John, since I've known our tires since the odometer had 75 miles on it, I know exactly how they have been treated. At 7 yrs. (date codes read from the 20th-42nd week of 2006) and 57,700 miles. I'm getting new tires at the end of the month from Pete's Road Service in Coachella, CA. I already placed my order through the FMCA Michelin program.
Personally, if I were you, I would have the tires inspected at a big truck facility and see what they say. They will have to come off the rim for a really good inspection. You might even want to rotate a dually set to the front if you have any wear on the front (if given the 'passed' vote).
I received a bad alignment once from Colton Truck Terminal in Colton, CA, and didn't realize it until I was almost 2,000 miles from home. I started to get severe wear on both of the inner front tires. I found a reputable big truck facility in Nashville (TAFA-Tire Alignment Frame and Axle)....I think it was the most perfect alignment I've ever had. They had to add a plate to the front suspension for a perfect alignment.
It was 6 months before I could get back to Colton so I never worried about a refund, etc. I certainly didn't want them to ever align it again. They have been really good in the past with oil changes, etc. But the alignment and then them not being able to fix my dash 3 times, but charged me for each visit, was the last straw. I go to Redlands Truck Service in Redlands where they fixed my dash air the first time and now the repair is a year and half old and running strong. They won a customer.
Good luck on your tires,
Mark
Mr.Mark
2021.5 Pleasure Way Plateau FL Class-B on the Sprinter Chassis
2018 Mini Cooper Hardtop Coupe, 2 dr., 6-speed manual
(SOLD) 2015 Prevost Liberty Coach, 45 ft, 500 hp Volvo
(SOLD) 2008 Monaco Dynasty, 42 ft, 425 hp Cummins