Originally Posted by
hermanchauw
The thumb button shifts down, ie go to a bigger cog.
The finger button shifts up, ie go to a smaller cog.
Not to be pedantic, but this description applies to the right shifter (rear derailleur) only. For the front, the thumb shifts *up* (to a bigger chainring/higher gear), and the finger shifts to smaller chainrings/lower gears (*down*).
Steve