If you are only ever on dirt I think your 8's would work. But if you get on concrete I would get the 12 ply's or look around for the truck tread type. They last 2-3 times as long as the standard bar tread anyway. Truck treads get plugged up with mud and you have to drive around and clean them out before you get stuck. We got 2 skidloaders. One at the dairy where we burn up truck treads in 800 hours, 12 ply standards in 400 hours but that machine is on wet concrete to dry concrete that is rough in the bunkers to going up and down the gravel road at 12 mph with 3 big squares. So we are pretty rough on it. But the other skidloader at the beef farm has 1200-1500 hours on standard 12 plys......Always on dirt.....If you are ever in a yard or building where you can spin around and hit the rim make sure the tires have rim gaurd. It really helps.