Skid Steer Stump Grinder – Miller Pro 75SS – Revolution wheel; teeth are slightly dull. ASV RC85. 38-gpm at 3300-psi approximately 73 theoretical hydraulic hp. I used to own an RG90; I would never go back to it. This will out grind it. Teeth are tougher. No poly chain. Jeff knows his stumpers. And these are built well.