Q. Is it possible for the chain to fall off even with a chainglider?
A. Yes! Happened today. I measured my T1-T2 slack to be 83 mm. I snugged it up after the measurement. Since I am away from my usual tools, I took a risk and tried to find an existing dent in the EBB just by feel! I hope I didn't mess it up too badly! I think this was my first EBB adjustment since I put on the chainglider with new chainring, sprocket, and chain. My odo now reads just over 15,000 miles. I don't remember the mileage when I put on the chainglider, but I would guess it was about 3,000 miles ago. Chain stretch is fastest with a new chain. I bet I won't need another adjustment for quite a long time!