Posted this on the Mech forum a couple days ago but got no takers, any MTBers that can help?

I'm in last stages of a build up and having problems getting front derailuer set up. All parts are new with exception of the frame itself, BB housing was faced by LBS before setup.

The crank is shimano xtr M-900. Specs for chainline and spindle lenght are 47.5-50 and 107-113 respectively. A 113 spindle did not give me enough clearance of small chainring to frame so a 115 was installed. Frame clearance to small chainring is ~ 2mm and chainline is 50-51 mm. I was afraid a bit of frame flex would cause the small ring to eat into the chainstay with a 113 spindle.

I installed the front mech with the suggested clearance (1mm) to clear large chainring and can set low limit O.K. Problem is getting clearance/adjustment on large chainring (e.g. rubbing on large ring). Have tried moving the mounting position slightly up/down on the frame and adjusting the angle too. It seems as if I need more travel outward from the frame that the mech can't provide. Chainline is very close to spec. for both the crank and front mech., both call for 47.5-50 and both are compatible as to the size of the chainrings, so I'm at a loss to figure out where to go from here. This is my frirst attempt setting up a front mech with an articulating cage. Have noticed that the cage acutually comes DOWN a bit at it's farthest outward travel.

The old XT mech I took off (FD-M737) works fine with the new crank/BB, so I don't think I'm too far off on chainline. A bit of more info the new xtr mech. is top pull/top swing, the old XT top pull/bottom swing, Sram pc-68 chain. Any ideas/suggestions? Are these just very touchy to get dialed in? Thanks in advance!