I feel uneasy over 15 degrees, but with the tilt meter for reference know I'm safe until the mid-20's, probably higher if I keep the implements (FEL and/or brush cutter) low. Came close today, though, and was thankful I had a ROPS and a seatbelt. I was brush cutting along a 3-4 foot bank around a boggy area. The downhill front tire dropped into very soft soil (OK, it was mud, and really dumb to drive a tilted tractor into), and as the tractor tilted the same side back tire settled in a bit - so the tractor went from about a 15-18 degree tilt to about 24 degrees, within ? 3 seconds. Not good. So, hit the clutch, and dropped the FEL and brush cutter onto the ground - then, after my angina settled down, I did manage to turn into the direction of the tilt, and slowly reorient the tractor down the slope. Then I could reverse out (in 4WD) of the situation. It does get your attention, and you have my sympathies. Now, as to your tractor free-wheeling towards your house - lucky your wife didn't kill you. Unfortunately for you, she was a witness - me, I was alone, so when my wife asked "how'd things go, dear", I said, "fine".