I ran 30-33 percent in mine all the time, added caster oil to bring the oil percentage up around 18-20 percent and never had any trouble with it, other than cleaning up the one way bearings. Never had any trouble with the truck either as far as that goes. Breaking the fragile wheels was easy, but it was a wheelie monster. You have to be careful about blocking the truck up when starting to keep from chewing up the left rear axle with the starting rod. I still have five or six of them. Glen
