My Front derailleur won't shift?

My front derailleur is not shifting how do i fix this?

• ok this is the problem... my front derailleur was only shifting to the third gear. then i was messing with the H & L thing on the front derailleur and now it will not shift anything how can i fix this

• Answer:

  Ok, the H and L thing on the front derailleur set the limit of how far in or out the derailluer will travel. If you have them screwed all the way in the derailluer will not move. back these screws out to a point where the derailluer only moves far enough to the inside and out as to not push the chain off the chain rings to the inside or outside. after this you might need to check your cable tension. The cable tension is usually the problem when it comes to shifting problems. The cable will stretch and this does not allow for a clean or quick shifting response over time.