How to Effectively Fix a Front Derailleur on a Mountain Bike
To fix a front derailleur on a mountain bike, start by shifting the bike into the lowest gear and loosening the clamp bolt that holds the derailleur to the frame. Check the alignment of the derailleur and adjust it if necessary by turning the high and low limit screws. Check the cable tension and adjust it if necessary by turning the barrel adjuster. Finally, tighten the clamp bolt and test the shifting.