You can use a 140mm but it will steepen the head angle by a degree and more importantly lower the BB height even more (I'm striking the cranks a lot with the 150mm forks)......this is on a new 2011 575 by the way.
the new 2011 575 had the head angle designed around a 150mm fork to work better with the 146mm rear travel.
the new 2011 575 had the head angle designed around a 150mm fork to work better with the 146mm rear travel.