One of the most satisfying things to do as a cyclist is work on your bike.
Keeping your trusty steed in tip-top condition makes the riding much more fun and stops those pesky mechanical mishaps that many of us have come to expect.
One job that many cyclists struggle to get right is front derailleur adjustment. Typically it is set up when you buy a bike, and rarely after do you find yourself having to mess with it. There will be a time when learning this skill will come in handy though.
The annoying thing about a front derailleur is that if you make adjustments wrong, it can really mess it up. In this article, we want to explain the process of adjusting front derailleurs properly. It’s actually much more simple than you might think!
We’ll be covering:
- What Is The Front Derailleur?
- Why Might You Need To Adjust The Front Derailleur?
- What Tools Will I Need For Front Derailleur Adjustment?
- Front Derailleur Adjustment Explained In 6 Steps
- Robbie’s Video Maintenance Guide: How To Adjust Front Derailleurs
Let’s dive in!
What Is The Front Derailleur?
The front derailleur is the component that shifts the chain between the chainrings (the front set of gears).
Front derailleurs come in all shapes and sizes, and are normally attached to the bike’s seat tube. Some have the ability to shift into three positions, while others can only go into two. They are generally controlled by a shifter which is located on the handlebars.
Front derailleurs typically work best with the groupset they are designed for, and you don’t get much cross-compatibility between brands. They work on very precise measurements to ensure smooth, effective shifting.
- Want to know more? Check out The Bike Derailleur Explained: Everything You Need To Know!
Why Might You Need To Adjust A Front Derailleur?
There are many reasons why you will find yourself needing to adjust a front derailleur. Here are the most common:
To Ensure It Shifts Properly
The derailleur might need adjusting to ensure that it works properly. If it isn’t adjusted correctly, you will find shifting performance suffers, which is an easy way to ruin a good bike ride.
To Keep It Quiet
Your front derailleur adjustment can be good enough to ensure it works, but it won’t be quiet if it’s not 100%.
If the derailleur is just slightly out, the chain can rub on the derailleur cage, which is annoying when riding as it makes a grinding noise in certain gears.
To Stop The Chain Falling Off
One of the most common reasons your chain will fall off is if your front derailleur limit screws are not dialed correctly. You can reduce the chance of chain drops by adjusting the front derailleur properly.
Installing A New Derailleur
When you order a derailleur, it will need to be adjusted to suit your bike when installed. With bikes coming in all different shapes and sizes it’s vital that when installing the correct adjustments are made.
What Tools Will I Need For Front Derailleur Adjustment?
For front derailleur adjustment, you are not going to need much – in fact, you can get away with as little as a multi-tool!
Here’s what we recommend you have:
- Bike Stand
- Allen Key Set
- Small Phillips or Flathead Screwdriver
Before You Start: Is Everything In Working Order?
Before getting into the task, it’s important to check if everything is in working order. It’s easy to mistake a broken part or component with a derailleur that is out of adjustment.
Here’s what you need to check:
#1. Cable Inners And Outers
Check the cable run is smooth and they look in good condition, not rusty or splitting anywhere.
#2. Is The Derailleur Broken?
Ensure the derailleur is moving properly and responding to shifter input (even though it’s not properly adjusted), and that the cage is not bent.
#3. Does The Shifter Work Properly?
Finally, the last part you need to check is the shifter. Ensure it’s not damaged and it works as it should.
Front Derailleur Adjustment Explained In 6 Steps
We recommend allowing around 20 minutes to complete this task. Prepare to be patient, as it can take time to get it right until you’re familiar.
Step #1. Set The Derailleur Position
The first step you need to take is to ensure the derailleur is in the correct position.
The two factors to check are height and angle. Start by undoing the cable pinch bolt to release the tension, then loosen the derailleur mounting bolt so you can move it freely.
To get the correct height, put the derailleur into its lowest position, where it would sit the chain on the smaller chainring. Then position the cage roughly 2 mm above the teeth of the chainset.
To get the correct angle, look from above and then line the cage up with the chainrings so they are both parallel. Once you have it all perfect, tighten up the derailleur mounting bolt.
Step #2. Tighten The Gear Cable
Ensure the shifter is in its lowest position, where it gives the most cable slack. Then take the end of the cable and pull it nice and tight.
Maintaining tension, hold the cable with one hand and then tighten the pinch bolt with the other. Once this is done, bend the cable end so the end doesn’t rub on the rear tire or your frame.
Step #3. Adjust Low-Limit Screw
Now, locate the low-limit screw. You’ll find this on top of the derailleur. It will be one of two screws next to each other – one will have an L (low limit) and the other an H (high limit).
With the derailleur in its lowest position, put the chain in the largest cog on the rear cassette and the smallest chainring at the front.
Using your screwdriver, adjust the L screw so the edge of the cage is roughly 1 mm away from the chain. This is enough to stop it from going over the edge, but not so much that the chain rubs against the derailleur’s cage.
Step #4. Fine-Tune The Tension
Next, we need to fine-tune the tension of the cable.
Shift up while running the chain around the system, and the derailleur’s cage will try and pull the chain across. It might work perfectly for you the first time, but more than likely, you will need to add tension to get it to jump.
You will either have a barrel adjuster on the cable run or a small adjustment screw. Click the shifter up and run the chain around the drivetrain. You will find the chain trying to jump, but it might not be able to get across.
Slowly start adjusting the tension until the chain jumps across. Once it has jumped across, shift back down and attempt to shift back up again. Hopefully, it should jump across straight away. If not, add more tension until it shifts perfectly up and down.
Step #5. Set The High-Limit Screw
Finally, for the high-limit screw. This ensures the chain doesn’t jump off the top and get stuck on your pedal.
With the chain in the smallest cog on the cassette and the largest chainring, adjust the screw until the cage wall is roughly 1 mm away from the chain.
Step #6. Test (And Road Test!)
With the bike still in the stand, test the derailleur to ensure that after all the adjustments, it’s working as it should.
Once you are satisfied, it’s time for a short road test, and providing it all works correctly, you’re done. If it doesn’t work as it should, return to the process to see where you might have gone wrong!
Robbie’s Video Maintenance Guide: How To Adjust Front Derailleurs
Check out the BikeTips YouTube Channel here for walk-through bike maintenance guides and more!