How to Adjust a Front Derailleur
We may earn an affiliate commission at no extra cost to you when you buy through links on our website. Learn more
One area of bike maintenance that’s overlooked is the alignment of the front derailleur. This is a huge shame because even the smallest of front derailleur problems can have a huge impact on the functionality of the bike’s gearing. Thankfully, learning how to adjust the front derailleur isn’t all that difficult. We are going to walk you through the process on this page.
How to Adjust Your Front Derailleur at Home
The process for how to adjust a front derailleur on a road bike is going to be wildly different than how to adjust a front derailleur on a mountain bike. Therefore, use this guide as nothing more than a general guideline.
It’s worth looking at the manual for the derailleur that you own to see if there are any quirks when it comes to adjustment there.
You don’t need that much in the way of tools for this job. Try to ensure that you have a small spanner set and a screwdriver set handy, and you should be able to do all of the adjustments that you need, no matter what type of derailleur you have.
Knowing What a Well-Adjusted Derailleur Should Look Like
The first step in knowing how to adjust a front derailleur is to know exactly what a derailleur should look like when it has been properly adjusted.
Quite often, many people don’t realize that they need to carry out a front derailleur adjustment simply because they don’t know what they are looking for.
A properly set derailleur should be slightly above the largest chainring. It should be close, but not so close that it’s touching it.
The curve of the derailleur should be in line with the curve of the chainring. The chain should be running parallel with the chain.
You’ll know if you’re having derailleur problems if the derailleur keeps getting caught, or if the curve doesn’t follow the curve of the chainring exactly. This means that it’s out of line.
Shift the Bike into the Lowest Gear
If you do need to adjust the derailleur, then you’ll need to switch the bike into the lowest possible gear.
Ideally, your bike will be placed in a bike stand at this point. It’s going to make the adjustment a whole lot easier for you.
Undo the Cable Bolt
Located just about the derailleur will be a bolt. This will be holding the cable that connects up to the derailleur. You’ll need to loosen this cable.
Once you have loosened the bolt, pull the connected cable up through the bolt as far as you can. You want it to be as tight as possible. When you feel that the cable has been pulled as far as it can, retighten that bolt.
Adjust the ‘L’ Screw
On the derailleur, there will be two screws. One of them will be labeled as ‘L’ and the other one will be labeled as ‘H’.
Once you have located that chain, your bike chain will now need to be shifted so that:
- The front part of the chain is on the smallest chainring.
- The back part of the chain (i.e. on the rear end of the bike) should be on the largest chainring.
If you do this, then the chain should be up close to the bike.
Now, turn the ‘L’ screw. As you do so, the derailleur will start to move. You’ll want to continue turning this screw until there’s a 3mm clearance on either side of the chain as it runs through the derailleur.
Unless you have been completely neglecting your bike maintenance, this shouldn’t take too long. It may barely take a turn of the screw.
Adjust the ‘H’ Screw
Now you need to do the complete opposite to before. This means that you should be shifting the bike so:
- The front part of the bike chain is on the largest chainring
- The back part of the bike chain is on the smallest chainring
If you have shifted into the correct position, the bike chain should now be the furthest it can possibly be from the bike.
You now need to adjust the ‘H’ screw in the same way. This means turning it until you have at least 3 mm of clearance on either side of the chain when it passes through.
Again, this is likely not going to be taking that much in the way of adjustment.
Test the Alignment
Now all you need to do is to test that everything is properly aligned. If you have followed this guide, then it should be.
To begin testing, you’re going to need to shift your gears so that the back of the bike chain is on the middle gear. Don’t adjust the back gear during this process.
Now you can start pedaling and shifting up and down through the gears. If you have adjusted everything properly, then your pedaling and gear shifting should be smooth as butter. There should be no chain catching and the derailleur shouldn’t be touching the chainrings at all.
If you notice that there’s some catching, then you may need to adjust the derailleur again. The screw that you need to adjust will be dependent on whether it’s catching on the highest gears or the lowest gears.
In rare cases, if you have adjusted the bike derailleur a little bit too far in one direction, then the chain may fall off as you shift between gears. Again, this is nothing that a small amount of adjustment shouldn’t be able to sort out.
Once you know that everything is properly aligned, you should repeat this process every couple of months. Trust us, your cycling experience will be a whole lot better.
As you can see, learning how to adjust the front derailleur on a bike isn’t too tricky. As long as you have a couple of bike tools and about 30 minutes to spare, the process is pretty quick.
You’ll be surprised at just how much of an impact it will have on your cycling too. It’s suggested that you try and ensure that you adjust that derailleur at least once every couple of months.
You won’t ever have to make huge adjustments if you are doing things this frequently, but it will make the whole cycling better when you carry out this bit of maintenance.