Adjusting Rudder Pedals in XPlane

I have had problems getting a Cesna 172 to roll down the runway on takeoff EASILY in the center of the runway.  I have set/adjusted the pedals in XPlane but have not had GREAT succes.  I recently wrote a post asking this question and someone answered the question as to what I should do BUT I did not write it down.  I do remember that person suggested I do something with, as it was put, some letters.  That is the reason I returned to find this suggestion BUT have been unable to find the information.

Does this site have a search?  I could not find one although I am very new to this site.

Thanks for any help anyone can supply.