How to Calibrate a Derailleur

Most multi-geared bicycles have a front and rear derailleur. The derailleurs allow a cyclist to seamlessly switch between gears. Calibrating the derailleurs is a tricky process that requires a great deal of patience. Derailleurs are adjusted by tightening cable tension, adjusting limit screws, and positioning height and angle. A well-calibrated derailleur will shift gears smoothly with hardly any effort or sound. With the right instructions you can adjust your bicycle's derailleurs and enjoy a ride with clean shifting.

Things You'll Need

  • Philips screw driver
  • 5 mm Allen wrench
  • Light bike lubricant (Triflow, for example)
  • Rope
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Instructions

  1. Front Derailleur

    • 1

      Shift the front derailleur up to the largest front sprocket. Loosen the positioning clamp that attaches the front derailleur to the bike frame until you can move it freely by hand, using the 5 mm Allen wrench (don't unscrew the clamp entirely).

    • 2

      Position the bottom of the derailleur cage as close as possible to the largest sprocket's teeth, preferably with a 2 mm clearance. It should be positioned as close as possible without rubbing; the lower the cage the better it will shift.

    • 3

      Adjust the angle of the front derailleur cage so that an imaginary line running down the middle of the cage lines up perfectly with the center line of the bike's frame. It helps if you are looking down at the derailleur cage from above. Tighten the positioning clamp using the 5 mm Allen wrench.

    • 4

      Shift the rear derailleur to the largest sprocket and the front derailleur to the smallest sprocket to adjust the front derailleur's low limit screw, found next to the positioning clamp and indicated by the letters "Lo." Turn the screw using a Philips screw driver until the inner plate of the derailleur cage clears the sprocket; the closer it is without rubbing on the sprocket the better.

    • 5

      Adjust the high limit screw found next to the low limit screw, indicated by the letters "Hi," by shifting the rear derailleur to the smallest sprocket and the front derailleur to the largest sprocket. Turn the screw using a Philips screw driver until the inner plate of the cage just clears the largest sprocket; again, it's best to be close without rubbing.

    • 6

      Shift the rear derailleur to the largest sprocket and the front derailleur to the largest sprocket and loosen the anchor bolt that secures the shifting cable attached to the front derailleur using a 5 mm Allen wrench. Pull any slack out of the cable and tighten the anchor bolt.

    • 7

      Shift the front derailleur to the middle sprocket and run the rear derailleur through all of the rear gears. If the front derailleur doesn't rub against the chain or the sprockets it is adjusted well; if, when looking down at the derailleur from above, the chain rubs against the left side of the inner plate on the cage, adjust the low limit screw to fix the issue, and the high limit screw if it is rubbing on the right side of the inner plate.

    • 8

      Apply a few drops of lubricant to all of the derailleur moving parts to prevent rust and ensure smooth shifting.

    Rear Derailleur

    • 9

      Shift the rear derailleur to the largest sprocket and the front derailleur to the middle sprocket. Examine the distance between the guide pulley, the bottom pulley on the rear derailleur, and the largest sprocket.

    • 10

      Loosen the B-screw, found directly above the guide pulley, if there's a large gap between the guide pulley and the largest sprocket, until the pulley is as close to the largest sprocket without rubbing; or tighten the B-screw a 1/4 turn at a time until the guide pulley clears the sprocket, if the guide pulley is rubbing against the largest sprocket.

    • 11

      Shift the rear derailleur to the smallest sprocket and loosen the cable tension by turning the cable barrel adjuster, located where the cable feeds into the derailleur, counterclockwise.

    • 12

      Examine the position of the chain, if it looks like it's going to fall off the sprocket toward the spokes tighten the rear derailleur's hi limit screw, found on top next to the words "Hi," a 1/4 turn at a time using the Philips screw driver until the chain is perfectly centered on the sprocket; if the chain looks like it's going to fall off the sprocket toward the next sprocket loosen the hi limit screw until the chain is centered.

    • 13

      Tighten the cable barrel adjuster counterclockwise until the rear derailleur smoothly shifts from the smallest sprocket to the second smallest sprocket.

    • 14

      Shift the rear derailleur to the largest sprocket. Examine the position of the chain: if it looks like it's going to fall toward the spokes turn the low limit screw, found next to the hi limit screw and indicated by the letters "Lo," clockwise a 1/4 turn at a time, using a Philips screw driver until the chain is perfectly centered on the sprocket; if the chain looks like it's going to fall off the sprocket away from the spokes turn the low limit screw counter clockwise until the chain is centered on the sprocket.

    • 15

      Shift through all the rear gears with the front derailleur set to the middle sprocket by moving up two gears and down one until you reach the top and then down two, up one until you reach the bottom.

    • 16

      Examine the chain while shifting through the gears to make sure the chain is centered on each sprocket. Turn the cable barrel adjuster clockwise if the chain is moving toward a larger sprocket on any sprocket to loosen the tension until the chain is centered on the sprocket. Turn the cable barrel adjuster counterclockwise if the chain is moving toward a smaller sprocket to increase the tension until the chain is centered.

    • 17

      Apply lubricant to all of the moving parts of the rear derailleur to avoid rust and ensure smooth shifting.