I have recently bought the Saitek X-55 and installed the drivers and software from the Saitek website so I have the latest versions.

 

When I check the calibration using the Windows system its confirms that all the extremities and full movement of the X-55 axis is recognised.  However when I run FSX, the Throttle and other axis like the Rotary controls are not producing full movement of these controls, if the X-55 throttle is fully at idle the FSX aircraft (any, default and 3rd party) throttle is slightly forward and only comes to the full idle position is if I press F1.  Its the same at the other end, full throttle cannot be achieved using the X-55 throttle lever.  I have also programmed the X-55 Rotary axis for things like Mixture and Propeller but these also will not reach the extremities of their movement.

 

Any ideas how to fix this problem ?

You should be able to adjust the ranges in the Saitek software that comes with the X-55.  Short of that, FSUIPC does a great job of mapping the ranges on any control.

I found the problem, for some reason I had moved the axes sensitivity slider in FSX Controls menu from 127 to 100.  I don't know why this was moved, but resetting it to back 127 has fixed the problem I described above.