Have you listened to this noise when you ride? Does your chain come off you try and shift into a big ring? If so, you need to adjust your front derailleur, which fortunately is actually a really simple thing to do.
Some chain lube and a rag
It is hard to adjust broken equipment so before you start it, check the status of your equipment first. Before you adjust the front derailleur, you should make sure that your derailleur is working properly
First, look at your cable and housing, if the frayed or broken you will need to replace it.
Next, make sure your shifter is working by detaching the cable and shifting through all the gears. The mountain shifters contain one less click than a number of gears; road shifters have more clicks due to a trim adjustment;
Then, leave the cables to detach, and check your derailleur to see if the cage is bent and the outside of the cage should run in a straight line.
Next, check for overall wherein the derailleur by giving it a little wiggle if it has a lot of play, then the springs and pivots are most likely worn and the whole derailleur should be replaced.
Placement & Alignment
The first step to adjusting your front shifting is to make sure that your front derailleur is in right place. You can look at the derailleur from the side view, and see that the cage is one to two millimeters above the biggest chain ring when it shifted out there, do this by using your fingers to pull the derailleur out and look at the distance between the bottom of the cage and the top of the chain ring.
Next, you should make sure the cage is aligned with the chain rings. Looking down from the top to see that it runs parallel with the chainrings if you need to change the placement or alignment it’s done by loosening your front derailleur clamp bolt and moving it by hand to the desired location carefully of over-torque this bolt though because you could crack or dent your frame or derailleur mount now.
Low limit adjustment
Importantly, the process is to keep your chain from falling off to the inside start by the rear derailleur into the lowest gear. It moves chain as far inside.
Now use the low limit screw to move the derailleur just until it touches the chain then back it off one millimeter. When it is done, you are ready to reattach the cable set the cable tension start by closing any barrel adjusters and releasing all the cable from the shifter by clicking into the lowest gear.
Pull the cable tight with your fingers and clamp it to the derailleur. Remove any slack by opening the barrel adjuster pedal and shift up one click. It should go to the next chain ring unless you have a road shifter with trim adjustments, then it will only move halfway to the next trim adjustment is used to prevent chain rub. Use the trim adjustment winning the higher gears in the rear to go past your trim and shift directly to the next ring. Just push the shifter as far as it will go.
The chain should move to the gear effortlessly if it doesn’t make the shift then try tightening the cable by opening the barrel adjuster. If it over shifts, loosen the cable by closing the barrel adjuster; if you have a triple that means three rings in the front just shift one more time to get yourself into the biggest chain ring.
High limit adjustment
The high limit is used to make sure your chain doesn’t shift off the biggest ring.
Adjust this by turning the high limit screw, just until the derailleur touches the chain, and then back it off a millimeter or two.
Put a little chain lube on the pivot point and try out your shifting. You should have perfect front shifting right; if you don’t, you can do some fine-tuning with the barrel adjuster.
Note that the front derailleur is one of the more touchy pieces of equipment on your bike, so don’t frustrated if you don’t get it tuned correctly the first time, be patient and if all else fails, buy your mechanic a 6-pack and watch them go.