SRAM XX Low Clamp Front Derailleur $135.95
2 x 10 bliss.
For those who worry about clearances between front derailleurs and both rear suspension linkages and swing arms, SRAM's XX Low Clamp's cage is shorter and narrower than a triple-specific front derailleur. And it's not just a compact-double road front derailleur, either -- the XX Low Clamp is its own thing, specific for mountain bike use.
The aluminum links that shape the travel of the cage are extremely wide, increasing the distance between the pivots for greater stiffness. And the derailleur cage itself is made from steel for maximum durability. Both of these features play into XX's superior gear changes.
SRAM claims that the XX front derailleur will work on just about any bike. That's because SRAM has both high and low clamp versions in four sizes each and four different direct mount versions (and there are three different clamps for each chainring configuration within the direct mount line).
In addition, both the high and low clamp versions use a thin, flexible steel band clamp that holds quite well at relatively low clamping pressure -- a safe recipe for carbon fiber frames.
The SRAM XX Low Clamp Front Derailleur is available configured as either top or bottom pull. The 34.9 clamp size is adjustable, and with an included shim kit, it can be used with frames that require a 31.8mm clamp.