Your front derailler has two adjusting screws. A High & Low stops. Usually marked H & L. Some aren't marked. If it over shifts,, and sometimes past the biggest chain ring, The "H" High adjustment needs to be turned clockwise. I go 1/4 to 1/3 of a turn at a time. You can get it perfect on the repair stand,, but sometimes riding the bike you might need to adjust it. If the chain falls off during a ride, I use a wrench or a stick to put it back on. Whatever's on the side of the road, Keeps your hands cleaner. chris