Bike chain skipping – how to adjust your gears and fix it
Difficulty: Medium · Time: approx. 20 minutes
The chain drops off the sprocket, rattles when you shift or climbs onto the next cog uninvited: annoying, but in most cases no reason to visit a workshop. Almost always the culprit is slightly-off cable tension – and you correct that with a small knurled screw, no special tools required.
In this guide you'll first put a dropped chain back on, then dial in the gears in quarter turns, and finally check whether the chain is simply worn out. Allow around 20 minutes – test ride included.
What you'll need
- A rag or work gloves (the chain is oily)
- Chain wear gauge (a few euros at the bike shop)
- Small Phillips screwdriver for the limit screws
- Some chain lube for afterwards
- Optional: a repair stand – or flip the bike onto its bars and saddle
Step by step
- 1
First aid: put a dropped chain back on
Push the rear derailleur forward with one hand to release the chain tension. Lay the chain onto the smallest sprocket at the back and guide it onto the chainring at the front. Turn the crank slowly backwards or forwards until the chain catches again – a rag or glove keeps your fingers clean.
- 2
Narrow down the problem
Calmly shift through all the gears and watch: does the chain refuse to climb onto the bigger sprocket? Does it jump to a bigger one by itself? Or does it fall off beyond the smallest or biggest sprocket? That decides which screw you'll turn.
- 3
Adjust the cable tension at the barrel adjuster
Where the cable enters the derailleur sits a small knurled screw, the barrel adjuster. Only ever turn it a quarter turn at a time, then re-test: if the chain won't climb onto the bigger sprocket, add tension (anticlockwise). If it jumps to a bigger one uninvited, release tension (clockwise).
- 4
Limit screws H and L only as an exception
The H and L screws limit how far the derailleur can travel outwards and inwards. Only touch them if the chain jumps BEYOND the smallest or biggest sprocket – into the spokes or the frame. They're not responsible for ordinary rattling or hesitant shifting.
- 5
Check the chain for wear
Drop the chain wear gauge into the chain. If it shows more than 0.8 to 1 percent elongation, the chain is stretched and will skip even with a perfect setup. Then only a replacement helps – with heavy wear together with the cassette, otherwise the new chain will keep skipping on the old sprockets.
- 6
Test ride and re-lube
After every tweak, turn the crank and shift up and down through all the gears several times, ideally on a short test ride. Once everything runs quietly and cleanly, finish with a few drops of chain lube and wipe off the excess.
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Upload a photo →Frequently asked questions
- The gears are set up correctly but the chain still skips – why?
- Then the chain is very likely worn. A stretched chain no longer sits cleanly on the teeth and skips especially under load. Measure with the wear gauge: from about 0.8 to 1 percent elongation it's due for replacement.
- Which way do I turn the barrel adjuster?
- Memory aid: the chain wants to go up (onto the bigger sprocket) but doesn't make it – add cable tension, i.e. anticlockwise. The chain jumps up by itself – release tension, clockwise. Always work in quarter turns and test in between.
- How much is a new chain – and when does the cassette need replacing too?
- A chain usually costs 15 to 30 euros depending on the drivetrain. Replace it in good time and a cassette outlasts several chains. But if the old chain was ridden too long, the sprockets wear with it – then the cassette (from roughly 20 to 60 euros) has to be replaced as well.