Identify this two-player game with wheels in a wall
In Dutch it was called "Onderuit". Also known as Downspin.

There where several discs that could be replaced to make the game harder or simpler. The later versions of the game worked with keys (one for each player) to avoid turning one disk when your opponent has just turned it. The early versions could be turned without key. 

As far as I know, the board was blue and the disks where white. There where 4 sets of coins (4 colors) each player had to dock 2 sets. And they where numbered. So you could rule that you had to dock them in order to make the game harder.