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    Under pressure, my chain keeps hopping on the highest gear. This bike is merely driven 2000 km so far, the gears and chain look fine, I adjusted the H screw, too. What now?


    I am a bit confused as to how to fix this chain hopping. The video above is a bit so so, but you see the issue. The sprockets look fine, too. I adjusted the H screw back and forth and washed and re-greased the chain (after I took the images). What can I even do now? This is a simple Shimano Altus.

    Under pressure, my chain keeps hopping on the highest gear. This bike is merely driven 2000 km so far, the gears and chain look fine, I adjusted the H screw, too. What now?
    byu/SjalabaisWoWS inbikecommuting



    by SjalabaisWoWS

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    7 Comments

    1. Adept_Spirit1753 on

      I’ve bought two bikes new, and in both I had to do derailleurs adjustment myself.

      Does it make noise in that gear or in different gears? Something in identical intervals.

    2. Milters711 on

      Seems like a chain stretch issue. If your chain is old, this may be the cause. A 0.75mm stretch is enough to cause the skipping

    4. RibEyeSequential on

      Chances are your chain is worn and stretched. Looks like it hasn’t been lubricated in a while.

    5. wanklez on

      Are you positive you’re not bumping the shifter when pedaling hard? Because what’s happening here, with the derailleur falling, shouldn’t be possible without a change in shift cable length.

    6. Ok_Pause419 on

      Hard to say from this video, Look at the Park Tools video for how to setup a rear derailleur and follow the steps: [https://www.youtube.com/watch?v=UkZxPIZ1ngY](https://www.youtube.com/watch?v=UkZxPIZ1ngY) The simple fix would be if the indexing is a little off (see step 3 in the Park video, but do all the steps in order).

      If it still isn’t working after adjusting the derailleur per the video, you likely need to replace at least the chain and maybe the cogs too.

      Regarding the chain, it may look fine, but the wear on the chain happens with the pins and the rollers and isn’t visible. A chain gauge measures the distance between the pins to see if the chain has elongated (it’s not really stretching, it’s just that the pins wear the holes in the side plates so they become wider).

      The cogs will also wear, and that wear is most pronounced on the smallest cog since it has the fewest teeth, so more force is applied to each tooth engaged with the chain.

    7. Joggann on

      old stretched chain? This would be my guess, and it’s better to change it before it wears out the sprockets.

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