If you {OP} only got 16,000 miles out of the Michelins you are doing something seriously wrong. Overloaded, underinflated or serious issues with your suspension all come to mind. Got 32,000 {so far} on my LTX M/S 2's {that were free thanks to the recall}.
Would not run any tires on my coach that were over 5 years old but that is just me. Larger Class C's tend to have serious rear axle overloading issues {that air bags have zero affect on}. Get that rig weighed and put the proper load tires with enough PSI to handle what they are actually carrying.
As always... opinions and YMMV.
:C