Zero turn owners have all been there when it comes to hills. My property is hilly. The government mandates that ZT makers post charts in their manuals showing 18 degrees as the max. I'm sure everyone of us have pushed that. Some a little, some a lot. Personally, I have one slope that's probably around 20 degrees that I am very comfortable mowing sideways. I have another that approaches 30 degrees that I mow by driving straight up, and then slowly backing down. In our quest for efficiency, many ZT operators have become very proficient at maneuvering their machines on slopes as great as 45 degrees. Some have gotten seriously hurt trying, and a few haven't lived through it at all. Front brakes have been invented, which apparently work very well. Others have even fabricated locks that keep the front casters from swiveling. Still others have made a foot pedal with a linkage to the parking brake to stop the back wheels if an out-of-control situation should arise. This of course kills the engine, unless the parking brake wiring is defeated. I'm curious to hear some thoughts and ideas here. Obviously, the safest approach would be not to attempt steeper grades at all, especially if you're the least bit uncomfortable trying. Then again, he who is leary of trying is likely to be more cautious than the guy that wants to impress his friends with a "Hey, watch this!" As I said at the beginning, those of us that use our machines for their intended purpose of mowing, and not trickery, all know of some hilly situations that we would love to be able to safely conquer.