How to Adjust a Derailer

How to Adjust a Derailer
Your derailleur (pronounced, and sometimes spelled, "derailer") is the focal point of your bike's shifting mechanism. Derailleurs need periodic adjustments to perform well, and learning to tweak your own can save you time, frustration and even some cash.

Remember that derailleurs respond to very small adjustments. Keep your changes small, and work through small increments. Use a workstand to get your wheels off the ground.
 

Instructions

Difficulty: Moderately Challenging

Things You’ll Need:
  • Bicycle workstand Screwdriver
  • Bicycle workstand
  • Screwdriver
 
Step 1
Find the high- and low-gear limit screws. These screws are usually on the rear of the derailleur and are labeled "H" and "L." The limit screws determine how far the derailleur can travel at the extremes of its shifting range.
Step 2
Put the bike on the workstand, turn the pedals with your hands, and shift to the highest gear (smallest cog and largest chainring).
Step 3
Watch closely from the back of the derailleur and turn the high-limit screw. You should see the upper derailleur pulley move slightly in one direction. Set the screw so that the pulley is lined up just beneath or slightly to the inside of the smallest gear cog. Shift down one gear, then back. The chain should should not drop over the edge of the cog.
Step 4
Shift to the lowest gear configuration (largest cog and smallest chainring) and set the low-limit screw. Turn the screw until the derailleur pulley sits just beneath or to the inside of the largest cog. Shift up and then back to make sure the chain seats on the cog without dropping over.
Step 5
Shift to the second-highest gear setting. Find the cable tension barrel screw where the shifter cable connects to the derailleur.
Step 6
Crank the pedals and tighten the barrel screw until you hear the chain rubbing on the next largest cog. Loosen the screw just until the noise stops.
Step 7
Shift through the entire gear range. Shifts should be smooth and quick. If the chain hesitates shifting to a lower gear (larger cog), tighten the cable barrel screw. If it hesitates moving to higher gears, loosen the cable.
 

Article Written By Greg Johnson

Greg Johnson earned his Bachelor of Arts in creative writing from The Ohio University. He has been a professional writer since 2008, specializing in outdoors content and instruction. Johnson's poetry has appeared in such publications as "Sphere" and "17 1/2 Magazine."

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