Adjust your rear derailleur
A gear that hesitates, a chain that skips or ticks: nine times out of ten, all it takes is a quarter turn of cable tension, with the adjuster built in for that. No tools needed.
What you need
- None for the barrel adjuster
- A small Phillips screwdriver, for the limit screws (advanced step)
- A work stand, or someone to lift the rear wheel
Why
The derailleur moves the chain from one sprocket to another by pulling more or less on a cable. Over time the cable stretches slightly (especially on a new bike, over the first few hundred kilometres): shifts become hesitant or noisy. The barrel adjuster re-tensions the cable without tools.
How the derailleur works
- The barrel adjuster (1), where the cable (6) enters the derailleur, changes the cable tension.
- The limit screws H (2) and L (3) stop the derailleur's travel towards the smallest sprocket (H, high) and the largest (L, low). Once set, you leave them alone.
- The upper jockey wheel (4) guides the chain: when it's well adjusted, it sits lined up under the current sprocket.
- The derailleur hanger (5) attaches the derailleur to the frame; it's designed to bend in a crash.
| The symptom | The cable is… | What to do |
|---|---|---|
| The chain hesitates going up to the bigger sprockets | too slack | unscrew the adjuster (out of the derailleur) |
| The chain hesitates coming down to the smaller ones, or ticks | too tight | screw in the adjuster (into the derailleur) |
Steps
1. Set up the bike
Put the bike in a work stand, or ask someone to lift the rear wheel, so you can turn the pedals by hand. Shift to the smallest sprocket, and to the middle or big chainring at the front.
2. Test the shift to the second sprocket
Turning the pedals, shift up one gear only. The chain should move cleanly and quietly onto the second sprocket.
3. Correct by a quarter turn
- If the chain hesitates or won't climb: unscrew the adjuster a quarter turn, and try again.
- If it jumps two sprockets at once, or rubs and ticks: screw in the adjuster a quarter turn.
Always correct by quarter turns, testing in between. Watch the upper jockey wheel: it should sit right under the sprocket.
4. Run through all the gears
Shift up one gear at a time to the largest sprocket, then back down. If a shift hesitates in one direction, correct a quarter turn as in the table. The adjustment is right when every shift is crisp, both ways, and the chain runs quietly on every sprocket.
5. Check while riding
Go for a short ride and use every gear, pedalling normally: shifting under load shows what adjusting on the stand doesn't. Fine-tune by a quarter turn if needed.
If adjusting isn't enough
| Problem | Likely cause |
|---|---|
| The chain drops between the smallest sprocket and the frame | H limit screw too loose |
| The chain won't reach the largest or smallest sprocket, adjuster set | limit screw too tight |
| Good at one end of the cassette, poor at the other | bent derailleur hanger |
| Stiff shifting, cable slow to return | dirty or frayed cable or housing: replace |
| The chain skips under load, even when well adjusted | worn chain or cassette |
| Noise or slow shifts on the big sprockets, jockey wheel very close to the teeth | B-screw: the wheel should sit 5 to 6 mm from the sprocket |
Look at the bike from behind: the cage and jockey wheels should be vertical, parallel to the sprockets. If they lean towards the wheel, the hanger is bent: it can be straightened with a special tool, or replaced, at a shop.
Common mistakes
- Touching the limit screws for a simple tension problem: it's almost always the adjuster.
- Turning several turns at once: you lose track. One quarter turn, one test.
- Adjusting with a dry or worn chain: clean and lube it first, and measure wear if it skips.
What next
A new bike often needs this adjustment after the first 200 to 300 kilometres, while the cables bed in. Keep the chain clean (guide): a dirty drivetrain shifts badly, even when perfectly adjusted.
Sources
This guide was checked against the following documents:
Values vary between models: your part's manual always takes precedence.