I am running Cooper S/T's 285, and just rotated them. tires still have 10/32 left to the wear indicators. They start at 18/32. So, with 32,000 miles, I still have 32,000 miles left.
They have just a little noise, nut bad especially with the windows up. Next set will be a little less aggresive.
I have had issues with some Coopers, but they were all P series tires not LT's. And they were on other cars not my Cummins.