Answer: This is most often brought on by inadequately setup derailleur limit screws and these would require adjusting. It can also be caused by a bent derailleur hanger Meticulously and slowly shift the rear derailleur manually even though pedalling to make sure the chain doesn’t drop off either stop on https://indexing-bike-gears59258.blogdun.com/33459012/indexing-bike-gears-fundamentals-explained