There are few more upsetting occurrences than shifting gears in expectation of an imminent sprint or climb only to have your front derailleur throw the chain, leaving you with legs twirling but a bike that’s going nowhere.
Less dramatic but nearly as trying is the grating and grinding of a front derailleur that’s somewhat out of adjustment.
It’s a simple-looking bit of componentry, but one that’s susceptible to minute changes in position and cable tension, which means front derailleurs can demand regular attention.
Luckily, an unhappy front derailleur doesn’t ordinarily require an excursion to the bike shop – at least not if you follow our tips to get yours working smoothly again.
Want to ensure both ends are working as well as possible? You can find our guide to adjusting a rear derailleur and indexing your gears here.
Related questions you can explore with Ask Cyclist, our new AI search engine.
How to adjust your front derailleur
Time taken: About 20 minutes
Workshop saving: £10
1. Adjust to the right height
The front derailleur should run parallel to the chainrings. If it doesn’t, slacken the bolt fastening it to the frame and rotate it into the right position.
When directly above the largest chainring, the outside edge of the derailleur should sit 2-3mm above the teeth of the chainring. If necessary, shuffle it up or down before retightening the bolt.
2. Limit screws
Shift into the smallest front chainring and biggest rear sprocket. Of the two screws on top of the derailleur, the one closest to the frame ordinarily controls the lower limit.
This prescribes how close to the frame the derailleur can travel. Adjust it so the inner plate sits just clear of the chain. Rotate the crank to ensure the chain isn’t catching.
3. Cable tension
Disconnect the cable attached to the derailleur at the anchor bolt. Pull the cable as tight as feasible with your fingers and retighten the anchor bolt.
Try to shift up to the larger chainring. If the chain won’t shift or feels sluggish, twist the inline barrel adjuster further up the cable (turn it anti-clockwise) to increase the tension and try again.
4. Shifting
The second screw on the top of the derailleur controls how far outwards it can move. It may be necessary to back it off to allow the chain to reach the big ring.
Once engaged on the largest ring, adjust the screw so the derailleur can move no further than 1mm past the chain. This will ensure the chain can’t over-shift and fall off.
5. Fine-tuning
With everything now secured in position, try shifting through the gears. If you can, use the barrel adjuster to fine-tune the position of the derailleur. Turning it anti-clockwise will increase the tension, making it shift into the big chainring more readily.
Don’t forget to shift across the cassette as well to make sure each individual gear combination works.
6. Derailleur trim
Riding with the chain in the smallest sprocket and smallest chainring, or biggest chainring and biggest sprocket, will wear out your drivetrain. On Shimano groupsets, it will also cause the chain to rub against the derailleur.
Shimano shifters have a built-in half-click (press the lever halfway) to allow small adjustments on the move, known as trimming.
How to adjust your rear derailleur
Now you know your barrel adjusters from your limit screws, why not also have a go at adjusting your rear derailleur?
