Common Bicycle Front Derailleur Problems [ How To Adjust Front Derailleur]
First things first, let’s understand what your bike’s front derailleur is. According to the front derailleur article by REI.com, the front derailleur is simply the mechanism that shifts your bike chain from chain ring to chain ring. Its sole purpose is to move back and forth to help you shift gears.
Now what happens if that movement starts to become impeded or sluggish? Let’s see how we can tackle that problem and get your bike shifting back the way that it should be.
You can also view the article “How To Adjust a Front Derailleur” to get some more details on derailleur adjustments.
Solutions to Common Front Derailleur Problems
Problem #1 – Your front derailleur is not positioned correctly.
Solution – Reposition the front derailleur
This seems like a no brainer, I know but it really is quite a common problem on many bikes. The REI article above goes into some nice detail on how to check the position. In summary, when you have shifted into your large chain ring, your derailleur cage should be situated approximately 2mm above the chain ring teeth and should also be sitting parallel to your chain ring.
If the derailleur cage is not in the above location, then adjust it as per the details in the article.
Problem #2 – The derailleur limit screws are improperly adjusted
Solution – Adjust the limit screws
The front derailleur limit screws set the maximum allowable travel that your derailleur can move either to the inside or to the outside. The screw adjustments are not complicated, but they do require only small adjustments to get the job done. To see the details on how to adjust the derailleur screws.
Problem #3– Your cable barrel adjuster is not properly centered
Solution – Adjusting the Barrel
The majority of bikes that are on the market right now have a mechanism attached to the derailleur cables called a Barrel Adjuster. What this handy little turning mechanism does is to adjust the tension of your cables (and in doing so moves the front derailleur back and forth – depending on which direction you turn the adjuster knob).
By turning the barrel adjuster, you can make minor changes to the gap between the derailleur and your chain. Turning the adjuster clockwise moves the derailleur outwards and counter clockwise moves it inwards.
By starting with your chain in the big ring up front and the biggest cog in the back, you can start fine tuning the distance between your chain and your cage. Simply go through each of the gears and make sure that there is at least a 0.5mm gap between the chain and the cage.
Problem #4 – Your derailleur has grit in it which is affecting its movement
Solution – Clean Your Front Derailleur
This is one area that seems to catch a lot of people. Our bikes have many small moving parts that are constantly getting exposed to dirt and grime. Over time, if not cleaned regularly, the parts will become less and less free moving.
Your front derailleur is no exception. The cables need to be able to slide freely in their casing and the derailleur cage needs to be able to freely move back and forth. You should be cleaning the derailleur on a frequent basis and the pivot points between the moving parts should also be lubricated. Perform these 2 easy tasks and your derailleur will work as it is designed to.
Sum It All Up
So there you have it. The front derailleur is a very critical piece of our bike’s gearing system and needs to be regularly maintained.
The maintenance as described above is not time consuming and it does not have to be done by a bike mechanic. Just keep the above points in mind if you ever find that your front derailleur’s shifting ability starts to become reduced. You will enjoy riding your bike much more when it shifts as it should.