Drivetrain
What is a Front Derailleur?
The cage that shoves your chain between chainrings, if your bike has more than one.
Simplified schematic — not to scale.
In plain English
On bikes with two or three chainrings, the front derailleur is the metal cage around the chain near the pedals, which pushes it sideways to change ring.
A simple analogy
“It's a gate that gently steers the chain from one track onto another.”
How it works
Pulling the cable moves the cage outward, nudging the chain onto a bigger ring; releasing it lets a spring pull the cage back in.
Signs of trouble
- ⚠Chain rubs the cage in certain gear combinations
- ⚠Chain drops off the chainrings entirely
- ⚠Sluggish or incomplete shifts between rings
Rough UK cost
£15 – £80
Always get a written quote. Prices vary by bike, region and parts brand.
Heads up: Bikeautonomy is for general guidance only. If your bike is behaving oddly or you're not confident, get it looked at by a qualified bike mechanic.