How to Adjust the Shimano Deore LX Front Derailleur

Updated November 21, 2016

Produced by Shimano Cycling, Deore LX components are designed for use with off-road bicycles. Among these components, the front derailleur has the responsibility of transferring the drive chain from one chain ring (or gear) to another. To work efficiently, the derailleur must first be adjusted.

Use the gear shifters and shift the chain to the smallest front chain ring and largest rear cog. Visually, the chain is now as far to the inside of the bike as the gears will allow.

Use a 5mm Allen key (or hex key, as it’s sometimes called) and loosen the derailleur cable pinch bolt. This bolt anchors the cable to the derailleur. The cable will go slack.

Stand over the Deore LX front derailleur and observe the clearance between the chain and the derailleur cage (the chain passes through this portion of the derailleur). The gap should only be 1 to 2mm. To adjust the gap, use a Phillips screwdriver and turn the “L” screw, located atop the derailleur. The screw is marked with an “L.” Turning the screw clockwise will move the derailleur closer to the chain.

Turn the cable adjuster barrel all the way into the shifter, and then give the barrel two full turns in the opposite direction. The cable adjuster barrel is located where the cable exits the body of the shifter, on the handlebar.

Remove all slack from the cable, by pulling the end taught with a pair of needle nose pliers. While maintaining tension on the cable, use the 5mm Allen key and re-tighten the cable pinch bolt onto the cable.

Shift the chain to the large front chain ring and smallest rear cog combination. This will place the chain furthest from the inside of the bike. If the chain does not shift to the chain ring (or shifts sluggishly), turn the cable adjuster barrel 1/8 turn away from the shifter and try again. Continue the adjustment as needed.

Check the gap between the chain and the derailleur cage, with the chain in the large chain ring/smallest rear cog combination (from Step 6). As before, the gap should be 1 to 2mm. To adjust the gap, use the Phillips head screwdriver and turn the “H” screw. The screw is marked with an “H” and is located beside the “L” screw. Turning it clockwise will move the derailleur closer to the chain.

Things You'll Need

  • 5mm Allen key
  • Phillips screwdriver
  • Needle-nosed pliers
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