My class A has a 22.5 tire all the way around, a friend at a trucking company (he buys loads of tires the same size that is on our motorhome) A Continental is $520 he will mount and balance free, ...
OP, it would help if you shared what size tire other than 22.5. What is the one year old front tire and why not buy another so you will have a matched set on the front? Instead of putting 295/80/22.5 back on the rear of my DP I went with 6 Hankook 11R 22.5 (probably the most common truck/trailer tire) which has the same revs/mile BUT I had to increase the psi 10 lbs because of the lower load rating.