Originally Posted by
BlueMoon
my mistake the only difference is the Mmo on the 900 is limited to .84 above 34000' instead of .85 like the 70/50..
No, not the "only difference".
From CRJ-700/705/900 Pilot Reference Manual, Volume 2, Bombardier Aircraft Services - Customer Training Manual, 15 Dec 2008:
Page 1-36 Figure 1.8 has the numbers you quote. In addition, on page 1-37 are the "RVSM Maximum Cruise Mach Number" of .83 for <CRJ700> and .82 for <CRJ900>.
Also, flap 20 speeds are different. Tire speeds are different. Thrust reverser speeds are different. That's all between the 700 and 900. Don't have books anymore for a -200.