Well, I might be blind here, but I can only find deadzone for the steering wheel, and none for the pedals. This is a bit hard for me, because I need to run 20% deadzone at the moment for the brake pedal not to kick in. Have anyone seen a deadzone-choice for the pedals in rF2?
Press pedal for about 20% and while holding it at this value press 'Set min' button in the 'Controls' tab
You can also use the buttons in the game itself. If you go to the controller section of the options, you have the graphical lines in the left bottom of the screen for clutch, brake and throttle. There are MIN and MAX buttons there. Press the pedal where you want it to be, and click the appropriate button. You can also set the reaction curve (sensitivity) there. At least thats where it was in the previous build. Havent checked in 89.