[Richard]

This is MY opinion. I ran the first set of 365 tires for six years. No cracking. However, I put over 10k a year on the coach and the tires do not sit for long periods. They are covered from the Florida sun in the winter.

I think the 3 yrs is Newell's recommendation. After all, relative to front tire issues, better to err on the side of caution. But some owners drive a lot faster than I.

There are too many variables to predict the life of any tire. Michelin says yearly inspections after 5 years, and run no longer than 10 years.