Originally Posted by
dsbrantjr
I am unfamiliar with these particular components. How does one go about installing/removing this "hidden" bolt? Does it thread into the crank arm or?
There is a threaded boss cast into the drive side crank arm that is in the same plane as the other arms and is the mounting point for the "hidden" 5th bolt. It installs from the back. Campy has been doing this for a long time and my 2006 Chorus crank used the same hidden bolt design.