My rear tires were far from being worn, lots of tread left. But they were 2004 mfg date, and I am pretty sure original to the 2005 chassis. They were Bridgestone, and were getting some quite visible sidewall cracking near the bead area. I only bought mine earlier this year, so this was one thing I have been wanting to do, even though I put about 5000 miles this summer on the Bridgestones.
So to avoid any potential road blowout, or body/wheelwell damage, I bit the bullet and got 8 new rear tires installed last Friday. Purchased General S360 model, made in USA, 11R22.5 size. Mounted and balanced, tax and all new valve extensions came to $3300.
I previously had upgraded my fronts to 315/80R22.5 to get back some safety margin on the front axle loading. The original 11R22.5 were actually overloaded past the max load. I have 14,600 lbs on front axle, and 20,600 on both rear axles. The ironic thing is the rear tires are so underloaded, about 40% of rated load. I may have been able to run the Bridgestone tires longer, but did not want to take the chances. I like to run around 70-75 mph and feel better with the new tires. Although my wallet does not feel better
Oh well, gotta pay to play