Remedy: This can be most commonly because of inadequately setup derailleur Restrict screws and these would require altering. It can even be due to a bent derailleur hanger Turn the barrel adjuster accordingly and keep track of the number of rotations you make so you know how much you’ve absent. https://indexingbikegears93792.blog-kids.com/33014499/helping-the-others-realize-the-advantages-of-indexing-bike-gears