I realize this maybe a dumb question but rear tires are expensive and I read that people run tires until cords are showing and I do not see any. The tires are the originals made in 1995 and are on a 650 hour B2150hst 4wd. They are tubed and have a liquid ballast. If the tractor was used on level ground I'd just run them til they got worse. However, I rotary cut steep slopes on my property and in some areas their is not a flat exit or landing point at the bottom of the slope. Just a wall of trees on an even steeper grade. What do you guys think?