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my bicycle is not shifting. The shifter is working fine (cable tense up and down with it).

I think the problem has to do with the derailleur. I have seen videos that manually press it to diagnose potential problems. However, when I manually press it, it does not move an inch. I tried to do the same with a working bicycle, and in that case it moved.

picture of the rear derailleur and rear cassette with an arrow pointing to the derailleur

Do you guys know what could be the problem with a derailleur that does not move?

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    Usually that the L and H screws have been set to lock the derailleur to one gear. Can you try loosening each of these off and see if you gain some movement?
    – Noise
    Jul 25, 2022 at 15:31
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    @Noise makes a good point. If the shifter moves the cable without the derailleur moving, there's something up with the cable, which would be a reason to lock off the derailleur
    – Chris H
    Jul 25, 2022 at 15:36

1 Answer 1

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Essentially this is an exercise of divide and conquer. Obviously a working shifter will move if its not obstructed, you 'just' need to find the obstruction.

First and simple check is remove the wheel. Check the derailleur moves freely using the shifter, if it moves, the problem is related to the cassette and chain. Are you turning the wheel while you move the derailleur? If so, as suggested in comments, the H and L screws might be set to lock it.

If it does not move with the wheel removed, you want to check if the problem is cable and/or shifter related, or the derailleur itself. Undo the cable - you can often do this adequately by removing one of the outers ends from a stop. If the cable is free and the derailleur moves, the problem is in the shifter.

With the cable loose, check its free to move. Any stiffness gets amplified when pressure comes on the cable, lubing may help, but new cables are often the fix required, especially if its the cause of a derailleur not moving (usually poor cables result in poor shifting long before it gets this bad)

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