You want to do these "half shifts" when your front derailleur is rubbing your chain. It happens as you move up and down your cassette. When you do those little "half shifts" it should be moving your FD over slightly, which should eliminate chain rub. Hope that helps a little.
Nick
edit: Blast, Bbattle beat me to it.
Originally Posted by bbattle
Also, when rolling up to the coffee shop, always have the chain on the big ring in the front and the small gear in the back.
