temp.
I won't be pulling the tires off unless somthing happens to them in five years.