Front mech question

[cyb]

Hello everybody, today I rode, for first time, my FRM.
I've had a problem with front derailleur: it won't get down from middle to small chainring.
This is the setup: 22-36-48 rings, xtr m900 bottompull front mech, duraace barends (mounted on paul's thumbies).
Q-factor seems between 45 and 50 mm, H and L screw and mech height are correct. Cable tension was regulated on handlebar shifter.
What could be the problem?
Thanks for your advices

cyb

 

[gibbleking]

bottem bracket may be wrong length or the spring in the mech may be week or mis aligned ...could be a ton of reasons why....

 

[elite504]

f/mech woes can be tricky. Often BB length related. Large diameter seat tubes can cause a colission between the mech and the tube on a low clamp/ top swing M950 style, requiring a longer axle. But with your M900, I'd say its down to capacity- 22 to 48. . . too much for that mech. Seat tube angle can inerfere with how closely the cageplates sit to the ring too, but seriously man, its over-capacity.
Try a 24 or 26 inner and see hwo you go. run a 32 at the rear if you need the low gears. M900 was designer for a 26t inner as stock.