B+ motorhomes

I was looking for a tire that would improve the ride and had been directed toward Michelen which I purchased at Costco because the date stamp indicated they were less than a month old. Other vendors could supply the tire but I saw some as much as a year old already! As we know ageing is a bigger factor than miles on most motorhomes.
Unfortunately it still rides hard especially in the rear and Bilstein shocks and as little as 60psi.