How To Adjust a Mountain Bike Front Derailleur
Tools you will need:
allen key
lube - should lube pivot points while adjusting
Screwdriver
When Paul Vivie invented the derailleur system and gave us the francophone spelling in 1928, he no doubt realized that having a derailleur in the front as well as the rear would allow allow him to nearly double the number of gearing combinations his system delivered.
It also held the potential to increase frustration by an order of magnitude. The grinding!
He smartly never launched a front derailleur. Had Vivie owned a mountain bike, he would have immediately recognized the safety advantages of that marvelous, magical cage that keeps one's chain from wrapping around one's pedals sending groin into top tube and
chest into bars. Paradoxically, a maladjusted front derailleur can ensure problems.
So, it is a great idea to keep your mountain bike's front derailleur in tune. It is a fairly easy job, but does take time to do the job properly.
There are a bunch of different ways a front derailleur connects to mountain bikes:
- Clamp
- Most front derailleurs are mounted around the frame's seat tube via
clamp. Below is a lovely picture of a Shimano Dura Ace front derailleur. The black clamp is visible wrapping around the seat tube. 
- Braze-on
- A later development in frame building added a brazed-on tab to the
seat tube above the chain rings. The derailleur is then mounted by
bolting onto that tab. 
- Direct-Mount-Derailleur
- Specialized Bicycles' proprietary front derailleur mount, called
DMD, is bolted directly to bosses on the chainstay of the bike. This
method is used most often on dual suspension mountain bikes where
frame angle change is dramatic. 
- E-type
- This type front derailleurs are attached to the frame by a plate
mounted under the drive side bottom bracket cup and a screw threaded
into a boss on the seat tube. This style is usually employed on
mountain bikes with dual suspension. 
- Steps to adjust:
- 1) Put in lowest gear- smallest chainring in the front and largest
cog in the rear. -
2) Loosen cable bolt to release cable tension.
3) Set height of front derailleur at 2-3 mm above chainring.
4) Turn your low setting screw clockwise if you need more clearanceon the inside, clockwise if your chain is rubbing on the outside. Move cage until
5)
