How to Set a Rear Derailer

Setting and adjusting a rear derailer, or derailleur, is key to the shifting performance of the bicycle component. A rear derailleur is responsible for shifting the chain over the rear cassette, also called the sprockets. As the chain moves up and down the individual gears, the ratio is changed allowing faster or slower speeds. Setting the rear derailleur to the proper setting requires two different adjustments: one off the screws on the derailleur and another via the adjustment barrel at the shifter.

Things You'll Need

  • Bike work stand
  • 4mm and 5mm hex wrenches
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Instructions

    • 1

      Place the bicycle into the work stand. Turn the pedals by hand and shift the bicycle into the largest sprocket and the smallest chain ring (the large rings next to the pedals). Feel for loose shifts and watch the chain to ensure it slides over the cassette gears.

    • 2

      Insert either a 4mm or 5mm hex wrench, depending on the model, into the set screws on the back of the rear derailleur. Turn the screws 1/4 turn clockwise to tighten the shifting, and 1/4 turn counterclockwise to loosen. Use the counterclockwise turn if the chain moves sluggishly over the gears. Use the clockwise turn if the chain fails to shift over all gears. Pedal and shift to check all gears are being hit by the chain.

    • 3

      Take the bike off the stand and go for a pedal. Shift and feel the chain move. Turn the plastic adjustment barrel at the end of the right hand shifter on the bicycle in 1/4 turn increments to fine tune the shifting. Feel for shifts that are almost imperceptible. Turn the barrel until the chain moves through the cassette gears with little or no noise and skips.